This study investigates the effect of a new pore filling material, named sodium silicate-based nanosilica (SS), on resisting the diffusion of the chloride ions. The proposed SS is chosen, mainly due to its smaller particle size, compared to the conventional ethyl silicate-based nanosilica. Each particle of SS is chemically treated to have the negative (−) charge on its surface. Four types of mixes with different amounts of partial replacement with fly ash and slag are prepared. Effect of water to binder ratios  is also examined. Test results showed that the inclusion of SS was significantly beneficial for protecting the concrete from chloride attack. At a given strength, the SS inclusion in concrete was up to three times more effective than the control concrete without SS. It is believed that these excellent results are attributed to the small particle size and the chemical surface treatment of SS. In this study, experiments of compressive strength, hydration heat, accelerated neutralization, and sulfate erosion tests were also conducted to find the general effect of SS inclusion on the fundamental properties and durability of concrete. The reinforced concrete that is used in structures constructed in coastal resorts and areas, which are likely to increase in number due to increases in maritime trade and city construction on coastal landfills, is impacted by chloride-induced corrosion by chlorine ions. Corrosion damage to such structures is often visible in rust staining of the surface cracking and detachment of the concrete cover due to the corrosion and expansion of reinforcement bars , 2. Rust3A·3CaSO4·12H2O) and replace sulfate ions. The other reason is that, after concrete is cured, the chloride penetration from the outside is hard to resolve [The cause of the presence of the chloride ions in concrete takes place in two ways: one is from the pure components of concrete, such as water, aggregate, and cement, and the other is the intrusion of the chloride ions from atmosphere. In the case of structures that are exposed to marine environments, the chloride ions directly penetrate from the sea water or by sea salt particles, whereas in nonmarine environments, penetration caused by winter deicing salt is the primary path , 6. The  resolve , 9.In general, measures designed to suppress corrosion due to salt damage in reinforced concrete structures can be divided into three types. The first one is the use of a primary barrier by the coating of the concrete surface. Secondly, barriers may be used in which the chloride ions are bound by the physical method of increasing the density of the concrete itself and the insoluble chloride. Finally, the third type of barrier involves the formation of a passive film on the surface of the rebar.In this paper, the second type of barriers is adopted. In previous research work conducted by authors , a new nVarious mineral and chemical admixtures are able to improve the performance of concrete and to meet the design requirements for this type of work , 12. AmoSodium silicate-based nanosilica (SS) is introduced in previous work . This waFinal product of SS is in powder form with surface coating with membrane so that the organic oligomer was polymerized. A sol-gel process involving hydrolysis and condensation using tetraethyl orthosilicate (TEOS) is widely used to synthesize nanosilica. A number of researchers , 16 haveHowever, nanosilica cement based on ethyl silicates such as TEOS can cause many weaknesses in the application of cement composites. Firstly, the particle size of ES is about 3 times greater than that of SS Figures  and 3. TIf SS is applied to the concrete in a marine structure, it affects this concrete through the following three actions. The first action is quick pozzolanic reaction, and the second one is the pore-filling effect within the cement matrix. These actions physically create the dense concrete and prevent the intrusion of sea water and sea salt particles. The third action is to chemically prevent the diffusion of Cl (−) ions while inducing electrochemical equilibrium through the negative (−) charge formation of the nanosilica surface and the inert halogen in the same group as the internal Cl (−) ions, as shown in The inert halogen group formed on the surface is made by synthesis of the nanosilica and organic oligomers. For synthesis of the organic oligomers, denatured halogenated epoxy acrylate was synthesized through the half-esterification reaction from anhydride or halogenated anhydride. In this section, various engineering properties are reviewed in order to evaluate the performance of the marine blend cement formed using sodium silicate-based nanosilica with high resistance against chloride. Four types of binder containing the marine mixed cement were used, and, for each group, the percentage of binder to water ratio was also varied across three conditions, set to be 35, 40, and 45%. Consequently, a total of 12 batches were prepared for this investigation.The detail of the binders applied in this experiment is listed in 3; those of the furnace slag powder and the fly ash were 2940 and 2200 kg/m3, respectively. Each of these materials was stirred through premixing before the main mixing, ensuring that all the mixing materials were uniformly distributed in the final cement. The physical and chemical properties of the premixed binders are listed in Tables 3 and a maximum size of 5 mm and crushed aggregate with a density of 2620 kg/m3 and a maximum size of 25 mm were used as the aggregates.The density of OPC used in this experiment was 3150 kg/m3 and the water to binder ratio was set to be 0.35, 0.40, and 0.45 across each condition. As such, this work assesses the impact on the applicability of each concrete mix according to the quantity of the unit binder as well as the kind of binder. The mixture proportions of the concrete used in this experiment are listed in In this experiment, the unit quantity was fixed to 165 kg/mA forced mixing type mixer was used, into which the coarse and fine aggregate and the premixing binder  were inserted, after which dry mixing was conducted for 30 s. After this dry mixing, the water and superplasticizer were inserted and mixed for 60 s so as to be evenly released throughout the mixture.For the compressive strength test mold, Ø100 × 200 mm cylinders were used, and demolding took place 24 h later. Curing was then carried out until the experiments were performed, in an environment set at 20°C. 2) could diffuse only into the specimens in a two-dimensional model. The specimens were inserted into an accelerated carbonation tester so as to maintain a temperature of 20 ± 2°C, a relative moisture of 60 ± 5%, and CO2 concentration of 10 ± 0.5%. From this, we measure the depth of carbonation by using phenolphthalein solution at the ages of 7, 28, 56, and 91 days.Specimens of accelerated carbonation were produced in 100 × 100 × 400 mm cubic moulds. After 28 days, the two ends of each specimen were coated with epoxy resin to ensure that carbon dioxide  was the positive pole and 10% NaCl solution (100 g NaCl in 900 g tap water) was the negative pole .3 solution by splitting  the specimen after completion of the test. The chloride migration coefficient could then be calculated in accordance with NT build 492 [The penetration depth of the chloride was measured as the depth of discoloration of the specimen when spraying with 0.1 M AgNOuild 492  on the bThe binder type and the compression strength by age, as according to the W/B ratio, are shown in It is known that increasing the amount of OPC increases the heat of hydration. Partial replacement with mineral admixtures leads to low hydration heat as observed in Mix B, Mix C, and Mix D in Carbon dioxide and sulfate are the external harmful chemical species that deteriorate the durability of concrete .  Figure2, which in turn deteriorates the level of resistance against carbonation [In general, partial replacement with mineral admixtures such as fly ash and slag consumes the amount of Ca(OH)bonation , 21. HenSulfate attack becomes the main subject for the degradation of RC structures in marine environments involving chlorine ions . EttringIt should be noted that, in marine structures, the W/B ratio of concrete placing in practice is mostly high, in order to reduce the heat of hydration. This is because the overall volume of the concrete applying to the marine structures is large. From the results observed in This study found that the inclusion of sodium silicate-based nanosilica (SS) even under a high W/B condition  can resi2 in the cementitious composites. Less amount of the Ca(OH)2 in Mix B and Mix C decreased the amounts of gypsum and ettringite formation, which is the cause of an expansive chemical reaction. The excellent result in Mix D is arising from the combined effect of the inclusion of SS and the partial replacement with fly ash and slag.In addition, in In general, low W/B ratio increases the compressive strength of concrete. Hence, the reason for the good results in Mix C and Mix B as compared with Mix A in Most importantly, however, the parameter of the W/B cannot explain the results observed in Mix D, which has the best result in −12 m2/s to 8.35 × 10−12 m2/s and Celik et al. [−12 m2/s to 10.18 × 10−12 m2/s. These results are much higher than the results obtained from Mix D with SS inclusion, ranging between 1.11 × 10−12 and 7.89 × 10−12 m2/s , test apparatus (NT build 492) with the voltage setting of 30, Teng et al.  investigk et al.  examinedIn The compressive strength of Mix D with ordinary Portland cement (OPC) of 35%, blast furnace slag (BS) of 39.5%, fly ash (FA) of 25%, and sodium silicate-based nanosilica (SS) of 0.5% is similar to other concrete of Mix A (100% OPC), Mix B (60% OPC + 40% BS), and Mix C (40% OPC + 40% BS + 20% FA). Hence, the adverse effect of SS is not found in this test. This is probably due to that fact that the amount of SS inclusion is small.The heat of hydration testing indicates the differences in temperature based on the extent of the hydration reaction for OPC. It can be suggested that Mix C and Mix D have clear advantages for the reduction of temperature cracking because Mix A, Mix B, Mix C, and Mix D indicated 23.8°C, 18.0°C, 14.3°C, and 13.9°C, respectively, at both 35% W/B and the highest heat-generating temperature.2 of cement hydration products, and the carbonation resistance is superior in the order of Mix A, Mix B, Mix D, and Mix C at most ages.In this study, three durability measuring items are used to assess the suitability of the proposed marine concrete, namely, carbonation, sulfate attack, and chloride migration. Among these, carbonation shows a particularly significant change according to the mixed amount of OPC in the binder, that is, the amount of cement substitute used. This variable is analyzed based on the results of the consumption Ca(OH)In the sulfate attack results, which is another important tool for testing as applicable to marine environments, the item for which the resistance showed the lowest (reduced) value is the Mix A with a higher W/B ratio. However, if Mix D is applied as the binder, the sample shows superior erosion resistances of 5.1%, 11.5%, and 13.2%, at W/B ratios of 35, 40, and 45%, respectively, compared to the results for the Mix A.The resistance characteristics for chloride diffusion are superior in the order of Mix D, Mix C, Mix B, and Mix A. This performance difference is shown proportionally, and it is clear that Mix D shows the strongest diffusion coefficient across all W/B ratios.In order to increase resistance to the external chloride penetration of concrete structures in saline environments, a new sodium silicate-based nanosilica is used as partial replacement of cement. The following conclusion can be drawn from the experiments tested in this study.


The rapid emergence and dissemination of antimicrobial-resistant microorganisms in ICUs worldwide constitute a problem of crisis dimensions. The root causes of this problem are multifactorial, but the core issues are clear. The emergence of antibiotic resistance is highly correlated with selective pressure resulting from inappropriate use of these drugs. Appropriate antibiotic stewardship in ICUs includes not only rapid identification and optimal treatment of bacterial infections in these critically ill patients, based on pharmacokinetic-pharmacodynamic characteristics, but also improving our ability to avoid administering unnecessary broad-spectrum antibiotics, shortening the duration of their administration, and reducing the numbers of patients receiving undue antibiotic therapy. Either we will be able to implement such a policy or we and our patients will face an uncontrollable surge of very difficult-to-treat pathogens. Optimal antibiotic use is crucial in the critical care setting, especially in an era of rising antibiotic resistance and lack of new antimicrobial development -3. StudyUnfortunately, improving in-ICU antibiotic use is particularly difficult for three main reasons: infection severity often precludes withdrawing or postponing antibiotics, the complex decision-making process frequently involves doctors with limited expertise, and it is difficult to ensure disease-long continuity of care by the same medical team 24 hours a day, 7 days a week. Here, we review how in-ICU antibiotic therapy could possibly be optimized and rationalized.Most published observational data suggest that the time to appropriate antibiotic administration is a major outcome determinant for ICU patients with severe bacterial infections. Indeed, each hour of delay in administering effective antibiotics for septic shock is associated with measurably increased mortality ,21-25. THowever, owing to methodological concerns, the harmful effects of inadequate therapy are not accepted by all -36. BecaThe inaccuracy of conventional approaches to diagnose hospital-acquired infections (HAIs) and the impossibility of those strategies to avoid antibiotic overprescription led some investigators to hypothesize that using biological markers - for example, C-reactive protein, soluble-triggering receptor expressed on myeloid cells-1, or procalcitonin (PCT) - might better identify true bacterial infections and facilitate therapeutic decisions. However, although PCT is a good marker of community-acquired infections (CAIs), it does not seem to be for HAIs -41. IndePseudomonas aeruginosa, extended-spectrum β-lactamase-producing Enterobacteriaceae, and carbapenemase-producing Klebsiella pneumoniae) and the increasing role of Gram-positive bacteria , empirical broad-spectrum antibiotics are justified for most ICU patients with clinically suspected HAIs . Fre. FrefT >a priori dosing algorithms based on MIC, creatinine clearance and weight, and the clinician-specified AUC target might improve management of these patients, obtaining more precise antibiotic use than current guidelines [Development of idelines ,83,84,86idelines ,88.P. aeruginosa-infected patients [A double-blind randomized trial comparing 7 days of doripenem three times a day (4-hour infusion of 1 gram) with 10 days of imipenem-cilastin (1-hour infusion of 1 gram) for GNB VAP was prematurely stopped after random assignment of 274 patients because of inferior efficacy and higher day-28 all-cause mortality in the subgroup of doripenem-treated, patients . Despitepatients .For patients on MV, aerosolized antibiotics delivered via an efficient system, synchronized with inspiration, achieved airway drug concentrations 100- to 300-fold higher than the MICs of most bacteria, including multidrug-resistant pathogens -95. Thos3) or leukopenia , or purulent tracheobronchial secretions - or an alternative non-infectious diagnosis is confirmed; (b) non-significant tracheobronchial aspirate culture results; and (c) no severe sepsis or shock [The need to ensure that ICU patients with true bacterial infections receive prompt and appropriate antibiotics can lead to many more patients receiving antimicrobials than necessary, because of non-specific clinical signs of infection. This is particularly true for HAP/VAP, which represents the first in-ICU indication for starting antibiotics. Thus, regardless of the diagnostic strategy used for suspected HAP/VAP, serial clinical and microbiological evaluations are highly relevant to re-assess therapy after 48 to 72 hours and to stop it if infection is unlikely . To accoor shock . Direct or shock . Pertineor shock .P. aeruginosa, Acinetobacter spp., or MRSA) is recovered or because the isolated pathogen is sensitive to a narrower-spectrum antibiotic than that prescribed empirically [Candida isolated from respiratory secretions alone [Enterobacteriacaea with inducible β-lacatamase , the emergence of resistant variants may lead to treatment failure. Unfortunately, study results showed that de-escalation, though not associated with any adverse outcomes, was not consistently applied in many ICUs [For many ICU patients with infections (including late-onset infections), therapy can be de-escalated, once respiratory tract, blood, or other specimen culture results become available, if no resistant organism , and this lower antibiotic consumption was not associated with poorer outcomes. Furthermore, regardless of infection site and the infectious agent, results were consistent  determinations (or both). The rationale for using the latter to customize treatment duration relies on evidence that the inflammatory response is often proportional to infection severity. When the response is absent or mild, antibiotics might logically be discontinued earlier. Thus, adapting treatment duration to PCT kinetics seems reasonable and was demonstrated to be useful in several randomized trials, including seven in the ICU, targeting patients with acute respiratory infections ,139-143.In summary, shortening the treatment duration for ICU patients with infections is possible and not detrimental for most of them. Indeed, the diversity of patients enrolled in those trials and the consistency of the findings suggest that the conclusions may be applicable to most critically ill patients who develop infections, including severe sepsis or septic shock, with the possible exception of those who are immunosuppressed, those who are infected with multiresistant microorganisms or whose course deteriorates despite treatment, or those whose initial regimen was inappropriate for the responsible pathogens. That strategy should help contain health-care costs and limit in-ICU emergence of bacterial resistance.Optimizing in-ICU antimicrobial therapy is difficult. No single measure alone can succeed, emphasizing the need to devise a structured antibiotic stewardship program. Unfortunately, the exact set of key interventions essential to this multifaceted and multidisciplinary ‘care bundle’ remains unknown, as do the factors contributing to its success ,144-146.Computerized decision-support programs linked to electronic patient records can facilitate the dissemination of information to physicians for immediate use in therapeutic decision making and improving quality of care -154. ParThe high antibiotic resistance observed in ICU patients who develop infections limits treatment options and justifies using regimens combining several broad-spectrum antibiotics, even when the presumed infection probability is low, because initial inappropriate therapy has been linked to poor prognoses. More than its economic impact, this ‘spiraling empirical’ practice increasingly leads to undue antibiotic administration to many ICU patients without true infections, paradoxically causing the emergence of more antibiotic-resistant microorganisms causing infections that, in turn, are associated with heightened mortality and morbidity. Therefore, antibiotic therapy for ICU patients with infections should be viewed as a two-stage process: the first involves administering broad-spectrum antibiotics to avoid inappropriate treatment of true bacterial infections, and the second focuses on trying to achieve the first without antibiotic overuse or abuse. In general, the first goal can be accomplished by rapidly identifying patients with infection and starting empirical therapy likely to treat the institution’s most common etiological agents. This strategy requires that initial antibiotic choices be guided by local antibiotic resistance patterns and laboratory test results (including Gram staining), rapidly yielding identities of likely responsible pathogens. The second aim involves stopping therapy when the probability of infection is low, focusing and narrowing treatment once the microorganism is known, switching to monotherapy after day 3 whenever possible, and shortening treatment to 7 to 8 days for most patients, based on the clinical response and bacteriology findings. Therefore, every effort should be made to obtain reliable specimens from the specific suspected infection site in each patient for direct microscope examination and cultures in order to de-escalate antibiotics.The rapid in-ICU emergence and dissemination of multidrug-resistant microorganisms worldwide constitute a problem of crisis dimensions that is linked directly to inappropriate antimicrobial use.Appropriate antibiotic stewardship is a two-stage process.Stage I includes rapidly identifying patients with infection, starting an empirical regimen likely to treat the institution’s most common etiological agents, and optimizing bacterial killing by adjusting antibiotic doses and administration modalities based on PK-PD characteristics.Stage II involves stopping therapy in patients unlikely to have infections, focusing and narrowing treatment once the responsible pathogen is known, switching to monotherapy after day 3 whenever possible, and shortening antibiotic administration to 7 to 8 days for most patients, based on the therapeutic response and microbiology data.Any antibiotic stewardship program should be implemented in a structured manner and requires an interdisciplinary team, educational interventions, system innovations, process indicator evaluation, and feedback to health-care workers.Antibiotic resistance in the ICU, edited by Steven Opal. Other articles in this series can be found at http://ccforum.com/series/antibioticresistance.This article is part of a series on


Beta-lactam antibiotics form the backbone of treatment for Gram-negative pneumonia in mechanically ventilated patients in the intensive care unit. However, this beta-lactam antibiotic backbone is increasingly under pressure from emerging resistance across all geographical regions, and health-care professionals in many countries are rapidly running out of effective treatment options. Even in regions that currently have only low levels of resistance, the effects of globalization are likely to increase local pressures on the beta-lactam antibiotic backbone in the near future. Therefore, clinicians are increasingly faced with a difficult balancing act: the need to prescribe adequate and appropriate antibiotic therapy while reducing the emergence of resistance and the overuse of antibiotics. In this review, we explore the burden of Gram-negative pneumonia in the critical care setting and the pressure that antibiotic resistance places on current empiric therapy regimens (and the beta-lactam antibiotic backbone) in this patient population. New treatment approaches, such as systemic and inhaled antibiotic alternatives, are on the horizon and are likely to help tackle the rising levels of beta-lactam antibiotic resistance. In the meantime, it is imperative that the beta-lactam antibiotic backbone of currently available antibiotics be supported through stringent antibiotic stewardship programs. Antibiotics for the treatment of serious bacterial infections have immeasurable benefits for the critically ill patient and have greatly reduced morbidity and mortality since their widespread adoption in the 1950s. However, global overuse of these drugs has led to the development of resistance and decreased effectiveness, making it increasingly difficult to choose appropriate antibiotic therapy options for life-threatening infections, such as pneumonia, in the intensive care unit (ICU).The term ‘antibiotic backbone’ was coined to describe those drugs that form the foundation of antimicrobial therapy; these backbone antibiotics treat most bacterial infections effectively, and appropriate empirical use reduces both mortality and the emergence of resistance –3. The cHospital-acquired pneumonia (HAP) is one of the most common infections in the ICU , 11; pubIn addition to recognizing HAP and VAP, current guidelines recognize health care-associated pneumonia (HCAP); this classification includes patients with pneumonia who were recently hospitalized in an acute care hospital, resided in a nursing home or long-term care facility, or received recent intravenous (IV) antibiotic therapy . Many ofMortality rates for HAP/VAP are influenced by many factors, such as patient age, presence of underlying comorbidities, adequacy of antibiotic treatment given, and, for those with VAP, time on mechanical ventilation . MortaliStaphylococcus aureus, whereas the most common Gram-negative pathogen was Pseudomonas aeruginosa. Other common Gram-negative pathogens included Klebsiella spp., Enterobacter spp., Acinetobacter spp., and Escherichia coli [The distribution of pathogens that comprise the etiology of pneumonia  varies from region to region , 23. TheTo treat pneumonia in the ICU, current guideline recommendations focus on the initiation of effective and timely empiric antibiotic therapy combined with resuscitation and supportive measures. Beta-lactam antibiotics alone or as part of a combination regimen are the mainstay of empirical antibiotic guideline recommendations –6. DespiP. aeruginosa to most antimicrobials tested, including ceftazidime (79.6/68.7 % susceptibility in USA/Europe), meropenem (76.3/65.8 %), and piperacillin/tazobactam (72.9/63.9 %). Furthermore, Klebsiella spp. showed extended-spectrum beta-lactamase (ESBL) phenotype prevalences of 19.5 % and 35.1 % in the USA and Europe, respectively; meropenem was active against 62.3 % and 78.7 % of ESBL Klebsiella spp. [K. pneumoniae [Rates and patterns of antibiotic resistance differ between countries, regions, and hospitals , 23, 31,lla spp. ; the repeumoniae . In addieumoniae . Given teumoniae –6.Table P. aeruginosa nosocomial pneumonia, infection with MDR strains was associated with significantly higher in-hospital mortality compared with infection with non-MDR strains  [A broken beta-lactam antibiotic backbone means that bacterial infections cannot be reliably treated empirically with a particular antibiotic regimen. The emergence of resistance to beta-lactam antibiotics has exerted significant pressure on the antibiotic backbone, resulting in increased morbidity, mortality, and health-care costs , 33, 34.< 0.001) . However< 0.001) , 42.How can the pressure on the beta-lactam antibiotic backbone be relieved? Current protective strategies include antimicrobial stewardship, the optimization of beta-lactam pharmacokinetic/pharmacodynamic (PK/PD) exposure, and the use of combination therapy with other drug classes .Ideally, antibiotic stewardship in ICUs should include the rapid identification of bacterial etiology, optimization of treatment based on PK/PD characteristics of the antibiotic(s), avoidance of unnecessarily broad-spectrum antibiotics, shortening of treatment duration, and reduction in the number of patients receiving antibiotic therapy for non-infectious syndromes , 44. To Guidelines advise that de-escalation of antibiotics be considered once information is available on the results of lower respiratory tract cultures and the patient’s clinical response . A meta-De-escalation of therapy may be guided by scores such as the clinical pulmonary infection score (CPIS) . In a raBiomarkers offer an alternative method to shorten duration of therapy. Several large randomized trials in critically ill patients of antibiotic duration based on falling procalcitonin levels have demonstrated that this approach can safely shorten duration without adverse consequences . HAP/VAPP < 0.03) [fT > MIC was significantly associated with a favorable microbiological response (eradication or presumed eradication of pathogen) to anti-pseudomonal cephalosporins [fT > MIC of greater than 62 % of the dosing interval) strongly correlated with microbiological eradication and clinical cure in patients with nosocomial pneumonia [The beta-lactam antibiotic backbone may be further supported by optimizing beta-lactam antibiotic PK/PD exposure, which could include considerations of the length of infusion and the use of appropriate loading doses. The pharmacokinetics of systemic antibiotics in critically ill patients are highly variable because of patients’ physiological changes affecting drug absorption, distribution, metabolism, and elimination . These c < 0.03) . In lineosporins . Similarneumonia . These aneumonia ) emphasineumonia –61.P = 0.037) [One way to optimize beta-lactam antibiotic dosing may be the use of prolonged or continuous infusion, which could benefit critically ill patients with severe illness –64. Cont= 0.037) ; however= 0.037) . Indeed,= 0.037) , 64; one= 0.037) . Clearly= 0.037) –64.Another potential strategy to help overcome the antibiotic dosing challenges in patients in the ICU may be therapeutic drug monitoring (TDM). However, a recent systematic review found that only a small number of the included studies reported that TDM may improve beta-lactam dosing in critically ill patients . The sysEnterobacteriaceae (CRE)-causing respiratory infections found that combination therapy was associated with significantly lower clinical failure rates  [Evidence suggests that the pressure on beta-lactams could be relieved by support from other antibiotic classes . A systematic review comparing outcomes of combination therapy and monotherapy for carbapenem-resistant  = 0.03) .Pseudomonas species, Acinetobacter species, or MDR Gram-negative bacilli (n = 56), combination therapy demonstrated better microbiological outcomes and was associated with shorter durations of mechanical ventilation and ICU stay, although it should be noted that the study was not powered to demonstrate statistical significance for this comparison [In contrast, in a study that included 740 mechanically ventilated patients with suspected VAP, monotherapy was associated with outcomes similar to those of combination therapy . Unfortumparison . Finallymparison . The revmparison .P < 0.003) compared with using no monitoring [Biomarkers are under investigation as a tool to reduce unnecessary antibiotic prescribing and further facilitate antimicrobial stewardship –75. In onitoring ; procalcnitoring . These fnitoring .New tools for the rapid detection of antibiotic resistance may soon aid physicians in predicting the effectiveness of empiric antibiotic therapy and enable them to quickly readjust the treatment regimen . BalanciAnother approach for optimizing antibiotic concentrations involves the delivery of high drug concentrations to the lung via aerosolization , 80. TheP < 0.0001) [P. aeruginosa, outcomes for aerosolized amikacin + ceftazidime were not significantly improved compared with IV administration of amikacin + ceftazidime  [Aerosolized antibiotic therapy is already administered widely in European ICUs during mechanical ventilation , despite 0.0001) . Further 0.0001) . A recen 0.0001) . However = 0.33) .Ongoing, prospective, randomized clinical studies with aerosolized antibiotics appear to be promising. Several options are in development: a combination amikacin–fosfomycin solution delivered via a PARI eFlow inline system, which is currently in phase 2 ; a trial with nebulized tobramycin , which will explore the use of nebulized tobramycin in combination with IV meropenem and an aminoglycoside (either amikacin or tobramycin); and Amikacin Inhale, an integrated drug–device combination for the delivery of specially formulated Amikacin Inhalation Solution through a Pulmonary Drug Delivery System, which is currently being investigated in two phase III studies  in combination with standard of care (SOC) treatment to demonstrate clinical superiority versus SOC IV antibiotics (plus aerosol placebo) in Gram-negative pneumonia in intubated and mechanically ventilated patients in the ICU.A phase 1 trial (n = 9) of combination amikacin–fosfomycin solution delivered via a PARI eFlow inline system reported that both drugs achieved high tracheal aspirate concentrations . FurtherIn the completed phase 2 studies of Amikacin Inhale , 92, micFor physicians treating pneumonia in critically ill patients, the use of the beta-lactam antibiotic backbone is increasingly fraught with uncertainty. Although beta-lactam antibiotics have played an important role in the treatment of pneumonia in the ICU, resistance rates are high; in part, this has been exacerbated by widespread inappropriate prescribing of extended-spectrum beta-lactam antibiotics. The current state of resistance across many antibiotic classes is highly concerning, and the increasing difficulty of treating infections has been described as a ‘major blooming public health crisis’ .The diligent application of antimicrobial stewardship principles, together with optimized PK/PD dosing strategies, can help preserve efficacy of the beta-lactam antibiotics—at least for the time being. However, to relieve the pressure on the beta-lactam antibiotic backbone in the long term, new approaches are urgently needed; these are likely to include the increased use of biomarkers, rapid diagnostic techniques, and new treatment approaches such as inhaled antibiotics.


Various psychosocial studies on health related lifestyles lay emphasis on the fact that the perception one has of himself as being at risk of HIV/AIDS infection was a necessary condition for preventive behaviors to be adopted. Hierarchical Multiple Regression models was used to examine the relationship between eight independent variables and one dependent variable to isolate predictors which have significant influence on behavior and sexual practices.A Cross-sectional design was used for the study. Structured close-ended interviewer-administered questionnaire was used to collect primary data. Multistage stratified technique was used to sample views from 380 students from Takoradi Polytechnic, Ghana. A Hierarchical multiple regression model was used to ascertain the significance of certain predictors of sexual behavior and practices.β=14.202, t=2.279, p=0.023, variable is significant; for the marital status; β=0.092, t=1.996, p<0.05, variable is significant; for the knowledge on AIDs; β= 0.090, t=1.996, p<0.05, variable is significant; for the attitude towards HIV/AIDs; β=0.486, t=10.575, p<0.001, variable is highly significant. Thus, the best fitting model for predicting behavior and sexual practices was a linear combination of the constant, one’s marital status, knowledge on HIV/AIDs and Attitude towards HIV/AIDs.,The variables that were extracted from the multiple regression were; for the constant; Y  = β0 + β1  + β2 (Knowledge on HIV AIDs issues) + β3 (Attitude towards HIV AIDs issues)β0, β1, β2 and β3 are respectively 14.201, 2.038, 0.148 and 0.486; the higher the better.Attitude and behavior change education on HIV/AIDs should be intensified in the institution so that students could adopt better lifestyles. Human Immunodeficiency Virus (HIV) is the virus that causes Acquired Immune Deficiency Syndrome (AIDS). AIDS has become one of the most serious health problems in the world. Since the past three decades when the virus was first identified, the body of research into the disease has been steadily growing. Today, research on the topic covers a wide range of areas ranging from medical, demographical, economical, sociological and psychological issues. These areas cover preventive, curative, and best practices that may help to halt the spread of the disease.A greater percentage of all new HIV infections take place in Africa . There iHIV is transmitted through direct contact with a mucous membrane or the bloodstream with a bodily fluid containing the HIV, such as blood, semen, vaginal fluid, pre-seminal fluid and breast milk .This transmission can involve anal, vaginal, oral sex, blood transmission, contaminated hypodermic needles, and vertical transmission during pregnancy, childbirth, breastfeeding or other exposure to one of the above bodily fluids. According to The average time from infection to development of AIDS is about nine years. Thus, on the average, people do not develop AIDS until nine years after becoming infected . For most part of this incubation period, they may not have any symptoms and therefore, may not even be aware that they are infected. This contributes to the spread of HIV since they can transmit the infection to others without knowing.Unprotected sexual acts are riskier for the receptive partner than the insertive partner, and the risk of transmitting HIV through unprotected anal intercourse is greater than the risk from vaginal intercourse or oral sex. However, oral sex is not entirely safe, as HIV can be transmitted through both insertive and receptive oral sex. Sexual assault greatly increases the risk of HIV transmission as condoms are rarely employed and physical trauma to the vagina occurs frequently, facilitating the transmission of HIV .It has been established that the knowledge level of students on HIV/AIDs was fair and correlates positively with their sexual behaviors . SimilarClose to 60 children are raped every day in South Africa, some schools of thought are of the view that this practice culminate from the belief in the “Virgin Cure” .This belief system, though absurd, is gaining alarming proportion in Sub-Saharan Africa. The African Traditional Religion (ATR) also holds the view that if the traditional sex laws were respected and preserved, if husbands kept to their wife or wives, if the youth avoided premarital sex, HIV/AIDS would not have come to Sub-Saharan Africa. They also hold the belief that Africans have abandoned their gods and broken the sanctity of the body, therefore the HIV disease was a punishment from the gods for sexual immorality. Finally, there is the belief that whatever has a beginning has an end, and therefore the menace of HIV will come to an end .Literature on health related behavior emphasize that the perception one has about being at risk of HIV/AIDS infection is a necessary condition for preventive behaviors to be put in place, what this means is that, low risk perception of the menace lead to unprotected sexual practices. Abera (1999) points out that interventions in curbing the spread of HIV/AIDS can be achieved when individuals acquire knowledge to create the desired attitude leading to behavior modification.The 2005 Demographic Health Survey demonstrates that among those who had sexual intercourse, 1% of women and 4% of men had two or more sexual partners. 3% of women and 9% of men were involved in higher risk sexual intercourse. Also, among the sexually active youth, who engaged in high-risk sexual activity, only 25% of women and just under 50% of men used condoms in their last higher risk sexual encounter. Quite a great and impressive work have been done on HIV/AIDs and related issues, these works range from tracing the history and origin of the disease, to establishments of connections between sets of the variables; knowledge, beliefs, attitude, behaviors and practices, further studies have been done on monitoring, preventive measures, and care and cure of people living with HIV/AIDs. Others have assessed the prevalence rates of the disease within regions in the world and communities. Indeed, one can say without any shadow of doubt that the disease has become a global decimator of humankind and thus requires such urgency from researchers.It is an established fact that knowledge about HIV/AIDs does correlate positively with sexual practices though some authors argue differently. Belief systems also have some degree of association with sexual practices, these belief systems must not be left uninvestigated.Observational studies made at Takoradi Polytechnic on the indicators of the students’ knowledge level on HIV/AIDS vis-à-vis their latent practices are highly suspicious making them vulnerable and open to more risky behaviors. Though the youth is the greatest hope for turning the tide, they highly remain the center of the HIV/AIDS epidemic in terms of rate of infection, impact and potential for change. They have grown up in a world tainted by HIV/AIDS. Their attitude towards the disease and their practical approach to curbing the spread of the disease also leave much to be desired. It is for this perceived ignorance, their lackadaisical attitude and risky practices that necessitated this study. The objectives of the study were;To identify the predictors of behavior and sexual practicesTo model the relationship between independent variables and sexual behavior and practices of students towards HIV/AIDS.In carrying out the objectives set out in this study, certain hypotheses were formulated and tested. The following were four of the hypotheses;Hypothesis one: Students sexual practice  is independent on their level of knowledge about HIV/AIDS.Hypothesis two: Students behavior and sexual practices is independent on genderHypothesis three: There is no relationship between marital status of person and sexual practices.Hypothesis four: There is no relationship between student’s belief system and sexual practices.The importance of this study cannot be overemphasized; firstly, it unearths the knowledge base of the students about HIV/AIDS; secondly, it isolates the predictors of behavior and sexual practices. Finally, it provides stakeholders of Polytechnic Education enough grounds upon which preventive and healthy lifestyles would be inculcated into the students.The study population consisted of all students of Takoradi Polytechnic. The student population as at November 2012 was 8779. More than half of the student population was female. The city in which the Polytechnic is situated is rich in Gold, Oil, Gas, Timber, and Rubber. The city prides itself with a Port and harbor and an airport. Various activities and businesses are booming in the city.nd, 2012 and November 29th, 2012. The methodological considerations were well planned and executed, the relationships between variables were studied carefully, correlation and causation relationships were carefully distinguished.Cross- sectional design was used to conduct the study. Data on Takoradi Polytechnic student’s knowledge, attitude and practices towards HIV/AIDS was thoroughly investigated. Data was collected between November 22The main data collection instrument used was a closed-ended questionnaire. The questionnaire was in five sections;Section A dealt with the demographic characteristics of the students.Section B covered the level of knowledge of students about HIV/AIDS issues.Section C covered the belief systems of students towards HIV/AIDS.Section D covered the attitudes of students towards HIV/AIDS. Section E looked at the behavior and sexual practices students have adopted regarding HIV/AIDS.A pilot study was conducted to assess the reliability of the instrument. In order to obtain a sample size which was representative of the population at a confidence level of 95 percent and a margin of error of 5 percent, the formula below was used;n= the sample size;Where N= total student population;e=margin of error of 5%.Again, to maintain the relative proportion of the students by school (faculty), the total student population was stratified according to the four schools using the formula,n_h is the sample drawn from “school h”, h is the stratum number; n is the total sample drawn from all the strata (schools); N_h is the total population for stratum “h” and N is the total population.Where The sample sizes collected from School of Business and Management Studies (SOBAMS), School of Applied Science (SAS), School of Applied Arts (SAS) and School of Engineering (SOE) were 223, 23, 71 and 66 respectively.The number of students from each school was further stratified according to programs offered in the school, in other words, the researcher adopted the multistage sampling technique. In the school of business for instance, students from Accountancy, Purchasing, Marketing, Secretaryship and Tourism departments were included. Due to the sensitivity of the questions, some students felt reluctant to complete the questionnaire, and as such the quota sampling technique was adopted at a point in time. In this case, sampling units were selected according to their readiness to complete the questionnaire. The main objective for using this method aside the challenges was to select a sample that will represent the major characteristics of the students from each of the programs within the school.Permission was sought from each of the would-be-respondents; those who accepted the terms and conditions were asked to complete the questionnaire; those who thought otherwise were allowed to leave without completing the questionnaire. Each student was encouraged to be truthful as far as the responses to the questions were concerned. No student was asked to write down his or her name.Responses for each of the four variables; Knowledge, Attitude, Beliefs and Practice were then summed up. The score ranged from 14 to 70 for all the four variables, a score of 70 on the knowledge scale indicated that the knowledge level on HIV/AIDS issues was high, a score of 14 meant the level of knowledge was very poor. On the attitude scale, a score of 70 represented a positive attitude towards the HIV/AIDS menace while a score of 14 showed a negative attitude towards the disease. On the belief system scale, a score of 70 represented a strong belief system towards HIV/AIDS while a score of 14 meant a lesser belief system towards the disease. Finally on the behavior and practices scale, 14 represented a risky practice while a score of 70 represented a risk free practice. These scores were keyed into the Statistical Package of Social Science (SPSS) version 17 and analyzed using the Hierarchical Multiple Regression Analysis.The model for the study is given as;β values are called regression weights and are computed in a way that minimizes the sum of squared deviations;The β0) term  term .A group of variables were controlled. Firstly, multiple regression analysis was performed with the controlled variables serving as independent variables. A second multiple regression was done with a new set of independent variables together with the first step independent variables. This allowed estimates of the contributions of the independent variables to be computed. The process was continued until all the independent variables had been entered into the regression model.From It was also noted that out of the respondents, 52.1% were males, while 47.9% were females. In addition, 86.2% of the respondents were single, 11.7% were attached, and 2.1% were married. 19.7% of the students were from School of Applied Arts, 58.4% from the School of Business, 15.8% from the School of Engineering and 6.1% from the School of Applied Science. Finally, 2.9% were employed, 5.8% were self-employed, while 91.3% were unemployed.To ascertain whether the Hierarchical Multiple Regression model could be used for the study and to ensure the validity of the data, some first line test were conducted. Firstly, the sample size of 380 was deemed adequate given the number of independent variables (8) subjected to the test. The ratio for this analysis was 380 valid cases to 8 independent variables.This boiled down to 48 to 1, which satisfies the minimum requirement of 15 to 1 . The assThis implies that there was no multi-collinearlity . A six s2 (0.028 or 2.8%) was significant at F  = 5.463, p < 0.05, since it could account for 2.8% of the variance. Model 2, with four predictor variables , was an improvement over the earlier model, with an R of 0.180 and an R2 change of 0.033, thus 3.3% of the variance had been accounted for. The change in R2 was not significant F , p > 0.05; this shows that the second set of predictors (religious affiliation and employment status) could not predict behaviour and sexual practices. Model 3, with five predictor variables , gave a better value for R= 0.208, with an R2 of 0.043, thus 4.3% of variance was accounted for. The change in R2 was significant F  = 4.119, p < 0.05, thus marital status was a predictor of behavior and sexual practices. Model 4, with six predictor variables , was quite better, with an R of 0.307 and an R2 of 0.094, thus 9.4% of the variance had been accounted for, the change in R2 was highly significant F  = 21.007, p < 0.001, consequently knowledge on HIV/AIDs issues had been isolated as a predictor of sexual behaviors. Model 5, with seven predictor variables , escalated the R value from 0.307 to 0.561, with an R2 value of 0.315, thus 31.7 % of the variance had been accounted for. The R2 change was also highly significant F  = 119.886, p < 0.001. This results clearly showed that attitude towards HIV/AIDs contributed significantly towards behavior and sexual practices. The sixth and final model comprised of eight predictor variables , gave an R value of 0.563 and an R2 of 0.317, again 31.7% of the variance had been accounted for. The R2 change was not significant F  =1.146, p>0.05. Thus one’s belief systems on HIV/AIDs issues do not have any significant effect on behavior and sexual practices.The RF value was largest for the model with seven predictors. The F values were the overall predictive effects which were different from the F for the amount of change experienced when adding an additional variable.The ANOVA result  gave us β coefficients for the constant and eight predictors of behavior and sexual practices were as follows; Constant β =14.202, t =2.279, p=0.023: significant; Gender, β = 0.072, t=1.623, p=0.166: not significant; Age, β =0.068, t=1.581, p=0.115: not significant; Religious affiliation, β =-0.031, t=-0.075, p=0.481: not significant; Employment status, β =-0.027, t =-0.595, p=0.511: not significant; Marital status, β =0.092, t=1.996, p<0.05: significant; Knowledge on AIDs, β =0.090, t=1.996, p<0.05: significant; Attitude towards HIV/AIDs, β =0.486, t=10.575, p<0.001: highly significant; Beliefs about HIV/AIDS, β =0.075, t=1.071, p=0.285: not significant.From The best fitting model for predicting behavior and sexual practices from the analysis above would be the linear combination of the constant, marital status of the person, knowledge on HIV/AIDs and Attitude towards HIV/AIDs.The ModelY  = β0 + β1  + β2 (Knowledge on HIV AIDs issues) + β3 (Attitude towards HIV AIDs issues)β0, β1, β2 and β3 are respectively 14.201, 2.038, 0.148 and 0.486.Where, Several studies have linked the relationship between knowledge and attitude as predictors of sexual practices  and a dependent variable  to isolate the predictors which have significant influence on behavior and sexual practices. We were also to model the relationship among the variables; knowledge, beliefs, attitude, and sexual practices of students towards HIV/AIDS.A Cross-sectional design was used for the study. A structured close-ended interviewer-administered questionnaire was used to collect primary data. Multistage stratified technique was used to sample views from 380 students from Takoradi Polytechnic, Ghana. Six stage Hierarchical multiple regression models were used to ascertain the significance of certain predictors on sexual behaviors and practices. At the sixth and final stage, it was gathered that the best fitting model for predicting behavior and sexual practices was a linear combination of the constant factor, marital status of the person, knowledge on HIV/AIDs and Attitude towards HIV/AIDs.On account of the above revelation, all the stakeholders of health education are being called upon to help minimize the menace of the HIV/AIDS disease. We note in particular that knowledge about HIV/AIDs issues and attitude of students towards the disease were the significant predictors of practices and sexual behaviors, on that note, we call on the following;HIV/AIDs risk behaviors among students include, unprotected sex, commercial sex work, injection of drugs, homosexuality and lesbianism. All students are therefore called upon to be wary of the seeming benefits that they hope to derive from the aforementioned activities; they are to note in particular that these activities have the potential of driving them to their early grave. There should also be peer education and role plays by PLWHA. Quizzes and debates on HIV/AIDs issues must also be intensified in the institution to help step down their negative attitudes.The provision of HIV/AIDs information should be done with the seriousness and tenacity it deserves to all health seekers. The providers must also organize AIDs fora with the view of disseminating information.They must be educated to know how to prevent the transmission of the disease from an infected person to an uninfected person.


Since the first description in 2002 by Paley and Herzenberg, antibiotic bone cement nails (ACNs) have become an effective tool in the orthopaedic trauma surgeons' hands. They simultaneously elute high amounts of antibiotics into medullary canal dead space and provide limited stability to the debrided long bone. In this paper, we perform a systematic review of current evidence on ACNs in orthopaedic trauma and provide an up-to-date review of the indications, operative technique, failure mechanisms, complications, outcomes, and outlooks for the ACNs use in long bone infection. Musculoskeletal infections remain a challenge for orthopaedic surgeons and infectious disease specialists. Bone provides a unique milieu for bacteria, with low vascularity and turnover rate. Most of the orthopaedic trauma infections are caused by biofilm-forming bacteria . BiofilmAntibiotic loaded bone cement can be customized intraoperatively to different shapes and forms. In intramedullary infections, antibiotic bone cement nails or antibiotic cement nails (ACNs) are preferable. The primary objective of this paper is to perform a systematic review of current evidence on ACNs in orthopaedic trauma. The secondary objective was to provide an up-to-date review of the indications, operative technique, failure mechanisms, complications, outcomes, and outlooks for the ACNs use in musculoskeletal infection.To identify relevant papers, we searched Medline database via PubMed interface with no restriction on language or publication date. The search string included word “intramedullary” and one of the following words, “osteomyelitis,” “infection,” “nail,” “nailing,” “debridement,” and “reaming” and was performed on January 1, 2015. We searched all fields in the Medline database, with no restriction applied to full-text availability. Additionally, we manually reviewed the reference lists of the articles retrieved by database search for potentially missing papers. in vitro and in vivo studies, although we did not use the “restrict to human studies” filter in PubMed.The clinical studies selected were original articles on antibiotic cement nails. We excluded all the studies on bone cement use in arthroplasty and spine surgery as well asDetails such as the number of patients, anatomical site, the age of the patients, the preparation and composition of nail, length of follow-up, and final outcome were collected.Literature review of antibiotic cement nails cases is given in The indication for the use of ACN is medullary infection, whatever the cause and presentation. Intramedullary infection is a well-recognized complication of intramedullary nailing for trauma . It spreAll these diagnoses share a common trait; there is usually no sequestrum and dead bone is limited to within the medullary canal . HoweverThere is one paper stating that, in bone deficits exceeding 6 cm, other alternatives for restoring stability and infection control should be used . There iIn a 2013 Cochrane review, the authors could not show any significant difference in osteomyelitis recurrence rates after parenteral or oral antibiotic administration . AlthougMultiple techniques for the fabrication of the nails have been described, from manual rolling of the cement , throughK-wire, Ender nail, etc.) is selected and cut a little bit longer than the tube and its end is bent to facilitate later extraction from the medullary canal. It can also be bent to adapt to the dead space, for example, with the Herzog angle in case of replacing a tibia nail. Later, antibiotic powder is mixed with poly(methyl methacrylate) powder. The next step is to add liquid monomer, usually more than would be used for the single batch of cement, to compensate for large volume of antibiotics. Next, the cement is poured into the cement gun and injected into the tube. The precut wire is inserted into the middle of the cement in the tube. At some point, either when the cement begins to harden and heats up or after the exothermic reaction, the tube is cut with surgical knife and peeled from the cement. Then the surgeon waits for the nail to cool and for the monomer to evaporate, which usually takes around 15 minutes. The nail can then be inserted into the medullary canal, with the bent/looped end extruding for easier retrieval.Usually, a chest tube or another kind of drainage tube with an inner diameter similar to the outer diameter of the removed nail or the diameter of the last reamer used is selected and closed at one end, for example, with Kocher forceps. Some kind of guide wire  in the cement powder). However, this is often the only way to make the bone cement appropriate to the sensitivity profile of the causative pathogen. Adding another antibiotic powder not only increases the activity spectrum but also increases the antibiotic elution rates. Most studies evaluating combinations of antibiotics have demonstrated a synergistic effect, in that adding a second antibiotic seems to increase the elution of both antibiotics , 71, 83.Díez-Peña et al. tried to predict the gentamicin elution from low- and high-loaded bone cement (containing up to 10 wt% of gentamicin sulfate and more than 20 wt% of gentamicin sulfate in relation to the weight of entire block of bone cement) by means of mathematical equations in an experimental model. They found out that each differently loaded PMMA has a different equation describing the release process. Moreover, for low-loaded cement, the release was mainly controlled by the imperfections of the matrix, whereas in the high-loaded PMMA an abrupt increase in the amount of drug released was evident allowing the almost complete release of the drug incorporated .Lastly, the method used to mix the antibiotic seems to play an important role. Hand mixing with a spatula has been shown to increase the total antibiotic release when compared with mixing with a specialized cement mixer . It is hThe most used antibiotic for the fabrication of ACNs is gentamicin, followed by vancomycin , 44. ConOnly low serum concentrations and minor systemic toxicity are achieved while using ACNs and other local cement delivery devices , 90. ResAnother important complication of ACNs is resistance induction. There are two articles describing ability of bacteria to adhere to and colonize gentamicin  and mixe Staphylococcus aureus osteomyelitis in a rabbit model [As far as the authors know, there is no report on the use of ACNs in an animal model. Most probably this is due to the technical difficulties and availability of similar models, that is, antibiotic-coated implants. Local application of a biodegradable coating with 10% gentamicin was shown to be effective in reducing implant-related infection in a rat model . Similarit model .Elson et al. performed one of the most important early laboratory studies. They showed that when antibiotic loaded acrylic bone cement is placed next to cortical bone, dense cortical bone is penetrated by the eluted antibiotic and its concentration in the bone is much higher than what can be achieved safely by systemic administration .The benefits and risks of ACNs are summarised in First and foremost, local antibiotic carriers have never been shown to be superior to intravenous administration of antibiotics in terms of cure rate. At the same time, most of them require some sort of repeat surgery, unless they biodegrade, which is not the case in ACNs .There has been one report linking high failure rate to the use of ACNs in infected nonunion with bone defect exceeding 6 cm . The autOne of the concerns with all the PMMA carriers for antibiotic is the emergence of resistance. There have been reports on induction of coagulase-negative staphylococci after applying gentamicin-loaded bone cement . HoweverFrom the technical point of view, there is a possibility of debonding of the cement from the nail upon its introduction or removal from the medullary canal. However, this situation is usually quickly resolved with reaming or using long-reaching surgical tools and, in our experience, as with every surgical complication, the rate of debonding decreases with the familiarity with the technique and increasing expertise in nail fabrication , 46.In the past, bone cement liquid monomer, methyl methacrylate (MMA), was believed to be carcinogenic. However, the lack of consistency in the results of various studies and the absence of dose response lead to the conclusion that MMA in not carcinogenic to humans under normal conditions of use . MoreoveThe novel concept of local antibiotic delivery by gentamicin-impregnated acrylic bone cement was introduced by Buchholz et al. in the early 1970s for the treatment of infected hip arthroplasty . AntibioIn a study of two cases, Tandon and Thomas were able to provide a proof of concept of using hollow, slotted nail with gentamicin cement beads. Based on the observation that commercially available beads are 7 mm in diameter, they argued that two to three strings of beads could be inserted into most intramedullary nails and effectively treat infection . UnfortuIt is perceived that with future developments local antibiotic delivery systems will likely supplant the traditional use of systemic antibiotics for the treatment of musculoskeletal infections , 109.Another field of development is the MRI-compatible ACN. There has been only a single, short follow-up case report by Mauffrey et al. The authors claim that serum inflammatory markers might not always be reliable and that MRI monitoring of the infection might provide better insight into whether or not the infection has healed and one could move to the definitive fixation by a metallic nail . On the Since 2005, there are also prefabricated interlocking antibiotic-coated titanium nails, which use polylactic acid (PLA) coating loaded with gentamicin and offer both sustained release kinetics and biodegradability. Promising 6-month results have been reported in primary fracture setting .It is important to realize that as long as none of the ACNs is FDA-approved, which is the current state as of 2015, their use is off-label and prospective clinical trials cannot be undertaken .There is only one short paediatric case series, in which ACNs have been used. It was found to be safe and effective in the treatment of chronic osteomyelitis, with special attention to protecting the epiphyseal growth plates of long bones. The authors believed also that using the nail instead of other forms of local antibiotic carrier enabled for prevention of further tissue loss . We beliThere are certain substances other than antibiotics, such as dextran, glycine, or xylitol, which could be used to impregnate PMMA for the enhancement of the antibiotic elution. However, the ideal filler material and amount of filler are yet to be established . We are Another technical development is the introduction of the Reamer-Irrigator-Aspirator (RIA) system  which, in animal models and cadaver studies, offers an advance on existing reaming devices, as it is less traumatic , 42. It  P. aeruginosa and E. coli. The other effect of ultrasound waves is presumably to increase the transport of oxygen and other small molecules, which may increase the metabolic state and render cells more susceptible to antibiotics [Ultrasound was also found to increase the transport of gentamicin across and within the biofilm ofibiotics , 114. Thibiotics . FurtherSince the introduction of antibiotic loaded acrylic bone cement by Buchholz and Engelbrecht, it remains a golden standard in local antibiotic delivery. This is also true in case of long bone medullary infections, where antibiotic cement nails remain an important treatment option. The major advantage of ACNs is the local release of high antibiotic concentrations, which vastly exceed those after systemic administration with no or low systemic toxicity. At the same time, they are able to provide limited stability to the fracture/nonunion site, which promotes infection healing. They are used as a clinician directed application; therefore, there is no issue with availability and antibiotic specificity, as it can be based on preoperative culture. Antibiotic elution rates, mechanisms, and ways to improve total amount of drug delivered are still debated and researched. Despite promising short- and midterm results from clinical studies, further basic science and translational studies are desirable before routine use of ACNs in clinical practice.


Geopolymer concrete mixes were cast using fly ash, kaolin, sodium hydroxide, potassium hydroxide, sodium silicate and aggregates. Portland cement concrete (M30) was used as a reference sample. The effect of silica fume, temperature , sodium and potassium hydroxides and different superplasticizers on the compressive strength are reported  Data on mechanical strength are presented.44.1Commercially available kaolin and the fly ash obtained from National Power Station, Dadri, Uttar Pradesh, India, were used during the experiments. OPC-43 was used for making OPC concrete for comparing the compressive strengths of geopolymer concretes. Coarse aggregates of sizes 20 mm and 10 mm and river sand as fine aggregate were used. Sieve analyses were performed to determine the particle size distribution as per BS 812, Part1, 1975. Distilled water was used in all the experiments. Naphthalene sulphonate(N.S), Malamine-formaldehyde (GN-51) and Polycarboxylate ester (Chryso-730) based superplasticizers were used as admixtures. The alkali activators used were solutions of sodium hydroxide, potassium hydroxide and sodium silicate.4.2Solutions of sodium and potassium hydroxides (14 M each) were prepared separately. The solutions prepared were left for 24 h before mixing with sodium silicate. The mixtures of sodium hydroxide/potassium hydroxide and sodium silicate solutions were left for one day and then used for geopolymerisation process.4.33), aggregates occupy 75–80% by mass in geopolymer concretes. In the present mix design of geopolymer concrete, coarse and fine aggregates were taken as 77% by mass of the entire mixture. Fine aggregates were 30% by mass of the total aggregates. For maximum strength NaOH/KOH concentration was taken as 14 M [The geopolymer concrete was prepared by conventional method as OPC concrete. Since the density of geopolymer concrete is almost equal to that of OPC concrete  for maximum compressive strength. After demoulding, all the Mixes were transferred in the oven for heat curing at 100 °C for 72 h. The samples were then left at room temperature after curing until the day of testing. The compressive strengths of the cubes with 100 wt% fly ash, 100 wt% kaolin and 100 wt% OPC was determined after 3 days, 7 days, 14 days, 21 days and 28 days . Lower v4.6Mix 5 given in 4.7Variation of compressive strength with time in presence of different superplasticizers is shown in 4.8Variations of compressive strength of Fly ash and Kaolin based-geopolymer concretes in presence of silica fume are given in


In total, 139/376 (37.0%) patients had MET protein overexpression; of whom, 7/139 (5.0%) had MET amplification. MET overexpression was significantly associated with locoregional failure (P = 0.009), distant metastasis (P = 0.006) and death (P < 0.001); MET amplification was significantly associated with death (P = 0.021). A positive correlation was observed between MET copy number status and MET protein expression . Multivariate analysis demonstrated MET overexpression was an independent prognostic factor for overall survival  and disease-free survival , and MET amplification was independently associated with poorer OS  and DFS . In conclusion, MET protein overexpression and gene amplification are independent prognostic factors for OS and DFS in locoregionally advanced nasopharyngeal carcinoma, and may provide therapeutic biomarkers to identify patients in whom MET inhibitors may be beneficial.This study assessed the incidence and prognostic value of MET protein overexpression and gene amplification in locoregionally advanced nasopharyngeal carcinoma (NPC). Specimens from 376 consecutive patients with locoregionally advanced NPC were subjected to immunohistochemistry to analyze MET protein expression and fluorescence  Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies in Southern China, where the rates vary from 30 to 80 cases per 100,000 . UnfortuMET proto-oncogene encodes the receptor tyrosine kinase MET, which is activated by its ligand, hepatocyte growth factor (HGF) [MET, paracrine or autocrine activation via HGF, and protein overexpression [MET amplification were associated with poorer clinical outcomes in non-small cell lung cancer and gastric cancer [The or (HGF) , 11. Binor (HGF) , 13. Noror (HGF) , 15. Conor (HGF) , 17. Abepression , 19. Recc cancer –22. On tMET amplification can be used to identify subgroups of patients with gastric cancer who are sensitive to MET inhibitors [MET amplification in NPC has not yet been determined.Currently, a number of MET inhibitors have been developed and are in clinical trials at different phases –26. The hibitors . Howeverhibitors –30. MoreMET amplification in patients overexpressing MET. In addition, we analyzed the association with clinicopathological features, as well as the prognostic value of MET overexpression and MET amplification to assess the value of MET as a potential therapeutic target for personalized treatment of patients with NPC.Therefore, in this study, we aimed to evaluate the frequency of MET protein overexpression in patients with locoregionally advanced NPC, and the incidence of P = 0.004; Table P = 0.009), distant metastasis  and death , 163 (43.3%), 104 (27.7%) and 35 (9.3%) patients had a MET immunohistochemical (IHC) staining score of 0, 1+, 2+ and 3+, respectively Figure . Overexp9.7%, 163MET copy number status of the patients with high MET expression (n = 139) was analyzed using fluorescent in situ hybridization (FISH). In total, 7/139 (5.0%) patients demonstrated MET amplification; 24 (17.3%), 29 (20.9%), 31 (22.3%), 29 (20.9%) and 19 (13.7%) patients displayed high polysomy, low polysomy, high trisomy, low trisomy and disomy, respectively . The MET/CEP7 ratio ranged from 0.9 to 4.1 .The y Figure . The aveMET amplification status and the clinicopathological characteristics of the patients with high MET expression are shown in Table MET amplification was significantly associated with death . However, there was no significant association between the MET copy number status and any other clinicopathological factor.The correlation between the MET copy number status correlated significantly with MET protein expression  in univariate analysis, and patients with MET amplification had significantly poorer 5-year OS  and disease-free survival  and DFS . TNM stage and gender were also found to be independent prognostic factors for OS and DFS  and DFS . Taken together, these results indicate that MET protein overexpression is associated with unfavorable OS and DFS, and that MET amplification can be used to identify a subgroup of patients with high MET expression at risk of poor survival outcomes.Multivariate analysis revealed MET protein overexpression was an independent prognostic factor for OS  and disease-free survival (DFS). These results suggest that MET overexpression and MET amplification are potential biomarkers that could enable identification of a subgroup of patients with NPC who may be sensitive to MET-targeted therapy.In the present study, we report that MET protein was overexpressed in the tumors of 37.0% of the patients with locoregionally advanced NPC, with MET is aberrantly activated in a wide range of tumors, including lung cancer, gastric cancer, glioblastoma and renal-cell carcinoma , 31, 32.MET is amplified in ~5% patients with non-small cell lung cancer and gastric cancer [MET amplification have a poorer clinical prognosis [MET amplification, and MET amplification was rare in patients with low MET expression, ranging from 0% (0/283) to 0.6% (1/163) [MET amplification can identify subgroups of patients with lung or gastric cancer who may benefit from MET inhibitors, suggesting that MET amplification as a may represent a putative biomarker [MET amplification was unknown in NPC. This study demonstrated that 5.0% of patients with high MET expression had MET amplification. A significantly positive correlation was observed between MET amplification and MET protein overexpression, in agreement with previous data in gastric and lung cancer [MET amplification had a MET IHC score of 3+, and the majority of the remaining patients with a MET IHC score of 3+ had polysomy. Moreover, MET amplification was an independent prognostic factor for OS and DFS, further indicating that MET amplification may identify a subgroup of patients with high MET expression at risk of poorer survival who may benefit from MET inhibitor therapy.Gene amplification is another well-recognized mechanism that can lead to constitutive activation of MET , 40. Basc cancer , 35, 41.rognosis , 42, 43. (1/163) , 35. Preiomarker , 44, 45.MET amplification in locoregionally advanced NPC, and demonstrated that both MET overexpression and MET amplification were associated with poorer OS and DFS. These results enhance our knowledge of the mechanisms underlying aberrant activation of the MET pathway in NPC, and may help to establish MET as a novel prognostic biomarker and therapeutic target for the treatment of subgroups of patients with locoregionally advanced NPC.In conclusion, this study evaluated the frequency of MET overexpression and th edition of the AJCC Cancer Staging Manual. The clinical characteristics of the patients are summarized in Table Paraffin-embedded biopsy specimens from 376 consecutive patients with histologically-confirmed, non-distant metastatic NPC treated at Sun Yat-sen University Cancer Center between January 2006 and December 2009 were evaluated; all samples were pathologically confirmed by two pathologists. No patients received radiotherapy or chemotherapy before biopsy. All MRI/CT materials and clinical records were reviewed and patients were restaged according to the 7All patients received radiotherapy, as previously described ; 337 patAll patients were followed-up at least every 3 months during the first 2 years and then every 6 months thereafter until death. Median follow-up was 62.4 months . The following end points were assessed: overall survival (OS) and disease-free survival (DFS). OS was calculated from the first day of treatment to death; DFS, from the first day of treatment to disease progression or death from any cause.Immunohistochemistry (IHC) for MET was performed using an automatic staining system , according to the manufacturer's instructions with CONFIRM anti-total MET antibody . Immunostaining was evaluated on the basis of the staining intensity  and the percentage of cells stained, according to the MET IHC scoring criteria for non-small cell lung cancer , 37. TheMET copy number was evaluated using fluorescence in situ hybridization (FISH), as previously described [MET (red) and CEP7 (green) signals were evaluated for at least 100 non-overlapping nuclei in each slide.escribed . BrieflyMET copy number status, according to the University of Colorado Cancer Center criteria [MET amplification . MET amplification was defined as MET FISH-positive; the remaining cases were classified as MET FISH-negative. MET copy number status was determined by two investigators while blinded to the clinical and molecular characteristics of the patients and IHC data.Patients were classified into six groups based on the criteria : 1, diso2 and Fisher's exact tests. The association between MET FISH status and MET protein expression was evaluated using the Spearman's rank method. Actuarial rates were calculated using the Kaplan-Meier method; differences were compared using the log-rank test. Multivariate analysis using a Cox proportional hazards model was performed to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), and assess independent significance by backward elimination of insignificant explanatory variables. Covariates including host factors , tumor factors , radiotherapy (RT) technique and chemotherapeutic intervention  were included in all tests. All tests were two-tailed; P-values < 0.05 were considered statistically significant.All statistical analysis was performed using SPSS 16.0 software . Categorical variables were compared using the χ


Introduction. Researchers’ productivity is usually measured in terms of their publication output. A minimum number of publications is required for some medical qualifications and professional appointments. However, authoring an unfeasibly large number of publications might indicate disregard of authorship criteria or even fraud. We therefore examined publication patterns of highly prolific authors in 4 medical specialties.Methods. We analysed Medline publications from 2008–12 using bespoke software to disambiguate individual authors focusing on 4 discrete topics (to further reduce the risk of combining publications from authors with the same name and affiliation). This enabled us to assess the number and type of publications per author per year.Results. While 99% of authors were listed on fewer than 20 publications in the 5-year period, 24 authors in the chosen areas were listed on at least 25 publications in a single year . Types of publication by the prolific authors varied but included substantial numbers of original research papers .Conclusions. Institutions and funders should be alert to unfeasibly prolific authors when measuring and creating incentives for researcher productivity. The productivity of researchers is usually measured in terms of the number of publications they author. Some medical qualifications and academic appointments  require a minimum number of publications in recognised, peer-reviewed journals . Press rThe link between extreme productivity and fraud is supported by anecdotal evidence. For example, the physicist Jan Hendrik Schön produced about 40 research papers in one year (submitting 7 in a single month), all of which were later retracted . SimilarWe therefore examined researchers’ publication outputs to provide some initial insights into and measurements of the phenomenon of prolific authorship.Since simple searches of Medline by author name do not accurately identify individuals and cannot distinguish publications from different authors who have the same name, we used a bespoke, semi-automated tool  that considers additional author characteristics such as affiliation, publication history, and patterns of co-authorship. To further reduce the chance of combining publications from different authors with the same name, we focused on 4 discrete (arbitrarily chosen) topics  which were defined by keywords in the Medline database. For each topic, we analysed all publications listed on Medline from January 2008 to December 2012. Using the software we characterized: the number of publications per individual, the types of publication, and patterns of author order. We also manually checked outputs for a convenience sample of the 10 most prolific authors for each topic using Medline to verify that these did, indeed, appear to be from single authors and to check the types of publication and authorship order.We assessed 58,400 publications for 163,993 researchers. During the 5 years studied, 99% of researchers  were listed on fewer than 20 publications . In contDetailed, manual inspection and analysis of the output of the 40 most prolific authors  revealed great variations in the types of publications produced . For exaThe 40 most prolific authors were based in 5 continents (none from Africa) and a range of countries, the most common being Germany (6), the Netherlands (6), and Japan (4). We did not find any Medline retractions associated with these authors.Using specially designed software, we were able to calculate the number of publications per individual researcher and thus provide some measures of prolific authorship in a range of medical fields. More detailed analysis also revealed the publication patterns of the most prolific authors and we found these to be highly variable.Judging by our manual analysis of the 40 most prolific authors, the software  successfully identified the output of individual researchers. We limited our search to Medline and did not consider other publications such as conference abstracts or those in non-listed journals. This means our estimates of prolific output are conservative and may not be generalizable to other disciplines. This was an exploratory, observational study to give an initial impression on the phenomenon of high author productivity. We did not attempt to assess the causes for high productivity.Since our initial study, another group has examined authorship patterns among diabetes researchers and noted that the most prolific were named, on average, on 7 articles reporting clinical trials per year, for 10 years . One limhttp://orcid.org) rather than relying simply on author names for identification. Although the absolute number of highly prolific authors in each field is probably small, asking researchers to justify their authorship, if there are any suspicions, shows that institutions take research integrity seriously. Abusive authorship patterns, such as senior figures who demand to be listed on publications despite having had little or no involvement in research are well documented  and that institutions should have systems in place to handle suspected abuses. Many guidelines note that authorship entails accountability for the research being reported  and this


Reason for Corrigendum:In the original article, the name of the third author was mistakenly shortened to Elien van Wonterg. The correct name should be Elien Van Wonterghem instead of Elien Van Wonterg. The authors apologize for this miscommunication.This error does not change the scientific conclusions of the article in any way.The original article has been updated.Original Work: SL performed most of the experiments. EW, RV, and CL performed the hydrodynamic gene delivery. SL and MO planned and performed the cloning. KG and RM performed GC-MS measurements. JH did the histological analysis. SK, SL, and AK planned experiments, analyzed data, and wrote the manuscript. AK designed and directed the study. All authors critically revised the work, approved the final version of the manuscript to be published, and agreed to be accountable for all aspects of the work. Corrigendum: SL, SK, and AK wrote the Corrigendum.The project was funded, in part, by the Else Kröner-Fresenius-Stiftung (2012_A250 to AK and SK) and the Graduiertenförderung of Saarland University (to SL).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structural isomers of xylene  can be efficiently separated with an elution sequence inversed with those for conventional mechanisms. More importantly, the separation mechanism is comprehensively and quantitatively visualized by single-crystal X-ray crystallography coupled with multiple computational simulation methods, in which the small apertures not only fit best the smallest  Separation, detection and identification of such isomers with very similar chemical and physical properties are of great importance and challenge in industry and environmental sciences12345678910o-, m-, and p-xylenes, denoted as oX, mX, and pX, respectively, follow oX > mX ≈ pX as reflected by their boiling points) interacts stronger with the surface to give stronger adsorption or longer retention time. However, because the physical properties of the oX, mX, and pX are extremely similar, complete separation can be hardly achieved by the differential interaction mechanism, even when porous solids with high surface areas are used to enhance the host-guest interaction12131414Xylene and many other disubstituted benzene derivatives are generally produced as mixtures of the Porous coordination polymers (PCPs) or metal-organic frameworks are new generation adsorbents combining advantages of versatile/tunable framework2122232412132628293031Owning to the long-range ordered crystal structures of PCPs, the host-guest interacting structures may be directly and straightforwardly visualized at the molecular level by diffraction techniques, especially using single-crystal samples262733343536373839414243444546Herein, we report a unique xylene separation mechanism observed for a new PCP featuring hierarchical and flexible pore structure, in which the host-guest structures, energies, and dynamisms are comprehensively and quantitatively visualized by combined single-crystal X-ray diffraction (SCXRD) and computational simulation studies.H-imidazole-4,5-diyl)dibenzoic acid (H3pidba) and ZnCl2 in N,N-dimethylformamide (DMF) gave light yellow block crystals of a new metal carboxylate framework [Zn(Hpidba)]∙2.6DMF∙H2O  in high yield. SCXRD revealed that 1∙g processes a high-symmetry (space group R-3) three-dimensional (3D) non-interpenetrated coordination network  running along the a- and b-axes -1 network  and a hid b-axes .1∙g can be readily activated by exchanging the guest with CH3OH and then heated at 50 °C, which gives guest-free 1 stable up to 350 °C , which possesses a slightly expanded unit-cell volume (+3.5%). Comparison of the crystal structures of 1∙g and 1 showed that the conformation change of the organic ligand is responsible for the framework flexibility. The 3D intersecting channel occupies 48.4% volume of 1, corresponding to a crystallographic pore volume of 0.513 cm3 g−1 .Thermogravimetry analysis and variable-temperature powder X-ray diffraction showed that o 350 °C . The fra1 was evaluated by N2 and CO2 gas sorption at 77 K and 195 K, respectively. The N2 isotherm exhibits a two-step character with an obvious hysteresis at P/P0 = 0.24–0.56  separation of highly similar molecules such as isomers of xylene and similar disubstituted benzene derivatives. A capillary column with microcrystalline 1 coated on its inner surface was fabricated by a dynamic coating method . Comparison of the molecular sizes , indicating that there should be a distinctive separation mechanism for 1.Considering the hierarchical pore structure and good thermal stability, g method 8. As shog method , which aar sizes  and the 1, we tested its separation performance for other disubstituted benzene derivatives including ethyltoluene, chlorotoluene, and methylanisole, whose separation is also challenging for most commercial capillary columns such as HP-5MS .To directly visualize the different host-guest interactions and thus understand the separation mechanism, we tried to measure the single-crystal structures of 1∙oX and 1∙mX are very similar with that of 1∙g, while that of 1∙pX is similar with that of 1 , the guest molecule obviously adopts an orientation that minimizes steric hindrance and host-framework distortion. On the other hand, one methyl group of mX inserts a little into the quadrilateral aperture, while the other part of the molecule lies on the pore wall outside the aperture. Similar with oX, pX also completely inserts into the quadrilateral aperture, with its molecular center exactly overlapping with that of the aperture.The oX molecule completely inserts into the aperture, with its phenyl ring and methyl groups residing at two opposite sides of the aperture and its molecular plane parallel with the Zn· · ·Zn diagonal. Considering the effective sizes and shapes of oX  compared with that of guest-free 1  for pX among the three xylene isomers, and indicate that the abnormal retention trend between oX and mX is very likely resulted from the combination effects of host-guest fitting and structural transformation of the host.In t-free 1 , indicat 1∙ompX, , in whic1 is not large enough for accommodation of oX and mX, and the flexibility of host-framework should be taken into consideration to obtain reliable host-guest structures and energies. We then carried out periodic density functional theory (PDFT) calculation, which allows the whole host-guest structure to change, to further optimize the host-guest structures obtained by GCMC simulation. As expected, oX completely inserts into the aperture in this case, while mX and pX barely change their positions during the PDFT optimization  simulation, which allows the guest molecule to freely rotate and translate while treats both the host framework and guest molecule as rigid bodies, to obtain the primary adsorption sites and corresponding host-guest structures. In the most energetically favored simulation results, mX and pX were found at positions close to those determined by SCXRD  and S14bmization .ΔEfitting)−1) > oX (−58.48 kJ mol−1) > mX (−58.27 kJ mol−1). However, to adsorb the guest molecules, the host framework undergoes different structural distortions from the guest-free form, in which the small aperture expands 0.09 Å and 0.04 Å for oX and mX, respectively, and shrinks 0.03 Å for pX (ΔEtrans) of 3.32, 0.88 and 2.21 kJ mol−1 for oX, mX, and pX, respectively. Taking the host-guest fitting and host-framework distortion energies both into consideration, the total adsorption heats (ΔEads) can be calculated as –55.16, –57.39 and –59.74 kJ mol−1 for oX, mX, and pX, respectively, being consistent with the trend observed by GC  simulations with the same temperature (453 K) for the GC experiments. As shown by the obtained guest moving trajectories  × 10−10, 5.25(2) × 10−10, and 3.81(2) × 10−10 m2/s, respectively, which are similar with other PCPs with channel diameters of ca. 10 Å421 for the abnormal xylene separation behavior can be also demonstrated by MD simulations for two hypothetical materials derived from 1, in which pX molecules were fixed into the small apertures as observed by the crystal structure (1a) or the host framework was treated as a rigid body (1b). Without the small aperture, the self-diffusion coefficient of xylene isomers in 1a follows oX < mX < pX, which is conversed with that for 1 but the same as those for conventional stationary materials based on differential interaction mechanism  images were recorded on a Quanta 400 field-emitted SEM device. Sorption isotherms were measured on an automatic volumetric sorption apparatus . Before sorption experiments, the as-synthesized crystalline sample was soaked in methanol for one week, and then placed in the sample tube and dried under high vacuum at 100 °C for 12 h. GC separation experiments for the capillary column coated with 1 were performed on an Agilent 7890A system equipped with a thermal conductivity detector. The data acquisition and processing were controlled by the ChemStation software. Before GC injection, all analytes were first diluted in methanol.Elemental analyses  were performed with a Vario EL elemental analyzer. Powder X-ray diffraction data were collected on a Bruker D8 ADVANCE X-ray powder diffractometer (Cu Kα). Thermogravimety analyses were performed on a TA Q50 instrument with a ramp rate of 5.0 °C min2 , H3pidba , and DMF (3 mL) was sealed in a 10-mL Teflon-lined stainless steel container and kept at 120 °C for 3 days, followed by cooling to room temperature at a rate of 5 °C/h. Light yellow block crystals were obtained with the yield of 69% based of Zn. EA calc. (%) for [Zn(Hpidba)]∙2.6DMF∙H2O (ZnO7.6N5.6C29.8H33.2): C, 54.49; H, 5.09; N, 11.94; found: C, 54.79; H, 4.87; N, 12.24.A mixture of ZnClF2 by the SHELXTL packagePLATON SQUEEZE treatment was applied to all guest molecules in as-synthesized 1∙g because the guest solvent molecules are extremely disordered and cannot be modeled. A fraction of xylene in the large 1D channel is also extremely disordered and cannot be modeled, resulting in solvent accessible voids.All diffraction data were collected on a Rigaku XtaLAB P300DS single-crystal diffractometer with graphite monochromated Cu Kα radiation λ = 1.54178 Å). Single crystal specimens were sealed in glass capillaries either in vacuum or with corresponding pure xylene, respectively. Absorption corrections were applied by using the multiscan program REQAB178 Å. Si6 following with 1 × 107 production steps. All energies were calculated by the PDFT method by the Dmol−5 Ha, 4 × 10−3 Å and 5 × 10−3 Å, respectively. The energy balance is expressed by the following equationsAll simulations/calculations were performed by the Materials Studio 5.0 package. The preferred sorption locations were searched through GCMC simulations by using the loading task in the Sorption module. The simulation box consisted of one unit cell and the Metropolis method based on the universal forcefield (UFF) was used. Both the framework and the xylene molecules were regarded as rigid body and the QEq partial charges and ESP charges were employed to the atoms of the framework and guest molecules, respectively. The cutoff radius was chosen as 18.5 Å for the LJ potential, and the maximum loading steps and the equilibration steps were both 5 × 10ΔEads is the calculated heat of adsorption, ΔEtrans is the energy change of the host framework after adsorption of guest, ΔEfitting is the interaction energy between the guest and the final host framework, and Ehost+guest, Eguest, Eapohost and Ehost are the energies of the guest-adsorbed structure, the guest, the guest-free host framework, and the transformed host framework after adsorption, respectively.Where The diffusion behaviors were simulated by MD. The initial configurations for the MD simulations were produced by the GCMC loading results followed with global geometry optimizations through the universal forcefield with the same partials charges as mentioned above. All of the MD processes adopted the canonical ensemble with constant volume/temperature (NVT) using Nose thermostat and random initial velocities. The time step was 1.0 fs with relaxation time 2.0 ps and total simulation time 4 ns. The electrostatic interactions and the van der Waals interactions were evaluated by the Ewald summation method, while all the Buffer widths were set as 0.5 Å. The first 2 ns were used as equilibrium and the following 2 ns were adopted for statistical analysis such as for mean square displacements.How to cite this article: Lin, J.-M. et al. Structural, energetic, and dynamic insights into the abnormal xylene separation behavior of hierarchical porous crystal. Sci. Rep. 5, 11537; doi: 10.1038/srep11537 (2015).