BACKGROUND & AIMS: :Biocompatible and biodegradable polyurethanes were prepared with fixed aliphatic diisocyanate level and varying ratios of isosorbide, and PCL diol via a simple one-shot polymerization without a catalyst. The successful synthesis of the polyurethanes was confirmed by gel permeation chromatography, (1)H-nuclear magnetic resonance and Fourier transform-infrared spectroscopies and the thermal properties were determined by differential scanning calorimetry and showed glass transition temperatures of around 30-35 °C. The degradation tests were performed at 37 °C in phosphate buffer solution (approx. pH 7.3) and showed a mass loss of around 5 % after 12 weeks, except for the polymer with the highest isosorbide content which showed an initial rapid mass loss. The in vitro cytocompatibility test results following culture of osteoblasts on the polymer surface showed that relative cell number on all of the polyurethane films after 5 days of cultured on polymer films was lower compared to the proliferation rate on the optimized tissue culture plastic. These polymers offer significant promise due to the simplicity of the synthesis and the controlled degradation.

背景与目标： : 通过不带催化剂的简单的一次性聚合反应，以固定的脂肪族二异氰酸酯水平和异山梨醇和PCL二醇的不同比例制备了生物相容性和可生物降解的聚氨酯。通过凝胶渗透色谱，(1)H-核磁共振和傅立叶变换红外光谱证实了聚氨酯的成功合成，并通过差示扫描量热法确定了热性能，并显示了约30-35 °C的玻璃化转变温度。降解试验在37 °C的磷酸盐缓冲溶液 (约pH 7.3) 中进行，并且在12周后显示质量损失约5%，除了具有最高异山梨醇含量的聚合物显示初始快速质量损失。在聚合物表面上培养成骨细胞后的体外细胞相容性测试结果表明，在聚合物薄膜上培养5天后，所有聚氨酯薄膜上的相对细胞数低于优化组织培养塑料上的增殖率。由于合成的简单性和受控的降解，这些聚合物提供了重大的前景。

BACKGROUND & AIMS: BACKGROUND:We reported T-cell senescence to be similar in people living with HIV (PWH) with suppressed viremia (predominantly men who have sex with men (MSM)) and HIV-negative otherwise comparable controls, but greater than in healthy blood donors. This lead us to compare CD4+ and CD8+ T-cell counts and CD4+/CD8+ ratios between HIV-negative MSM and men who only have sex with women (MSW), and relate observed differences to behavioral factors and infectious exposures, including cytomegalovirus (CMV) infection. METHODS:In 368 HIV-negative MSM and 72 HIV-negative MSW T-lymphocyte phenotyping was performed 3 times biennially. Baseline CMV serology, and STI-incidence/-seroprevalence, sexual and substance-use behavior data were collected during study visits. RESULTS:MSM, compared to MSW, had higher CD8+ counts (551 vs. 437 cells/mm3, P<.001), similar CD4+ counts (864 vs. 880 cells/mm3, P=.5) and lower CD4+/CD8+ ratios (1.84 vs. 2.47, P<.001). Differences were most pronounced for MSM with >10 recent sex partners, and partly explained by higher CMV seroprevalence in MSM. DISCUSSION:These findings suggest that factors other than HIV may, both in PWH and certain HIV-negative MSM, contribute to a low CD4+/CD8+ ratio. Whether this, like in PWH, contributes to comorbidity risk in HIV-negative MSM requires further study.

背景与目标：

BACKGROUND & AIMS: :It is common in population-based cancer registries to use the relative survival ratio to estimate patients' probabilities of surviving if their cancer were the only cause of death. Results from the recently proposed new methods of age-standardisation can be interpreted as ratios between the observed and expected survival proportions. Like the non-standardised ratios, these age-standardised relative survival ratios have, however, the desired probability interpretation only under a specific condition. The condition involved is the survival with respect to other causes up to the given point of follow-up. With different lengths of follow-up, this condition is also different. As a consequence, the non-standardised relative survival ratios and those standardised with the two newest methods produce, for different lengths of follow-up, mutually incomparable estimates with respect to age. Not accounting for this may, for example, lead to erroneous conclusions about the cure of the patients. The traditional method of age-standardisation does not have this problem of incomparability. Results of relative survival analyses of data from the Finnish Cancer Registry are used to illustrate this issue. To avoid overinterpretation and confusion, the different interpretations of the relative survival ratios, both non-standardised and age-standardised, must be known. For example, the very popular cumulative relative survival curves, consisting of consecutive cumulative relative survival ratios, should not be produced for the non-standardised ratios or for ratios age-standardised with the two newest methods. In practical applications, it is crucial to know which method of standardisation, and not only which standard population, has been in use.

背景与目标： : 在基于人群的癌症登记处中，如果癌症是唯一的死亡原因，则通常使用相对生存率来估计患者的生存概率。最近提出的新年龄标准化方法的结果可以解释为观察到的生存比例和预期生存比例之间的比率。与非标准化比率一样，这些年龄标准化的相对存活率仅在特定条件下才具有所需的概率解释。所涉及的情况是直到给定的随访点为止与其他原因有关的生存。随着随访长度的不同，这种情况也不同。结果，对于不同的随访时间，非标准化的相对存活率和使用两种最新方法标准化的相对存活率产生了关于年龄的互不可比的估计。例如，不考虑这一点可能会导致关于患者治愈的错误结论。传统的年龄标准化方法没有这种不可比性的问题。芬兰癌症登记处数据的相对生存分析结果用于说明这一问题。为了避免过度解释和混淆，必须知道对相对存活率的不同解释，包括非标准化和年龄标准化。例如，对于非标准化比率或使用两种最新方法进行年龄标准化的比率，不应产生由连续累积相对生存率组成的非常流行的累积相对生存率曲线。在实际应用中，至关重要的是要知道使用了哪种标准化方法，而不仅仅是使用了哪种标准人群。

BACKGROUND & AIMS: BACKGROUND:Few studies have examined the impact of balanced resuscitation in pediatric trauma patients requiring massive transfusions. Adult data may not be generalizable to children. METHODS:Retrospective analysis assessed patients seen at a level I trauma center between 2003 and 2010 aged ≤18 years requiring massive packed red blood cell (PRBC) transfusion, defined as transfusion of ≥50% total blood volume. After excluding mortalities in the first 24 hours, the impact of plasma and platelet ratios on mortality was evaluated. RESULTS:Of 6,675 pediatric trauma patients, 105 were massively transfused (mean age, 12.4 ± 6.3 years; mean Injury Severity Score, 25.8 ± 11.4; mortality rate, 18.1%). All deceased patients sustained severe head injuries. Plasma/PRBC and platelet/PRBC ratios were not significantly associated with mortality. CONCLUSIONS:In this study, higher plasma/PRBC and platelet/PRBC ratios were not associated with increased survival in children. The value of aggressive blood product transfusion for injured pediatric patients requires further prospective validation.

背景与目标：

BACKGROUND & AIMS: OBJECTIVES:The aim of this study was to investigate the effects of parental consanguinity on the 2D:4D digit ratio of newborn infants, whose parents were the first cousins. METHODS:The study included healthy and full-term newborn infants, delivered in a hospital, at the gestational ages from 37 to 41 weeks. A total of 225 newborns and their parents were included in the study. Of these 225 newborns; 100 were inbred and 125 were outbred infants. We used a Vernier caliper to measure the length of the second and fourth digits of the newborns (accuracy: 0.01 mm). RESULTS:Controlling for education and number of pregnancies, male newborns had lower digit ratios than female newborns, for both left and right hands. There were, moreover, differences between inbred and outbred samples. We determined that inbreeding was related to a reduction in the digit ratios regardless of the side of the hand and the sex of the infant, showing a consistent tendency to appear more masculine. Interaction between marriage type*sex was highly significant. CONCLUSIONS:Parental consanguinity appears to cause fetal masculinization of digit ratios by increasing fetal stress among Turkish newborns.

背景与目标：

BACKGROUND & AIMS: :Polycyclic Aromatic Hydrocarbons (PAHs) molecular diagnostic ratios (MDRs) are unitless concentration ratios of pair-PAHs with the same molecular weight (MW); MDRs have long been used as a tool for PAHs source identification purposes. In the present paper, the efficiency of the MDR methodology is evaluated through the use of a multimedia fate model, the calculation of characteristic travel distances (CTD) and the estimation of air concentrations for individual PAHs as a function of distance from an initial point source. The results show that PAHs with the same MW are sometimes characterized by substantially different CTDs and therefore their air concentrations and hence MDRs are predicted to change as the distance from the original source increases. From the assessed pair-PAHs, the biggest CTD difference is seen for Fluoranthene (107 km) vs. Pyrene (26 km). This study provides a strong indication that MDRs are of limited use as a source identification tool.

背景与目标： : 多环芳烃 (PAHs) 分子诊断比 (mdr) 是具有相同分子量 (MW) 的PAHs的无单位浓度比; Mdr长期以来一直被用作PAHs来源鉴定的工具。在本文中，通过使用多媒体命运模型，计算特征行进距离 (CTD) 以及估算各个PAHs的空气浓度 (作为距离的函数) 来评估MDR方法的效率。初始点源。结果表明，具有相同MW的PAHs有时具有明显不同的ctd特征，因此，它们的空气浓度和mdr预计会随着距原始源的距离增加而变化。从评估的PAHs对来看，荧蒽 (107千米) 与芘 (26千米) 的CTD差异最大。这项研究有力地表明，mdr作为来源识别工具的用途有限。

BACKGROUND & AIMS: :In a hospital environment that demands a careful balance between commercial and clinical interests, the extent to which physicians are involved in hospital leadership varies greatly. This paper assesses the influence of the extent of this involvement on staff-to-patient ratios. Using data gathered from 604 hospitals across Germany, this study evidences the positive relationship between a full-time medical director (MD) or heavily involved part-time MD and a higher staff-to-patient ratio. The data allows us to control for a range of confounding variables, such as size, rural/urban location, ownership structure, and case-mix. The results contribute to the sparse body of empirical research on the effect of clinical leadership on organizational outcomes.

背景与目标： : 在需要在商业利益和临床利益之间谨慎平衡的医院环境中，医生参与医院领导的程度差异很大。本文评估了这种参与程度对员工与患者比率的影响。使用从德国各地604家医院收集的数据，这项研究证明了全职医疗主任 (MD) 或大量参与的兼职MD与更高的员工与患者比率之间的正相关关系。这些数据使我们能够控制一系列混杂变量，例如大小，农村/城市位置，所有权结构和案例组合。该结果有助于对临床领导对组织结果的影响进行实证研究。

BACKGROUND & AIMS: OBJECTIVE:To compare Jarman-derived hospital standardised mortality ratios (HSMR) and Linkage-derived cumulative mortality ratios (CMR). METHODS:HSMR and CMR values for four groups of hospitals were derived from four single-year cohorts of linked patient admissions and deaths, and compared; differences were explored and reasons for non-matching and discordance were suggested. RESULTS:For the group of metropolitan teaching hospitals the Jarman-derived HSMR value of 0.95 (95% CI 0.93-0.97) was significantly lower than the Linkage-derived CMR value of 0.99 (95% CI 0.97-1.01). The opposite result was seen for the group of metropolitan non-teaching public hospitals: the Linkage-derived CMR of 0.81 (0.77-0.85) was significantly lower than the Jarman method HSMR of 1.03 (0.98-1.07). CONCLUSIONS:Incorrect deaths in the Jarman method can be overcome by using the Linked method. The Jarman method, unable to adjust for the contiguous transfers related to the death, apportioned excess deaths unfairly to the teaching hospitals group. WHAT IS KNOWN ABOUT THE TOPIC? HSMR based on hospital separation record information can reflect hospital performance if monitored over a regular period. Despite considerable variability, inter-hospital comparison league tables of hospitals based on such ratios have been published. WHAT DOES THIS PAPER ADD? This study demonstrated that the Linkage-derived CMR, utilising valid details from the state death registry, more accurately ascertains number of deaths than does the Jarman method-derived HSMR. WHAT ARE THE IMPLICATIONS FOR PRACTITIONERS? Where data linkages are possible, dual death derivations by the Jarman method and the Linked method can identify any unmatched or discordant deaths. Detailed exploration may help identify any differing hospital discharge practices.

背景与目标：

BACKGROUND & AIMS: :The relative effect of glucose and lipids on whole-body protein-metabolism kinetics was assessed in seven infants undergoing parenteral feeding. Protein intake was kept constant and nonprotein energy was either provided as glucose alone or as an isoenergetic glucose-lipid mixture according to a randomized crossover trial. Protein metabolism and energy-substrate utilization were assessed by a primed, constant L-[13C]leucine infusion, combined with indirect calorimetry. There was a significant difference in the pattern of energy-substrate utilization according to regime. Protein turnover (11.3 +/- 0.7 vs 9.8 +/- 0.4 g.kg-1.d-1; P less than 0.05), protein breakdown (8.4 +/- 0.6 vs 7.1 +/- 0.4 g.kg-1.d-1; P less than 0.05), and amino acid oxidation rates (2.7 +/- 0.4 vs 1.4 +/- 0.5 g.kg-1.d-1; P less than 0.05) were higher for the glucose than the glucose-lipid treatment, whereas protein-synthesis rates did not significantly differ. These results suggest that the nature of energy substrates delivered to parenterally fed infants may affect protein metabolism.

背景与目标： : 在接受胃肠外喂养的7名婴儿中评估了葡萄糖和脂质对全身蛋白质代谢动力学的相对影响。根据一项随机交叉试验，蛋白质摄入量保持恒定，非蛋白质能量既可以单独作为葡萄糖提供，也可以作为同能葡萄糖-脂质混合物提供。通过定量的L-[13C] 亮氨酸输注评估蛋白质代谢和能量底物利用，结合间接量热法。根据方案，能量-底物利用模式存在显著差异。蛋白质更新 (11.3 +/- 0.7 vs 9.8 +/- 0.4g。kg-1.d-1; P小于0.05)，蛋白质分解 (8.4 +/- 0.6 vs 7.1 +/- 0.4g。kg-1.d-1; P小于0.05) 和氨基酸氧化速率 (2.7 +/- 0.4 vs 1.4 +/- 0.5g。kg-1.d-1; P小于0.05) 的葡萄糖比糖脂处理高，而蛋白质合成速率没有显著差异。这些结果表明，给肠胃外喂养婴儿的能量底物的性质可能会影响蛋白质代谢。

BACKGROUND & AIMS: BACKGROUND:It was recently reported that genetic polymorphisms of UDP glucuronyltransferase-1 polypeptide A1 (UGT1A1), a glucuronidation enzyme, were associated with irinotecan (CPT-11) metabolism. The active metabolite of CPT-11, 7-ethyl-10-hydroxycamptothecin (SN-38) was glucuronidated (SN-38G) by UGT1A1. Genetic polymorphisms of UGT1A1 were associated with potentially serious adverse events, including neutropenia. Several studies have suggested that the dose of CPT-11 should be decreased in patients homozygous for UGT1A1*6 or UGT1A1*28, or double heterozygotes (*6/*28). However, the reference dose for patients with these genetic polymorphisms is unclear. METHODS:We investigated the relationship between the SN-38G/SN-38 concentration ratio and the dose of CPT-11 in 70 patients with colorectal cancer who received FOLFIRI-based regimens, by measuring the plasma concentrations of CPT-11, SN-38, and SN-38G. RESULTS:The SN-38G/SN-38 concentration ratio was lower in patients who were homozygous for UGT1A1*6, heterozygous for UGT1A1*6 or UGT1A1*28, or were double heterozygotes compared with patients with wild-type genes. The relative decreases in the SN-38G/SN-38 concentration ratio in patients homozygous for UGT1A1*6 and in double heterozygotes were greater than in patients heterozygous for UGT1A1*6 or UGT1A1*28. Interestingly, decreases in the SN-38G/SN-38 concentration ratio were associated with decreases in the neutrophil count and the final infusion dose of CPT-11. CONCLUSION:Our results suggest that the SN-38G/SN-38 concentration ratio is an important factor for guiding dose adjustments, even in patients with wild-type genes. Therefore, the SN-38G/SN-38 concentration ratio, as an index of the patient's metabolic capacity, is useful for assessing dose adjustments of CPT-11.

背景与目标：

BACKGROUND & AIMS: :One of the most intriguing features of biological systems is their ability to regulate the steady-state fluxes of the underlying biochemical reactions; however, the regulatory mechanisms and their physicochemical properties are not fully understood. Fundamentally, flux regulation can be explained with a chemical kinetic formalism describing the transitions between discrete states, with the reaction rates defined by an underlying free energy landscape. Which features of the energy landscape affect the flux distribution? Here we prove that the ratios of the steady-state fluxes of quasi-first-order biochemical processes are invariant to energy perturbations of the discrete states and are only affected by the energy barriers. In other words, the nonequilibrium flux distribution is under kinetic and not thermodynamic control. We illustrate the generality of this result for three biological processes. For the network describing protein folding along competing pathways, the probabilities of proceeding via these pathways are shown to be invariant to the stability of the intermediates or to the presence of additional misfolded states. For the network describing protein synthesis, the error rate and the energy expenditure per peptide bond is proven to be independent of the stability of the intermediate states. For molecular motors such as myosin-V, the ratio of forward to backward steps and the number of adenosine 5'-triphosphate (ATP) molecules hydrolyzed per step is demonstrated to be invariant to energy perturbations of the intermediate states. These findings place important constraints on the ability of mutations and drug perturbations to affect the steady-state flux distribution for a wide class of biological processes.

背景与目标： : 生物系统最有趣的特征之一是它们调节潜在生化反应的稳态通量的能力; 但是，其调节机制及其理化性质尚未完全了解。从根本上讲，通量调节可以用描述离散状态之间过渡的化学动力学形式主义来解释，反应速率由潜在的自由能景观定义。能源格局的哪些特征会影响通量分布？在这里，我们证明了准一阶生化过程的稳态通量之比与离散状态的能量扰动是不变的，并且仅受能量壁垒的影响。换句话说，非平衡通量分布是在动力学而不是热力学控制下的。我们说明了这一结果对三个生物学过程的一般性。对于描述蛋白质沿竞争途径折叠的网络，通过这些途径进行的概率显示出对中间体的稳定性或其他错误折叠状态的存在不变。对于描述蛋白质合成的网络，误差率和每个肽键的能量消耗被证明与中间状态的稳定性无关。对于诸如肌球蛋白V之类的分子马达，向前步与向后步的比率以及每步水解的5 '-三磷酸腺苷 (ATP) 分子的数量被证明对中间状态的能量扰动是不变的。这些发现对突变和药物扰动影响各种生物过程的稳态通量分布的能力构成了重要限制。

BACKGROUND & AIMS: BACKGROUND:Persons with mental health disorders (MHD) have higher rates of smoking and poorer cessation of smoking outcomes than those without MHD. A decreased level of motivation may partially explain lower cessation rates, but there is little information on motivation among inpatients with MHD. OBJECTIVES:Primary aims were to compare (1) motivation to cease smoking among those hospitalised with MHD or non-MHD, (2) the proportion that attempted smoking cessation, and (3) use of aids to cessation. A secondary aim was to assess cessation up to six months post-discharge. METHODS:Smokers were recruited at a tertiary hospital in Perth, Western Australia. Surveys were administered upon admission and at 5 and 14 days and 6 months post-discharge. RESULTS:We recruited 64 MHD inpatients and 43 non-MHD inpatients. At baseline there were no significant differences between the groups on any measures of the five measures of motivation. Significantly more of the MHD sample attempted smoking cessation than those in the non-MHD sample (34 versus 13: chi(2)(1)=5.472, P=0.028). Nicotine replacement therapy (NRT) alone was used by 70% of those attempting to quit but was only provided as part of discharge medication to two people and few persons (<21%) in either group used NRT post-discharge. By 14 days, three (4.7%) of the MHD group and none (0%) of the non-MHD group reported abstinence, at 6-months one from each group reported continuous abstinence since discharge from hospital. CONCLUSIONS:Motivation to cease smoking among inpatients with MHD was similar to those without MHD, as was use of NRT while hospitalised. The low provision of post-discharge NRT may contribute to the poor cessation of smoking outcomes and does not fulfil evidence based guidelines.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:We use a simulation-based model to study the impact of female philopatry and heterogeneity of habitat quality on the evolution of primary sex ratio. RESULTS:We show that these conditions may lead to strongly biased ESS habitat-dependent sex ratios, under two kinds of density-dependent population regulation. ESS sex ratios are always biased towards females in good habitats, towards males in poor habitats, and are generally equilibrated considering the whole population. Noticeably, the predicted bias of sex ratio usually increases with decreasing female philopatry. CONCLUSION:The selection forces responsible for these results are fully described. This study provides a new perspective on the evolutionary significance of temperature sex determination. We discuss the case of turtles by comparing our theoretical results with field observations.

背景与目标：

BACKGROUND & AIMS: Purpose:To investigate monocyte to high-density lipoprotein (HDL) ratio (MHR) and neutrophil-to-lymphocyte ratio (NLR) as indicators of systemic inflammation in acute central serous chorioretinopathy (CSC). Methods:The HDL levels, hematological profiles, erythrocyte sedimentation rates (ESR), and C-reactive protein (CRP) levels of 38 patients with acute CSC (Group I) and 38 controls without CSC (Group II) were measured. Results:MHRs were significantly higher in Group I (13.30 ± 2.95) than in Group II (11.52 ± 2.42, P = 0.005), whereas NLRs, CRP values, and ESR values did not significantly differ between the groups (P = 0.726, P = 0.219, and P = 0.441, respectively). Multivariate analysis revealed that the MHR was an independent predictor of acute CSC (OR = 1.266, 95% CI = 1.054-1.521, P = 0.012). Conclusion:Indicating an association between increased MHRs and acute CSC, the MHR might represent simple, inexpensive, reliable biomarkers of inflammation in acute CSC.

背景与目标：

BACKGROUND & AIMS: :Determining the mechanisms governing sex-ratio variation in dioecious organisms represents a central problem in evolutionary biology. It has been proposed that in plants with sex chromosomes competition between pollen tubes of female- versus male-determining microgametophytes (certation) causes female-biased primary sex ratios. Experimental support for this hypothesis is limited and recent workers have cast doubt on whether pollen-tube competition can modify sex ratios in dioecious plants. Here we investigate the influence of variation in pollination intensity on sex ratios in Rumex nivalis, a wind-pollinated alpine herb with strongly female-biased sex ratios. In a garden experiment, we experimentally manipulated pollination intensity using three concentric rings of female recipient plants at different distances from a central group of male pollen donors. This design enabled us to test the hypothesis that increasing pollen load size, by intensifying gametophyte competition, promotes female-biased sex ratios in R. nivalis. We detected a significant decline in pollen load at successive distance classes with concomitant reductions in seed set. Sex ratios of progeny were always female biased, but plants at the closest distance to male donors exhibited significantly greater female bias than more distant plants. The amount of female bias was positively correlated with the seed set of inflorescences. Hand pollination of stigmas resulted in approximately 100-fold higher stigmatic pollen loads than wind-pollinated stigmas and produced exceptionally female-biased progenies (female frequency = 0.96). Our results are the first to demonstrate a functional relation between stigmatic pollen capture, seed set, and sex ratio and suggest that certation can contribute towards female-biased sex ratios in dioecious plants.

背景与目标： : 确定控制雌雄异株生物性别比例变化的机制是进化生物学的核心问题。有人提出，在具有性染色体的植物中，决定雌性与雄性的微配子体 (certation) 的花粉管之间的竞争会导致女性偏向的主要性别比。对该假设的实验支持有限，最近的工人对花粉管竞争是否可以改变雌雄异株植物的性别比例表示怀疑。在这里，我们研究了授粉强度的变化对Rumex nivalis性别比例的影响，Rumex nivalis是一种风授粉的高山草本植物，具有强烈的女性偏向性别比。在花园实验中，我们使用距雄性花粉供体中心组不同距离的三个雌性受体植物同心环，通过实验控制授粉强度。此设计使我们能够检验以下假设: 通过加剧配子体竞争来增加花粉负荷大小，从而促进了R. nivalis的女性偏向性别比。我们检测到连续距离等级的花粉负荷显着下降，同时种子结实减少。后代的性别比总是有女性偏见，但是与男性供体距离最近的植物比较远的植物表现出更大的女性偏见。雌性偏倚的数量与花序的种子组呈正相关。柱头的手工授粉导致柱头花粉负荷比风授粉的柱头高约100倍，并产生异常偏向雌性的后代 (雌性频率 = 0.96)。我们的结果首次证明了柱头花粉捕获，种子结实和性别比之间的功能关系，并表明certation可以促进雌雄异株植物中女性偏向的性别比。