The aim of this study was to evaluate the effect of the temperature (15 or 45 °C) and the duration (15–120 min) of the modification process on the selected physicochemical, thermal, and rheological properties of phosphorylated potato starch. The modified starches contained 93.6–98.2 mg P/100 g . Phosphorylation caused color changes with a total color difference between the starches below 0.55, but these changes were less than those that were recognizable by the human eye. The thermal analysis showed two opposite processes appearing during the modification: the loosening of the structure (dominant among starches obtained at 15 °C) and the strengthening of the structure (dominant among starches obtained at 45 °C). The higher phosphorylation temperature reduced native starch recovery from 140% to 87–116% and increased the hysteresis loop area from −169 to 1040. All of the pastes made from the modified starches showed a weaker tendency for retrogradation (during 21 days of storage) than native starches. The results of the regression analysis conducted between the properties of the starch pastes obtained at 45 °C indicated that the modification time appeared to be a better indicator of the rate of modification progress than the phosphorus content. The PCA  results made it possible to distinguish starch phosphates obtained at 15 °C from those obtained at 45 °C and those from natural starch. Starch represents a carbohydrate reserve in plants and is found in leaves, flowers, fruits, seeds, and roots. A starch granule is a densely packed structure with semi-crystalline structures composed of two major starch polymers: essentially linear amylose and branched amylopectin. The specific properties of starches are dependent on their botanical origin and by the size and surface of the starch granule; the lipid, protein, water, and phosphorus content; and the amylose and amylopectin ratio ,2. For environmental reasons, potato starch is an important industrial raw material in Poland. Its physicochemical properties  distinguish it from cereal starches, allowing, among other things, to form pastes (at low temperature) with high transparency and viscosity but that are less thermally stable ,3,4,5,6.Starch is a very popular and multifunctional compound in the food industry. It mainly offers thickening, gelling, and dispersed system-stabilizing properties; therefore, it is used to improve textural properties  and wateAmong the modifications allowed by law for food products, the modifications that are very interesting are phosphorylation ,13,14, nStarch is chemically phosphorylated with phosphoryl chloride, sodium trimetaphosphate (STMP), sodium tripolyphosphate (STPP), or sodium or potassium orthophosphate . The incPhosphorus is a constituent element of a potato starch granule. Either by its presence in the covalently bound orthophosphate groups or by binding metal ions, it imparts ion exchange properties to starch ,8,18. Thquantum satis levels.Owing to their functional properties, the starch phosphates E 1410 (monostarch phosphate), E 1412 (distarch phosphate), E 1413 (phosphated distarch phosphate), E 1414 (acetylated distarch phosphate), and E 1442 (hydroxypropyl distarch phosphate) were approved for use as food additives by the European Union  and for However, the use of chemical ingredients in food production is causing concern in a growing number of consumers. This is due to the presence of many allergies of unknown aetiology and a growing awareness of the risks and effects of such products on the human body. An alternative to genetic or many chemical starch modification methods may be the use of phosphorus compounds. It therefore seems advisable to bring phosphorylation back into the focus of scientific attention and to expand knowledge on this subject.The knowledge of the transformations occurring in starch during phosphorylation and of the properties of the phosphates formed under different modification conditions will allow the selection of modification conditions to optimize the production costs while obtaining the most favourable functional properties of the phosphates.The use of STMP for the preparation of distarch phosphates allows the modification to be conducted under mild conditions using low-cost reagents that are safe for humans and for the environment.Given the above, this study aimed to evaluate the effect of the temperature (15 or 45 °C) and the duration (15–120 min) of the modification process on the selected physicochemical, thermal, optical and rheological properties of phosphorylated potato starch.6 and amylopectin with an average molecular weight of 9.4 × 107 was purchased from Potato Industrial Enterprise PEPEES S.A. . Commercial potato starch with average molecular weight of amylose at 9.0 × 102CO3, NaCl) and Sigma Aldrich (STMP—sodium trimetaphosphate). Urea-dimethylsulphoxide (UDMSO) solution was prepared from dimethylsulphoxide  and urea .Salts  were purchased from Avantor Performance Materials Poland S.A. Gliwice Poland (Na2CO3 (5 g) and NaCl (5 g). The pH of the solution was adjusted at level 10.5 using 5% solutions of HCl or NaOH. The starch (220 g d.w.b.) was dispersed in the solution, and the pH was then readjusted. Next, the obtained solution was mixed at a controlled temperature (15 °C or 45 °C) and time . The crude product was filtered through a 1G Schott funnel, was washed with water, and was air-dried. The dried starch was ground using a mortar grinder RM 200  and was passed through a 200 µm sieve using a vibratory sieve shaker AS 200  before the analysis.Starch modification began by melting STMP (2.7 g) with 440 mL of deionized water (15 °C or 45 °C) with NaAccording to Lim and Seib , the staDuring modification, cross-linking bonds may be formed between C2, C3, and C6 atoms .The moisture content was calculated as the percentage weight loss of a 1 g sample heated at 130 °C for 1 h and cooled to room temperature in a desiccator . 3 and H2SO4 using a Wet Digester B-426 . A reaction with (NH4)6Mo7O24 and ascorbic acid was followed by the spectroscopic measurement of the intensity of the blue color at a wavelength of 825 nm  [The total phosphorus content in native and phosphorylated starch dry matter was determined after mineralization in a hot mixture of HNO, Japan) . 2-KI solution at 635 nm and 20 °C). The amylose content in the starch dry matter was determined using a V-530 spectrophotometer , according to the methods of Morrison and Laignelet . The appThe total fat content was determined using petroleum ether (b.p. 40–60 °C) and was determined according to the methods of Soxhlet , whereasThe color of the starches under investigation was determined using a Color i5 spectrophotometer . D65 illuminant was applied for the d/8 geometry. The color was determined in the specular excluded mode (SPEX) for an additional observer (CIE 1964). The CIE L*, a*, b*, C*, and h° coordinates  were detThe CIE 1976 total color difference (ΔE) between two color stimuli was calculated as the Euclidean distance between the points representing them in the CIE L*a*b* color space :ΔE = [(ΔC), Uchida (WIU), and Judd (WIJ) [Based on the experimentally determined L*a*b* coordinates, the whiteness indexes were determined using the formulas developed by CIE (WIdd (WIJ) ,33: WIC Finally, the yellowness index (YI) and the tint index (TI) were determined: 900 · 0.38 − x − or space .Thermal properties of the modified starches were analyzed using a Differential Scanning Calorimeter Phoenix 204 F1  that was calibrated using iridium. An empty pan was used as a reference.1 J per g d.w.b. of starch) was measured from the endotherm of DSC thermograms using the Netzsch Proteus–Thermal Analysis software  based on the mass of the dry solids. The onset temperature (To1), peak temperature (Tp1), and conclusion temperature (Tc1) were calculated. The gelatinization temperature range (ΔT1) was calculated as Tc1-To1. The peak height index (PHI1) was computed from the ΔH1/(Tp1-To1) ratio as described by Kaur [Starch 3.5 mg) was loaded into an aluminum pan  and distilled water was added using a micropipette to create a suspension with a 75% moisture content. Samples were hermetically sealed and equilibrated for 24 h at room temperature before being heated in the DSC. The measurements were conducted at a heating rate of 10 °C/min from 20–100 °C. The enthalpy of the phase transitions (ΔH.5 mg was2), onset temperature (To2), peak temperature (Tp2), and conclusion temperature (Tc2) were determined. The transition temperature range of the melting of recrystallized amylopectin (ΔT2), the peak height index (PHI2), and the retrogradation ratio ΔH2/ΔH1 were calculated. The reported values are the means of four measurements.After being heated for gelatinization analysis, the samples  were cooled to 4 °C and were stored at this temperature. After a week, the stored samples were heated from 20–100 °C at 10 °C/min (the second run). The enthalpy (ΔHw/w) starch pastes prepared in water (at 95 °C for 30 min with continuous stirring). The produced pastes were immediately placed into the rheometer’s measuring system and were thermostated at 50 °C prior to determination.Rheological analysis was performed using a rotational rheometer Rheolab MC1  with coaxial cylinders (gap 2.12 mm) as a measuring system programmed using the US 2000 software. The rheological properties were determined for 5% :0 is the yield stress (Pa), −1), K is the consistency coefficient (Pa·sn), and n is the flow behavior index.The curves were fitted using the Ostwald de Waele model, the Herschel–Bulkley model, and the Casson model. The publication discusses the parameters of the Herschel–Bulkey model because it was characterized as the best fit to the measurement data (R2 ≥ 0.994) and the Casson model (R2 ≥ 0.985), which taken for correlation analysis. −1, a constant shear rate of 300 s−1, and a constant shear rate 1 s−1 in the subsequent steps.The in-shear structural recovery of the paste samples was determined according to a procedure modified from Mezger . The tesap3) based on the value determined in the first step (ηap1):The recovery (R) was calculated as the percentage of the mean apparent viscosity obtained during the last 450 s of the third step (ηw/w) pastes was measured using the Jacobson et al. [The turbidity of the 2%  of the starch pastes was determined at 640 nm against a distilled water blank using a V-530 spectrophotometer . The remaining seven samples were stored at 8 °C for three weeks. After 1, 3, 5, 7, 10, 14, and 21 days of storage, the cuvettes with the samples were equilibrated for 30 min at 25 °C, and the turbidity was measured.The obtained batch of paste was poured into eight 2 mL plastic cuvettes (1 mm thick). The initial turbidity (Tx) after x days of storage was calculated as: x—turbidity after x days of storage, T0—turbidity before storage (0 day), and T21—turbidity after 21 days of storage.The normalized turbidity  test was applied to determine the differences between means using the statistical package Statistica 11 . Pearson’s correlation coefficients were determined to evaluate the relations between the modification time, phosphorus content, and the rheological and thermal variables in the three distarch phosphates groups, i.e., those obtained at a lower temperature (L), those obtained at a higher temperature (H), and all phosphates (L + H).A principal component analysis (PCA) was used to provide a ready means for visualizing the similarities or differences among the analyzed starches.The physical properties of starch  are vital indicators of starch quality and applicability. These properties are related to the non-carbohydrate components in starch: water, phosphorus, amylose, protein, and fat. The physicochemical properties of native potato starch and derived modified starches are shown in The phosphorylation of potato starch was performed using reactions described by Lim and Seib . AccordiNative starch contained 85.2 mg P/100 g and 23.5% amylose , which iWhen the modifying phosphorus was incorporated into the starch, the total phosphorus content increased with the process temperature to 93.6–97.1 mg P/100 g in the L-starches and to 95.9–98.2 mg P/100 g in the H-starches. Because the results of an earlier work by Fortuna  indicateIn accordance with the EU legislation  and the The apparent amylose content in the starches was very similar (23%), but three starches H45, H60, H120) were insoluble in UDMSO, and their analysis could not be continued. The poor solubility of some starches in UDMSO may have been due to the greater degree of cross-linking. According to Singh et al. 0, H120 w, and SulThe fat and protein content were determined to assess the purity of the starch raw material (N-starch). The total fat content of the starch did not exceed 0.3% (d.w.b.), and the protein content did not exceed − 0.5% .The D65 illuminant used  is the preferred illuminant for color description . All of J = 92.98), while all of the modified starches were darker (WIJ = 92.37–92.82).Whiteness is a sensorially important property of color appearance in various industries. White is the attribute of a visual sensation according to which a given stimulus appears to be void of any hue or grayness. Its quantitative analytical measure is a whiteness index, the higher value of which indicates the greater whiteness of the sample. The value of the whiteness index (WI) of native starch determined according to the equation developed by CIE was 73.70. Phosphates obtained at the lower temperature showed a 1–3% lower WI, while the WI of those obtained at the higher temperature was similar to native starch. The results of the whiteness analysis using the equation developed by Uchida were lower by 1.5 units. In the case of the Judd’s equation, the native starch was the most white (WIA yellowness index parameter (YI) is an indicator of the yellowness contributing to the visual evaluation of starch products  and needEuclidean distances in the CIE L*a*b* color space can be used to approximately represent the perceived magnitude of the color differences between object color stimuli of approximately the same size viewed in identical white to middle-grey surroundings. The total color differences (ΔE) between the starches presented in o1, Tp1, and Tc1 did not depend on the modification time. Increasing the phosphorylation temperature increased To1 and Tp1 by at least 0.5 °C (compared to the L-starches). Moreover, those temperatures increased along with the modification time. The onset temperature ranged from 61.05 °C (H15) to 62.8 °C (H120), whereas the peak temperature reached 66.0 and 67.3 °C . When starch is heated in an excess of water, its gelatinization occurs with a heat flow change. The results of the DSC analysis of the starch gelatinization test are summarized in o1) in the L-starches (compared to the N-starch) indicates the loosening of the structure during phosphorylation. In the case of H-starches, the gradually increased cross-linking  ensured a protective effect. As the gelatinization temperatures (such as To1 and Tp1) reflect the structure ordering degree in the starch granules, it may be assumed that the H-starches were harder. As suggested by Gunaratne and Hoover [During modification, starch is mixed in an aqueous medium, which may cause the partial disordering of its structure (combined with the hydrolysis of some phosphate groups), which will be counteracted by the cross-linking effect. Since the melting point of starch crystallites is influenced by the surrounding amorphous regions, an earlier start of gelatinization  and the modified starches (21.37–23.83 J/g d.w.b.), and the peak height index  did not differ.After the gelatinization analysis, the samples were stored for 7 days, and the DSC analysis was performed again. The results of the DSC analysis of the retrogradated samples are summarized in o2. A higher modification temperature increased the peak temperature by about 1–2 °C. The thermal transition of all of the samples ended at similar temperatures (70.3–71.9 °C). Extending the phosphorylation time reduced the width of the DSC peaks (ΔT2), while the modification temperature had no effect. The enthalpy of re-gelatinization was similar to data reported for native starch by Singh et al. [All of the modified starches showed wide and low endothermic peaks between 38 and 72 °C. Similar results were reported by Singh et al. , Morikawh et al.  and Pycih et al.  and was h et al. ,41,46 deh et al. . A starch paste is a diphase system of amylose  and starch granules composed mainly of amylopectin (a dispersed phase). Rheological properties of such systems depend on many factors, including the type of starch, the starch content, the paste preparation method, and the measurement temperature ,48,49.−1) than the native starch (215 Pa). This is confirmed by calues that are similar  to those of the calculated rheological models . Therefore, the thixotropy hysteresis area  was negan (H120). The higher τ0 and K of the H-starches compared to the N-starch may be attributed to the longer chain length of the cross-linked starches as observed in the DSC profiles. The flow index of all of pastes was lower than one (n < 1), pointing to their shear-thinning character, but there was no regularity in the course of changes in n against the modification time, although H-starches had significantly lower n than the N-starch and L-starches.All starch pastes tended to the yield stress: 5.36 Pa (N-starch), 2.25–4.61 Pa (L-starches), and 2.51–20.88 Pa (H-starches). For the starch pastes obtained at 45 °C, the consistency coefficient (K) increased 3–11 times compared to the starches obtained at 15 °C , and thi−1), the starch pastes obtained at the temperature of 15 °C showed a low apparent viscosity (7–11 Pa·s) that was similar to that of native starch paste (1 Pa·s), while the apparent viscosity of starch pastes obtained at a higher temperature increased noticeably over the modification period (14–63 Pa·s).In-shear structural recovery measurements were performed to evaluate the possibility of paste recovery after the destruction of their original structure due to a sudden change in the shear rate ,34,50. CAfter the shear rate increase or decrease, all of the analyzed pastes quickly reached a stable viscosity. The recovery percentage of their structures is shown in Light transmittance is one of the essential starch paste indicators. The process of retrogradation is associated with the release of the insoluble starch form from the suspension, leading to a reduction in the light transmission of the paste through the progress of retrogradation ,10.Changes in the turbidity of the starch pastes during storage at 8 °C A,B are dThe turbidity of the N-starch was lower than the values calculated by Morikawa and Nishinari  and CraiThe pastes made with modified starches (even starches insoluble in UDMSO) are twice as transparent as the native starch paste. The transparency increased with phosphorylation process duration, and the starches that were modified at a higher temperature (H-starches) had a lower turbidity than the corresponding L-starches. On the other hand, literature data  show thaTo compare the rate of the process of opacification during storage, the curves of relative turbidity progressed as the normalized turbidity curves were plotted C,D. TheyThe statistically significant coefficients of Pearson’s correlation among the physicochemical parameters and the phosphorus content and the modification time of various starches (L or H) and all of modified starches (L and H) are shown in o, Tp) obtained after the gelatinization and retrogradation analysis were highly positively correlated with the modification time and the phosphorus content and were negatively correlated with the temperature range, while the conclusion temperature was not strongly correlated with them. No significant correlation between the discussed parameters and the measured enthalpy may be due to the two opposite effects described by other authors.In the case of starches obtained at the lower temperature, no significant correlation was found between the parameters of the rheological models and the modification time or the phosphorus content. This may be due to mild modification conditions that do not cause major changes in the starch granule . Strong correlation relationships occurred in starches obtained at a higher temperature (H-starches), and higher values of the correlation coefficients for the physicochemical parameters with the modification time than with the phosphorus content indicate that the modification time has a greater impact on the properties of starch and its pastes. The coefficients of correlation determined for all of the modified starches (L + H) showed an opposite tendency, which indicates a multitude of processes taking place during the modification and prompts the development of models based on many variables. In turn, the weaker correlations found for all of the modified starches (L + H) than for the H-starches emphasize the influence of the modification temperature. The discussed rheological parameters were positively correlated, except for the flow indices . The thermal properties variables  were related to the first component, and that the composition parameters (Mo and Ph) contributed significantly to Component 2. The parameters describing the retrogradation process significantly contributed to the values of both principal components. The PCA allows the reduction of the number of variables using the correlation between the parameters describing the properties of the object. Reducing the number of variables makes it easier to visualize differences between the compared samples. J. In turn, strongly positively correlated WIU and WIC as well as h° and TI contributed to the formation of Principal Component 1. As shown in The second part of the principal component analysis involved the color analysis of the outer layers of the starch granule. The study showed that the duration of phosphorylation affected most of the rheological and thermal properties of starch. It appeared to be a better indicator of the rate of modification progress than the phosphorus content. The phosphorus content and the moisture content of the obtained starch phosphates met the EU legal requirements in the field of substances added to food and determined that the phosphorylation imparted valuable technological properties to the starch.The modification process was accompanied by the loosening of the starch granule structure (observed in DSC measurements) caused by the reaction medium. All phosphorylated starch pastes showed non-Newtonian flow, shear-thinning, and thixotropic behavior. The hysteresis loop area of paste curves of the samples obtained at 45 °C was much higher compared to the samples of native starch or starch modified at 15 °C. Pastes obtained from phosphorylated starches had a significantly lower recovery values than those obtained from native starch, while the higher temperatures during modification resulted in lower recovery values. The transparency of the pastes increased with phosphorylation process duration, and the starches modified at the higher temperature had a lower turbidity than the corresponding samples modified at lower temperature. Phosphorylation caused color changes, but these changes were imperceptible to the human eye.The PCA results made it possible to distinguish starch phosphates obtained at 15 °C from those obtained at 45 °C and from native starch. However, further studies are needed to determine the importance of various modification factors on the distribution of phosphate crosslinking bonds as well as the position of the formed crosslinking bonds.


Results revealed that players competing in international matches covered significantly greater total distances, greater high-speed running distances and greater sprinting distances as well as spending a greater duration accelerating in band 4 compared to players in domestic competitions (p < 0.05). Players competing in international matches spent significantly less duration decelerating in bands 2 and 3, compared to players in domestic competitions. International defenders and midfielders recorded significantly higher total distances and high-speed running distance compared to players in domestic matches. Our findings suggest that preparing players for international-level competition should include progressive exposure to high-speed running and sprinting distances, as well as high magnitude accelerations. Furthermore, the higher running speeds experienced by players during international matches appears to be a result of less time spent decelerating. The optimal deceleration necessary for specific situations appears important and emphasizes the need for specific deceleration training. The increased effort of high-intensity activity that is required for players competing in international matches affects defenders and midfielders to the greatest degree. Gradual exposure to the increased running demands for midfielders and defenders competing in international matches is needed to improve performance and reduce the potential risk of injury.Acceleration and deceleration are important given football is an intermittent sport with constant changes in velocity and direction. It is unclear, however, if the accelerations and decelerations performed by players differ between competition levels. The aim of the present study was to compare the acceleration, deceleration, and high-speed running profiles of players during international and domestic matches and to determine if differences were apparent across playing positions . GPS data from 21 Australian women's domestic football league matches over 2 seasons (2016–2018) and 15 Australian women's international matches (2017–2018) were collected and analyzed. Movement pattern data was collected using VX Sport and GPSports 10 Hz GPS receivers. Variables analyzed included: total distance, distance covered high-speed running (16–20 km·h Evidence from time-motion analysis studies demonstrates that total distance covered during match-play is similar between international and domestic women's football matches . Maximal acceleration and deceleration are considered “high-intensity” efforts as they impose the greatest physiological and mechanical loading demands on players of any running metric  and international matches . Data for goalkeepers were excluded given the unique running profile and technical skills of that position.Fifteen female football players  from the same club team in the Australian women's domestic football league and eighteen female football players  from the Australian women's national football team participated in the present study. Players were analyzed based on three playing positions from domestic  over two seasons (2016-2018) were collected from the domestic competition. International matches included data from a total of fifteen games  that were collected from the 2017 Algarve Cup in Portugal, the 2017 Tournament of Nations in the United States of America, the 2018 Asian Cup in Jordan and international “friendlies” in Australia. Only data where a player completed the full match  was included in the study. This study was approved by the Griffith University Human Ethics Committee and Football Federation Australia.Domestic competition movement data were collected during match-play using VX Sport technology  whereas GPSports technology  was utilized during international competitions. Individual players positional and time data was collected by attaching the GPS receivers (VX Sport or GPSports), sampling at 10 Hz, between the scapulae of each player using manufacturer designed elastic vests. Both GPS technology used in the present study have been reported to have acceptable accuracy and both between- and within-manufacturer reliability for quantifying movement patterns during team sport  as the primary outcome measure for accelerations and decelerations. It has been demonstrated that the total cumulative distance covered decelerating may not be a true representation of deceleration, given that a player is aiming to cover less distance while decelerating as opposed to more  and GPSports software . To minimize the effect of filtering and data processing differences that occur between the manufacturer's software, the raw data was exported to Microsoft Excel and analyzed using R programming language  . Decelerations account for ~15% of total game duration for players competing in both domestic and international matches, suggesting substantial cumulative loads are placed on the lower-body musculoskeletal system during a match and over a season  accelerations during training to prepare them for the increased demands of an international match. In the current study, players covered 26% more distance high-speed running during international matches compared to domestic matches. This is an important consideration in preparing players for international matches. Specifically, acceleration ability needs to focus on producing higher magnitude (band 4) accelerations, by applying greater force to the ground over a shorter ground contact time. Given acceleration or prior speed are needed for deceleration training, it is recommended that speed and deceleration are trained simultaneously as it may offer the most time-efficient approach to integrating both of these important elements into a time-restricted training program.Results from the present study demonstrate that players competing in international matches perform more explosive, faster efforts, with greater outputs of high magnitude (band 4) accelerations, high-speed running, and sprinting. To prepare players for these increased running demands, players need to be progressively exposed to high-intensity activities during training. To maintain the faster speeds that are required during international matches, it appears that the ability to decelerate specific to the situation is important. The use of magnitude bands in the current study provides novel insights into differences between players movement patterns during international and domestic matches, highlighting the need for deeper understanding around the distribution of specific magnitudes of acceleration and deceleration efforts. The increased effort of high-intensity activity that is required for international matches in comparison to domestic matches, affects defenders and midfielders to the greatest degree. Therefore, it is important that these playing positions are gradually exposed to the increased stimulus to improve performance and reduce the potential risk of injury.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by Griffith University Human Ethics Committee. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.JG: project concept, data collection and analysis, and preparation of manuscript. CM: project concept, refining, and synthesizing manuscript. SH: data preparation, refining, and synthesizing manuscript. JK: refining and synthesizing manuscript. TN: data analysis and preparation of results (tables and figures). MA: project concept and provision of data collection. All authors contributed to the article and approved the submitted version.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.


The purpose of this study was to evaluate the effect of veneering and aging on the translucency of newly introduced extra and high translucent zirconia with different thickness. n = 10) for veneering with base dentin ceramic with thicknesses of 0.5 + 0.5, 0.5 + 1, and 0.5 + 1.5 mm. A spectrophotometer was used to calculate the translucency parameter (TP) and contrast ratio (CR) of all specimens before and after aging. Statistical analysis was performed using 3-way ANOVA and Tukey HSD tests (p < 0.05).  One hundred forty disk-shaped specimens were fabricated from two translucent zirconia blocks (VITA YZ XT and VITA YZ HT), and they are milled with CAD/CAM system. Then, specimens were divided into nonveneered  and veneered groups . Nonveneered groups were prepared with four different thicknesses (0.5-1-1.5-2 mm). Veneered groups were divided into three subgroups (p < 0.001). VITA YZ XT was significantly found more translucent than VITA YZ HT. The highest translucency was observed in the XT-0.5 mm group. There is no significant difference between translucency of the veneered and nonveneered groups in the same thickness for XT. On the contrary, veneering significantly affected translucency of HT. TP values significantly decreased after aging for all groups. After aging, translucency value difference before and after aging was the highest in the XT-0.5 mm group whereas the HTV-2 mm group showed the lowest difference after aging. TP decreased significantly as thickness of specimen increases regardless of the material type. Extra translucent and nonveneered zirconia groups are more prone to hydrothermal aging.  TP values were significantly affected by thickness of specimens ( The translucency parameter of zirconia ceramics was significantly influenced by both material type and veneering. Also, extra translucent and nonveneered zirconia groups are more susceptible to hydrothermal aging. Increased demand of patients has led to the increase in use of zirconia restorations compared to porcelain-fused-to-metal (PFM) restorations. Zirconia restorations gained attention thanks to their biocompatibility, high fracture strength, and esthetic properties . ConventMonolithic zirconia restorations have been increasingly used due to their esthetics and high translucency. Recently, extra translucent zirconia which has isotropic crystal structure has been introduced into dentistry . CliniciTranslucency has been considered as one of the primary factors in maintaining esthetics and so that is important for material selection . TransluTranslucency of zirconia is dependent on thickness , 10, graOn the other hand, large grains are more prone to hydrothermal degradation . TetragoY) of the test material when placed over a black background to the illuminance of the same material when placed over a white background [The translucency of a material is usually determined using the translucency parameter (TP) and contrast ratio (CR). TP is defined as the color difference between a uniform thickness of a material over a white and a black backing. CR is defined as the ratio of illuminance  for veneering with base dentin ceramic  with thicknesses of 0.5, 1, and 1.5 mm. The shades for the veneer ceramics were selected to correspond to A2 shade. Dentin ceramics were prepared with custom-made molds which were used for standardizing the dentin thickness.A total of 140 disk-shaped specimens (14 mm in diameter) of color A2 were fabricated from two translucent zirconia blocks  milled with CAD/CAM system . Chemical composition of the materials is shown in Then, firing process was performed at 910°C in the furnace (VITA Vacumat 6000 M). Then, veneered specimens were ground and polished on a device  using 400 to 2400 grit SiC papers whereas nonveneered specimens were polished with 1200 to 2400 grit SiC papers (English Abrasives). The final thickness of specimens (zirconia plus veneering ceramic) was set to 0.5 (no veneering), 1, 1.5, and 2 mm. The final thickness of the specimens was confirmed using a digital micrometer with an accuracy of ±0.01 mm.Before the measurements were made, all specimens were ultrasonically cleaned in distilled water for 10 min to eliminate the debris.L∗, a∗, b∗) values of each specimen were measured on a black background and on a white background with a spectrophotometer  in the wavelength range of visible light, 400 to 700 nm, at 10 nm intervals. D65 illuminant and 2-degree observer were selected. Prior to each measurement, the spectrophotometer was calibrated according to the manual. The probe tip was placed perpendicularly to the specimen surface. PTFE (polytetrafluorethylene) mold was used to create a dark environment. Three measurements were performed on different points of each disk by the same researcher, and the means were calculated.CIELab  and white (w) background. The greater the TP value, the higher the translucency of the material.where Y) of the specimens with a black and white background. The mean CR was calculated as CR = Yb/Yw. A value of 0 shows the specimen is translucent, whereas 1 shows total opacity.CR was measured from the luminous reflectance . Then, TP and CR values were measured after the aging process.p values of <0.05 were considered significant for all analyses.Statistical analysis was performed for translucency values using SPSS software . Data distribution was normal according to Kolmogorov-Smirnov. Thus, 3-way analysis of variance (ANOVA) was used to compare groups. Tukey HSD post hoc test was used to determine which group differed. The correlation between TP and CR values was analyzed using the Pearson correlation test. p < 0.001). The mean TP values and standard deviations for each group are presented in Three-way ANOVA revealed that the TP values of the specimens were significantly influenced by material, thickness, and aging  showed more translucency according to the nonveneered groups . However, post hoc pairwise comparisons among all groups indicated that the difference in TP values between HT and HTV is statistically significant, whereas the difference between XT and XTV is not.Differences in TP values before and after aging are presented in CR difference before and after aging is presented in Pearson correlation test results revealed a negative correlation between TP and CR values of specimens. This study investigated the effect of veneering and aging on translucency of extra and high translucent zirconia blocks with different thicknesses. Based on the results of the study, the hypothesis that type of material, veneering procedure, thickness, and aging would not affect the optical properties was rejected.Translucency is an important factor that affects esthetics of restoration. In the present study, a spectrophotometer was used to measure the translucency. According to the CIELab color system, the translucency of the specimens was evaluated with TP and CR. TP uses color differences, and CR is a ratio of reflectance values .In the current study, minimum thickness was determined to be 0.5 mm. Thickness of zirconia ceramics significantly affected its translucency, which is supported by some studies , 23, 24.In the present study, all specimens of VITA YZ XT showed higher translucency compared to those of VITA YZ HT. These findings are in compliance with the results of some previous studies. The results of Sen and Isler also showed significant difference between those two high-translucency zirconia blocks. This finding can be associated to larger grain size and more cubic phase of VITA YZ XT according to VITA YZ HT. Cubic phase which is optically isotropic increases the translucency by avoiding the high scattering and birefringence of light . AdditioBased on the findings of our study, there is no significant difference between veneered and nonveneered specimens of VITA YZ XT blocks in the same thickness. Although it is expected much higher translucency due to the high translucency of feldspathic veneering ceramics, the reason why a significant difference is not found may be porosity between the layers and the light transmittance of the core-veneer material after firings. These factors were also mentioned in Heffernan et al.'s previous study . On the No glazing was performed on the specimens in this study since it could influence the final optical properties which were in agreement with previous studies. Glazing produces smooth surface and it helps increase light transmittance . On the Steam autoclave application is used for accelerated aging test method of low-temperature degradation (LTD). Hydrothermal aging was done at 134°C and 0.2 MPa for 5 h which is equivalent to 15-20 years in oral environment . There wVITA YZ XT is more affected by aging compared to VITA YZ HT which might be due to larger grain size and more cubic phase of extra translucent zirconia. These findings are consistent with Fathy et al.'s study . Change The limitation of the study was that aging process simulates oral environment without chemical and mechanical factors. Therefore, further studies are needed to evaluate the effects of different aging conditions on optical properties of zirconia blocks to reflect clinical conditions.Within the limitations of the present study, the following conclusions were reached. The translucency parameter of zirconia ceramics was significantly influenced by both material type and veneering. As thickness of specimen increases, translucency decreases. VITA YZ XT was found more translucent compared to VITA YZ HT. Veneering caused a statistically significant increase in translucency of HT, but not in XT. As specimen thickness decreases, it becomes more prone to aging. Also, extra translucent and nonveneered zirconia groups are more susceptible to hydrothermal aging.


To evaluate and compare subjective and objective knee outcomes following hamstring tendon (HT) and quadriceps tendon (QT) anterior cruciate ligament reconstruction (ACLR) with or without suture tape (ST) reinforcement. It was hypothesized that the addition of an intra-articular synthetic augmentation with a ST would reduce postoperative knee laxity and graft ruptures after ACLR.A 1:1 matched-cohort comparison of patients who underwent HT and QT autograft ACLR with or without ST reinforcement was performed. Patients with ST reinforcement were consecutively assigned to the study groups until a number of 20 in each group was achieved. Medical records were reviewed for demographic characteristics and additional injuries. Laxity measurements with KT-1000, strength measurements and physical examination findings were collected both preoperatively and at 6 months and patient reported outcome (PRO) scores were collected both preoperatively and at 12 months, and comparison was made HT vs HT + ST and QT vs QT + ST. Reoperations and re-ruptures were recorded during the 24-month follow-up period.p < 0.05. No differences were found between the QT and QT + ST group. At 6 weeks patients treated with ST, both QT and HT, had a significant deficit in flexion compared to those without ST. However, this resolved at 6 months. There were no significant differences between HT + ST vs HT, or QT + ST vs QT, regarding postoperative PROs or strength measurements. Furthermore, the incidence of subsequent surgery and graft rupture was not significantly different between the groups.Overall, 80 patients who underwent ACLR were included. Patients with HT + ST had significant less laxity postoperatively compared to HT at 6 months, 1.9 vs 0.8 mm, ACLR with HT + ST reduces laxity at 6 months compared to ACLR without ST, a difference not seen when ACLR was performed using QT with or without ST. No other differences were seen between the two techniques comparing subjective and objective findings.Level III. Anterior cruciate ligament (ACL) reconstruction (ACLR) is a common orthopedic procedure, aiming at reducing knee instability. Although ACLR techniques have developed over the years and are today performed with an anteromedial femoral drilling technique, allowing a more anatomical positioning of the graft, the risk for subsequent surgery is still high , 2. An A. Proponents of HT have reported minor donor-site morbidity, good tissue strength and easy access [In Sweden, a hamstring graft (HT) is utilized in more than 85% of ACLRs, but quadriceps graft (QT) is gaining popularity . Proponey access , 14, buty access , 16. HTsy access , 18. They access , 19–21.Graft augmentation was first introduced in the 80s to increase tensile strength of the graft, but outcome data showed high failure rate and complications , 23. HowOnly a few studies have compared HT ACLR with or without ST reinforcement and none using QT , 31.The optimal surgical methods, graft choice and rehabilitation for ACLR have not yet been established. Rehabilitation must be fine-tuned in order to limit strain on the graft during graft incorporation and maturation. Although ACLR allows return to sports for the majority of patients , there iThe purpose of this study was to compare subjective and objective outcomes for patients undergoing ACLR with either a HT or QT graft, with or without complementary ST. It was hypothesized that the addition of an intra-articular synthetic augmentation of the graft with a ST would reduce the risk of residual laxity and graft rupture after ACLR.Ethical approval for this study was obtained from the regional ethics committee, Karolinska Institutet 2017–401/31.Patients presenting with an isolated ACL deficiency at the orthopedic outpatient clinic were assessed and received standardized written and oral information about the trial. Informed consent was obtained from each patient prior to participation to the study. Inclusion criteria were: Physical examination and magnetic resonance imaging (MRI) showing ACL injury, age between 18 and 40 years, active participation in pivoting sports and an ambition to return to the same sport. Exclusion criteria were: (1) previous ACL injuries to the ipsi- or contralateral knee, (2) multi-ligament injuries.After patient and surgeon agreed on ACLR and graft choice, the patients were consecutively assigned to the study groups until a number of 20 patients with HT graft and ST and 20 patients with QT and ST were achieved.The patients were then matched in a 1:1 ratio to a control group  consisting of patients who underwent surgery at the clinic during the same time frame and with the same surgical technique, apart from the ST reinforcement, Fig. Patients included in the study underwent anatomical single-bundle ACLR with autologous HT graft or mid-portion, full-thickness, all-soft tissue QT graft, with or without the addition of an independent ST . Surgery was performed by one of two experienced knee surgeons.The HT graft was harvested through a short, anteromedial oblique incision, a semitendinosus autograft was used in all cases and all grafts were between 8 and 10 mm in diameter as a quadruple.The QT was harvested at full depth from a position slightly lateral to the central part of the patella. A graft with one-centimeter width was harvested with a length of seven centimeters and cut with a quad tendon graft cutting guide and quad tendon stripper/cutter  without the use of a bone-plug.The graft ends were prepared using a SpeedWhip ripstop technique with No. 2 FiberLoop with a FiberTag . Graft diameter was 10 mm.Suspensory fixation was used on both sides, a TightRope® RT  was used on the femoral side, and a TightRope® ABS  with a 14- or 20-mm button on the tibial side.For the ST-reinforced grafts, the reinforcement was done after graft preparation with a FiberTape®  intended to be an internalbrace™ . The FiberTape® was passed through the proximal TightRope plate, Figs. The femoral tunnel was drilled through the anteromedial portal in maximum knee flexion and was placed in the center of the native ACL footprint. For tibial tunnel placement, the ACL stump and the anterior horn of the lateral meniscus were used as landmarks.The graft was first positioned in the femoral socket by tightening the Tightrope RT. A Tightrope ABS button was mounted on the ABS sling on the anterior tibia and the FiberTape was also passed through the button. The graft was fixed over the ABS button in 30 degrees flexion and the FiberTape - InternalBrace – sutures were tied over the tightrope button in full extension. Primary tension of the graft combined with a fibertape supposedly allows for creating a protective safety belt for soft tissues grafts . TensionThe rehabilitation was standardized according to the clinic’s routine. Full weight bearing and full range of motion were allowed immediately postoperatively. Quadriceps strengthening was restricted to closed kinetic chain exercises during the first three months and thereafter rehabilitation was progressed with introduction of sport-specific exercises in order to enable return to the desired activity after 9 months and Biodex® testing showed 90% strength. If the menisci were in need of suturing, a brace was used with a fixed ROM 0–30° for 2 weeks, 0–60° for 2 weeks and 0–90° for another 2 weeks, full weight-bearing was permitted with the support of crutches during the first three weeks. Otherwise the same rehabilitation protocol was used.Demographics were obtained at baseline and included age, gender, injured side, time from injury to surgery and concomitant injuries.The Knee injury and Osteoarthritis Outcome Score (KOOS) , was obtThe KT-1000 arthrometer , was used to evaluate anterior knee laxity preoperatively and 6 months postoperatively. A standard 30 lbs. force, corresponding to a 134-N anterior tibial load, at 20° of knee flexion, was applied. At least 3 measurements of each knee were made, and the median value was registered. Postoperative difference in displacement (side-to-side (STS) difference) values were stratified according to the IKDC knee examination form in three groups: ≤ 2, 3–5, and > 5 mm . “SurgicFollow-up examinations at the clinic with visits to the surgeon and physiotherapist were performed at 6 weeks and 6 months postoperatively. At the follow up visits, patients underwent a full physical examination and at 6 months isokinetic strength was also measured with Biodex system 3  .Additionally, ACL graft failures, contralateral ACL ruptures and meniscal repair failures with necessity of revision meniscus surgery were recorded during the 24-month study period.p < 0.05.For statistical analysis, SPSS® 25.0  for Mac was used. Comparisons were made in pairs, HT vs. HT + ST and QT vs. QT + ST. To compare parametic and nonparametic variables between the groups the independent t-test and Mann-Whitney U test were used. Nominal variables were tested by the Pearson Chi-squared test. Paired-sampled t test was used for Longitudinal statistics for normally distributed scale variables. The significance level was set at To determine the effect size and the power of the study, a post hoc power analysis using G*Power 3.1.9.2  was used. Based on laxity with KT1000 at 6 weeks follow-up, the analysis revealed that for HT, a sample size of 20 patients in each group would yield a power of 61% to detect a 5% significance level in laxity and an effect size of 0.73 was obtained. The total sample size needed for a power 80% would be 62 patients, 31 in each group. For QT, a sample size of 20 patients in each group would yield a power of 5% to detect a 5% significance level in laxity and an effect size of 0.06 was obtained. The total sample size needed for a power 80% with QT would be 8140 patients, 4070 in each group.Demographic data of the study groups are displayed in Table The mean preoperative and postoperative anterior STS difference showed that the HT with ST had significantly less laxity postoperatively compared with HT alone, no difference was found between the QT with or without ST, Fig. At 6 weeks patients treated with both QT + ST and HT + ST had a significant deficit in flexion. This difference resolved at 6 months, Table No differences were found in hydrops, clinical laxity or in strength measurements between the groups, Table Figure All patients with graft rupture reported a new trauma. The incidence of subsequent surgery and graft rupture did not differ significantly between the groups, Table The principal finding in this matched-cohort comparison pilot study was that the use of an HT graft with ST reinforcement significantly reduced laxity with KT-1000 at 6 months compared with HT alone. However, at 6 months no differences in laxity were seen with the QT + ST compared to QT. Further, this study did not identify significant differences in re-rupture and reoperation rates, objective measurements and PROs between the groups.The results of this study showed neither a higher complication rate nor hydrops in the cohort with ST compared to the control cohort. This is in contrast with the results reported in the 1980s, when the use of augmentation led to high rates of failure and noninfectious knee synovitis/effusion . HoweverOne of the primary goals of ST reinforcement in ACLR is protection of the graft, especially early in the healing process. The ST is supposed to act as a safety belt that supports the graft during the remodeling phase offering protection from high strains . There iThere were no differences in postoperative KOOS subscales scores at 1 year. However, there were significant improvements for all groups on all subscales from preoperative level.The main strength of this study was that we could show that the technique is feasible without any” red flags” that previously have been described with other augmentation techniques .Being a pilot study there are limitations. There was no randomization between the groups, neither were the patients nor surgeons blinded to the treatment and reported outcomes could have been subject to bias. There is a limitation that the KOOS values are only at one-year follow up, even though KOOS results are shown to be equivalent between 1 and 2 years in register data . AnotherA post hoc analysis revealed a high effect size for the ACLR with HT graft and ST, but for the ACLR with QT graft and ST the effect size was very low. The results from the post hoc analysis revealed that the total sample size needed to detect a difference in laxity for the HT + ST was 62 patients if desired power is set at 80%.The results from this pilot study are important and show that further studies are feasible, and that there are potential benefits regarding laxity, foremost with HT + ST.Anterior cruciate ligament reconstruction with HT + ST reduces laxity compared to ACLR without ST, a difference not seen when ACLR was performed with QT + ST compared without ST. No other differences were seen between the two techniques comparing subjective and objective findings.


Magnetic resonance elastography (MRE) is a reliable noninvasive method for assessment of hepatic stiffness. Liver stiffness is known to be affected by elevated postprandial portal blood flow in patients with chronic liver disease. The goal of this study was to determine whether food intake affects liver stiffness in the absence of known liver disease. We evaluated 100 volunteers (35 men and 65 women) who met inclusion criteria. The subjects had two MRE examinations, first while fasting and then 30 min after a test meal. Fourteen subjects also had two additional MRE exams 1 h 30 min and 2 h 30 min after the meal. Liver stiffness was measured by placing the largest possible polygon ROIs on the four widest liver slices and calculated as a mean of stiffness values from each slice. The correlation of liver stiffness values before and after the meal was assessed using a paired t-test. To evaluate the relationship between the change in postprandial liver stiffness and fasting liver stiffness values, linear regression was performed. The liver stiffness values in the fasting state ranged from 1.84 to 2.82 kPa, with a mean of 2.30 ± 0.23 kPa (95% CI 2.25–2.34). At 30 min after the meal, liver stiffness values ranged from 2.12 to 3.50 kPa, with a mean of 2.70 ± 0.28 kPa (95% CI 2.64–2.75), demonstrating a systematic postprandial increase by 0.40 ± 0.23 kPa (17.7 ± 3.5%). Meal intake significantly increases liver stiffness in healthy individuals, which persists for at least 2 h 30 min. Patients should fast for 3–4 h before MRE examinations to avoid fibrosis overstaging due to postprandial liver stiffness augmentation. Hepatic fibrosis is a dynamic process that can be reversed if detected early and treated appropriately4. Delayed diagnosis and inadequate treatment of liver fibrosis can lead to liver cirrhosis with subsequent complications5. Liver biopsy with histopathologic analysis has long been regarded as the gold standard for the diagnosis of liver fibrosis6. However, this procedure is invasive, expensive, and affected by sampling error. Magnetic resonance elastography (MRE), has emerged as a non-invasive option for detecting and staging liver fibrosis with high diagnostic performance6. MRE uses magnetic resonance (MR) phase-contrast techniques to obtain images of propagating mechanical waves, generated in the liver by an external source of vibration. The images of waves are automatically processed by the MRI system to produce tissue stiffness maps called elastograms. Mean stiffness values are obtained from regions-of-interest (ROI) in the liver and used for interpretation.Chronic liver diseases are an important health problem worldwide. Regardless of the root cause , they often lead to liver fibrosis6. Multiple studies have documented the relationship between MRE-assessed liver stiffness and the presence and stage of liver fibrosis13. MRE acquisition requires only a minute or less of imaging time, so the procedure can easily be included in a standard abdominal MRI protocol, enabling a comprehensive assessment that can also include rapid assessment of hepatic steatosis, and anatomic imaging to detect focal liver lesions and varices due to portal hypertension5. MRE is currently considered the noninvasive method with the highest performance for detecting and assessing liver fibrosis14. Normative values of liver stiffness in healthy people have been determined15.Patient variables such as age, sex, obesity, and hepatic steatosis have been shown to have little or no effect on MRE-based measurements of liver stiffness16. This effect has been best documented in patients with chronic liver disease and could result in overstaging fibrosis18. However, less evidence is available about the magnitude of this effect in patients without a history of chronic liver disease.It has been recommended that patients should fast for at least 4 h before MRE exams, in order to avoid transient postprandial liver stiffness augmentation that is known to occur in some patientsThe aim of the present study was to investigate whether food intake affects liver stiffness measurements in patients without clinical evidence of liver disease.The eligibility criteria included: no history of liver disease; negative family history of chronic liver disease; normal aspartate transaminase , alanine transaminase , lipase (23–300 U/l), and liver iron  levels, no drug use, normal diet and alcohol consumption < 30 g/day. Exclusion criteria included: absolute contraindications for MR imaging, abnormal serum lipase, liver enzymes or liver iron, current or history of liver disease.The research was carried out in the Magnetic Resonance Laboratory of the Center for Medical and Natural Sciences Research and Innovation of Rzeszow University, Poland, from December 2018 until July 2019.All participants were examined on a 1.5-T whole-body unit MR OPTIMA MR360 Advance  with software version SV23. The device was equipped with a gradient system having a maximum amplitude of 33 mT/m and a slew rate of 120 mT/m/ms.For liver MRI and MRE examinations, all participants underwent the scan in the feet-first supine position; an 8-channel torso phased array coil was placed over the patient’s abdomen. A drum-like passive driver was secured on the right side of the chest wall with its center at the xyphoid process. A 29-foot long polyvinyl chloride tube (3/4-in. diameter) connected the passive driver to an active driver, which was the source of vibration and stationed in the equipment room.MR Touch  with a modified 2dimensional gradient‑recalled echo‑based pulse sequence and a 60-Hz frequency was used for the MRE examination. The parameters were as follows: field of view = 40 cm, repetition time = 33.3 ms, echo time = 20.5 ms, acquisition matrix = 224 × 64, recon matrix size = 256 × 256, slice thickness = 10 mm, flip angle = 30°; number of time offset segments = 4, time of acquisition = 1 min 8 s.Nine slices were obtained through the liver in 3 or 4 breath-holds, with the participants asked to hold their breath at the end of expiration. Scanner console-generated elastograms were transferred offline for further analysis and measurements.All participants underwent MRE examinations of the liver after fasting for at least 4 h, and then were provided a meal comprising two bananas, a serving of high-calorie yogurt, and a protein bar. The overall calorific value of the meal was 1000 kcal. The MRE examinations of the liver were repeated 30 min after the participants finished the meal. Additionally, for the group of 14 randomly selected participants, the liver stiffness assessment was also carried out at 1 h 30 min and 2 h 30 min after the meal.To measure liver fat concentration, the IDEAL-IQ technique , with a gradient-echo multi-echo MR sequence, was used. The imaging parameters were as follows: FOV = 39 cm, TR = 12.4 ms, acquisition matrix = 160 × 160, slice thickness = 10 mm, slice number = 28. The scanner automatically generated fat-fraction images by collecting data at six echo times within a single breath-hold of 17 s.2) while staying at least 2 mm within the outer liver capsule. In addition, areas of wave interference, large vessels, artifacts, and the central biliary tree were avoided when drawing the ROIs.Liver stiffness was measured by placing 1 or 2 irregular polygon ROIs of various size and shape on the 4 widest liver slices in the right hepatic lobe on the elastograms. ROIs were drawn to encompass as much of the liver parenchyma as possible  software was used to perform the statistical analysis.Liver stiffness values are presented as mean ± SD. In our study, the liver stiffness in healthy volunteers was found to be relatively normal distributed in a narrow range. To assess the change of liver stiffness in the fasting state with liver stiffness after the test meal, a paired The study protocol was approved by the Medical Department of the Rzeszow University Ethics Committee (Resolution No 10/01/2019) and conformed to the guidelines of the 1975 Declaration of Helsinki . After receiving an explanation of the study, each participant provided written informed consent to enroll in the study.Among the 115 participants, 15 were excluded because of abnormal (elevated) values of ASPAT and/or ALAT. The remaining 100 were considered eligible and were enrolled in the study. All MRE exams were successfully completed. None of the participants reported any discomfort during the procedure.2 .Of the 100 participants included in the study, 35 (35%) were men and 65 (65%) were women; mean age was 22.9 years (range 20–32 years). Mean (SD) body mass index (BMI) value was 21.33 ± 0.22 kg/mP = 0.19).The liver stiffness value in the fasting state in the healthy participants ranged from 1.84 to 2.82 kPa, with a mean of 2.30 ± 0.23 kPa (95% CI 2.25–2.34). Mean liver stiffness for women was 2.31 ± 0.23 kPa . For men, this parameter was 2.27 ± 0.23 kPa . There was no correlation between liver stiffness and sex , indicating an increase by 0.40 ± 0.23 kPa  or 17.7 ± 10.7% .P = 0.56; Table Mean (SD) liver stiffness after the meal for women was 2.71 ± 0.28 kPa . For men, this parameter was 2.67 ± 0.29 kPa . Liver stiffness after the meal did not correlate with sex . For men, this parameter was 2.69 ± 0.88% (95% CI 2.39–2.99%), range 1.70–4.90%. For women, this parameter was 2.41 ± 0.66% (95% CI 2.25–2.58%), range 1.40–4.87%. The liver fat fraction did not correlate with sex  and “fasting liver stiffness (P = 0.04) were significantly correlated with the increase in liver stiffness after the meal . The postprandial increase in liver stiffness in our study was higher, which may be attributed to differences between the patient populations and the meal used in the experiment.The presented research is the largest prospective study to evaluate postprandial MRE-based stiffness liver changes in patients with no previous history of chronic liver disease. We observed a postprandial increase in liver stiffness by 0.40 ± 0.23 kPa  documented in the QIBA consensus profile for MRE20, and a dynamic factor reflecting perfusion pressure21. Changes in hepatic artery flow parameters potentially affect the LSM: after a meal, the flow rate decreases while the hepatic artery resistance index increases22. According to Ohm's law, an increase in the portal vein flow after a meal would increase portal pressure, provided the resistance of intrahepatic vessels remains constant. Autoregulation of blood flow may depend on intrahepatic pressure at the level of the vascular bed, which maintains constant pressure parameters in the portal bed23. Currently, the researchers are inclined toward the thesis that changes in intrahepatic pressure caused by increased blood flow in the portal vein and postprandial hyperemia of the liver lead to changes in sinusoidal pressure, thereby preventing overpressure on the portal system in healthy people17. If autoregulation is impaired, an increased portal vein flow will increase venous pressure and therefore also tissue stiffness17. Indeed, researchers describe as much as a 30% to 40% increase in the portal blood flow and portal blood velocity and hepatic venous pressure gradient after a meal in patients with cirrhosis24.Liver stiffness measurements (LSM) are considered to be influenced by 2 factors: a static factor reflecting the structural properties of tissues, including changes in the extracellular matrix occurring during the course of inflammatory and fibrotic processes25.In our study, the highest average liver stiffness value was recorded 30 min after a meal. Liver stiffness then gradually decreased, but even at 2 h 30 min after the meal, the liver stiffness was greater than that measured with an empty stomach: 2.41 vs. 2.25 kPa. This finding is consistent with reports by others who demonstrated a decrease in liver stiffness compared with baseline values after more than 3 h after consuming a meal26. It remains to be determined whether a similar phenomenon occurs in sick people.In addition, we observed that patients with lower liver stiffness levels on an empty stomach had greater increases in postprandial liver stiffness. Identical observations were reported by Petzold et al.17, we showed no correlation between hepatic stiffness and BMI, in contrast to Petzold et al.26, who reported a significant positive correlation between postprandial LSM and BMI, using ultrasound based elastography.Our study revealed no correlation between liver stiffness and age, sex, or selected laboratory parameters. Similarly to Yin et al.One limitation of the presented research is the narrow age range of the study group. Therefore it was not possible to investigate the postprandial liver stiffness changes with reference to different age subgroups. Further studies should involve participants within a wider age range to analyze such potential differences. It would also be very interesting to extend the investigations on other populations as a multicenter study to confirm the universalism of presented results.Meal intake causes significant increase of liver stiffness in healthy individuals. Postprandial liver stiffness changes persist for more than 2 h 30 min. Patients should fast for 3–4 h before MRE examinations to avoid fibrosis overstaging due to postprandial liver stiffness augmentation.


Reduction of graft-resident leucocytes before transplantation is a well-known approach for prolonging organ survival without interfering with the recipient’s immune system. As previously shown by our group, injecting mice with IL-2/anti-IL-2 complexes (IL-2cplx) to augment expansion of CD4 T regulatory cells (Tregs) induces tolerance towards islet allografts, and also to skin allografts when IL-2cplx treatment is supplemented with rapamycin and a short-term treatment of anti-IL-6. In this study, we investigated the mechanisms by which graft-resident leucocytes impact graft survival by studying the combined effects of IL-2cplx-mediated Treg expansion and passenger leucocyte depletion. For the latter, effective depletion of APC and T cells within the graft was induced by prior total body irradiation (TBI) of the graft donor. Surprisingly, substantial depletion of donor-derived leucocytes by TBI did not prolong graft survival in naïve mice, although it did result in augmented recipient leucocyte graft infiltration, presumably through irradiation-induced nonspecific inflammation. Notably, treatment with the IL-2cplx protocol prevented early inflammation of irradiated grafts, which correlated with an influx of Tregs into the grafts. This finding suggested there might be a synergistic effect of Treg expansion and graft-resident leucocyte depletion. In support of this idea, significant prolongation of skin graft survival was achieved if we combined graft-resident leucocyte depletion with the IL-2cplx protocol; this finding correlated along with a progressive shift in the composition of T cells subsets in the grafts towards a more tolerogenic environment. Donor-specific humoral responses remained unchanged, indicating minor importance of graft-resident leucocytes in anti-donor antibody development. These results demonstrate the importance of donor-derived leucocytes as well as Tregs in allograft survival, which might give rise to new clinical approaches.The importance and exact role of graft-resident leucocytes  in transplantation is controversial as these cells have been reported to either initiate or retard graft rejection. T cell activation to allografts is mediated  T cell reactions to organ allografts are directed largely to major histocompatibility (MHC) antigens expressed on donor cells, both within the graft and on graft-resident leucocytes; these “passenger leucocytes” migrate from the graft to the periphery to activate host T cells . In partvia either prior organ culture in vitro or pre-transplantation on host-type mice. With both approaches, depletion of passenger leucocytes retarded rejection and thus prolonged survival of skin allografts in rodent models  largely depleted of graft-resident bone-marrow (BM)-derived cells. Donor mice (BALB/c) were subjected to lethal TBI (8.5 Gy) at day 8 prior to skin graft donation and were reconstituted with bone marrow (BM) cells from isogenic donors at day -7 . When irvs 32% non-IR; p = 0.02; vs. 42% IL-2cplx IR; To study the immunological mechanisms leading to graft rejection, graft-infiltrating leucocytes (GILs) were investigated starting at day 6 after skin transplantation. Analysis of GILs in untreated recipients (wild type C57BL/6 grafted with BALB/c skin) revealed ~2.5-fold higher CD45+ cell frequencies in grafts previously exposed to IR in comparison to naïve (non-IR) grafts . For the IR grafts, by contrast, levels of CD45+ cells did not increase between day 6 and day 20 (mean 58% d6 vs 62% d20)  and IA-d (MHC II) specific ELISA showed that recipient mice receiving IL-2cplx do not develop donor specific IgG responses (b), BALB/c  and C3H (H-2k) mice were purchased from Charles River Laboratories  and housed in ventilated HEPA-filtered cages at the Medical University of Vienna under specific pathogen-free like conditions. Mice were used for experiments between 6 and 8 weeks of age with an average weight of 18 to 21 g. All experiments were approved by the ethics votum of the Austrian Federal Ministry of Science, Research and Economy (Permission number GZ: BMWFW-66.009/0292-V/3b/2018).Female C57BL/6  were subjected to lethal total body irradiation (TBI) of 8.5 Gy at day -8 and were reconstituted with 10 x 10The IL-2 complex protocol was administered as previously described . BrieflyFull thickness tail skin of naïve BALB/c (donor) mice or BALB/c mice previously subjected to lethal TBI and reconstituted with isogenic BM were grafted on the flank  of naïve C57BL/6 (recipient) mice. After transplantation skin grafts were secured with band aids for 6 days, followed by visual inspections at short intervals. Skin grafts were considered rejected if less than 10% remained viable. During transplantation mice were anesthetized with Ketanest  and Rompun . Postoperatively mice received Temgesic  and Dipidolor  in drinking water ad libitum for 1 week.d (34-2-12), CD3 (17A2), CD4 (RM4-5 and GK1.5), CD8 (53-6.7), CD44 (IM7), CD62L (MEL-14), CD25 (PC61.5), CD80 (16-10A1), CD86 (PO3), CD11b (M1/70), CD11c (N418), MHC II (M5/114.15.2), 7AAD , Foxp3 (FJK-16s) and fixable viability dye (Fixable Viability Dye eFlour 450 and 506 purchased from eBioscience) were used. Cell suspensions were stained for surface markers for 30 min., 4°C in the dark. Intracellular Foxp3 staining was done using a Fixation/Permeabilization kit (eBioscience) according to the manufacturer’s instructions. Erythrocyte lysis in spleen cells was performed utilizing red blood cell lysis buffer (Sigma). Analysis was done with BD FACS Canto II and FlowJo software.For characterization of leucocyte subtypes antibodies against mouse CD45.2 (104), H2DSkin grafts were cut into small pieces in RPMI medium before digestion using a murine Tumor Dissociation Kit (Miltenyi Biotec) according to the manufacturer`s instructions. Cells were resuspended in cold PBS and the number of viable cells was determined using a CASY cell counter (Innovatis) before flow cytometrical staining. GILs were defined as viable single cells expressing CD45.d or I-Ad monomers at 4°C, overnight. Serum samples obtained 14 days post rejection of skin allografts were diluted 1:100 before incubation with monomers at 4°C, overnight. Donor-specific antibodies bound to monomers were detected utilizing monoclonal rat anti-mouse IgG1, IgG2a/b, IgG3 in combination with an HRP-coupled goat anti-rat serum (1:2000). ABTS was used as substrate for HRP and absorption was measured using a Victor microplate reader (405nm). The biotinylated MHC monomers were kindly provided by the National Institutes of Health’s Tetramer Core Facility (https://www.niaid.nih.gov/research/nih-tetramer-core-facility).To detect IgG and IgM against donor MHC I (H2k-d) and MHC II (IA-d), a donor MHC-specific ELISA was performed as previously described . Brieflyp-value < 0.05 was considered statistically significant.The statistical analysis was performed using GraphPad Prism 5.0 . Error bars indicate standard deviation (SD) and differences between groups were compared using a 2-tailed Student´s t-test with unequal variances. Survival of skin allografts was calculated based on Kaplan-Meier product limit method and compared between groups using the log-rank test. Fold change in GILs was calculated dividing the mean value of two independent experiments for d20 by the mean value of d6. A The role of passenger leucocytes and its impact on graft survival after solid organ transplantation is complex. Although several groups demonstrated increased survival of mismatched organs depleted of graft-resident cells in rodent models (5-8), there is also contrary evidence suggesting beneficial immunomodulatory effects of passenger leucocytes in transplantation . StudiesContact with DCs is crucial for immune responses after solid organ transplantation with DCs being 100 times more potent in activating T cells than MHC II-bearing macrophages or B cells . Within versus-graft response. This notion is in line with the report that early infiltration of donor-reactive CD8+ T cells promoted fast allograft rejection via IFNγ production in a cardiac transplant model  formation since DSAs are known to be one major issue in graft injury and chronic rejection . As prevex vivo organ perfusion with depleting antibodies or anti-thymocyte globulin (ATG) to reduce the number of specific graft-resident leucocyte subsets within the graft.Although this study is restricted to skin allograft transplantation, it clearly demonstrates that the absence of graft-resident cells (in this study achieved by IR pre-treatment of the donor) is beneficial for long-term transplant survival if early IR-related pro-inflammatory processes are overcome. As already mentioned IR is accompanied by a variety of side effects , discourIn this proof-of-principle study we could demonstrate the importance of donor-derived leucocytes in recipient sensitization and allograft rejection, which may lay the ground to new translational approaches. Graft survival and long-term outcome could be improved by targeting early allogeneic responses and acute rejection episodes due to rapid recognition of allogeneic MHC in direct T cell allorecognition. Studies investigating the effect on long-term survival and chronic rejection in primarily vascularized grafts are clearly warranted.More importantly, these data suggest that treatment with the IL-2cplx protocol ameliorates  inflammatory processes caused by e.g. IR and therefore counteracts the early augmented infiltration of leucocytes into the graft, which could trigger acute rejection and early graft loss.The original contributions presented in the study are included in the article/The animal study was reviewed and approved by Federal Ministry Republic of Austria Education, Science and Research.All authors have actively contributed to this project. RS and NP designed all experiments and analyzed data. RS, NP, and AW performed experiments. RS, NP, JS, and TW interpreted data and wrote the manuscript. All authors contributed to the article and approved the submitted version.This work was supported by the Austrian Science Fund (J3671-B19 and P31186-B28 to NP) and grants from the National Health and Medical Research Council of Australia to JS.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.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Acute kidney injury (AKI) is a common finding in kidney donors and recipients. AKI in kidney donor, which increases the risk of delayed graft function (DGF), may not by itself jeopardize the short- and long-term outcome of transplantation. However, some forms of AKI may induce graft rejection, fibrosis, and eventually graft dysfunction. Therefore, various strategies have been proposed to identify conditions at highest risk of AKI-induced DGF, that can be treated by targeting the donor, the recipient, or even the graft itself with the use of perfusion machines. AKI that occurs early post-transplant after a period of initial recovery of graft function may reflect serious and often occult systemic complications that may require prompt intervention to prevent graft loss. AKI that develops long after transplantation is often related to nephrotoxic drug reactions. In symptomatic patients, AKI is usually associated with various systemic medical complications and could represent a risk of mortality. Electronic systems have been developed to alert transplant physicians that AKI has occurred in a transplant recipient during long-term outpatient follow-up. Herein, we will review most recent understandings of pathophysiology, diagnosis, therapeutic approach, and short- and long-term consequences of AKI occurring in both the donor and in the kidney transplant recipient. Acute kidney injury (AKI), a common problem in kidney transplantation, can take place both in the donor before organ harvesting, and in the recipient early after transplantation. It manifests as delayed graft function (DGF) or de novo post-transplant acute deterioration of graft function. In either setting, AKI in the graft could affect short- and long-term transplant outcomes.DGF, which is a heterogeneous condition resulting from factors related to procurement, organ quality, recipient medical condition, surgical insult, and graft injury-related to dialysis treatment itself, is most commonly defined as the requirement of dialysis sessions in the first week of post-transplantation in a patient who eventually becomes free of dialysis . HoweverAccording to recently published data, AKI affects 30% of kidneys coming from deceased donors and 50% of those coming from deceased donors after cardiac death (DCD) ,3. AlthoAKI may develop post-transplantation after an initial recovery of kidney function or may occur late after transplantation. In both settings, AKI can originate from severe and often unrecognized clinical conditions that may require a prompt intervention to prevent graft loss.The present review focuses on the etiology, diagnosis, prognosis, and treatment of AKI in both the donor and the recipient, both in the short and long term.The organ shortage is causing an ever-increasing gap between the availability of organs and transplant candidates, therefore the use of less than optimal donor kidneys, like organs from expanded criteria donors (ECD), or donors after cardiac death, has augmented over the last two decades in order to expand the deceased-donor pool . These pAKI, which occurs in more than 25% of critically ill patients, depends on the underlying disease, the duration of kidney impairment, and the patient’s baseline kidney condition . From exSeveral studies have been published to assess the effect of donor AKI on primary no function, DGF, and long-term graft dysfunction. By and large, those studies showed that donor AKI might cause DGF but not necessarily increase the risk of early graft loss or graft failure in the long term.Kayler et al. , by analp < 0.005), and PNF rates were significantly higher for AKIN stage 3 kidneys  [A subsequent retrospective study  analyzed = 0.04) .In a US study from five organ procurement organizations in the period 2010–2013, Hall et al.  reportedSince both donor AKI and prolonged CIT are associated with an increased risk of DGF, Dube et al.  tested tp = 0.10). In this setting of biopsy-driven acceptance criteria, the severity of deceased-donor AKI did not affect the relation between DGF and graft loss [A recent mono-centric study examined the long-term outcomes of a large cohort of kidney transplants from donors with AKI, in which pre-specified criteria for acceptance were based on pre-implantation biopsy . Kidneysaft loss .In conclusion, current evidence supports the notion that, for standard-risk donors, donor AKI does not impair transplantation outcomes. The evidence is less convincing for marginal donors, such as elderly donors or donors with elevated KDPI . For the latter type of donors, we would suggest that protocols for organ quality assessment, minimization of cold ischemia times, and/or use of machine perfusion be implemented at each transplant center.As outlined above, DGF may have an unfavorable impact on allograft outcomes, including long-term kidney allograft function, and on patient and graft survival. This unfavorable association is modified by the severity of DGF, as indicated by the duration of dialysis dependence after transplant: the longer the dialysis-dependent period, the higher the hazards of rejection and of graft failure ,20. The As mentioned above, DGF recognizes a multifactorial pathogenesis involving donor-related risk factors, recipient-related risk factors, and perioperative risk factors  22,23,2,223,24. Recipient-related risk factors are due in part to pre-transplantation variables and in part to surgery. Pre-transplantation oliguria, especially in patients with long dialysis vintage, is an important risk factor for DGF as well as the need of pre-surgery hemodialysis sessions with ultrafiltration. In addition, high immunological risk profile  is an independent predictor of DGF related to immunosuppressive therapy, mainly due to the requirement of high dosage of calcineurin inhibitor (CNI) .Moreover, a complex vascular surgery or the occurrence of vascular complications implicates a prolonged warm ischemia time, defined as the time from organ removal from cold storage to allograft reperfusion. Also, concomitant surgery  and increased body mass index (BMI) may significantly prolong warm ischemia time .Finally, perioperative factors such as post-transplant hypotension and hypovolemia and high CNI blood levels may increase the risk of DGF.Most of the above-mentioned risk factors for DGF act by promoting ischemia-reperfusion injury. The molecular and cellular events that occur in IRI are complex, involving oxidative damage and the activation of the innate immune system . Signalin = 13), after implantation and reperfusion , and at 3 or 12 months after transplant (n = 5 each). Methylation increased drastically in all allografts as a result of graft ischemia. Graft ischemia preferentially reduced the expression of genes involved in suppressing kidney injury and fibrosis in terms of glomerulosclerosis and interstitial fibrosis [Formation of graft fibrosis is the most likely mediator of the relationship between DGF and reduced long-term graft survival. Ischemia may also induce graft fibrosis by mechanisms that do not involve inflammatory injury. For instance, one study has shown that DNA hypermethylation of kidney transplants after ischemia is directly proportional to the duration of cold ischemia . In thatfibrosis . DNA metfibrosis . Interesfibrosis . Klotho fibrosis ,36,37,38Unfortunately, despite the new advances in knowledge of the mechanisms that link DGF to long term outcomes, evidence of benefit of newer strategies for diagnosis and management of AKI are still lacking.Monitoring of DGF in transplanted kidneys has been traditionally based on a combination of clinical , immunological , instrumental , and histological parameters. Because of the limits and the complexity of the “traditional biomarkers”, over the last decade, new biomarkers have been introduced that can be easily measured in biological fluids, such as perfusion solution, patient’s serum, plasma, or urine . Among tAmong the most promising predictive donor biomarkers are elevated donor plasma mitochondrial DNA levels , donor uPromising biomarkers are also the extracellular vesicles, membrane structures of different size released by cells that could act as mediators of cellular crosstalk between immune system and graft . Some ofDespite the extensive number of biomarkers that have been put forward over the recent years, still no consensus exists on the utility of any of them for routine clinical practice.Most therapeutic strategies to prevent DGF experienced so far have targeted the donor before harvesting or the recipient during the peri-operative period. The use of low-dose dopamine for donor pre-treatment before procurement is the strategy that is best supported by evidence coming from clinical trials .The most traditional preventive strategies have been based on preventing graft ischemia by recipient volume expansion before reperfusion with the use of various isotonic saline solutions , as wellhttps://www.clinicaltrials.gov/ct2/show/NCT02056938, accessed on 1 February 2021) specifically designed for this purpose was preliminarily stopped due to poor enrollment.Because rabbit anti-thymocyte globulin targets, besides T cells, also endothelial adhesion molecules and may help minimizing CNI use, they have been the induction treatment of choice to prevent DGF. However, no published studies demonstrated a real benefit  and the https://clinicaltrials.gov/ct2/show/NCT02134314, accessed on 1 February 2021) that treatment with c1-esterase inhibitor (time 0 and 24 h after transplant) did not reduce DGF incidence but reduced the number and duration of dialysis treatments, with significantly improved kidney function 1 year later [Encouraging data came from the use of complement inhibitors. Jordan et al. in 2018 preliminarily showed in a phase I/II double blind, placebo-controlled study , deliver a pulsatile flow, and optionally provide oxygenation (oxygenated versus non-oxygenated machine perfusions). A meta-analysis has shown that hypothermic machine perfusion is superior to static cold storage in preventing DGF in deceased donor kidney transplantation . This isAmong the most promising pharmacological treatments that may be administered to the graft via machine perfusion to prevent DGF and fibrosis is cell therapy based on multipotent adult progenitor cells (MAPC) . MultipoOne additional strategy is the complement inhibitor APT070 (Mirococept) with a unique ‘cytotopic’ property that permits its retention in the organ microvasculature. This latter drug is currently being investigated in the EMPIRIKAL trial for the prevention of DGF in deceased-donor kidney transplantation .AKI might develop early after transplantation after an initial recovery of graft function. The most common causes are surgical or medical complication, including acute rejection, whose diagnosis requires biopsy. Acute tubular necrosis, in the absence of inflammatory injury, is reported as one of the possible phenotypes of antibody-mediated rejection . SurgicaAKI after transplantation is a risk factor for graft failure ,67. MostAmong the cases of AKI with symptoms, bacterial infection and especially urinary tract infections are by far the most common cause . The preGarg et al. recently analyzed trends in rates of hospitalizations in kidney transplant recipients with primary diagnosis of AKI, secondary diagnosis of AKI, and AKI-requiring dialysis over an 11-year study period . IncidenAn automated real-time electronic (e)-alert system for AKI, based on the Kidney Disease Improving Global Outcomes (KDIGO) change in creatinine diagnostic criteria, was developed in England and Wales in order to identify AKI in the general population and facilitate a better outcome ,74. ReceBecause the evidence that these alerts impact outcome is lacking, further developments of those electronic alerts and clinical studies are needed before implementation can be recommended for routine clinical care.In December 2019, a novel strain of Coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified as the causative agent in a cluster of patients presenting with severe pneumonia in Wuhan, China. Multiple reports converged to indicate that kidney transplant recipients have higher mortality than the general population, possibly because of the ongoing immunosuppression and multiple co-morbidities ,77. AKI AKI, a common event in kidney transplantation in both the donor and the recipient, may have consequences on both short- and long-term graft functions. Several studies have been performed trying to identify biomarkers for predicting which donor AKI carries the highest risk of graft failure, and to implement treatment strategies to minimize the impact of AKI on short- and long-term graft dysfunction. While the research on biomarkers has not translated into clinical applications, the use of hypothermic machine perfusion has become a consolidated practice to prevent DGF. AKI occurring after early post-transplantation after initial recovery of graft function is usually related to surgical or medical causes that may occasionally cause graft failure if left untreated. Development of AKI later after transplantation often has an unfavorable impact on allograft outcomes because it may reflect the chronic use of nephrotoxic drugs or serious underlying medical conditions. E-alert systems have been proposed to help in identifying outpatients developing AKI during long term follow-up, but evidence on the beneficial effect on patient outcomes is still lacking. Longer follow-up studies are needed to understand the impact of COVID-19-assoaicted AKI in kidney transplant recipients.