Antibiotic stewardship (ABS) programs aim to combine effective treatment with minimized antibiotic-related harms. Common ABS interventions are simple and effective, but their implementation in daily practice is often difficult. The aim of our study was to investigate if a single, short, peer-to-peer teaching intervention (junior doctor to junior doctor) during clinical routine can successfully improve antibiotic prescriptions. We performed a quasi-experimental before–after study on a regular care cardiology ward at a large academic medical center in Germany. We evaluated antibiotic use metrics retrospectively and calculated defined daily doses (DDD) with the anatomical therapeutic chemical/DDD classification system of the World Health Organization. We hypothesize that the over-representative use of intravenous administration is a potentially modifiable target, which can be proven by antibiotic use metrics analysis. After a single peer-to-peer teaching session with a focus on indications for iv to po conversion, the normalized percentage of intravenous compared to oral administration significantly decreased (from 86.5 ± 50.3% to 41.4 ± 70.3%). Moreover, after the intervention, antibiotics with high oral bioavailability were no longer administered intravenously at all during the following quarter. Our results indicate that even a single peer-to-peer training session is highly effective in improving the iv to po conversion rate in the short term. It is common knowledge that increased antibiotic resistance directly leads to increased morbidity and mortality ,2,3. FurDesigning programs and interventions to achieve this goal is an extremely multifaceted process. Therefore, selecting the most appropriate measures for each situation remains a key challenge. The World Health Organization (WHO) provides support for clinicians who are part of ABS teams worldwide by identifying the most commonly used stewardship measures and by contributing considerations for their implementation . MoreoveStep 1: Plan—Assessment of antibiotic use. The very beginning of most ABS interventions is challenging. A detailed analysis is crucial for addressing the current state (identifying problems regarding antibiotic use) and defining realistic goals based on available resources. For care provision  outcome measures , a detaiStep 2: Do—Designing an ABS intervention that respects the limited resources available and meets the prevailing demands of the institution. Whereas the first step does not differ among various ABS measures, the interventions themselves are very different. As broad as the spectrum is, clinician education and training is a central and promising component of all structured ABS programs and most ABS measures ,16. TherStep 3: Check—Re-Evaluation of antibiotic use metrics and the identification of possible intervention-related problems. The main part of this step is identical to the first analysis in step 1. Furthermore, additional aspects of the intervention—which are not captured by use metrics—could be detected by direct feedback mechanisms.Step 4: Act—Implementation of the results in clinical practice. In the last step, the knowledge gained during the course of the intervention needs to be implemented in daily clinical practice, i.e., in the daily medical routine of all staff members. A successful ABS intervention can be a nice individual success, but a successful ABS program does not only consist of singular individual measures, but of a combination of different measures.Using this approach, we performed a quasi-experimental before–after study  in the To identify possible intervention targets for a new ABS measure, we performed a detailed analysis of our department’s antibiotic consumption from 2018 to 2020. During this period, we analyzed the antibiotic use of 106,423 patient days from 26,773 cases, resulting in an average length of stay (LOS) of 3.98 days per case. In total, the regular wards of our department used 32 ± 2.7 RDDs per 100 patient days, which estimates that 32% of the inpatients received one RDD every day. To classify our values, we compared our data with published amounts of antibiotic use from other German hospitals . In compIn the next step, we aimed to identify the predictors of antibiotic use in our department. First, we could find a highly significant positive correlation between the DDD per 100 cases and patient days/case B. This fThe evaluation of antibiotic use metrics revealed a highly significant predominance of iv antibiotic administration A in our We detected a significantly higher use of the aminopenicillin/BLI-combination Ampicillin/Sulbactam on ward C . Iv use of Clarithromycin and Levofloxacin were higher on ward A, whereas the DDDs of iv Ciprofloxacin and Clindamycin did not differ between wards. Due to the significant differences in the total iv DDDs, which were caused by the more frequent use of Ampicillin/Sulbactam, we selected ward C for our ABS intervention. After analyzing antibiotic metrics, we found that low iv-to-po conversion rates were a major problem associated with ABS on regular care wards at our institution. We implemented peer-to-peer education on the ward with the highest number of DDD per 100 patient days. The intervention consisted of a 10 min slide-based teaching session delivered by a resident who was not a member of the regular ward staff , after the intervention (2020 Q4), and the two quarters after the new staff had taken over duties on the ward where the intervention had taken place (2021 Q1–2). After the intervention, normalized iv rates of all antibiotics significantly decreased A on the Levofloxacin, Ciprofloxacin, and Clindamycin were the key reasons for the observed effect B. The hiEducation is considered an essential component and a core element in most—some authors even say every —ABS progAs the focus and target of all ABS projects can be summarized as improvements in the quality of treatment and patient care, it makes perfect sense to rely on established quality management (QM) procedures for guiding ABS projects. In recent years, QM methods such as the Plan–Do–Check–Act (PDCA) cycle have become increasingly popular in the healthcare sector and have proven their effectiveness . The PlaThe initial metrics analysis in our department revealed the fact that the overall use of antibiotics on our regular care wards did not significantly differ from their average use in other German hospitals. At first glance, this shows that there are no serious problems with increased antibiotic use at our institution; however, the comparative data were not collected on cardiology wards only, but included entire clinics such as emergency medicine, hematology, oncology, and intensive care, all of which are known to be heavy users of antibiotics . We furtAs interesting as this fact is, it did not constitute a modifiable cause for our planned ABS project. However, in further analyses of the antibiotic use metrics of our institution, we detected a significant iv application rate as proof of low iv-to-po conversion rates in the regular care wards of our institution. The benefits of early conversion from intravenous to oral medication are well studied ,31. SeveThe strength of our study consists of the very simple, extremely short, and therefore cost-effective design of our intervention. Whereas most published educational interventions consist of different educational interventions such as educational sessions, audits, and feedback, our peer-to-peer teaching was only based on one single presentation. Furthermore, the educated junior doctors were not aware of the fact that they were part of an interventional study or that the antibiotic use metrics of their ward were surveilled to avoid any bias. All the more pleasing is the significant decrease observed in the number of intravenously administered antibiotics on the ward after the intervention A, which Our study has limitations that we want to address. We can only present the data of a single-center study with only one selected ward as an intervention group. As depicted in Our study results indicate that even a very short and concise educational session in a peer-to-peer setting can significantly reduce iv antibiotic use. Our data contribute further evidence that education is a core element of every ABS program. The straightforward design of our intervention using established tools of quality management underlines that ABS measures do not need to be expensive or complicated to make a difference. In the hectic and stressful clinical routine, education and training often fall short. All facts taught in our ABS training are part of early training in medical school and are not newly discovered scientific facts, so we suspect a lack of ABS guidance, especially after graduation. It remains a core task of every ABS team to constantly spread and reactivate basic ABS knowledge.We retrospectively analyzed data of antibiotic use of all four normal care cardSiology wards (wards A–D) of the Center for Cardiology at the University Medical Center Mainz . For this purpose, we used the digital ordering system (SAP) of the University Medical Center, which tracks every drug order from the wards. Data about antibiotic use were acquired yearly for the years 2018/2019 and quarterly for the years 2020 and 2021. We obtained data about patient days and cases for the same intervals  retrospectively). https://www.whocc.no/atc_ddd_index/; access date 17 March 2022). Antibiotic consumption density was calculated as follows: number of daily doses (DDD) of the active ingredient/100 patient days (or 100 cases), as recommended by the WHO.As an independent comparator for quantitative and qualitative analyses of antibiotic use, we calculated defined daily doses with the ATC/DDD  classification system of the WHO . The intervention consisted of a 10 min PowerPoint slide-based teaching session. A junior doctor who was not part of the regular staff on the ward presented the slides in the doctor’s room on ward during the regular working day. The junior doctors of the ward were neither aware of the fact that the presentation was part of a study, nor that the metrics of antibiotic use are monitored. The slides of the PowerPoint presentation can be found in t-test were applied. If there was no normal distribution, a Kruskal–Wallis test with Dunn’s multiple comparison or a comparison of selected columns was used. Furthermore, simple linear regression was calculated as indicated. p < 0.05 was required to achieve statistical significance. Mean values are shown with SEMs. We performed statistical analysis with GraphPad Prism software . In the case of a normal distribution , a two-way ANOVA test with Tukey’s post hoc test or Student’s


The composite material textile reinforced concrete (TRC) requires a high bond performance between the fiber strand and the concrete matrix. While the influence of the textile on bond behavior is well known, in this publication the influence of the concrete matrix is investigated by means of single-sided pull-out tests. The results of the presented study show dependence between the concrete strength and bond performance of the composite material. When a concrete of a higher-strength class is used, the bond-flow–pull-out distance curve shifts upward independent of the textile geometry and the yarn impregnation. A simplified model is presented to predict the occurrence of a crack along the fiber strand. This model serves as a basis to investigate the correlation between concrete width per fiber strand and resistance against a splitting crack. The effective concrete tensile strength decreases to about 35% when the concrete width is increased from 10 mm to 50 mm. To quantify the decrease, a mathematical relationship, which describes the test results independent of textile and concrete type, is proposed. The composite material textile reinforced concrete (TRC), which is composed of a textile reinforcement and a concrete matrix with a small maximum grain size, is increasingly establishing itself in the construction industry. The use of TRC makes sense both in new construction and in repair work ,2,3,4. AIn addition to the high tensile strength of carbon fibers, the geometry of textile reinforcement combined with a stiff impregnation can lead to high bond performance. Thus, fine crack patterns and short anchorage lengths can be realized. However, large bond forces also place greater stress on the surrounding concrete and thus increase the risk of cracking along the fiber strand see . If the 0), a bond flow T = F/L0 (N/mm) can be calculated  related to the bond length of the fiber strand  of the fiber strand is pulled out of the concrete and the pull-out distance is measured. The result is a bond-flow–pull-out distance (crack opening) curve. This is necessary to calculate a bond-stress–slip relationship 0) are asp) is constant for all tests. Regarding the bond-flow–pull-out way-curves a higher bond flow is connected to a greater pull-out way. The greater the pull-out distance, the more the fiber strand is compressed. The question arises if the compression of the fiber strand influences the splitting tendency factor.The model to predict a cracking along the fiber strand presented here is supported by the assumption that the splitting tendency factor  . A smallThe results of the presented investigations show dependence between the concrete strength and the bond performance of textile reinforced concrete. A higher-strength concrete leads to a shift upward of the bond-flow–pull-out distance-curve independent of the textile geometry and the impregnating agent. However, the influence of the concrete is considerably smaller than the influence of different textile configurations. The higher bond forces between the textile and higher-strength concrete also result in a greater risk of splitting cracks.It is shown that a shift of the failure mode from pullout failure in the lower strength concrete to splitting failure in the higher-strength concrete is possible. This can be explained by the greater brittleness of the higher-strength concrete. A comparison of different textiles in combination with two concretes indicates that the splitting tendency tends to decrease with increasing bond strength, regardless of whether the concrete or textile parameter is varied.Testing three strands of yarn compared to one strand of yarn only has an insignificant influence on the failure load concerning a splitting failure in a single-sided pull-out test with short anchorage lengths (one mesh width). This leads to the conclusion that the test on a single fiber strand is thus representative of several fiber strands lying next to each other.When increasing the resistance against splitting failure by increasing the mesh width between the fiber strands, the reduction in the effective concrete tensile strength must be considered. The concrete tensile strength decreases to about 35% when the concrete width is increased from 13 mm to 60 mm. This can be attributed to the stresses in the concrete, which are reduced with increasing distance from the fiber strand. The mechanical model that is presented here includes the factor γ, which transforms the stresses in the concrete to a constant stress block. A polynomial relationship of the second degree is proposed for the determination of this reduction factor in dependency of the mesh width, which describes the test results independent of textile and concrete type. Besides, the correlation can be used to estimate the relative splitting tendency of textiles with different mesh widths.The question arises of whether the results can be transferred to a varying concrete cover. The concrete cover influences the resistance against a longitudinal crack. Therefore, it has to be considered whether the single-sided pull-out test is suitable. The restoring moments in the specimens presented here disproportionately counteract a longitudinal crack failure.Additionally, a verification of the transferability of the results to fiber strands with a larger yarn cross-section  and stiffer impregnation materials should be done. Presumably, a scaling factor with respect to fiber strand width and yarn cross-sectional area is required here.


The importance of gender equity and gender representation in academic publications has long been emphasized in medicine. It has been established that women represent a smaller proportion of primary and senior authors in high-impact medical journals than men and that original research articles written by women as primary and senior authors are less frequently sited than those authored by men. Currently, there is limited data evaluating whether this gender bias is present in plastic surgery and burn publications. We used bibliometric analysis of original research publications to analyze gender bias against women in one burn journal.Using the journal, Burns, we conducted a bibliometric analysis of research publications from 2009 to 2020. A gender determining application was used to characterize the gender of the first and senior author. Ratios of male:male, female:male, male:female, and female:female were obtained and analyzed.Of the 1677 publications included, 40% have female first authors and 25.5% had female senior authors. Male:male authorships had the highest number of publications. Female:female authorship had the lowest number of publications of all the other ratios from 2009-2012, however there was a steep increase in 2013 in which male:female authorship had the lowest number of publications. Male senior authorship was associated with 2.9-fold increase in male first authorship [OR=2.99; p < 0.0001).Female representation in senior authorship positions in burn and wound care publications is increasing, however is still far from reaching gender parity. By analyzing authorship ratios by gender, we recommend a new way to evaluate gender disparity in burn and wound care academia.


Many studies of stroke rehabilitation use the Action Research Arm Test (ARAT) as an outcome, which measures upper limb function by scoring the ability to complete functional tasks. This report describes an issue encountered when analysing the ARAT subscales in a trial of upper limb therapies after stroke. The subscales of the ARAT at three months followed a ‘U-shaped’ distribution, and therefore, comparing means or medians was not appropriate. A simple alternative approach was chosen that dichotomised the subscales. When analysing the ARAT, the shape of the distributions must be checked in order to choose the most appropriate descriptive and inferential statistical techniques. In particular, if the data follows a ‘U-shaped’ distribution, a simple dichotomising or a more sophisticated approach is needed. These should also be considered for heavily skewed distributions, often arising from substantial floor or ceiling effects. Inappropriate analyses can lead to misleading conclusions. Many clinical studies of upper limb rehabilitation after stroke use the ARAT as an outcome. It measures upper limb function by scoring the ability of a participant to complete a range of functional tasks . The scaThe ARAT has generally good psychometric properties , but theAlthough the ARAT can be reported as subscales, not all studies do: the psychometric properties have not been validated for the subscales . There iThe ARAT was reported in the RATULS trial . This coWhere ARAT subscales were reported, they have usually been summarised as either a mean , 8–11 orAlthough floor or ceiling effects have been reported, other studies have not reported a ‘U-shaped’ distribution of the ARAT subscales with floor and ceiling effects present simultaneously, so we looked at the distribution of the ARAT subscale in another trial of 333 patients evaluating treatment of upper limb spasticity due to stroke with botulinum toxin type A (BOTULS)  Fig. 2,. In BOTUWhen analysing the ARAT total and subscales, care must be taken to check the shape of the data distributions and choose the most appropriate descriptive and inferential statistical techniques. If the data has a ‘U-shaped’ distribution, an alternative to the estimation of means or medians is needed. This should also be considered for heavily skewed distributions, which may result from substantial floor or ceiling effects. Inappropriate analyses can lead to misleading conclusions.The views and opinions expressed here are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, the UK National Health Service (NHS), or UK Department of Health. We would like to thank participants, local investigators and site staff, co-ordinating centre staff and members of the trial oversight committees of RATULS and BoTULS for their contribution to these research projects.The employing institutions of all authors received funds from National Institutes of Health Research (NIHR) Health Technology Assessment Programme (HTA) in order for the main RATULS and BoTULS trials to be undertaken. The RATULS and BoTULS trial results are previously published, and part of this manuscript has been presented as a poster at the European Stroke Organisation Conference in May 2019.There are no conflicts of interest.


Measurement while drilling is an important part of the intelligent development of coal mines. The main purpose of this paper is to comprehensively analyze the response characteristics of borehole drilling parameters and find a better method to predict rock mechanical properties based on drilling parameters. Firstly, six concrete blocks and multiple specimens were prepared with different material ratios. Next, the concrete specimens were tested for mechanical properties in the laboratory. Meanwhile, the displacement, rotation speed, torque, and sound pressure level (SPL) were observed during the drilling of the concrete blocks. Finally, the response characteristics of drilling parameters such as rotation speed, rate of penetration (ROP), torque, and SPL were analyzed. Besides, multiple prediction models of rock mechanical parameters were obtained by data analysis. The research results indicate that the drilling process can be classified into the initial stage of drilling (fast speed) and the steady stage of drilling (slow speed). The torque work ratio accounts for more than 99%, which increases with the increase in rock strength. The penetration depth per revolution and torque work ratio are significantly related to rock uniaxial compressive strength, Brazilian tensile strength, cohesion, and elastic modulus. The ROP is the best choice for estimating rock mechanical parameters. This research provides an important reference for laboratory rock mechanics parameter testing and geological features detection based on drilling parameters. Rock formation characteristics are regarded as an important basis for the selection of support schemes and design parameters in coal mines. However, the traditional rock coring method has disadvantages such as slow speed, high cost, and high labor intensity, which can no longer meet the development trend of intelligent construction of coal mines . At presAt present, there are several MWD devices developed for laboratory testing. For example, the prediction models of rock uniaxial compressive strength (UCS), cohesion, and internal friction angle was established based on the drilling parameters obtained through the multifunctional rock drilling test system shown in In this article, an attempt has been made to extend the application of MWD to predict the mechanical properties of roadway roof strata. In coal mines, borehole drilling is an integral part of the working cycle. From previous research, it is found that most of the equipment drills down into the rock, which is more suitable for simulating drilling in petroleum reservoirs. Furthermore, most of the experimental methods use preset drilling parameters to simulate rock drilling such as preset rotation speed and ROP, measuring torque, and thrust, or preset thrust and torque, measuring rotation speed and ROP. Nevertheless, borehole drilling is an adaptive system in coal mines. The drilling parameters all change accordingly when the drill bit encounters different rock formations . At presTo address these problems, based on the developed MWD device, 6 concrete blocks of different strengths were poured to replace different strata. Meanwhile, the mechanical properties of each concrete specimen were determined in the laboratory. Then, the correlation between the borehole drilling parameters and UCS, BTS, cohesion, internal friction angle, elastic modulus, and Poisson’s ratio was comprehensively analyzed. Finally, the obtained prediction models of various rock mechanics parameters were compared. This research provides a reference for laboratory rock mechanics parameter testing and roadway roof rock formation detection in coal mines.As shown in The detachable mold with a size of 150mm×150mm×150mm was used to pour concrete blocks. Cylindrical molds with a diameter of 50mm and a height of 100mm, 50mm, and 25mm were used to process the test specimens for physical and mechanical properties. Using sand (particle size less than 3mm), loess, 42.5 composite Portland cement, 32.5 slag Portland cement, and water as raw materials, 6 different strength concrete blocks and test pieces were poured according to the ratio shown in The concrete was mixed for the same amount of time before being loaded into the molds and vibrated for the same amount of time after being loaded into the molds to ensure consistency throughout the specimens. These concrete samples were cured for 180 days under the same conditions. Finally, the UCS, BTS, and shear specimens were obtained by cutting machine and stone grinding machine.Firstly, all samples were numbered according to the following rules. The UCS, BTS, and shear specimens were denoted by A, B, and C, respectively. The number A1-2 indicates the No. 2 specimen of the No. 1 concrete block for the UCS test. Next, the diameter and height of all test pieces were determined by the average of 3 measurements with an electronic vernier caliper. Finally, the mass of each specimen was measured by an electronic scale to calculate the density of each concrete block.A set of strain gauges were attached to the symmetry plane of each UCS specimen to measure the Poisson’s ratio of various specimens. The BX120-20AA strain gauge was arranged transversely in the middle of the specimen, and the BX120-50AA strain gauge was arranged longitudinally on the specimen next to the transverse strain gauge.The angles of the designed shear experiment are 45°, 50°, 55°, and 60°. TAJ-1000 electro-hydraulic servo rock testing machine was used for physical and mechanical testing, and the loading rate was set to 0.5MPa/s.The drilling of boreholes was performed as follows: i. The total gravity of the gravity-loaded plate and the concrete block, which is regarded as the thrust during drilling. ii. The concrete block is fixed under the gravity loading plate, and lubricating oil is evenly spread on the guide column to minimize the impact of resistance during sliding. iii. The position of the rig is adjusted so that the drill bit is aligned with the center of the concrete block, and the magnetic is switched on to make the bottom of the rig attached to the base plate. iv. The rotation speed sensor, displacement sensor, torque sensor and SPL recorder are connected, and each of them is debugged through the computer to ensure that they are in a normal state. v. Drilling of boreholes stars and the data is recorded in real-time.After sample processing and testing, the effective data obtained by each group is as follows: For the UCS test, 3 effective data were obtained for No. 1 concrete, and 4 effective data were obtained for other concretes. For the BTS test, 3 valid data were obtained for No. 1 concrete, and 6 valid data were obtained for other concretes. For the shear test, 3 and 6 valid data were obtained for No. 1 and No. 4 concretes respectively, and 4 valid data were obtained for other concretes. The average values of the UCS, BTS, elastic modulus and Poisson’s ratio of each concrete block were taken as the physical and mechanical parameters of the concrete specimen. The following work was done to study the relationship between ROP and concrete mechanical parameters. Firstly, the average ROP at the drilling stable stage was regarded as the ROP of each specimen. The stabilized ROP for each specimen is displayed in Then, the exponential function, power function, logarithmic function, and linear function were respectively used to fit the ROP and UCS to obtain the optimal fitting function. Similarly, the optimal fitting functions of ROP and BTS, cohesion, internal friction angle, elastic modulus, and Poisson’s ratio can be obtained by the above method. 2 = 0.7278) and has no significant correlation with the internal friction angle (R2 = 0.1094). When the ROP is higher, the UCS, BTS, cohesion and elastic modulus of the specimen are smaller, and the Poisson’s ratio is larger. The ROP has the highest correlation with UCS.It can be seen from The average value of the SPL during drilling of the 30-50mm section was taken as the SPL of the concrete. Specimen No. 5 has the highest SPL (104.2dBA), while specimen No. 1 has the lowest SPL level (102.1dBA). The SPL tends to increase when the strength of the drilled specimen increases. To further analyze the relationship between SPL and concrete mechanical parameters, the same data fitting method described above was reused here. It can be seen from The same data fitting method described above was reused here. Ri. The torque decreases with the increase of rock strength when the UCS is greater than Ri; The torque decreases with the decrease of rock strength when the UCS is less than Ri.It can be seen from The average rotation speed in the stable stage was taken as the rotation speed of the specimen. The optimal fitting model of rotation speed and UCS, BTS, cohesion, internal friction angle, elastic modulus, and Poisson’s ratio can be obtained by using the same method mentioned above.2 = 0.7948). The rotation speed and UCS, BTS and cohesion are all exponential function models, and the correlation coefficients are mainly concentrated in the range 0.6–0.7. The rotation speed has a linear relationship with Poisson’s ratio, and the correlation coefficient is 0.6028. There is no significant correlation between rotation speed and internal friction angle (R2 = 0.0835). Also, it can be found that the rotation speed tends to first decrease and then increase when the UCS gradually increases.It can be seen from h represents penetration depth per revolution, mm/r, V indicates ROP, mm/s, N signifies rotation speed, r/min.The penetration depth per revolution varies with rocks of different strengths. Theoretically, when the strength of the rock formation is higher, the penetration depth per revolution becomes smaller. The penetration depth per revolution can be described as:To further analyze the relationship between penetration depth per revolution and concrete mechanical parameters, the same data fitting method described above was reused here. 2 = 0.1932).It can be seen from F and torque T, the bit top is subjected to reaction force FV and friction force Ff. Fs is the cutting force generated by the torque. Fn is the resistance when the rock is broken under the action of rotation.The mechanical model of the bit is shown in WF and WT respectively represent thrust work and torque work when drilling a unit volume of rock, N·m. F indicates thrust, N. r denotes borehole diameter, m. T signifies torque, N·m.The drill bit mainly intrudes into the rock by thrust and then breaks the rock under the action of rotation. Hence, work is mainly done by thrust and torque during the drilling process. Teale (1965)  proposedr/2, the frictional work can be expressed as:Wf denotes friction work, N·m. f indicates the friction coefficient between the drill bit and the rock, f = 0.21 [It is worth noting that the borehole diameter was replaced by the drill bit diameter in past studies , 25. Howf = 0.21 .According to formulas –4), the, the4), η can be solved as follow:The torque work ratio It can be seen from The optimal fitting model of torque work ratio with UCS, BTS, cohesion, internal friction angle, elastic modulus, and Poisson’s ratio were obtained by data fitting.2 = 0.041).It can be seen from 2 = 0.9491) and has no significant correlation with the internal friction angle. The correlation coefficients between torque work and BTS and Poisson’s ratio are 0.7723 and 0.6796, respectively. Compared with the torque work ratio, it is found that the correlation between torque work and various mechanical parameters is lower.As shown in The MSE of each concrete specimen can be obtained according to The limitations of this study and the solutions in other literature are as follows: i. In the actual drilling process, water is continuously used to cool the drill bit, the influence of water on the drilling was ignored due to the shallow drilling depth in this experiment. Many devices are equipped with corresponding pumping stations, which can provide flushing water , 11. ii.Based on the drilling parameters, a lot of research work on prediction methods of rock mechanical properties has been carried out in the laboratory –9. In thFirst, the drilling process can be divided into an initial stage and a stable stage. From the curves shown in Second, rotation speed and torque are not ideal for predicting rock physical and mechanical properties. Rotation speed and torque are not highly correlated with the concrete mechanical parameters. As shown in Figs Third, during drilling these boreholes, the torque work ratio accounts for more than 99%, which increases with the increases of rock strength , 4 composite indexes , and 6 rock mechanics parameters  was analyzed. Meanwhile, the best fitting model of each drilling index and rock mechanics parameter was obtained. These model coefficients change when drilling with the roof bolter, but the model type does not change. These research conclusions are significant for the intelligent detection of rock formation in coal mines.In this paper, borehole drilling parameters like rotation speed, ROP, torque, and SPL were recorded during drilling concrete blocks with various strengths. Furthermore, the response characteristics of each drilling parameter were comprehensively analyzed, which provides a reference for scholars to deeply understand the rock breaking process and the acquisition method of drilling parameters. Besides, the correlation between 4 drilling parameters (Vt) may have a strong correlation with rock strength and can be solved as:For long-distance roadway excavation, drill bits of different sizes may be used to drill boreholes. The drill bit diameter has a greater influence on ROP, which may cause misjudgment of the strength and thickness of the rock formation when the ROP is used as the prediction model. The volume of broken rock per unit time , which avoids misjudging the initial stage and stable stage as two distinct rock formations.Torque and rotation speed are not ideal choices for estimating rock physical and mechanical parameters. There is a UCS critical value so that the rotation speed increases and the torque decreases with the UCS increases when the UCS is greater than the critical value.The torque work ratio and the penetration depth per revolution are significantly related to UCS, BTS, cohesion, and elastic modulus. The torque work ratio accounts for more than 99%, and it increases with the rock strength increases.2 > 0.9). The ROP is highly correlated with BTS (R2 = 0.8718). There is a moderate correlation between ROP and Poisson’s ratio (R2 = 0.7278). There is no correlation between ROP and internal friction angle (R2 = 0.1094).At present, the ROP is the best choice for estimating rock mechanical parameters. There is a significant correlation between ROP and UCS, cohesion and elastic modulus (RS1 Data(ZIP)Click here for additional data file.


Interlayer bonding quality is the key to the stability and durability of dam concrete. In this study, interlayer splitting tensile strength, relative permeability coefficient, and electric flux of dam concrete at different temperatures were tested. The relationships between equivalent age and strength coefficient, relative permeability coefficient ratio, and electric flux ratio were established. Meanwhile, a comprehensive early-warning and control system of dam interlayer bonding quality based on the above relationships was proposed. The results showed that the interlayer mechanical properties, impermeability, and anti-chloride ion permeability of dam concrete decreased with the increase of temperature. Moreover, the equivalent age was linearly correlated with strength coefficient, relative permeability coefficient ratio, and electric flux ratio of concrete. The correlation coefficients were 0.986, 0.973, and 0.924, respectively. In addition, the interlayer bonding quality of dam concrete can be effectively controlled by the early-warning system established according to the relationship between equivalent age and interlayer properties parameters. The development of dam construction technology can be divided into artificial, mechanized, automatic, digital, and intelligent stage . The intThe Wudongde and Baihetan dam construction areas are of a typical dry hot valley climate. Extreme weather, such as high temperature, low humidity, strong wind, and short-time heavy precipitation, occurs frequently in dam construction areas . Under tMany studies have proved the existence of the above problems from macro and micro levels. Niu et al.  investigThe construction quality control of high arch dams covers many aspects, including the performance of raw materials, control of concrete temperature, operation of large machinery, pouring, and maintenance of concrete, etc. This research mainly focuses on the quality control of interlayer bonding in the concrete pouring process. The setting time method , maturitThe setting time method determines the pouring time node of the upper layer concrete by controlling the setting state of the lower layer concrete. If interval time exceeds the initial setting time of the lower layer concrete, pouring should be stopped.Maturity is a concept that has existed since 1950. At present, this method has been widely used in various fields, such as hydraulic engineering, construction, and transportation. In the field of construction engineering, the relationship between maturity and compressive strength was used to judge the time of the mold removal to avoid building collapse caused by premature demolding . In the Xu et al.  tested tThe environmental factors of the construction site changed with time, which affected the hydration process of the cement. Therefore, it is difficult to accurately test the setting time of concrete. In addition, the relationship between setting state and the strength of the concrete has not been established. In conclusion, the application of setting time method in the field needs to be further studied. Although the maturity method establishes the relationship between concrete maturity and compressive strength, compressive strength is not the most direct index to reflect the interlayer bonding quality of concrete. Although the water-strength method established the relationship between the water index and interlayer mechanical properties, the applicability of this method in the case of concrete bleeding was not considered. In addition, as a water retaining structure, the interlayer bonding quality should be controlled comprehensively from the aspects of interlayer mechanical properties and impermeability. Because the interlayer mechanical properties and impermeability are the key indexes affecting the stability and durability of the dam.The current dam construction process is very random and lacks a method that can automatically collect on-site construction information  and achieve interlayer bonding quality control. The interlayer bonding quality control method of dam concrete should establish the relationship between the key parameters of the lower concrete and interlayer performance to determine the specific construction node. In view of the shortcomings of above methods, the tests of interlayer splitting tensile strength, relative permeability coefficient, and electric flux of concrete at different temperatures were carried out, respectively. Then, the relationship between equivalent age and interlayer strength coefficient, relative permeability coefficient ratio, and electric flux ratio were established according to maturity theory. Finally, the control index of interlayer bonding quality was put forward according to the guaranteed rate of strength, permeability resistance, and chloride ion permeability resistance. In addition, a comprehensive control system of “monitoring-analysis-feedback-processing” has been established. This system realizes effective monitoring of quality parameters of the dam during concrete pouring and real-time warning of performance indexes. Furthermore, effective treatment measures were put forward for possible construction risks, which can guide the construction in concrete pouring and ensure the quality of interlayer bonding to meet the design requirements. The interlayer bonding quality control method proposed in this paper has been successfully applied in the Wudongde dam see a and the3. The coarse aggregate is crushed basalt with a particle size range of 5–20 mm. In addition, polycarboxylic acid superplasticizer was used to maintain the fluidity of concrete, and the water reduction rate was about 19%.The physical properties and chemical components of cement were provided by the manufacturer, which are shown in Concrete specimens were poured in three steps. First, the lower concrete  was poured. Then, the specimens were placed in environmental chambers . After 6 h, the specimens were taken out of the environmental chambers, and the upper layer of concrete was poured . All speThere were three types of molds: cube (150 mm × 150 mm × 150 mm), truncated cone , and cylinder (ϕ100 mm × 200 mm). Cube specimens were used for splitting tensile strength test, truncated cone specimens were used for relative permeability coefficient test, and cylinder specimens were used for electric flux test. Six samples were prepared for each analysis.The specimens were divided into four groups. The numbers of concrete specimens were C0, T20, T30, and T40, respectively. C0 represents the bulk concrete, and the other groups are layered concrete.The splitting tensile strength test of concrete was carried out according to the Chinese standard DL/T 5150-2017 . First, The relative permeability test of concrete was carried out according to the Chinese standard DL/T 5150-2017 . The maiThe rapid chloride ion penetration test of concrete was carried out in accordance with Chinese national standard GB/T 50082-2009 . The dirThe electric flux test method is shown in The results of electric flux test are shown in At the dam construction site, it is necessary to determine the decisive parameters affecting the interlayer bonding quality. Then establish the relationship between the parameters and the interlayer mechanical properties, impermeability, and chloride ion permeability. Thus, the judgment basis of interlayer bonding quality suitable for the construction site is obtained.The closed-loop control system of dam interlayer bonding quality includes problem, perception, analysis, control, and objective see . In the In order to effectively control the key parameters of the dam pouring quality, it is necessary to monitor the concrete temperature in real time. The main functions of the dam interlayer bonding quality control system include: (1) information monitoring; (2) when the key parameter exceeds the warning value, the system will automatically push the warning information to the construction personnel, supervisors and owners, and propose effective treatment measures—in addition, a real-time feedback mechanism needs to be established to close the early-warning information; and (3) statistical analysis of early-warning information.Data acquisition is the basis of the dam interlayer bonding quality control system. The data acquisition function can provide basic data guarantee for information query, information processing, and operation analysis in the system. Firstly, the collected original data are preliminarily screened to eliminate invalid data and duplicate data. In addition, duplicate data submitted due to hardware logic problems or acquisition program problems should be filtered, such as the same data submitted by the same machine at the same time point.The data acquisition module is mainly based on the data of concrete initial temperature, pouring temperature, interval time, and water content in the intelligent construction information management platform of the dam project. In addition, in order to deal with the construction risks that may be faced during the concrete pouring process, it is also necessary to monitor meteorological information, such as ambient temperature, relative humidity, wind speed, and light intensity. Meteorological information is mainly monitored by weather stations see a. In theData acquisition needs to comply with the following requirements: (1) data collection needs to be real-time, accurate, and comprehensive; (2) automatic data collection is independent and complete, and can be operated directly without other system modules; and (3) the automatic data collection system must back up the original data collected and ensure that data will not be lost when there is a problem with the network.Freiesleben  proposed(1)The Relationship between Equivalent Age and Strength CoefficientThe strength coefficient of concrete can be calculated according to Equation (6). Since the bulk concrete has no interlayer interval, its equivalent age is 0 and the strength coefficient is 1. The relationship curve between the equivalent age of concrete and the strength coefficient is shown in fficient .(7)As=−The strength coefficient of low-heat cement concrete is linearly negatively correlated with the equivalent age, and the correlation coefficient is 0.986.According to the relationship between the equivalent age and the strength coefficient, the strength coefficient can be controlled to 0.8, 0.7, and 0.6, respectively, and the corresponding equivalent ages are 4.7, 7.1 and 9.7 h. This indicates that if the interlayer splitting tensile strength is to be controlled within 80%, 70%, or 60% of the strength of bulk concrete, the equivalent age of the lower layer concrete should be controlled within 4.7, 7.1, or 9.7 h, respectively. If the equivalent age exceeds the corresponding control value, the interlayer bonding strength will not meet the control requirements.(2)The Relationship between the Equivalent Age and the Relative Permeability Coefficient RatioThe relative permeability coefficient ratio can be calculated according to Equation (8):According to the relationship between the equivalent age and the relative permeability coefficient ratio see , the rel(3)The Relationship between the Equivalent Age and the Electric Flux RatioThere are two methods to test the chloride ion penetration resistance of concrete, which are the fast chloride ion migration coefficient method ,35 and tThe electric flux ratio can be calculated according to Equation (9):According to the relationship between equivalent age and electric flux ratio see , the eleInterlayer bonding strength, water permeability resistance, and chloride ion permeability resistance of dam concrete can be controlled in accordance with the relationships between the equivalent age and the strength coefficient, the relative permeability coefficient ratio, and the electric flux ratio see .The early-warning thresholds were determined according to the early-warning model established in The early-warning system realizes the transmission, analysis , statistics , query, and other functions of pouring quality monitoring data. Among them, the trend analysis is to calculate the equivalent age according to the measured temperature of concrete and then draw the corresponding curve according to the relationship between the equivalent age and time. The reasons for the decrease of concrete interlayer bond strength can be found out by data analysis based on the change curve of equivalent age and environmental information. The final equivalent age statistics function can realize the statistics of the final equivalent age of each layer of concrete. The warning information quantity statistics function can collect statistics on the amount of warning information pushed in any period of time.(1)Increasing ambient temperature will reduce the mechanical property of concrete. On the contrary, the relative permeability and electric flux increase with the increase of temperature. It shows that the mechanical properties, impermeability, and anti-chloride ion permeability of concrete will deteriorate with the increase of temperature;(2)The equivalent age of lower concrete has a good linear correlation with strength coefficient, relative permeability coefficient ratio; and electric flux ratio. The equivalent age has a linear negative correlation with strength coefficient, and the correlation coefficient is 0.986. The equivalent age is linearly positively correlated with relative permeability coefficient ratio and the electric flux ratio, and correlation coefficients are 0.973 and 0.924, respectively; and(3)It is feasible to use the equivalent age to control the interlayer bonding quality of dam concrete. This method can effectively monitor the quality parameters of dam concrete. In addition, the dam interlayer bonding quality early-warning system can effectively deal with the possible construction risks and ensure the interlayer bonding quality.Based on the test results of interlayer mechanical properties, impermeability, and chloride ion permeability of concrete at different temperatures, the following conclusions are obtained:The interlayer bonding quality control method has been applied in the dam construction process. This method is effective for the control of interlayer bonding quality. In the future, it is planned to introduce the influence factors of humidity and wind speed into the calculation equation of equivalent age to deal with the interlayer bonding quality control of concrete under complex environmental conditions.


Standardized monitoring of antibiotic use underpins the effective implementation of antimicrobial stewardship interventions in combatting antimicrobial resistance (AMR). To date, few studies have assessed antibiotic use in hospitals in Uganda to identify gaps that require intervention. This study applied the World Health Organization’s standardized point prevalence survey methodology to assess antibiotic use in 13 public and private not-for-profit hospitals across the country. Data for 1077 patients and 1387 prescriptions were collected between December 2020 and April 2021 and analyzed to understand the characteristics of antibiotic use and the prevalence of the types of antibiotics to assess compliance with Uganda Clinical Guidelines; and classify antibiotics according to the WHO Access, Watch, and Reserve classification. This study found that 74% of patients were on one or more antibiotics. Compliance with Uganda Clinical Guidelines was low (30%); Watch-classified antibiotics were used to a high degree (44% of prescriptions), mainly driven by the wide use of ceftriaxone, which was the most frequently used antibiotic (37% of prescriptions). The results of this study identify key areas for the improvement of antimicrobial stewardship in Uganda and are important benchmarks for future evaluations.  Antimicrobial resistance (AMR) is a threat to global health and sustainable development, with adverse health and economic consequences, unless evidence-based efforts are implemented to control its emergence and spread ,2. The hNumerous factors contribute to the emergence of AMR ,11,12. ARecent efforts to measure antibiotic use in sub-Saharan African hospitals have been documented ,20,21,22Across the 13 included hospitals, de-identified data for 1077 patients was collected for analysis . Of thosData were collected on 1387 antibiotics that were prescribed to patients in our study. Of these prescriptions, ceftriaxone was the most prescribed antibiotic (37%), followed by metronidazole (27%), gentamicin (7%), and ampicillin (6%) .Among all the antibiotic prescriptions, the most common indication was for CAI (41.6%), followed by MP (29.1%), SP (23.0%), and HAI (6.3%) . For allIndications for antibiotics were much more common for CAIs than HAIs. Clinical sepsis, cellulitis, pneumonia, and gastrointestinal infections were the most common CAI diagnoses for antibiotic use. Ceftriaxone and metronidazole are the most prescribed antibiotics at 37% and 27%, respectively. p < 0.01)  . Ceftria < 0.01) . No patin = 423) were prescribed in compliance with the Uganda Clinical Guidelines 2016 [n = 12), and the highest proportion was at Kiwoko . Compliance with prescription guidelines for each antibiotic varied as well. Secnidazole, sulbactam, and tinizadole were always prescribed in accordance with guidelines, and metronidazole was prescribed with a relatively high rate of compliance (63%). All other antibiotics were not prescribed in accordance with guidelines more than half the time. Frequencies of compliance with treatment guidelines by hospital are summarized in Among all antibiotics, only 30.1% (nes 2016 . Complian = 1373) of all prescriptions. St. Francis Naggalama recorded the highest proportion of prescriptions with the reason for prescribing antibiotics documented in the notes at 96.8% (n = 61), and Lacor hospital recorded the lowest at 64.3% (n = 153). Among all SP prescriptions, 1% (n = 3) of prescriptions were for 1 dose, 0.7% (n = 2) were multiple doses on day 1, and the remaining was for a longer duration, which was 301 (98.4%) multiple doses on more than 1 day. Overall, the indication for treatment was documented in patient record notes for 80.1% (n = 519), ciprofloxacin (n = 45), azithromycin (n = 19), levofloxacin (n = 15), and erythromycin (n = 3). There were no antibiotic prescriptions in the Reserve group. The highest proportion of Access antibiotics was recorded at Lacor hospital (70.5%) and the lowest Access proportion was in Moroto (25.7%). Similarly, the highest proportion of Watch antibiotics was recorded at Moroto hospital (58.4%) and the lowest proportion at Lacor (20.5%). Among all 1387 antibiotic prescriptions, 654 (47.2%) were from the Access group, 612 (44.1%) were in the Watch classification, and 9% were unclassified . The mosn = 24) had the highest proportion of courses that were not administered to patients, followed by metronidazole . By hospital, Lira hospital and Gulu hospital had the highest percentage of prescriptions that were not administered to patients , and five hospitals had prescriptions that were administered to all patients studied: Hoima, Kagando, Kiwoko, Kumi, and St. Francis Naggalama. The proportion of antibiotic courses that were administered by hospital are summarized in Among all antibiotics with more than 20 prescriptions, ampicillin-cloxacillin  were administered orally and 88% (n = 1230) were administered parenterally. A switch from parenteral to oral antibiotics was noted for 1.9% (n = 39) among all orally administered antibiotics. Among the antibiotics that were administered parenterally, 925 (75.3%) were administered intermittently, 302 (24.3%) were administered continuously, and 2 (<1%) were administered intramuscularly.Across all 1387 prescriptions, 11% (p < 0.001). In publicly owned hospitals, the mean number of antibiotics per patient was 1.66, and in private not-for-profit hospitals, the mean number of antibiotics was 1.70 (p = 0.41)  observed patients were on one or more antibiotics. By sex, 425 (69.8%) females and 369 (78.8%) males were on one or more antibiotics. Among patients on antibiotics, 302 (38%) were on one antibiotic, 440 (55%) were on two antibiotics, 44 (6%) were on three antibiotics, and two (<1%) were on four antibiotics. Among patients on any antibiotics, the mean number of antibiotics per patient was 1.55 (range 1–4). The mean number of antibiotics per patient ranged from 1.6 in St. Francis Naggalama Hospital to 2.0 in Ruharo Mission Hospital ( = 0.41) .p = 0.04). HIV and malnutrition patients had a nearly six-fold increase in antibiotic use (p < 0.001). Whether a patient was hospitalized in the previous 90 days did not increase the odds of antibiotic use. In the multivariate logistic regression, male sex (p = 0.003), HIV status (p = 0.003), and malnutrition status (p = 0.004) were significantly associated with odds of antibiotic use, while age and malaria status were not , positive HIV status , malnourishment status , and attendance at the following hospitals: Hoima , Kumi , Masaka , and St. Francis Naggalama . Among males, the characteristics associated with increased odds of antibiotic use were attendance at a public hospital  and attendance at the following hospitals: Masaka , Moroto , and Soroti   .The observed prevalence of antibiotic use of 73.7% is somewhat similar to findings from certain PPS studies conducted in Kenya (67.7%) , BotswanBoth sex  and gender  play important roles in AMR, based on sex differences in pharmacokinetics and pharmacodynamics and gender roles . Body weWe found that most patients received multiple doses on more than one day, an average of 2.3 antibiotics administered per patient, contrary to WHO recommendations of single antibiotic prophylaxis . In addiUse of parenteral antibiotics was very high (88%) compared to oral (12%) in the present study. These values are similar to the use of parenteral antibiotics in Indonesia (85.1%) and Pakistan (91.5%) ,47. The Our finding of poor adherence to Uganda’s Clinical Guidelines (30.1%), along with the high percentage of antibiotics used in the Watch category, further accentuates the need for effective antimicrobial stewardship programs in Uganda, in connection with progress toward universal health coverage . Many faContrary to the general view that inappropriate antibiotic prescribing with respect to indication and quantity is higher in the private sector and based on a situational analysis , our finThe finding of ampicillin-cloxacillin and metronidazole having a high proportion of doses not administered to patients (coded as “missed doses” in WHO PPS methodology) is not surprising since these drugs are administered at a higher frequency, i.e., every six hours and eight hours, respectively, compared to antibiotics like ceftriaxone, which is administered once a day. Public hospitals have a higher burden of patients and tend to use more higher-frequency dosing drugs. Other possible causes could be essential medicine stockouts, including certain Access group antibiotics, which means the antibiotics were not administered. The latter could also explain the high prevalence and, at times, lack of alignment with clinical guidelines for certain Watch group antibiotics, when the first-line Access group antibiotics ran out of stock ,58. ThesThe observed high proportion of parenteral antibiotics could point to overall stewardship challenges in health facilities. One possible explanation is the lack of adherence to the Uganda Clinical Guidelines. The observed low compliance with the guidelines (30%) could also explain the high proportion of parenteral antibiotics since most of the first-line drugs for treating common bacterial infections are oral medicines as per the guidelines. Additionally, implementing a hospital-parenteral-to-oral switch program requires regular patient review and availability of microbiology results to guide the switch to determine suitable oral medications. Human resource shortages could hinder regular patient review to switch antibiotics from parenteral to oral. Additionally, the lack of microbiology capacity in most hospitals may negatively affect the clinicians’ ability to empirically make decisions for the parenteral-to-oral switch. Lastly, the general belief that parenteral antibiotics work better than oral antibiotics could be a contributing factor . ContribAmpicillin-cloxacillin is listed as “not recommended” in the WHO AWaRe antibiotic classification database. It is considered as an inappropriate fixed-dose combination and is a problem not only in Uganda but in many low- and middle-income countries ,65. AmpiCeftriaxone, a Watch antibiotic, was the most prescribed antibiotic for patients in these 13 regional hospitals and was used routinely for CAIs, MP, and SP. Ceftriaxone was used empirically as the first-line treatment for CAIs, contrary to Uganda’s Clinical Guidelines. Inappropriate use of ceftriaxone, which is a third-generation cephalosporin, can accelerate the emergence of AMR of multidrug-resistant organisms, increase treatment cost, and result in avertable adverse drug effects. In Uganda, one study reported 32% inappropriate use of ceftriaxone in nine health facilities while another study reported a high level of ceftriaxone use at a tertiary care, private not-for-profit hospital ,68. A poNot using antimicrobial susceptibility testing when prescribing antibiotics in Uganda is also concerning. This situation is not unique to Uganda as only 2 out of 591 patients that received antibiotics in a PPS study conducted in Tanzania were specifically treated based on antimicrobial susceptibility testing results . Among tThis study informs antimicrobial stewardship strategies for Ugandan hospitals by establishing measurable antimicrobial use targets, such as reducing the use of broad-spectrum antibiotics, complying with treatment guidelines and increasing the uptake of antimicrobial susceptibility testing. There is a need to develop and implement feasible strategies for complementing antimicrobial stewardship interventions such as in infection prevention and control and hand hygiene interventions for prevention of health care-associated infection that can reduce the need for antibiotic use. Additionally, the study can serve as a baseline to evaluate future antimicrobial stewardship strategies in Uganda’s hospitals. Areas of action could include establishing a funded national system for surveillance of antibiotic use in health facilities to inform antimicrobial stewardship interventions. There is also a need to strengthen implementation and enforcement of policies on the use of antibiotics. This could help reduce the inappropriate use of Watch category antibiotics and increase compliance with the Uganda Clinical Guidelines. For hospitals, survey findings can be used to develop specific continuous quality improvement plans to address the identified gaps. Areas of future research include understanding the potential enablers of implementing antimicrobial stewardship programs in Uganda; behavioral, sex, and gender impacts; and other factors that influence prescribing and consumer behaviors for antibiotics. Comprehensive solutions and multi-pronged approaches to tackle weak laboratory capacity in Uganda and sub-Saharan Africa in general have been extensively described elsewhere. Our study provides further evidence on the need for Uganda to secure appropriate investments to solve this vexing problem, which is an essential component of antimicrobial stewardship ,71.Data collection took place over five months, rather than the WHO-recommended three-week window. A major cause of this limitation was the lack of capacity within health facilities to conduct antibiotic use surveys. The longer duration of our study may have resulted in some inconsistencies in antibiotic use patterns based on external factors, such as holidays and changes in disease transmission, including the COVID-19 burden. The PPS study design is restricted to assessing only inpatient antibiotic use. Consequently, antibiotics taken prior to hospitalization or those purchased externally and brought to the hospital are not recorded. The point-in-time nature of the PPS design further limits insight into seasonal patterns in antibiotic use. Even though the study included hospitals from different regions of the country as well as from government and private sectors, there are some limitations in the generalizability of our findings to other hospitals in Uganda and to hospitals in other countries with similar disease burdens and patient demographics. Our study has numerous strengths. Using the standard WHO PPS methodology allows for comparisons with future studies not only in Uganda but also in other East African settings and sub-Saharan African settings in general. Compared to other PPS studies performed in as few as 1–6 hospitals, the present study included 13 hospitals. Inclusion of public and private not-for-profit hospitals is another strength of the study along with the dispersed geographical coverage of the hospitals in Uganda. Our study built on the existing hospital medicines and therapeutics committee as the mechanism for stewardship interventions. Further, our findings go beyond measuring the use of antibiotics. Several study variables, such as the burden of surgical indications, reasons for antibiotic prescribing, and data on antibiotic use for specific sites, have the potential for additional utility to improve clinical decision making and ensure patient safety. Finally, we are the first to assess sex-disaggregated differences to understand inequities in antibiotic use among males and females by using the PPS methodology. All data were collected and analyzed based on the “WHO Methodology for Point Prevalence Survey on Antibiotic Use in Hospitals” version 1.1. The WHO Methodology for Point Prevalence Surveys, published in 2019, is intended to guide the collection of information on prescribing practices of antibiotics and other information relevant to treatment and management of infectious diseases in hospitalized patients . Given cThe study was conducted from December 2020 to April 2021 in 13 hospitals in Uganda. Six of the hospitals were public, government owned RRHs and seven were private not-for-profit hospitals. The public hospitals were chosen purposively based on ongoing involvement in related antimicrobial stewardship programs, and the private not-for-profit hospitals were chosen based on geographic location to cover four main regions of the country. Data were collected from all health facilities where our program is working to improve antibiotic use and no sampling of hospitals was done. Uganda has a decentralized health care system, with the lowest level being the Village Health Team and the highest being the National Referral Hospitals. General hospitals provide primary health care, covering the main disciplines of Medicine, Surgery, Pediatrics, and Obstetrics. The RRHs provide all the care provided by the general hospitals and provide specialized care in addition. Data collection was conducted by staff from each hospital’s medicines and therapeutics committee. Training on using the WHO PPS standardized data collection methods, including the paper form, took place one day before the data collection began and included practice sessions. Data were included for all patients admitted to the ward before 8:00 am on the study day as well as all patients discharged on the study day. Data were excluded for patient types listed in the WHO PPS protocol, including all patients who were admitted after 8:00 am, patients in the palliative long-term care wards, patients currently undergoing radiological or surgical procedures, and patients who are still physically present in the ward but who have been officially discharged. Each ward was surveyed completely within one day to minimize impact of patients moving between wards. The variables collected were all core variables in the WHO PPS methodology for hospital, ward, patient, antibiotic, and indication categories of variables.The Uganda Ministry of Health approved this study as part of ongoing technical assistance and implementation of the AMR national action plan .After data collection, de-identified data were entered into the WHO PPS Microsoft Excel-based tool by the study team for analysis. Data cleaning checks were performed for all 13 hospitals, and all data entry discrepancies were resolved using the original paper data collection forms. The data cleaning and entry was done as per the WHO methodology/protocol referenced above. Indication was grouped into four categories: community-acquired infection (CAI), hospital-associated infection (HAI), medical prophylaxis (MP), and surgical prophylaxis (SP). According to the WHO PPS methodology, infection is categorized as HAI if the date of onset is on: Day 3 onwards OR Day 1 or Day 2 AND patient transferred from another hospital OR Day 1 or Day 2 and patient discharged from a hospital  in preceding 48 h. Antibiotics were grouped according to 2019 WHO AWaRe classification of antibiotics for evaluation and monitoring of use . AntibioDescriptive statistics for the data are presented using mean ± standard deviation or median (IQR) for continuous variables. Results from categorical variables are expressed as proportions and the χ2 test or Fisher’s exact test was used, as appropriate, for comparisons. Univariate logistic regression to assess factors associated with increased odds of antibiotic use was conducted with the following prespecified factors: age , sex, ward, hospital ownership, hospital facility, underlying condition status , hospitalization within previous 90 days, indication category, and whether patient is a referral. This same univariate analysis was then performed disaggregated by sex as well. A multivariate logistic regression was also conducted which included pre-specified variables of interest: age, sex, HIV status, malaria status, and malnutrition status. Significance was evaluated at the alpha = 0.05 level. All analyses were performed using R Studio version 4.0.1 .This is the first study in Uganda that was based on the WHO methodology for PPS on antibiotic use in hospitals. These data provide insights into the most common antibiotics used in 13 public and private not-for-profit hospitals throughout the country, including prevalence by patient characteristics, hospital, indication, and diagnosis. Notable findings were the high use of antibiotics among hospitalized patients, the high proportion of patients receiving parenteral antibiotics, the high prevalence of Watch antibiotics (particularly ceftriaxone), antibiotic use for SP nearly always spanning more than one day, low adherence to Uganda Clinical Guidelines, and sex differences in antibiotic use. These findings support the Uganda National Action Plan on AMR in identifying targeted strategies for improving antimicrobial stewardship. The estimates provided herein may also serve as a helpful baseline for the national antimicrobial stewardship technical working committee to promote and facilitate locally appropriate stewardship strategies in hospital settings and catalyze experience sharing and cross-fertilization. Additional research is needed to identify the drivers of inappropriate use in relation to disease burden and operational enablers of effective antimicrobial stewardship programs.


The aim of this study is to evaluate the association of c-Met overexpression with survival of glioblastoma multiforme (GBM) patients. A systematic review with meta-analyses was conducted on related articles from PubMed, EBSCOhost, Scopus, and Cochrane databases with last updated search on October 31, 2020. A total of 7 studies regarding c-Met overexpression and overall survival (OS) and/or progression free survival (PFS) are included in this study. 2 values were 7,8% and 0,0%, respectively. All studies used immunohistochemistry to examine the expression of c-Met protein. The results showed that the positive rate of c-Met overexpression was detected in approximately 33,9% - 60,5% of GBM patients. c-Met overexpression was related to worse OS  and PFS  in GBM patients. Low heterogeneity of subjects was found in both OS and PFS analyses, IIn conclusion, c-Met overexpression is significantly related to shorter OS and PFS in GBM patients, so c-Met can be considered as a potential prognostic indicator in GBM. Glioblastoma multiforme (GBM) is a highly aggressive brain malignancy originating from glial cells and is classified as grade IV glioma according to WHO classification of CNS tumours 2016 . According to Central Brain Tumour Registry of the United States (CBTRUS), GBM accounts for 14,5% of all primary brain tumour cases and 80% of all high grade gliomas. The incidence rate was 3,23 per 100,000 populations and more common in male compared to female . In spite of the current standard treatment protocol, including maximal safe resection followed by concurrent chemoradiotherapy and adjuvant chemotherapy with the alkylating agent temozolamide (TMZ), the prognosis of GBM patients remains poor. The median survival for the newly diagnosed GBM patients with this therapy paradigm is approximately 12,1-14,6 months .Clinical prognostic factors that contribute to the survival in this devastating disease were firstly studied by Radiation Therapy Oncology Group (RTOG) in 1993, using Recursive Partitioning Analysis (RPA) based on patient, tumour, and therapy variables . In 2011, this RPA model were validated and simplified and three prognostic classes  were establised according to age, Karnofsky Performance Status (KPS), and extent of resection . This new RPA model is then frequently used in many clinical settings. However, similar to other malignancies that harbor molecular disregulation processes, there are also several molecular pathways responsible for the pathogenesis of GBM . Until now, many studies had been conducted in order to find which molecular pathways that could predict the prognosis of GBM patients .One of the most interesting moleculars is the receptor tyrosine kinase c-Met , which is coded by proto-oncogene MET located in chromosome 7q21-31 . c-Met is expressed in epithelial and endothelial cells, liver, pancreas, prostate, kidney, bone marrow, and at low levels in the brain . Its primary ligand is called hepatocyte growth factor (HGF). c-Met/HGF signalling pathway plays an important role in normal biological functions such as embryogenesis, tissue regeneration, wound healing, and formation of nerve and muscle . This pathway has also been known to involve in tumorigenesis by inducing cell survival, proliferation, adhesion, migration, invasion, anti-apoptotic responses, and angiogenesis . Abnormal activation of c-Met  has been linked to the development and progression of many types of cancer, including hepatocellular carcinoma, lung cancer, colorectal cancer, breast cancer, pancreatic cancer, ovarian cancer, prostate cancer, gastric cancer, and GBM .Growing evidence shows the involvement of c-Met in the GBM pathogenesis. It was suggested that the expression of HGF together with its receptor c-Met stimulated the growth of HGL4 GBM cell lines . A research using cell lines indicated the presence of multiple mechanisms of c-Met activation in GBM . Another study reported that c-Met was important for endothelial mesenchymal transition, aberrant vascularization, cancer progression, and chemoresistance in GBM . From a clinical standpoint, it had been showed that overexpression of c-Met was detected in 33,9% of patients with GBM, and this significantly associated with shorter overall survival (OS) and progression free survival (PFS) . According to a study by NRG Oncology RTOG 0525, protein biomarkers significantly correlated with shorter OS after multimarker modeling were c-Met, Ki-67, and MGMT . On the other hand, it was also reported that the survival of GBM patients was longer in those who harbored c-Met overexpression . Because of these contradictive results, we performed a systematic review of literatures with meta analysis to evaluate the prognostic value of c-Met in predicting the survival of patients with GBM.Literature search and selection criteriaThis systematic review with a meta-analysis was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations . Articles regarding c-Met expression and survival in GBM were systematically searched on PubMed, EBSCOhost, Scopus, and Cochrane databases, using these following keywords: (glioblastoma OR glioblastoma multifor*) AND (CMET OR MET) AND (prognos* OR surviv*). The search was done from May 1, 2020 until the last updated search on October 31, 2020. Only publications in English were collected with no restriction on the year of publication. Studies were included in this review if these following criteria were met: (1) articles were available in full paper; (2) expression of c-Met protein expression was assessed and was associated with the survival (OS and PFS) of GBM patients; (3) cut-off value for c-Met protein overexpression was stated; (4) data on hazard ratio (HR) and 95% confidence interval (95% CI) were provided or could be calculated from the sufficient data.Data extractionReview of all articles and extraction of the data needed were done by two reviewers independently. Disagreements were discussed and resolved among the authors. Information recorded from each study including name of the first author, year of publication, region, sample size, c-Met protein cut-off value, c-Met overexpression positive rate, OS and PFS data, and HR with 95% CI.Statistical analysis2). The pooled HR was estimated by the fixed-effects model if no obvious heterogeneity was found. Otherwise, the random-effects model was used.In every study, the OS and/or PFS of GBM patients were compared between the groups with and without c-Met overexpression. The result was considered significant if the calculated p-value was <0,05. The intensity of relationship between c-Met expression level and OS or PFS was presented in HR. The overexpression of c-Met predicted shorter survival of GBM patients if the value of HR > 1 and 95% CI not overlapping 1. In some articles, HR with 95% CI was available from univariate or multivariate analysis, and this value could be directly obtained. Otherwise, HR and its corresponding 95% CI were estimated from Kaplan-Meier survival curve using a specific reported method . To evaluate the prognostic value of c-Met, the pooled HR corresponding to the 95% CI was calculated using STATA 12.0. Statistical heterogeneity was determined by Cochrane’s Q test  and inconsistency  from 2008-2019 using retrospective cohort. The main information of the articles can be seen in Meta-analysis2 = 0,0%; p<0,001. These results suggested that overexpression of c-Met was significantly associated with shorter OS and PFS of GBM patients, so that high c-Met expression was a valuable molecular prognostic factor for OS and PFS in GBM. Low heterogeneity of subjects was found in both OS and PFS analyses .From the meta-analysis of 6 studies assessing c-Met expression and OS, the pooled HR was 1,74 . The receptor tyrosine kinase c-Met that binds to its ligand HGF is one of the exprected moleculars. c-Met/HGF has been known to connected with many physiological and pathological process . Deregulation of c-Met expression has been linked to the development, progression, and prognosis of many types of human cancers, such as hepatocellular carcinoma, colorectal cancer, ovarian cancer, breast cancer, gastric cancer, and osteosarcoma . c-Met/HGF signaling could induce proliferation, motility, cell adhesion, invasion, and anti-apoptosis. This pathway could also increase tumourigenicity and malignancy progression by activating cell cycle progression, cell migration, and tumour angiogenesis . The result of this systematic review with a meta analysis demonstrated that overexpression of c-Met was associated with worse OS and PFS in GBM patients. Interaction of c-Met and HGF on the cell surface leads to the autophosphorylation of Tyr1234 and Tyr1235 in the catalytic site, followed by phosphorylation of the tyrosine residue Tyr 1349 and Tyr 1356 in the docking site of the receptor . This processes trigger the recruitment and activation of many signaling effectors, such as Gab1 (Grb2-associated adaptor protein 1), Grb2 (growth factor receptor-bound protein 2), Src, Shc , Shp2 (Src homology protein tyrosine phosphatase 2), PLC-γ (phospholipase c-γ), FAK ; followed by the phosphorylations of transducers, including STAT3 , Ras/MAPK/ERK, PI3K (phosphatidylinositol 3-kinase)/Akt . These signals have been implicated in survival, proliferation, invasion, migration, angiogenesis, and stemness of glioma cells. Under normal conditions, cytoplasmic Tyr 1003 works as the negative regulator of c-Met that will recruit c-CBL, and phosphorylation of c-CBL leads to receptor degradation . A research using cell lines showed the existence of multiple mechanisms of c-Met activation in GBM . It had been demonstrated that c-Met was responsible for endothelial mesenchymal transition, aberrant vascularization, cancer progression, and chemoresistance in GBM . The overexpression of c-Met was also significantly associated with higher molecular phenotypes that represent invasiveness, MMP-2 and MMP-9, and tended to show invasive and multifocal features on the initial magnetic resonance images . From a result from an in-vitro research, a decrease in c-Met expression caused inhibition of cell migration and invasion capacity, and also increased the sensitivity to TMZ . In addition, it was reported that c-Met overexpression was more frequently found in recurrent GBM compared to primary GBM . All articles in this review used immunohistochemistry to detect the overexpression of c-Met. It could be seen that the positive rate of c-Met overexpression was quite high in each study . The cut-off values to define c-Met overexpression varied. Most studies used > 30% as cut-off value . One study took 75% as cut-off after it was found that cut-off 70,8% (from median) was not prognostic . According to a study with large sample size by NRG Oncology RTOG 0525, the level of c-Met protein expression within the cytoplasm when split by the top-tertile and top-quartile was significantly associated with shorter OS, with value from top-quartile reached significancy after a multimarker model. However, the specific number of cut-off value was not mentioned in this study .This article is the first meta-analysis that evaluates c-Met overexpression and survival in patients with GBM. In conclusion, c-Met overexpression is significantly related to shorter OS and PFS in GBM patients, so c-Met can be considered as a potential prognostic indicator in GBM. This study could also propose that c-Met targeted therapy in GBM may be promising.Authors’ contributions including conceptualization, S.G, R.A.A, R.M, E.S, H.S; methodology, S.G, J.A, S, H, T.B.M, H.K, E.N; validation, J.A, S; formal analysis, J.A, S, S.G; data curation, J.A, S, H, T.B.M, H.K, E.N; writing-original draft preparation, J.A, S, H; writing-review and editing, J.A, S, S.G, H, T.B.M, H.K, E.N. All the authors declare no conflict of interest.


IntroductionOver the past two decades, Asia has experienced the rise and integration of Western medicine and digital health in its field of medicine. In this study, we investigated the trends in orthopaedic publications from three Asian countries: China, Japan, and Korea.MethodsPubMed was used to measure the number of publications from China, Japan, and Korea in the past 21 years, from 1998 to 2020. The average percentage change in publications during this 21-year time period was analyzed using descriptive statistics. The average annual change in the number of publications from each country was also determined. One-way analysis of variance and two-group t-tests were utilized for statistical analyses with a p-value of <0.05 as the cut-off value for statistical significance.ResultsFrom years 1998 to 2020, there was a mean 35.5% ± 70.7% annual increase in the number of total publications from China, in comparison to a 5.1% ± 14.0% annual increase from Japan (p = 0.005) and a 27.3% ± 40.0% annual increase from Korea (p = 0.586).ConclusionFor the past two decades, there has been a strong positive trend regarding the total number of orthopaedic publications from China. This finding might be related in part to an increased integration of Western medicine and the use of digital medicine, which followed a similar trend during the time period we analyzed. Korea and Japan also exhibited a positive trend in orthopaedic publications, which may be indicative of an improving educational system and greater general support for research. Over the past 20 years, Asian countries have been integrating Western medicine practices and technologies into their clinical practice . These pWith regards to orthopaedic surgery, the growth in the number of peer-reviewed orthopaedic journals and the increased generalized importance of obtaining publications have led to the increase of articles in peer-reviewed orthopaedic journals over time . Many inIn this study, we sought to assess the contributions that Asian countries have provided to the field of orthopaedics. We analyzed the trend in total publications of six major orthopaedic journals from China and compared this to Korea and Japan. We suspect that Asia’s increased acceptance of Western medicine and developments in digital health are associated with a positive trend regarding publications in major orthopaedic journals.The PubMed advanced search builder was used to measure the number of publications in six major orthopaedic journals that came from three countries: China, Japan, and Korea, in the past 21 years, from 1998 to 2020. The six major orthopaedic journals that were selected were: Journal of Arthroplasty, The Bone and Joint Journal, British Journal of Sports Medicine, American Journal of Sports Medicine, Journal of Bone and Mineral Research, and Journal of Shoulder and Elbow Surgery. These journals were selected and analyzed based on their total number of citations and impact factors according to the SCImago Journal Rank . To measStatistical analysisThe results from each year for each country were directly downloaded from PubMed. The average percent change in publications during this 21-year time period was analyzed using descriptive statistics. The average annual change in the number of publications from each country was also ascertained. One-way analysis of variance and two-group t-tests were utilized to make comparisons between the number of publications from China, Japan, and Korea where appropriate. A p-value of <0.05 was statistically significant.During the study period from 1998 to 2020, there was a total of 1,227 publications from China in the six major orthopaedic journals. A total of 2,278 publications from Japan and 1,490 publications from Korea were seen in the six journals we analyzed  than there were in the 13 years from 1998 to 2010 (151 publications) , being one of the few countries to make contributions to visible human research alongside the US and China . In addiOn the other hand, our study showed that the annual increase in the total number of orthopaedic publications in Japan was not as large as that in China or Korea. This is not surprising as the Japanese government has also decreased the amount of funding available for research in the country . Their sThe observations from this study suggest that the new law instated by China prohibiting cash incentives for publishing articles has not affected the number of publications coming from China in 2020, as the numbers continue to rise. There may be a few reasons for these observations. There may be a lag time between publications being indexed on PubMed. Additionally, studies have shown that the increased international collaborations are correlated with publications in higher impact journals . Seeing This study has several limitations. The PubMed advanced search builder was dependent on publications reporting their country as “China,” “Japan,” or “Korea” under affiliation in the details in order to be counted as a publication from one of the countries. Therefore, the true yield of publications from these countries may be greater than what our results showed. Moreover, the predominance of the English language may be a reason why there may be a greater number of articles in these journals than our results suggest, since writing in a foreign language may be a hindrance to a country’s researchers. Additionally, this study did not provide metrics for original studies with high impact. The quantity of publications alone may not accurately reflect the true impact, especially if papers were published as follow-up studies or had relatively low citations.For the past two decades, there has been a strong positive trend regarding the total number of publications from Asian countries, specifically China, in orthopaedic journals. This finding might be related in part to an increased integration of Western medicine, increased funding for orthopaedic research, and increased international collaboration on studies. Korea also exhibited a similar positive trend in orthopaedic publications, whereas Japan only experienced a slight increase in the number of publications during the time period examined in the study.


Here, we carry out a new bioinformatics survey of known protein structures where we assay the propensity of three aromatic residues to localize around the [-CH2-S-CH3] of methionine. We term these groups “3-bridge clusters”. A dataset consisting of 33,819 proteins with less than 90% sequence identity was analyzed and such clusters were found in 4093 structures (or 12% of the non-redundant dataset). All sub-classes of enzymes were represented. A 3D coordinate analysis shows that most aromatic groups localize near the CH2 and CH3 of methionine. Quantum chemical calculations support that the 3-bridge clusters involve a network of interactions that involve the Met-S, Met-CH2, Met-CH3, and the π systems of nearby aromatic amino acid residues. Selected examples of proposed functions of 3-bridge clusters are discussed.Short-range, non-covalent interactions between amino acid residues determine protein structures and contribute to protein functions in diverse ways. The interactions of the thioether of methionine with the aromatic rings of tyrosine, tryptophan, and/or phenylalanine has long been discussed and such interactions are favorable on the order of 1–3 kcal mol Noncovalent interactions, such as hydrogen bonding, ionic interactions , and the hydrophobic effect play many roles in the three-dimensional structure of a protein ,2, interc peroxidase (CcP) [2 and Trp211. Oxidation of either Met in the apo-protein alters the ability of the protein to make Compound I [cP demonstrates some potential roles of Met–aromatic clusters in protein structure and function, which is the subject of this manuscript. Here, we provide a detailed analysis of the incidence and composition of 3-bridge clusters in structurally characterized proteins.We previously surveyed sulfur–aromatic interactions in metalloproteins  and sulfse (CcP) . In addimpound I , and mutmpound I ,14. This−1) of Met–aromatic interactions [−1 for the closed shell species [In general, the sulfur-containing amino acid residues, Met and cysteine (Cys), can stabilize protein microstructures through a noncovalent interactions that involve a Met or Cys sulfur and an aromatic ring . It is kractions  and an eractions . In addi species ,20. S–π  species ,22. The https://github.com/dsw7/MetAromatic (accessed on 20 September 2021) in a list of 33,819 protein X-ray structures with resolution better than 3 Å and sequence identity of less than 90%. Additional code and a list of structures and coordinates can be downloaded at: https://github.com/dsw7/n-Bridges (accessed on 20 September 2021). A file available as https://networkx.github.io (accessed on 18 March 2020) to find 2-bridge interactions. Herein, a similar approach was used to find 3-bridge clusters, which are defined as Met residues with the faces of three aromatic groups  oriented in any geometry about the CH2-S-CH3 of Met.We first found closely spaced Met–aromatic groups meeting the criteria specified by our previously described ,10 “Met–2-S-CH3) coordinates and three satellite points: C1, C2, and C3. The three satellite points were the centroids of the aromatic groups. All six 3-tuples were first mapped to the origin of a frame where SD assumed the origin . The system was temporarily isolated to CG-SD-CE and the direction cosine α between SD-CE and the x-axis was found. A Householder rotation of CG-SD-CE about the cross product of SD-CE and the x-axis by −α rendered the SD-CE bond axis colinear with the x-axis. The rotation was performed by a quaternion, Q1, subsequently rendering the CG coordinate free to rotate about the x-axis. Finally, the remaining CG coordinate was rendered coplanar with CE, SD, and the x,y-plane through rotation by angle −β about the x-axis and using a second quaternion, Q2. The aromatic centroids, C1, C2, and C3 were rotated into their final position using a composition of quaternions Q1 and Q2. All homogeneous transformations in this study were done with the assistance of the pyquaternion library (http://kieranwynn.github.io/pyquaternion/ (accessed on 18 March 2020)).To better understand how aromatic residues are positioned about Met, we examined the position of the various aromatic residues within the spherical region of space about the Met SD. Herein, we were interested in determining whether the aromatic residues assumed a preferential position relative to the Met CG-SD-CE scaffold. All 3-bridge clusters were assumed to consist of six 3-tuples: the CG-SD-CE . A complete list of PDB codes and interacting amino acid residues are available in a separate file as The summary of the compositions of the three aromatic residues surrounding a given Met are shown in 3-S-CH2 thioether of Met. Each dot corresponds to an aromatic centroid. Note that this figure shows the raw incidences of Phe, Tyr, and Trp, regardless of the composition of the cluster. Images for the locations of aromatics in the different bridge compositions . In somThermobispora bispora (PDB ID 5VWS) [In order to better understand the inter-residue forces that are at play in 3-bridge clusters, quantum chemical calculations were carried out using an example of a 3-bridge cluster from a cytochrome P450 found in ID 5VWS) . HydrogeID 5VWS) . HydrogeID 5VWS) ,25. ThreID 5VWS) .−1, which is comprised of −7.73 kcal mol−1 of uncorrected interaction energy and 0.24 kcal mol−1 of geometric preparation energy [−1, consistent with the interaction energy from a higher level of theory.Additional insights can be gained through Natural Bond Orbital (NBO) analysis . and enen energy . The NBOIn order to gain a more systematic view of how the interactions of aromatics affect the energetics of Met (and vice versa) in the context of the intact protein structure, the interaction energy matrix (IEM) web application  was usedThe largest values for pairwise interaction energies in the wild-type protein are observed for Met24-Trp20 and Met24-Phe41 pairs. This interaction energy also is roughly consistent with that obtained from NBO analysis (above). Consequently, replacement of either of those residues with Ala results in large changes in the net interaction energy of Met24 (shown in the first column of data). Interestingly, removal of either Trp results in a modest increase of the Met24-Phe41 pairwise interaction energy. The same is not true for removal of Phe41, in which case the pairwise interactions of Met24 with both Trp residues decrease. Replacement of all of the aromatics and Ala, or replacement of Met24 with Ala, results in a 75% decrease in the net energy of the residue at position 24. Analysis of a different bridge is shown in −1 increase in binding energy has been observed for these types of interactions, suggesting that they play roles in interprotein stabilization [−1 are possible when a cation  is surrounded by aromatics. Such a physical arrangement is similar to the Met–aromatic clusters described here. The energies of single cation–π interactions are only slightly more favorable than for single Met–aromatic interactions . Our results suggest that the 3-bridge clusters have interaction energies that are ca. 5–10 kcal mol−1 indicating that the cluster is favorable, but not as favorable as the analogous cation–π interaction. Finally, we note that cation–π interactions occur preferentially when the amino group is between 3.4 and 6.0 Å of the aromatic–π system [The 3-bridge interaction described here is a sub-class of Met–aromatic interactions that we ,10 and olization  and protlization . Howeverπ system . These daliH–π interaction  [aroH–π interactions . These interactions are thought to be stronger than their aliphatic counterparts [Similar to cation–π interactions, the CH–π interaction occurs between polarized CH and aromatic rings resulting in an attractive interaction that is dependent on amino acid conformation ,43. ConsH donor) . Overallterparts .The complete dataset for Met-aromatic 3-bridge clusters shows several proteins of the same, or similar, types. For example, iron superoxide dismutases (17 entries), DNA and RNA polymerases (38 entries), cytochromes P450 (28 entries), and chitinase (17 entries) enzymes appear in the dataset. These are intensely studied enzyme classes, so perhaps their high degree of representation is unsurprising. However, in all cases, the individual proteins show less than 90% sequence identity and can be found in different organisms. This suggests that the Met–aromatic clustering interaction is a general structural motif, rather than an isolated example in a single organism or class of proteins.c peroxidase  is the key component. Further studies of these Met–aromatic 3-bridge clusters, and other Met–aromatic interactions, will yield more insights on their properties and roles in protein structure and function.Structures where Met is surrounded by three aromatic groups are found in all types of proteins. In contrast to our previous surveys that focused solely on sulfur–aromatic groups ,10, this