At the senior level, no uneven distribution was identified. The comparison of the number of matches in each age category and the quartile of birth showed a difference in the women’s youth category, where players in quartile 8 had a significantly lower number of appearances compared to quartile 1. The results form part of a growing body of knowledge about selection mechanisms in sport, which favours relatively older athletes within Norwegian Handball. Such findings are important for policy and practice for informing TID programmes for inclusive selection opportunities for all players.Many elite sport organisations have introduced structured talent identification and development (TID) initiatives in youth sports to better facilitate elite sport performance. However, selection mechanisms for TID programmes  are biased towards relatively older athletes and limited studies exist with Scandinavian contexts. Therefore, the aim of this study was to explore the relative age effect (RAE) in youth, junior and senior male and female international team selections among Norwegian handball players (n = 657). A Chi-square goodness-of-fit test assessed whether a skewed birthdate distribution occurred at the youth, junior and senior international team levels and odds-ratios were calculated for RAE distribution. Moreover, a Kruskal-Wallis test was used to assess differences between the number of international youth, junior and senior level appearances by birth quartiles. Significant uneven birth date distributions were shown for youth (χ The regional programme is organised in annual-age categories while the national programme starts at age 15 and is organised in bi-annual age-categories. Such a policy decision results in age (dis)advantages based on an individual athletes birth date in comparison to the respective cut-off date [Most elite sport organisations have introduced structured talent identification and development (TID) initiatives in youth sport to better facilitate elite sport performance . Such TIoff date . The selThis well-documented systematic selection bias is known as the relative age effect (RAE) resulting in skewed birthdate distributions among athletes and an over-representation of athletes born closer to age cut-off dates in particular sports . The RAEHandball is an Olympic, complex and physically demanding team ball sport . It is aSeveral studies have evaluated the RAE in handball. For example, Schorer, Cobley, Büsch, Bräutigam and Baker  found siAlthough research examining RAEs in handball is available, to the authors knowledge, only a few attempts have been made to investigate the prevalence of RAEs in the context of Scandinavian team sport. Wiium, Lie, Ommundsen and Enksen  investigTherefore, the aims of this study were to (a) evaluate the prevalence of the RAE in international youth, junior and senior Norwegian male and female handball players; and (b) explore the relationship between relative age and the number of international youth, junior and senior level appearances. The results should be of particular interest to people developing elite sport policy and practitioners involved in formal TID programmes.The organisational structure of Norwegian handball includes multiple autonomous actors, such as clubs, sport schools, regional federation-level TID activities, and youth and junior international team activities. In the context of Norway, no actor has instructional authority over others, and no single actor has sole responsibility for talent development.In both women’s and men’s handball in Norway, the player development model of the National Handball Federation is broad-based: as many as one-third of all youth handball players participate in different TID initiatives during their early adolescence . AthleteThe European Handball Federation and the International Handball Federation each organise, respectively, the European Championships and World Championships once every two years. Both tournaments are played during Europe’s summer holidays and the teams must qualify to take part. Each international team is based on a bi-annual age category: players born in the same two-year period play together throughout their international team careers. The talent development initiatives in Norwegian handball from the age of 15 to 20 years, covers the entire time span for the international youth and junior teams, as shown in To evaluate the prevalence of the RAE in Norwegian handball a dataset was obtained from the Norwegian handball federation. The study sample consisted of female (n = 318) and male (n = 339) players, born between the years 1986 and 1999, who had been selected to international competitions for the Norwegian international youth , junior , and senior , international teams. Players in the youth category may re-appear in the junior and/or senior categories.In international handball, all team activities during adolescence are grouped into two-year age categories and those born in the same age-category play together until they enter senior international handball. Within each age category, players who are born in even-numbered years are always relatively older than those born in odd-numbered years. Thus, the study sample consisted of seven different international team cohorts: Players born in 1986–1987; 1988–1989; 1990–1991; 1992–1993; 1994–1995; 1996–1997; and 1998–1999. The international youth team level refers to the under 18 and the international junior team level is equal to the under 20 level.A list of the team players and their birthdates was obtained with permission from the Norwegian Handball Federation. The list included the number of matches players had played at the youth, junior and/or senior international teams. All the player’s names in this study were anonymised before analysis in compliance with the study’s ethical requirements. Research approval was granted by the Norwegian Centre for Research Data.st of January and the 31st of March; In Q2, the 1st of April and the 31st of June; In Q3, 1st of July and the 31st of September; and in Q4, 1st of October to the 31st of December, in even-numbered years. In Q5, players were born between the 1st of January and the 31st of March; In Q6, the 1st of April and the 31st of June; In Q7, 1st of July and the 31st of September; and in Q8, 1st of October to the 31st of December, in odd-numbered years. Only Q1 to Q4 was used when evaluating senior players.Each biannual age-category extended across two years and therefore consisted of eight quarters. Each player’s birthdate was coded into one of these categories (Q1-Q8). In Q1, players were born between the 1The statistical analyses were undertaken using the program IBM SPSS statistics v24. A Chi-square goodness-of-fit test was computed to assess whether there was a skewed birthdate distribution in selection to international team competitive activities in each of the two-year age-categories, in both women’s and men’s handball. Distributions were compared to expected frequencies, set from the official birth statistics of Norway across the years 1988–1999  Table 1Table 1. To assess possible differences between the quarter of the year in which a player was born and the number of international matches played at the youth, junior and senior international level, a Kruskal-Wallis test was conducted. The significance level was set at p = 0.05. P-values were adjusted by the Bonferroni correction for multiple tests.2(7) = 40.383 p <0.001) and junior (χ2(7) = 27.427, p <0.001) international players, favouring the relatively older player. No uneven distribution was identified at the senior level.The results show that 61% of all female players and 68% of all male players were born in even-numbered years in selections to the international youth and junior age categories. 2(7) = 105.716, p <0.001) and junior (χ2(7) = 30.948, p<0.001) international players, favouring the relatively older players. No uneven distribution was identified at the senior level.For males, significant uneven birth date distributions were shown for youth  evaluate the prevalence of the RAE in international youth, junior and senior Norwegian male and female handball players; (b) explore the relationship between relative age and international Handball appearances. Findings showed that relatively older athletes are over-represented in selections to youth and junior international team competitions in Norwegian handball but not at the senior level. These results are consistent with most studies about selection mechanisms in sport showing that there is a clear tendency to select relatively older athletes to formal TID programmes that diminish in adulthood. Such findings may have implications for TID policies in Norwegian male and female handball.Significant uneven birth date distributions were shown for all female and male players selected to the youth and junior international teams, favouring the relatively older players. Contrary to our findings, some researchers have contended that the RAE is less prevalent in women’s sport . For exaSome authors have speculated that the RAE co-varies with the depth of competition in a given sport . The depIn our analysis of the number of matches per player born in the different birth quartiles, only females at the youth international team level (comparison of Q1 and Q8) were found to be different from each other. This may indicate that while international team selections favour relatively older players, they do not strongly affect the possibility of a player achieving a successful international team career after first being selected. These findings echo those of other empirical studies, such as, Bjørndal, Ronglan and Andersen  showing In our study, and similar to other studies in competitive handball , no unevThe results from this study highlight how the particular selection to international youth and junior competitions in Norway are favouring relatively older athletes but these findings might also be discussed in relation to how the limited availability of positions is a challenge for all selection-based talent development programmes. This is because the most basic challenge of all talent development programmes that are based on selection is that all criterions for selection are, at best, limited. Most selections are  based on athletes’ current levels of performance, and for most immature athletes–statistically, the relatively older athletes–the probability of getting selected is greater than for younger athletes. Nevertheless, the fact that athletes are relatively younger does not indicate anything about their potential relative to their older peers. Neither researchers nor practitioners are able to determine athletic potential  and this remains a challenge for selection-based talent development models . ChristeWe are not suggesting that more objective measures of sports talent should be found. The complexity inherent in athlete development would limit the likely success of trying to do so. However, our findings indicate that talent identification has little to do with assessing ‘potential’, and more to do with strengthening the opportunities available to athletes to learn and develop using different material and personal resources . Future Future research should therefore focus more on the mechanisms underpinning talent identification and development. In such, qualitative enquiries may be a particularly promising approach. Moreover, Delorme, Boiché and Raspaud  have argThe results from this study suggest that the selection to Norwegian youth and junior international team competitions is skewed in favour of selecting relatively older players and add to the growing body of evidence that show how static and linear selection methods informing most talent development programmes may be fundamentally problematic. This create unequal opportunities for developing athletes . The effand minimise selection bias.Youth handball players’ experiences have revealed that international team experience can be an important developmental influence, and have a strong effect on motivation, skill development and athlete learning . Youth aIn handball, two possible strategies could help to counteract the relative age effect. Firstly, coaches involved in talent development programmes should be actively aware of the relative age effects that occur during selections, such as those for youth and junior international team competitions. Secondly, as Aguilar, García and Romero  have proS1 File(CSV)Click here for additional data file.


Working as an editor of a medical journal is quite a challenging duty. It requires personal commitment and motivation, experience in writing and reviewing scientific articles, publishing know-how, and probably a great deal of diplomacy and common sense in decision-making. Newly appointed editors-in-chief are confronted with an immense responsibility toward authors and reviewers, the entire critical professional audience, but also toward their editorial teams . MaintaiCroatian Medical Journal (CMJ). I remember the CMJ’s beginnings and have been witnessing its progress throughout my whole career as a scientist and teacher at the Zagreb School of Medicine – the CMJ was founded in 1992, the year in which I was employed as a PhD fellow at the Department for Chemistry and Biochemistry. In fact, as a naive and idealistic young scientist, I submitted a manuscript for publication in the CMJ. Although this attempt was not successful, I received unexpectedly constructive critical comments and detailed editorial suggestions for manuscript improvement. Not only did I publish a substantially improved article in a journal with a higher impact factor, but above all, this experience made me realize the immense importance of journal’s educational role and its editor's obligation to strive for maximum manuscript quality and originality.Knowing all that, in the spring of 2019, I took over the honorable duty of the editor-in-chief of the CMJ were hard enough, but a journal that started as a publication venue for scientists from developing countries has evolved significantly and admirably. The CMJ is today a modern journal covering broad aspects of biomedicine, with transparent editorial policy and an important advantage of providing open access to authors and readers. Moreover, it is a journal in continuous pursuit of excellence in every issue (CMJ publishes two thematic issues, and one of them is just in front of you. Being a neuroscientist, I am particularly happy to write my first editorial in the issue dedicated to the “International Conference on Neurological Disorders and Neurorestoration,” which takes place in May 2019 in the inspiring renaissance scenery of Dubrovnik. By becoming the CMJ’s editor-in-chief, I got the opportunity to observe the other side of manuscript managing and publication. At the same time, I took over a serious but fulfilling task that I intend to perform with all my heart and with full assistance of my editorial team.The beginnings of the ry issue . Realistry issue . The impry issue . In 2019


Human capital is considered a major asset of any business. This is even more vital in a knowledge-driven economy, where non-visible factors and services are of increasingly significant. The focus of this study was to determine the impact of training assistance on the performance of SMEs in Lagos, Nigeria. Only few studies have investigated how training support programmes by government facilitate the performance of SMEs under Small and Medium Enterprises Agency of Nigeria (SMEDAN) in Nigeria. Descriptive research method was adopted for this study. Statistical Package for Social Sciences (SPSS 22) was used to analyse 203 copies of questionnaire retrieved. The reliability and validity of research instruments was also established. This data set indicated that training and development can facilitate innovative processes among SMEs owners to create economic, social values and remain globally competitive. Specifications TableValue of the data•These data present information on training assistance as regards the performance of SMEs. This is important considering the fact that developing the right skill set implies improved capacity to deliver superior value to customer.•This data shows the significance of providing adequate training assistance particularly in conjunction with incubator system for Small and Medium Enterprises (SMEs), its impact and valuable contributions in enhancing the innovative performance.•The results can facilitate innovative processes among SMEs owners to create both economic and social values and remain competitive.1The data for this research was gathered from SMEs owners/managers in Lagos, who have benefited from government training assistance. A total of two hundred (203) copies of questionnaire were analysed. Descriptive statistics and regression analysis was used to facilitate the analysis of data obtained. It shows the degree of variability contained in the dependent variable (Performance of SMEs) as explained by the independent variable (Training Assistance).22.1Data was gather from SMEs operators across three states in Nigerian, who have benefited from government training assistance. The study population involves SMEs operators registered under Small and Medium Enterprises Development of Nigeria (SMEDAN), which has a population of 22,971 businesses and 400 business owners were selected as participant for this study. Data were collected based on the copies of questionnaire distributed to SNEs operators. Data was also collected from secondary sources which involve relevant information based on published journals [8]2.2Data collected from the questionnaires administered to respondents were analysed and presented as follows. 2.3Training assistance has no impact on innovative performance of SMEs in Nigeria.The model summary table shows how much of the variance of the dependent variable (innovation performance) is explained by the model. In this case, the R square is .334 if expressed by a percentage will be 33.4%. This means that our model explains 33.4% of the variance in the levels of innovation performance.=59.410. Hence, the alternative hypothesis is accepted.The F-value is the Mean Square Regression (12.851) divided by the Mean Square Residual (0.216), yielding F=59.410. From the results, the model in this table is statistically significant (Sig=.000) and hence the null hypothesis should be rejected. Therefore, training assistance has impact on innovative performance of SMEs at F2.3.1Thus, based on the result above, it is justified that the null hypothesis be rejected while the alternate hypothesis be accepted. It can therefore be concluded that training assistance has effects on innovative performance of SMEs.Covenant University for providing full sponsorship for this research work.The authors wish to acknowledge the management of


Symptoms of stiffness after total knee arthroplasty (TKA) cause significant morbidity, but there is limited data to facilitate identification of those most at risk after surgery. Stratifying risk can aid earlier directed treatment options.A retrospective cohort consisting of 2589 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and short form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed for 1 year. Patients with a worse WOMAC stiffness score in 1 year were defined as the “increased” stiffness group and the other cohort as the non-stiffness group.p < 0.001), and had significantly  less of an improvement in their pain, function and total WOMAC scores, and SF-12 scores compared to the non-stiffness group (n = 2460). Patient satisfaction was significantly lower (odds ratio (OR) 0.178, CI 0.121 to 0.262, p < 0.001) for the increased stiffness group. Logistic regression analysis identified male gender , lung disease , diabetes , back pain , and a pre-operative stiffness score of 44 or more  were significantly predictive of increased stiffness.At 1 year after surgery 129 (5%) patients had a significant increase in their stiffness symptoms  17.9–22.0, Patients with increased symptoms of stiffness after TKA have a worse functional outcome and a lower rate of patient satisfaction, and patients at risk of being in this group should be informed pre-operatively.Retrospective prognostic study, Level III. Total knee arthroplasty (TKA) for the treatment of end stage osteoarthritis of the knee has a patient satisfaction rate of between 80% and 90% . PersistThe Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)  assessesThe primary aim of this study was to compare the outcome  12, and satisfaction) of patients with increased symptoms of stiffness 1 year after TKA with those who had no change or improvement in symptoms. The secondary aim was to identify independent predictors of increased symptoms of stiffness 1 year following TKA. The novel hypothesis is that patients with increased symptoms of stiffness have a worse outcome, and identification of independent predictors of this group would allow targeted intervention to potentially avoid increased stiffness post-operatively and improve their outcome.n = 41) and for those patients that underwent a second TKA, after the index procedure, only the outcome of the first knee was used for analysis (n = 460). Patients who had a deep infection, did not complete the outcome assessments (n = 185), or were revised (n = 37) at before 1 year follow-up were also excluded from analysis. There were 2589 TKA performed during the study period with complete pre and post-operative data that met the inclusion criteria  3641 patients undergoing primary TKA at the study centre were asked to complete a pre-operative patient questionnaire. Only patients with primary osteoarthritis were included. Patients who underwent simultaneous bilateral TKA during the study period were excluded (The WOMAC  used in The Short Form (SF-) 12 is a generic assessment tool to measure a patients wellbeing, which is assessed using a physical component summary (PCS) and a mental component summary (MCS) . Both thPatient satisfaction was assessed by asking the question “How satisfied are you with the results of your knee replacement surgery?” at 1 year following surgery. The response was recorded using a four point Likert scale: very satisfied, somewhat satisfied, somewhat dissatisfied, and very dissatisfied. Patients who recorded very or somewhat satisfied were classified as satisfied.Patients who had a worse or negative (1 year—pre-operative) change in the WOMAC stiffness score were defined as the increased symptoms of stiffness group. This group with increased symptoms of stiffness were compared to those who had no change or improved symptoms at 1 year. Patients that had no change or an improvement in their stiffness symptoms were used as the comparative subgroup who did not report worsened stiffness as a symptom.The Freeman Joint Registry is an institutional audit registered with the Newcastle upon Tyne Hospitals NHS Foundation Trust since 2003   at Caldicott@nuth.nhs.uk.t test, unpaired and paired were used to compare linear variables between groups. Dichotomous variables were assessed using a Chi-square test. Receiver operating characteristic (ROC) curve analysis was used to identify thresholds (cut points) in linear variables that were significantly different between the groups. The area under the ROC curve ranges from 0.5, indicating a test with no accuracy, to 1.0 where the test is perfectly accurate by identifying all satisfied patients. The threshold is equivalent to the point (WOMAC score) at which the sensitivity and specificity are maximal in predicting patient satisfaction  points in the WOMAC stiffness score relative to their preoperative score.p < 0.001) for the increased stiffness group  when compared to the control group .Both groups had a statistically significant improvement in the components and total WOMAC scores and the SF-12 PCS and MCS, except for the WOMAC stiffness component which deteriorated for the increased stiffness group (Table p = 0.017), lung disease (p = 0.002), diabetes (p = 0.02), back pain (p = 0.005), and a pre-operative stiffness score of 44 or more (p < 0.001) were significantly predictive of increased stiffness 1 year following surgery (Table Univariate analysis identified pre-operative factors that were predictive of increased symptoms of stiffness at 1 year Table . ROC curThe important findings of the study were that patients with subjectively increase symptoms of stiffness have a worse functional outcome and a lower rate of post-operative satisfaction, and that male gender, lung disease, diabetes, back pain, and a pre-operative WOMAC stiffness score of 44 or more were predictive of this group.Arthrofibrosis is a significant complication following TKA, which is reported to have an incidence of between 1 and 13% . Post-opFulfilment of patient expectations after TKA is associated with a greater rate of satisfaction . ApproxiIt is interesting that lung disease, diabetes, and back pain were independent predictors of increased stiffness after TKA, as all have been associated with fibrotic or inflammatory pathologies previously. Chronic lung disease is associated with pulmonary fibrosis and this may explain why such patients are at risk of increased stiffness after TKA; the association has previously suggested . DiabeteA pre-operative WOMAC stiffness score of 44 or more was a significant predictor of increased symptoms of stiffness 1 year following TKA, and was demonstrated to be reliable with a AUC of 0.8. This score could be used as a screening tool, being composed of only two questions it would be simple to assess. This combined with the other risk factors identified could be used to identify an “at risk group” pre-operatively, who may benefit from peri-operative interventions or at least made aware during the consent process that they are at risk of increased symptoms of stiffness and are less likely to be satisfied. There are multiple post-operative interventions suggested to prevent stiffness from occurring . HoweverThe major limitation of this study was the retrospective design that did not enable range of movement data to be assessed. Recording the range of movement pre- and post-operatively would have been desirable as this could have been correlated with the patient’s assessment of their stiffness. Surgeons often define knee stiffness as limitation in the range of motion of the joint , but patSurgeons should be aware that a proportion of patients will have increased symptoms of stiffness after TKA and that they have a worse functional outcome and a lower rate of post-operative satisfaction. Patients at risk may benefit from increased early physiotherapy or other treatment modalities  to prevePatients with increased symptoms of stiffness after TKA have a worse functional outcome and a lower rate of patient satisfaction, and patients at risk of being in this group should be informed preoperatively.


Clostridium thermocellum is a multifunctional ethanol producer, capable of both saccharification and fermentation, that is central to the consolidated bioprocessing (CBP) approach of converting lignocellulosic biomass to ethanol without external enzyme supplementation. Although CBP organisms have evolved efficient machinery for biomass deconstruction, achieving complete solubilization requires targeted approaches, such as pretreatment, to prepare recalcitrant biomass feedstocks for further biological digestion. Here, differences between how C. thermocellum and fungal cellulases respond to senescent switchgrass prepared by four different pretreatment techniques revealed relationships between biomass substrate composition and its digestion by the two biological approaches.The thermophilic anaerobic bacterium C. thermocellum achieved highest sugar release and metabolite production from de-lignified switchgrass prepared by CELF and dilute alkali pretreatments demonstrating greater resilience to the presence of hemicellulose sugars than fungal enzymes. 100% glucan solubilization and glucan plus xylan release from switchgrass were achieved using the CELF–CBP combination. Lower glucan solubilization and metabolite production by C. thermocellum was observed on solids prepared by dilute acid and hydrothermal pretreatments with higher xylan removal from switchgrass than lignin removal. Further, C. thermocellum (2% by volume inoculum) showed ~ 48% glucan solubilization compared to < 10% through fungal enzymatic hydrolysis (15 and 65 mg protein/g glucan loadings) of unpretreated switchgrass indicating the effectiveness of C. thermocellum’s cellulosome. Overall, C. thermocellum performed equivalent to 65 and better than 15 mg protein/g glucan fungal enzymatic hydrolysis on all substrates except CELF-pretreated substrates. CELF pretreatments of switchgrass produced solids that were highly digestible regardless of whether C. thermocellum or fungal enzymes were chosen.Alamo switchgrass was pretreated using hydrothermal, dilute acid, dilute alkali, and co-solvent-enhanced lignocellulosic fractionation (CELF) pretreatments to produce solids with varying glucan, xylan, and lignin compositions. The unparalleled comprehensive nature of this work with a comparison of four pretreatment and two biological digestion techniques provides a strong platform for future integration of pretreatment with CBP. Lignin removal had a more positive impact on biological digestion of switchgrass than xylan removal from the biomass. However, the impact of switchgrass structural properties, including cellulose, hemicellulose, and lignin characterization, would provide a better understanding of lignocellulose deconstruction.The online version of this article (10.1186/s13068-018-1216-7) contains supplementary material, which is available to authorized users. Trichoderma reesei required to obtain sufficiently high sugar yields, challenge the economic competitiveness of cellulosic ethanol [Fuel ethanol derived from abundant lignocellulosic biomass has the highest potential to alleviate the dependence on fossil petroleum in the transportation sector while also dramatically reducing associated greenhouse gas emissions , 2. The  ethanol . Thus, iClostridium thermocellum is a particularly promising CBP cellulolytic microorganism [C. thermocellum as reported in this work. Thus, cellulose accessibility to digestion in a complex substrate such as biomass remains the primary barrier to economic production of cellulosic ethanol and methods to overcome biomass recalcitrance to breakdown remain a subject of intense study [C. thermocellum via ball milling during cotreatment of switchgrass has been shown to increase solubilization [Consolidated bioprocessing (CBP) is an improved method that reduces enzyme-related costs using cellulolytic microorganisms that have the ability to produce their own enzyme consortium to simultaneously hydrolyze biomass polysaccharides and ferment the released sugars into ethanol and other desirable bioproducts , 7. Closorganism , 6, 8 thorganism . In contse study , 10, 11.se study –15. In flization . Variouslization , 18.C. thermocellum cellulosomes reported in literature suggest that the organism adjusts the proportion of different activities in the cellulosome, such as endoglucanases, exoglucanases, xylanases, and pectinases, in response to substrate features [C. thermocellum.Substrate adaptive changes in features . Howeverfeatures –23. On tfeatures , 24–26. features –30. AlonC. thermocellum CBP (Stage 2) was observed for each pretreatment type. Sugar recovery was tracked starting from both glucan and xylan in unpretreated biomass as established elsewhere for integration of pretreatments with fungal enzymatic hydrolysis [Alamo switchgrass was selected as a fast-growing energy crop rich in both pentose and hexose sugars to serve as the model feedstock for this study . In addidrolysis .C. thermocellum and fungal enzymes differently. CELF pretreatment removed about 85–96% xylan and 67–76% lignin at pretreatment conditions applied in this study. Overall, removal of either xylan or lignin or both from switchgrass, thereby increasing macro-accessibility of cellulose to enzymes, is expected to aid further biological deconstruction of pretreated solids. Although glucan composition in solids varied across hydrothermal, dilute acid, dilute alkali, and CELF pretreatments, being 49–59, 59–60, ~ 55, 74–78%, respectively, CELF-pretreated solids contained the most glucan relative to xylan and lignin and are expected to be the most digestible. High xylan content of hydrothermal and dilute alkali solids and high lignin content of dilute acid-pretreated solids would serve to provide a wide range of compositionally distinct solids to evaluate substrate–enzyme/bacterium effects.Total mass of glucan, xylan, and lignin found in unpretreated switchgrass and pretreated solids was tracked starting from 100 g equivalent of the unpretreated material as shown in Fig. C. thermocellum was highly capable of releasing the remaining sugars from the solids during Stage 2. About 100% total sugar release was achieved by CELF pretreatment of switchgrass in combination with CBP, which is the highest ever shown. Higher glucan solubilization and total sugar release observed from CELF- and dilute alkali-pretreated biomass compared to those observed from dilute acid and hydrothermal pretreatments indicate that removal of lignin from biomass by pretreatment had a greater impact on digestion by C. thermocellum than removal of xylan and/or lignin relocation. This is further validated by the higher Stage 2 sugar release achieved by C. thermocellum on delignified materials  than on hydrothermal- and dilute acid-pretreated solids which are rich in lignin.Pretreatment conditions were varied to determine conditions at which maximum glucan plus xylan release from pretreatment/Stage 1 (l) combined with CBP/Stage 2 (s) of switchgrass was observed for each pretreatment technology as shown in Fig. C. thermocellum as well. Further, the greater effect of lignin removal on glucan solubilization by fungal enzymes has also been attributed to an increase in xylan accessibility and, therefore, digestibility due to the absence of lignin [C. thermocellum as well [C. thermocellum was able to break down xylan even though the wild-type strain used in this work is not known to ferment xylose or xylo-oligomers [C. thermocellum on glucan solubilization by the organism from dilute alkali-pretreated solids with low lignin content (~ 8% for solids pretreated at 120 °C for 60 min) compared to hydrothermal-pretreated solids with high lignin content (~ 27% for solids pretreated at 180 °C for 20 min) as shown in Fig. C. thermocellum removed 91% xylan from dilute alkali-pretreated solids but only 68% xylan from hydrothermal-pretreated solids supports the argument that lignin removal increased xylan accessibility to C. thermocellum. This increased xylan digestion from dilute alkali-pretreated biomass by C. thermocellum may have contributed to the higher glucan solubilization of 90% compared to only 55% from hydrothermal-pretreated solids as presented in Fig. C. thermocellum being able to achieve only 48% glucan solubilization from unpretreated switchgrass with high lignin content for which the organism could only remove 60% of the xylan. Further, removal of acetyl and uronic acid substitutions from biomass hemicellulose by dilute alkali pretreatments may have also contributed to the higher cellulose and hemicellulose accessibility to digestion [The greater effect of lignin removal on enzymatic saccharification has been attributed to increased cellulose accessibility to enzymatic digestion due to the absence of lignin and a reduction in unproductive binding of enzymes to lignin as reported for fungal enzymes –39. Lignf lignin , 41. Thi as well , 43. Intligomers . FurtherC. thermocellum breaking down 48% of the glucan in unpretreated switchgrass. As a reference point, 20 mg protein/g glucan loading has been projected to cost about $1.47/gal of ethanol [C. thermocellum as shown in Additional file C. thermocellum cellulosome and/or the enzyme–microbe synergy observed during C. thermocellum digestions [® 1500, is not known to contain xylanases. Better performance by CBP may be attributed to the ability of C. thermocellum to break down xylan in biomass to make cellulose more accessible. Others have reported synergies between xylanases and cellulases to boost hydrolysis performance on pretreated biomass by increasing cellulose accessibility either via xylan removal or increased swelling and porosity of cellulose fibers [The deconstruction performances of different pretreatment–CBP combinations were compared to deconstruction by traditional use of fungal enzymes following the same four pretreatments of switchgrass, with results shown in Fig.  ethanol . Althouggestions . It is ie fibers , 47. In C. thermocellum always performed better than fungal enzymes did at 15 mg protein/g glucan and the same as achieved by 65 mg/g glucan enzyme loadings. The presence of xylan in the substrate may have affected enzymatic hydrolysis at the lower enzyme loadings as also validated by low glucan yield on hydrothermal compared to dilute acid-pretreated solids at that enzyme loading. C. thermocellum, in contrast, showed slightly higher glucan solubilization on hydrothermal than dilute acid-pretreated solids suggesting minimal impact of higher xylan present in the former on the organism. The effect of the presence of xylan in the substrate on enzymatic hydrolysis is also evident from the low glucan yield from dilute alkali-pretreated solids at the low enzyme loading compared to that by C. thermocellum. Even though enzymatic hydrolysis at the higher enzyme loading was not significantly impacted by varying substrate features, the high enzyme loading is expected to affect processing costs negatively. Overall, C. thermocellum CBP showed high glucan solubilization, especially on substrates with low lignin content.As expected, glucan-rich material from CELF-pretreated switchgrass was the most digestible irrespective of the biological system considered. Enzymatic hydrolysis at 65 mg protein/g glucan and CBP both showed almost 100% glucan yield/solubilization from CELF-pretreated solids; however, a slightly lower glucan yield resulted at 15 mg/g glucan enzyme loading. Altogether, C. thermocellum is shown in Fig. C. thermocellum on CELF-pretreated solids, ~ 1% higher than metabolite yield on dilute alkali, ~ 10% higher than on hydrothermal, and ~ 15% higher than on dilute acid-pretreated solids and ~ 40% higher than metabolite production on unpretreated switchgrass. Overall, total metabolite production correlated with an increase in cellulose macro-accessibility and solubilization on solids produced by all the pretreatments employed; higher polysaccharide solubilization translated into higher product yields. Although the amount of ethanol produced is greater from dilute alkali-pretreated solids than from hydrothermal-pretreated solids, the amount of acetic acid produced remains the same. This result suggests that the organism shifted its carbon flux from acetic acid to ethanol production in response to stressful conditions. Acetic acid production is preferred by C. thermocellum due to the generation of adenosine triphosphate (ATP) [C. thermocellum production of lactic acid has been reported to be part of its overflow metabolism that is not essential for carbon and electron flow [The translation of glucan solubilization from biomass to production of fermentation metabolites by te (ATP) . A shiftron flow , 49. AloC. thermocellum was 73% from dilute alkali-pretreated solids, suggesting that C. thermocellum benefits more from lignin removal than xylan removal. Although C. thermocellum deconstruction of CELF-pretreated solids showed the greatest glucan solubilization of 98%, about 68% of this solubilized glucan was accounted for metabolite production, 5% lower than that from dilute alkali-pretreated solids. The lower utilization of solubilized glucan on CELF-pretreated solids may perhaps be because the organism was inhibited by higher product concentrations, particularly that of acetic acid, and/or a drop in pH to non-optimal conditions.Figure C. thermocellum compared to fungal enzymatic hydrolysis. Hydrothermal, dilute acid, dilute alkali, and CELF pretreatments substantially increased glucan solubilization compared to that realized from unpretreated switchgrass. Nonetheless, C. thermocellum was capable of achieving ~ 48% glucan solubilization on unpretreated switchgrass compared to about 7% glucan yield by fungal enzymes. The dramatic difference in deconstruction performance showed that C. thermocellum can break down lignocellulosic biomass more effectively than fungal enzymes. The fact that dilute alkali pretreatment increased glucan solubilization by C. thermocellum to ~ 90%, higher than from solids produced by either hydrothermal or dilute acid pretreatments at reasonable conditions indicated that lignin removal from switchgrass had a greater effect on total sugar release than xylan removal and/or lignin relocation. C. thermocellum was not adversely affected by the presence of xylan in the biomass (~ 2.5 g/L during fermentation at 5 g/L glucan loading) even though the wild-type strain of the organism is not known to ferment xylose or xylo-oligomers [C. thermocellum’s complex cellulosome can be useful in selecting industrial-scale pretreatments in the future. However, C. thermocellum is shown to be inhibited at higher concentrations of xylose and xylo-oligomers during fermentation at higher solid loadings [C. thermocellum showed that biomass augmentation through thermochemical pretreatments aids biomass digestion by the organism. Further, the trends in production of metabolites, ethanol, acetic acid, and lactic acid, by C. thermocellum correlated well with trends in its glucan solubilization from pretreated solids. These results suggest that CELF pretreatment combined with C. thermocellum CBP could serve as a useful reference point against which to measure deconstruction of lignocellulosic biomass in addition to offering a promising process of converting biomass to ethanol with high yields without added enzymes. Further, it is important to consider critical differences in processing attributes and their effects on costs associated with each pretreatment. Hydrothermal pretreatments have the advantage of not requiring neutralization or conditioning because of no use of chemicals but require higher pretreatment temperature and, therefore, pressure to produce digestible solids. Temperature, as high as 200 °C, was required for hydrothermal pretreatments to achieve the same total sugar release as dilute acid pretreatments at 160 °C. However, dilute acid pretreatment requires expensive reactor materials of construction due to the corrosive nature of sulfuric acid and encounters other challenges such as, high cost of acid, challenges in mixing acid, the need for acid neutralization [These results provide a unique picture on how compositional differences from switchgrass prepared by four different pretreatments impact subsequent deconstruction of solids by ligomers . Such beloadings . Nearly lization . Moreove® mill  equipped with a 1-mm sieve. The resulting milled biomass was mixed thoroughly before each use.Five-year-old fully mature Alamo switchgrass harvested in January 2014 that had been chopped to an approximate size of ¾ inch was obtained from Genera Energy Inc. The composition of unpretreated milled Alamo switchgrass was determined to be 38.18 (± 0.8)  % glucan, 26.96 (± 0.4)  % xylan, 2.97 (± 0.05) % arabinan, and 20.8 (± 0.2)  % K-lignin. This biomass was completely mixed before dividing and transferring it into multiple gallon-sized bags that were stored in a freezer. The entire contents of each bag were knife milled by Thomas WileyC. thermocellum or fungal enzymes.Hydrothermal pretreatments were performed at 180 °C for 20, 30, and 40 min and 200 °C for 10 and 20 min. Dilute acid pretreatments were done at 160 °C for 10, 20, 25, and 30 min, whereas, dilute alkali pretreatments were done at 120 °C for 60, 90, and 120 min. CELF pretreatments were performed at 140 °C for 20, 30, 40, and 50 min and 150 °C for 10, 20, 25, and 30 min. Dilute acid and CELF pretreatments used 0.5 wt% sulfuric acid, whereas dilute alkali pretreatments were with 1 wt% sodium hydroxide. CELF pretreatment employed THF as co-solvent at a 1:1 volume ratio with water/dilute sulfuric acid solution. These pretreatment conditions were based on prior work and reported in the literature, , 51–54 aC. thermocellum employed for all experiments were kindly provided by Dr. Lee Lynd at Dartmouth College, Hanover NH. A stock culture was grown in a 500-mL anaerobic media bottle  and aseptically transferred to 5-mL serum vials for storage at − 80 °C. A 2% by volume inoculum of these stock cultures were used to prepare the seed cultures grown with a 5 g/L glucan loading of Avicel® PH-101  in a 50 mL working volume for 8–9 h in media for thermophilic clostridia (MTC) without trace minerals . CBP was performed in 125-mL bottles  at a 0.5 wt% glucan loading of unpretreated or pretreated biomass in triplicates at a working mass of 50 g. Bottles containing biomass and water were purged with repeated 45-s application of vacuum and 14 psi nitrogen over a total of 27–30 min and then sterilized by autoclaving at 121 °C for 35 min. The bottles were incubated at 60 °C at a shaking speed of 180 rpm in a Multitron Orbital Shaker  after the injection of all medium solutions and 2% by volume inoculum. Insoluble solids left after CBP were recovered and rinsed thoroughly. Compositional analysis was performed on these CBP residues to determine carbohydrates left in the solids from which solubilization could be calculated. The solids were sampled in triplicates after 7 days of fermentation to determine carbohydrate solubilization. This approach of measuring solubilization was followed because sugars released in solution are immediately used by C. thermocellum for fermentation to metabolites and are not left in solution as they would be for fungal enzymatic hydrolysis. The fermentation liquor was also analyzed after 7 days of fermentation to determine production of ethanol, lactic acid, and acetic acid. The liquor samples were passed through 28-mm diameter polyethersulfone (PES) syringe filters with 0.2-µm pores  into 1.5 mL Simport® microcentrifuge tubes . These tubes were centrifuged at 15,000 rpm for 10 min and the supernatant was analyzed by HPLC.The seed culture was stored overnight in a refrigerator for about the same time for each experiment before inoculation the next day. The different media solutions were prepared separately and purged with nitrogen. All solutions except the vitamin solution were sterilized by autoclaving, whereas the vitamin solution was sterilized by passing it through 28-mm diameter polyethersulfone (PES) syringe filters with 0.2-µm pores  was used at 15 and 65 mg/g glucan protein loadings for all experiments, with the loadings based on the amount of glucan in unpretreated switchgrass as described elsewhere so as to not penalize a pretreatment for releasing more sugars before enzymatic saccharification [® 1500 was reported elsewhere to be 82 mg/mL [® microcentrifuge tubes . These tubes were centrifuged at 15,000 rpm for 10 min and the supernatant was analyzed by HPLC.Unpretreated and pretreated switchgrass solids were enzymatically hydrolyzed at a loading of 0.5 wt% glucan and working mass of 50 g in 125-mL Erlenmeyer flasks in triplicates following the NREL Laboratory Analytical Procedure “Enzymatic Saccharification of Lignocellulosic Biomass” . Accellefication , 58. The82 mg/mL . The flaPrior to analysis, unpretreated and pretreated solids were dried for 2 days to constant moisture content in a 40 °C incubator oven. CBP residues were bone dried in a 60 °C oven. The compositions of unpretreated and rinsed pretreated switchgrass and CBP residues were determined in triplicates according to the standard NREL Laboratory Analytical Procedure “Determination of Structural Carbohydrates and Lignin in Lignocellulosic Biomass” [Analysis of all the liquid samples was by a Waters Alliance e2695 HPLC system  equipped with a Bio-Rad Aminex HPX-87H column and a Waters 2414 refractive index detector. 5 mM sulfuric acid was the eluent at a flow of 0.6 mL/min. Integration of the chromatograms was by the Empower™ 2 software package. All experiments and analysis were in triplicates, unless otherwise specified. Error bars were calculated as the standard deviation for the triplicates, unless otherwise specified. Even though the pretreatments were only performed once the compositional analysis for all pretreated solids and pretreatment liquor was done in triplicates. Error for total sugar release was calculated based on a combination of standard deviation of glucan and xylan solubilization in CBP, glucan and xylan yields in pretreatment liquor, and glucan and xylan composition of pretreated solids following statistical rules for combining standard deviation.C. thermocellum from pretreated solids; both measurements are based on the initial amount of glucan plus xylan in unpretreated switchgrass. The term ‘sugar release’ includes both glucan and xylan in the calculations unless specified otherwise. Stage 1 and Stage 2 sugar releases combined are termed total sugar release. All of these sugar release calculations are done based on a dry mass basis. Detailed calculations are as follows:Sugar yield, conversion, and release were expressed in terms of the polymeric form of the sugar throughout this paper with anhydrous correction factors converting monomeric sugar concentrations measured by HPLC to the corresponding polymer carbohydrate. Thus, the amount of glucose measured via HPLC can be converted to the equivalent amount of glucan by multiplying the glucose amount by 0.9, while the factor for translating xylose to xylan and arabinose to arabinan is 0.88. The glucan release from the biomass for CBP is measured in terms of glucan solubilization and that for enzymatic saccharification is measured as glucan yield as described in the main text and calculations shown below. Stage 1 sugar release refers to sugars captured in the pretreatment liquor, whereas, the Stage 2 sugar release refers to sugar solubilized by Additional file 1: Fig. S1. Enzymatic hydrolysis (EH) glucan yield time profile on autoclaved vs. unautoclaved switchgrass with (a) 15 mg protein/g glucan and (b) 65 mg protein/g glucan enzyme loadings of Accellerase® 1500. A 0.5 wt% glucan loading with a working mass of 50 g was used for EH which was performed in triplicates with controls at 50 °C, 150 rpm.Additional file 2: Fig. S2.C. thermocellum growth profile in terms of production of metabolites (ethanol + acetic acid + lactic acid) and pellet nitrogen content (g/L) as a proxy for cell growth for 24 h under growth conditions in a bottle with 200 mL working volume and 5 g/L glucan Avicel® PH-101 loading without active pH control in MOPS buffer. Measured in triplicates from one culture bottle.


In this study, polybutylene succinate (PBS) was blended with five types of modified tapioca starch to investigate the effect of modified tapioca starch in PBS blends for food packaging by identifying its properties. Tensile and flexural properties of blends found deteriorated for insertion of starch. This is due to poor interface, higher void contents and hydrolytic degradation of hydrophilic starch. FTIR results show all starch/PBS blends are found with footprints of starch except OH stretching vibration which is absent in B40 blends. Besides, Broad O–H absorption in all specimens show that these are hydrogen bonded molecules and no free O–H bonding was found. SEM testing shows good interfacial bonding between PBS and starch except E40 blends. Therefore, poor results of E40 blends was expected. In TGA, a slightly weight loss found between 80 to 100 °C due to free water removal. Apart from this, insertion of all types of starch reduces thermal stability of blend. However, high crystallinity of starch/PBS blend observed better thermal stability but lower char yield. Starch A and B blends are suggested to be used as food wrap and food container materials while starch D blend is suitable for grocery plastic bags according to observed results. Food packaging is a frequent topic on global challenge as plastic packaging has largest demand especially developed countries that reliance on processed foods . ConventStarch is one of the most abundant low-cost natural resources and one of the important bioresources used in the food industry, such as paper, thickeners, and gelling agents . Starch The use of tapioca starch as bioplastics in industrial food packaging is still limited due to its hydrophilic nature, brittleness, thermal instability, as well as high production cost and the large area of land needed to produce bioplastic . SeveralAttention to aliphatic polyester has greatly increased in recent years with regards to promising sustainable and biodegradable material prospects. Polybutylene succinate (PBS) is one of the biodegradable aliphatic polyesters that has been produced using petroleum-based monomers ,16,17,18Starch/polyester blended plastics are meant to improve processing properties and better strength. Previous studies investigated two types of starch blended with PBS polymer . It was Modified tapioca starch can mix directly with PBS without undergoing the gelatanization process. It will fill the gap of knowledge by reducing the process period, as well as the production cost. In this study, the properties of modified tapioca starches/PBS blends will be studied and, most importantly, it is done by a simple fabrication method. This shall attract interest from researchers and industry, especially in food packaging. The PBS polymer simply blends with five different types of modified tapioca starch by using a rotating internal mixer and a hot press.3. Tapioca starch in the form of powder was obtained from PT Starch Solution in Karawang, Indonesia. It has five modified starch grades  with different properties. PBS in the form of pallets were bought from PTT Public Company Limited in Bangkok, Thailand. The density of PBS is 1.26 g/cmThe PBS pallets are first dried in an oven at 80 °C to prevent excessive hydrolysis which can compromise the physical properties of the polymer. After that, PBS was melted in a counter-rotating internal mixer  at 115 °C with rotation of 60 RPM. Subsequently, modified tapioca starch (A/B/C/D/E) was loaded into the mixer and blended for another 10 min until a homogenous compound was achieved. The compound was crushed into small pieces by using crusher machine  before being pressed. Next, the compound was molded by using a hot press at 115 °C for 4 min and left to cool for another 3 min. Then, specimens were cut into shapes according to specific characterization testing. Five specimens from every combinations will be tested for each conducted testing. The naming of specimens was done according to the type and the volume contents of starch in the PBS blends; for example, A40 represents 40 wt % of type A starch blended in PBS polymer. There are a total of 15 specimens constructed by five types of starch  and three volume contents of starch  in PBS polymer blends.The tensile test was carried out according to ASTM D638-14 test method at a strain rate 50 mm/min using an Instron universal tester  under room temperature. For flexural testing was carried out under room temperature following the standard ASTM 790-17 standard. Optimum loadings of specimens were selected to conduct the following characterizations.−1 with 4 cm−1 resolution. The positions of significant transmittance peaks at a wavenumber was tracked by using Nicolet software.Fourier transform infrared spectroscopy (FTIR) was performed using Perkin Elmer 1600 infrared spectrometer  to conduct in the wavenumber range of 500–4000 cmMorphology of the samples was observed using Hitachi S-3400N scanning electron microscope  equipped with energy dispersive X-ray  under an accelerating voltage of 15 kV. The samples were gold sputtered before observation to avoid the charging effect.−1 under nitrogen gas atmosphere.The thermal stability of the samples was characterized using a TA Instruments Q500 thermogravimetric analyzer, TGA, . About 6 mg of sample was scanned from 30 to 900 °C at a heating rate of 20 °C·minMechanical properties of starch/PBS blends are presented in Apart from this, increasing starch content produces more voids, resulting in a weakening structure of the blends due to poorer interfacial bonding between PBS and starch. Starch E/PBS blends show the lowest average tensile values because of high chain branches of the amylopectin component richly found in starch E blends, which will detangled easily . On the Flexural strength and flexural modulus of starch/PBS blends are given in Type D starch molecules tend to slip past each other under bending, leading to lower flexural modulus even though good tensile strength is observed . On the −1, that the spectral characteristic of all types of modified starch are similar. All starch/PBS blends have found footprints of starch which consist of alkene, esters, aromatics, ketone, and alcohol, with different oxygen-containing functional groups, e.g., OH (3400–3200 cm−1), C=O (1765–1715 cm−1), and C–O–(H) (1050 cm−1) excepted OH stretching vibration not found in sample B40. The O–H stretching mode is due to the hydrolytic effect of starch on the polymeric matrix, providing the formation of hydrogen bonded alcohol end groups [To study the interaction between starch and PBS polymer, FTIR spectra of the specimens were evaluated. d groups . Broad Od groups .−1 was associated with ordered structures of starch [−1 exhibiting complex vibrational modes due to the skeletal mode vibrations of the pyranose ring in the glucose unit.The band at 1156 cmf starch . Amorphof starch . All spe−1 represent the C–H stretch region. The peak in the 1710–1720 cm−1 region indicates the presence of C=O bonds in the presence of polybutylene succinate [−1 is associated with the presence of C–O bond stretching [−1 was associated with C–O bond flexion of the hydroxyl groups [PBS is a condensation biopolymer exhibiting hydroxyl and carboxyl terminated chains with the relevant end group content that is dependent on polymerization conditions . Meanwhiuccinate . The regretching . Additiol groups . All speMechanical properties are directly related to the morphology of composites. Cross-section cuts of the specimen variations were performed to explore the effects of different types of modified starches on the internal structure by SEM analysis . Figure Thermal degradation of starch/PBS blends have been studied by TGA testing. Nonetheless, the insertion of all types of starch had observed lower onset temperature. This is due to the degradation of the blend beginning at the surface of the filler, which, in this study, referred to the starch. However, the main components in the starch are composed of high-crystallinity amylose and highly-branched amylopectin . The higAs a conclusion, insertion of modified tapioca starch into PBS polymer blends show better strength properties and thermal stability as compared to pure starch. However, the increment of starch content in blends observed a deteriorated property for all types of starch/PBS blends. Low dispersion of starch molecules, poor interfacial bonding, and high void content are responsible for the reduction in mechanical properties. Slipped molecules found under bending loads resulted in losing flexural capabilities. FTIR results show all starch/PBS blended are found with footprints of starch, except OH stretching vibration, which is absent in B40 blends. Additionally, broad O–H absorption in all specimens show that these are hydrogen-bonded molecules and no free O–H bonding was found. Moreover, SEM images show good interfacial bonding between PBS and starch, except sample E40. The poor interface between starch and PBS caused an increment in void content, weakening the structure of the blends and further reducing the mechanical properties. On the other hand, a slightly weight loss found between 80 and 100 °C was due to water removal from the hydrophilic nature of starch. Furthermore, insertion of all types of starches caused lower onset temperature, but higher residual char, first onset temperature, and second thermal degradation temperature are due to starch and PBS, respectively. The objective of this study is investigating properties of starch/PBS blends. All type of blends are possible to be used in the food packaging industry. Starch A/PBS and Starch B/PBS blends are applicable on food wrap and food container materials as they have very good elongation of break and outstanding bending capability. The Starch D/PBS blend has good tensile properties and is suitable to be used for plastic grocery bags.The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.


Increased morbidity and mortality have been associated with weekend and night-time clinical activity. We sought to compare the outcomes of liver transplantation (LT) between weekdays and weekends or night-time and day-time to determine if ‘out-of-hours’ LT has acceptable results compared with ‘in-hours’.We conducted a retrospective analysis of patient outcomes for all 8816 adult, liver-only transplants (2000–2014) from the UK Transplant Registry.Outcome measures were graft failure (loss of the graft with or without death) and transplant failure (either graft failure or death with a functioning graft) at 30 days, 1 year and 3 years post-transplantation. The association of these outcomes with weekend versus weekday and day versus night transplantation were explored, following the construction of a risk-adjusted Cox regression model.Similar patient and donor characteristics were observed between weekend and weekday transplantation. Unadjusted graft failure estimates were 5.7% at 30 days, 10.4% at 1 year and 14.6% at 3 years; transplant failure estimates were 7.9%, 15.3% and 21.3% respectively.A risk-adjusted Cox regression model demonstrated a significantly lower adjusted HR (95% CI) of transplant failure for weekend transplant of 0.77 (0.66 to 0.91) within 30 days, 0.86 (0.77 to 0.97) within 1 year, 0.89 (0.81 to 0.99) within 3 years and for graft failure of 0.81 (0.67 to 0.97) within 30 days. For patients without transplant failure within 30 days, there was no weekend effect on transplant failure. Neither night-time procurement nor transplantation were associated with an increased hazard of transplant or graft failure.Weekend and night-time LT outcomes were non-inferior to weekday or day-time transplantation, and we observed a possible small beneficial effect of weekend transplantation. The structure of LT services in the UK delivers acceptable outcomes ‘out-of-hours’ and may offer wider lessons for weekend working structures. This is the first study to address whether there is a weekend effect on clinical outcomes for liver transplantation in the UK.The study was based on an assessment of a large, unbiased, multicentre dataset of all UK liver transplant operations occurring in the study period.The UK Transplant Registry is a well curated, highly complete database enabling the generation of risk-adjusted models including recipient, donor and technical parameters that may have influenced outcomes.Transplantation settings offer the ability to explore ‘out-of-hours’ outcomes where the timing of clinical event is not determined by the recipient’s clinical status.The major limitations of this study include the inability to identify causative factors, nor identify confounding factors that may be driving differences in outcomes.Increased morbidity and mortality have been observed with out-of-hours clinical practice in a range of settingsSeveral studies have reported excess mortality associated with weekend hospital admission in the UKThe current evidence for out-of-hours LT outcomes is mixed. No increased risk of mortality or graft failure was demonstrated with weekend or night-time LT in a multicentre American study of nearly 95 000 transplants.It remains unclear whether the observed excess mortality associated with weekend admission is a product of differing case severity,The UK delivers LT services with a high volume, low centre-number model, with seven centres providing services for a population of approximately 65 million people, each performing between 30 and 172 deceased donor, adult-recipient LTs annually.Data on all adult recipients (≥17 years) of liver-only transplants from deceased donors in the UK, under the National Health Service (NHS) between 1 January 2000 and 31 December 2014, were obtained from the UK Transplant Registry and followed up to 18 February 2016.Night-time procurement was deemed to be any liver donation where the liver perfusion start time was between 19:00 hours and and 07:00 hours. We estimated transplant operation time by adding donor liver perfusion start time  to cold ischaemia time (CIT) . Liver perfusion data were not collected before 2000, and so we have only included transplants since 2000 in the cohort. Night-time transplantation was defined as operation time between 19:00 hours and 07:00 hours. Weekend transplantation was defined as any transplant operation time between 17:00 hours on a Friday and 08:00 hours on a Monday whereas weekday transplantation included all other time points. These time points were selected to ensure that our findings were comparable to other published studies.The primary outcomes were graft failure and transplant failure. Transplant failure was defined as the earlier of graft failure or patient death , whereas graft failure classed graft failure before death or graft failure and death as an event. Therefore, patients who underwent retransplantation would have had an event of graft failure associated with their first liver transplant.2 and log-rank tests were used to compare continuous, categorical and failure rate data, respectively. Cox proportional hazards models were built to estimate graft and transplant failure at 30 days, 1 year and 3 years post-transplant. HRs for different time periods were found by including a period factor in the model. Factors considered for inclusion in the model are listed in Student’s t-test, χLess than 5% of values for each baseline patient, donor and operative characteristic were missing .Patients, carers and lay people were not directly involved in the design, conduct and analysis of this study, as it is based on routinely collected data from the UK Transplant Registry. However, the study was designed to assess outcomes that are important to patients including graft failure and mortality. The relevance and timeliness of the study was endorsed by the NHS Blood and Transplant Liver Advisory Group which includes transplant clinicians, patients and lay members.Data were available for 8816 adult LT performed at all UK centres. Follow-up information on graft failure or patient death was available at 30 days for all transplants, at 1 year for 91.4% and at 3 years for 76.2% of transplants. Follow-up information is obtained from annual follow-up appointments with patients, or notification of death. In the analysis, follow-up information was censored at the last known follow-up for the patient within the follow-up period of analysis .The mean recipient age (SD) at transplantation was 50 (13) years, 60% of the population were male and 88% were Caucasian. Alcohol-related liver disease was the leading indication for transplantation (20%) followed by chronic viral hepatitis (16%), acute liver failure (12%), retransplantation (10%), primary biliary cholangitis (10%), primary sclerosing cholangitis (8%), autoimmune hepatitis (8%), primary liver cancer (6%), metabolic liver disease (6%) and other diagnoses (5%). The donor population were 51% male with a mean average age (SD) of 46 (16) years. The mean CIT (SD) was 9.3 (3) hours. Eleven per cent of livers were from DCDs and the remainder from DBDs.Of the 8816 transplants, 3203 (36.3%) were performed in the weekend period and 6101 (69.2%) at night. Overall unadjusted transplant failure estimates were 7.9% at 30 days, 15.3% at 1 year and 21.3% at 3 years and graft failure estimates were 5.7%, 10.4% and 14.6%, respectively.Similar proportions of first transplant and retransplant procedures, organs from DCDs or DBDs and livers from paediatric or adult donors were observed between weekend and weekday procedures.The following factors were found to be non-significant when comparing weekday and weekend transplants, and in the risk-adjusted models: recipient gender, cause of recipient death, cause of graft failure, donor gender, outcome of first offer (decline/accept).In the unadjusted analysis, graft failure was similar for weekday and weekend transplantation with 6% and 5% graft failure at 30 days, respectively, 11% and 10% at 1 year, and 15% and 14% at 3 years. Transplant failure was higher among weekday recipients at 30 days , but not significantly different at other time points see .recipient factors: on renal support, ventilated, confirmed sepsis at time of transplantation, primary liver disease, age, inpatient at time of transplantation, acute liver failure, previous abdominal surgery, presence of oesophageal varices, presence of TIPS, Caucasian and graft factors: organ appearance suboptimal, CIT, donor age, DCD, split liver and transplant year and night-time transplant. Each model was built separately for the different endpoints and outcomes (graft failure or transplant failure) and any significant factors were included in the risk-adjusted models. Online The factors that significantly affected transplant failure at each of the three time points and were included in each model were The risk-adjusted HR (95% CI) of transplant failure for weekend transplant relative to weekday was 0.77 (0.66 to 0.91) within 30 days. The corresponding HRs for 1 year and 3 years were 0.86 (0.77 to 0.97), 0.89 (0.81 to 0.99), respectively . A weeke2, p=0.5), presence of TIPS  and prior abdominal surgery , although the mean length of ICU stay was longer with weekend transplantation (5.4 (SD 9) vs 6.1 (SD 12) days, p=0.008).Differences in surgical complexity could potentially have influenced outcomes between time periods if, for example, more complex patients were selected for transplantation during the week. There is no direct measure of surgical complexity available, but factors that may reflect this were similar between weekdays and weekends including the mean number of units of blood transfused intraoperatively , mean length of inpatient stay ), presence of portal vein thrombosis , recipient BMI  and the late week (Thursday 07:00–19:00 hours and Friday 07:00–17:00 hours), furthermore the day of the week did not significantly affect the risk of failure after risk-adjustment at any of the three time points. An interaction between weekend and night-time transplant was found to be non-significant . As there were large differences in the number of transplants performed per centre during the study period (range 533–2112), we tested whether there were variations in the frequency of weekend transplantation and in weekend outcomes on a per centre basis. The weekend effect was consistent across all transplant centres, and an interaction between weekend transplant and centre was non-significant .We considered whether there were different rates of higher risk organ use between weekends and weekdays. We observed that use of organs previously declined by another centre at their first offering was the same for weekdays (31%) and weekends (32%) (p=0.23) and the proportion declined due to donor factors, as compared with other factors, was identical. Donor age, use of DCDs, CIT and suboptimal organ appearance were similar.To determine when the factors leading to reduced outcomes following weekday transplantation were operating, analysis was restricted to those who did not suffer death or graft failure prior to 30 days. This resulted in no significant weekend effect on transplant failure after one and 3 years, indicating that the factors operate within the first month following transplantation and continue to affect long term failure rates.A similar analysis and model building strategy was undertaken for transplants assessed as day-time (operative start time 07:00–19:00 hours) compared with night-time and also for day-time compared with night-time organ procurement. A total of 2715 (31%) transplants were undertaken during the day-time and 6101 (69%) at night. Night-time procurement occurred in 6228 (71%) of transplants. Day-time compared with night-time transplant was associated with lower graft failure at 30 days , 1 year  and 3 years  and transplant failure at 30 days  and 1 year  and 3 years  in the unadjusted analysis. Day-time compared with night-time procurement was associated with lower graft failure at 30 days , 1 year  and 3 years  and transplant failure at 30 days , 1 year  and 3 years  in the unadjusted analysis. In the Cox proportional hazard models, using the same variables as for the weekend versus weekday model neither night-time procurement nor night-time transplantation had a significant effect on transplant or graft failure at any time point online .We have demonstrated no increased risk of graft or transplant failure with weekend LT, night-time LT or night-time graft procurement. These findings suggest that UK liver transplant outcomes do not have an increased risk of adverse outcomes associated with ‘out-of-hours’ operating. Interestingly, there was a possible reduction in the hazard of early graft failure and long-term transplant failure associated with weekend transplantation. The loss of this association when considering only survivors at 30 days suggested that any responsible factors were acting in the peritransplant and early post-transplant period. The effect was present in the unadjusted transplant failure data at 30 days, in the adjusted outcomes at all time points measured and was seen across all centres.There is a wide range of putative confounding factors that may have influenced the risk of graft and transplant failure during in-hours and out-of-hours transplantation. We attempted to control for those that were measured in the database including donor, operative and recipient characteristics  but whether this would improve outcomes, was a marker of a more unwell patient population or was of any clinical importance is unclear. Therefore, we are unable to explain this association and it may relate to other unmeasured factors in patient or graft selection or care.We speculate that the senior clinician-led and delivered service may obviate any inherent weekend risks. Although as previously noted, not all clinical scenarios are associated with ‘out-of-hours’ risks. However, this service structure would not explain the difference we observed between weekend and weekday outcomes. It is conceivable that there may be a protective effect of weekend staffing patterns or the hospital environment on LT outcomes, for example, the absence of routine elective work and competing clinical activity may potentially free clinicians and resources for a more prompt and responsive service.We have demonstrated no increased hazard of graft or transplant failure for liver transplants performed out-of-hours. Whether this was due to weekends being inherently more risky  but that the senior-led service and lack of competing clinical activity prevented this from resulting in poor patient outcomes, or conversely that in-hours and out-of-hours transplantation carried a similar baseline risk, cannot be unpicked in this study. If the inverse weekend effect we observed is true, we believe the modifying factor likely lies in differences in staffing and competing clinical activity as outlined above.The limitations of this work include that, as with all retrospective registry based studies, neither causality nor aetiological factors can be identified. Furthermore, registry data are dependent on the quality of data imputing, curation and assignation of variables. However, this is a well curated, highly complete dataset that has previously been used for multiple studies. Secondly, the definition of day and night with regard to transplantation surgery was artificial as combined organ retrieval, transfer and implantation straddles both day and night periods, however our methodology has been utilised in a previous similar study of LT.This study is an interesting comparator for published disease specific and unselected admissions studies of out-of-hours outcomes.The non-inferiority of out-of-hours LT, as seen in other LT and renal transplant studies,In summary, we have demonstrated that ‘out-of-hours’ LT outcomes are not worse than for ‘in-hours’ procedures, and that potentially weekend LT may be associated with reduced adverse outcomes. The weekend LT care structure in the UK may represent a model for the design of other critical out-of-hours services. Furthermore, these findings illustrate the complexity of observed weekend effects which are likely to be dependent on patient selection.


Lamballais et al.See Article by  Blood pressure (BP) and arterial stiffness are closely intertwined.There is increasing evidence linking arterial stiffness and BP, particularly SBP and pulse pressure to cognitive impairments and decline, among middle‐aged and older individuals.Journal of the American Heart Association (JAHA), Lamballais and colleagues examined the cross‐sectional associations of BP and arterial stiffness with cognition not only in a large population‐based sample of middle‐aged and older individuals from the Rotterdam Study , but also in a large population‐based sample of children who were born a half‐century later in the same area, and included in the Generation R study .In this issue of the neuroselection; that is, children with better cognitive functioning select into healthier (or avoid hazardous) behaviors and thus display healthier outcomes.Given the cross‐sectional nature of the Generation R results, like that of previous studies discussed among the young,Understanding the causal factors at the root of disease across the life course is essential for better targeted preventive and treatment strategies. For instance, evidence from clinical trials showing that antihypertensive treatment improves cognition remains inconclusive,None.


OBJECTIVES/SPECIFIC AIMS: Tissue engineered tracheal grafts (TETG) could provide a life-saving cure for children with long segment airway defects. Computational fluid dynamics (CFD) is a novel and promising technique used to evaluate TETG performance. This pilot study examines the correlation of objective CFD simulations with subjective respiratory symptoms in a TETG large animal model. METHODS/STUDY POPULATION: Three-dimensional geometries of 1 TETG implanted sheep trachea were reconstructed from serial fluoroscopic images, allowing analysis with CFD simulations. Peak flow velocity (PFV) and peak wall shear stress (PWSS) across the graft as well as changes secondary to stenting were determined. CFD metrics were compared with respiratory symptoms seen on exam. RESULTS/ANTICIPATED RESULTS: Two weeks after implantation, the animal developed respiratory distress, which correlated with PFV and PWSS elevations. Although the intraluminal graft appearance changed minimally after dilation, PFV and PWSS decreased across the graft . Long-term TETG stenting with dilation returned PFV and PWSS to baseline , which correlated with immediate symptom resolution. DISCUSSION/SIGNIFICANCE OF IMPACT: CFD is a noninvasive modality, which allows the evaluation of airflow metrics of symptomatic TETG recipients. This diagnostic tool will permit planned interventions and graft design optimization.