Propylene Polymerization Behavior of Fluorinated Bis(phenoxy‐imine) Ti Complexes with an MgCl2‐Based Compound (MgCl2‐Supported Ti‐Based Catalysts)

Summary: Fluorinated bis(phenoxy‐imine)Ti complexes 1 – 3 combined with MgCl₂/i‐Bu_nAl(OR)_3−n (MgCl₂‐supported catalysts) were able to polymerize propylene in a living fashion at room temperature to provide slightly to highly syndiotactic poly(propylenes) (PPs) with extremely narrow distributions of molecular weight. These represent the first examples of MAO‐ and borate‐free group 4 metal‐based living catalysts. The supported complexes 2 and 3 formed PPs with higher syndiotacticity and T_m's than the corresponding homogeneous MAO‐activation systems (e.g., 3 : rr 97%, T_m 155 °C; MAO activation: rr 93%, T_m 152 °C). The measured T_m of 155 °C represents the highest known T_m for syndiotactic PPs synthesized at room temperature.

Polymerization of propylene to poly(propylene) with supported Ti‐based catalysts.     

Changes in Hemodynamics and Respiration in Rats with Different Resistance to Acute Hypoxia

Effects of acute hypoxia on hemodynamics and respiration were studied in acute experiments on narcotized rats. The animals were divided into groups characterized by high, low-, and medium- resistance to hypoxia by the time of respiration arrest during inhalation of gas mixture containing 3% O2. Hemodynamic parameters of highly resistant animals were higher than in low-resistant rats throughout the entire hypoxic period. The development of a rare (with prolonged inspiratory phase) respiratory rhythm in highly resistant rats is an adaptive reaction, which allows them longer tolerate hypoxia compared to low-resistant animals.     

Block Copolymers of Methyl Vinyl Ether and Isobutyl Vinyl Ether With Thermo‐Adjustable Amphiphilic Properties

The thermo‐adjustable hydrophilic/hydrophobic properties of AB, ABA and BAB block copolymers in which A is poly(methyl vinyl ether) (PMVE) and B is poly(isobutyl vinyl ether) (PIBVE) have been investigated. The block copolymers were prepared by “living” cationic polymerization using sequential addition of monomers. The polymerizations were carried out with the system acetal/trimethylsilyl iodide as initiator and ZnI₂ as activator. The initiating system based on diethoxyethane leads to AB block copolymers whereas the initiating system based on tetramethoxypropane leads to ABA or BAB triblock copolymers. Well‐defined block copolymers of different composition with controlled molecular weights up to approx. 10 000 have been prepared. When IBVE is added to living PMVE, PIBVE‐blocks form only in the presence of an additional amount of ZnI₂, which is attributed to the fact that part of the ZnI₂ is inactive because of complex formation with PMVE. At room temperature, the combination of hydrophilic (PMVE) and hydrophobic (PIBVE) segments provides the copolymers with surfactant properties. Above the lower critical solution temperature (LCST) of PMVE, situated around 36 °C, the PMVE‐blocks become hydrophobic and the amphiphilic nature of the block copolymers is lost. The corresponding changes in hydrophilic/hydrophobic balance have been evaluated by investigation of the emulsifying properties of the block copolymers for water/decane mixtures as a function of the temperature. Below the LCST, the block copolymers have emulsifying properties similar to or better than those of the commercial PEO‐PPO block copolymers (Pluronic®). Either oil‐in‐water or water‐in‐oil emulsions can be obtained, depending on the polymer architecture and the water/decane volume ratio. The emulsifying properties are strongly reduced or completely lost above 40 °C. Emulsions obtained with a PMVE₃₆‐b‐PIBVE₅₄ block copolymer for a water/decane (v/v) ratio of 85/15 remained stable for more than six months.

50/50 and a 85/15 water/decane w/o emulsion (15 g/l) with the PMVE₃₆‐b‐PIBVE₅₄ block copolymer at 20 °C.     

Modification of Redox Sites of N-Methyl-D-Aspartate Receptors Affects Anoxia-Induced Changes in the Bioelectrical Activity of Rat Brain Olfactory Cortex Slices

Living slices of Wistar-Kyoto rat brain olfactory cortex were used to study the effects of the thiol-oxidizing agent 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), which inhibits NMDA receptor activity, on changes in the generation of evoked focal potentials (NMDA and non-NMDA EPSP) in response to long-term and short-term anoxia, which induces functional damage and facilitates increases in the resistance of neurons to severe hypoxia respectively. These studies showed that DTNB (200 'M) efficiently prevented the suppression of focal EPSP generation due to long-term anoxia in most slices. In addition, DTNB partially reversed the protective effect of preconditioning with short-term anoxia on the impairment of focal EPSP generation induced by long-term anoxia. This affected the NMDA component of the EPSP to a greater extent than the non-NMDA component. The possible role of changes in the state of modulatory redox sites of NMDA receptors in the mechanisms of functional damage and increases in neuron resistance due to hypoxia is discussed.     

脑卒中后抑郁及其对神经功能康复的影响

目的:观察脑卒中后抑郁(Post-Stroke Depression,PSD)的发生率和相关因素;探讨选择性5-HT抑制剂对脑卒中后抑郁神经功能康复的影响.方法:选取急性脑脑卒中患者132例(脑梗死78例,脑出血54例),分别在病程2周、1,3,6,12月时给每一位入组患者行PSD诊断、神经功能缺损评分、日常生活能力评分(Activity of Daily Living Scale,ADL)、汉密尔顿抑郁量表(Hamilton Depression Scale,HAMD)评分;同时完成Zung's抑郁自评量表(Self-Rating Depression Scale,SDS)和焦虑自评量表(Self-Rating Anxiety Scale,SAS).结果:①脑卒中患者中约44.70%出现抑郁症状;②脑卒中类型和性别与PSD发生率无相关性(P＞0.05);③PSD的发生率和严重程度与神经功能缺损和日常生活能力下降程度有关.④PSD与病变部位、病灶大小、病灶单侧性均无明显相关(P＞0.05);⑤氟西汀抗抑郁治疗能明显改善病程3、6个月时的神经功能缺损,病程12月时不仅抑郁症状减轻,日常生活能力改善,神经功能缺损减轻尤为显著.结论:脑卒中后抑郁是急性脑血管病患者常见的长期并发症,并可影响患者功能康复的速度和程度.抗抑郁剂治疗能在抑郁症状明显改善的同时,促进患者日常生活能力和神经功能的恢复.     

Predictability of Individual Differences in Activation Processes in a Field Setting Based on Laboratory Measures

The predictability of individual differences in activation processes was investigated in a multi-method laboratory-field study. Male students of physical education (N=58) were examined under various emotionally activating and physically demanding conditions (mental arithmetic, reaction time, free speech, cold pressor test, bicycle ergometer). The assessment included multi-channel recordings of pre-start phases in an athletic stadium and performance on a 1000 m run. Basal heart rate was also recorded during sleep. This multi-situational assessment was repeated after three weeks, three months, and, for most (N=42) subjects, after one year. Significant relationships exist between scores from corresponding conditions of relaxation, anticipation, and performance of physical exercise. However, with the exception of heart rate, correlation coefficients are rather small and seem to be of questionable predictive validity. A generalizability study further supports the general conclusion: To increase the practical relevance in psychophysiological investigations of stress/strain phenomena, such studies should directly assess individual differences in the criterion situations themselves.     

Cross-cultural perspectives on widowhood

Widowhood causes four problems: how to replace the functions of the dead spouse and those of the dead parent? who should inherit the property of the dead spouse/ parent? and, where should the surviving family live? Typical solutions to these problems are related to demographic characteristics of developing and developed countries.     

Validating Restricted Mean Survival Time Estimates From Reconstructed Kaplan-Meier Data Against Original Trial Individual Patient Data From Trials Conducted by the Canadian Cancer Trials Group

ObjectivesThe development of novel cancer therapies, including immuno-oncology agents, has increased interest in reconstructed individual patient data (IPD) based restricted mean survival time (RMST) analyses. Additionally, reconstructed IPD–based RMST is recommended in cost-effectiveness analyses when original trial IPD are not available. Nevertheless, recently concerns regarding potential bias of reconstructed-IPD RMST have been presented, because reconstructed-IPD RMSTs have not been validated and previous validation endpoints may not capture the entire Kaplan-Meier (KM) curve, especially the “tail.” Our study aims to validate the recommended method of IPD reconstruction by comparing reconstructed IPD– and original trial IPD–based RMST.MethodsCanadian Cancer Trials Group trials from 1990 to 2017 were included. Overall survival and progression-free survival IPD were reconstructed based on published KM curves using the Guyot method. Analysts were blinded to original trial IPD. RMST was calculated at 1 year and over the entire KM curve. Reconstructed-IPD and original trial–IPD (gold-standard) RMSTs were compared for accuracy and predictive error via mean deviation, mean absolute error (MAE), mean percentage bias, and Bland-Altman plots and across KM curve quality (vector traced or bitmapped).ResultsWe identified 39 trials. The mean deviation, MAE, and mean percentage bias of RMST between the reconstructed IPD and original trial IPD were small. In particular, the mean deviation was ?0.01 months and ?0.04 months, MAE was 0.19 months and 0.24 months, and mean percentage bias was 0.82% and 0.84% in overall survival KM curves in control and experimental arms, respectively. Accuracy was generally not associated with KM curve quality.ConclusionsRMST derived from reconstructed IPD displayed excellent accuracy and predictive error compared with the gold standard. Reconstructed IPD could be used to calculate RMST in lieu of original trial IPD, to facilitate decision making for clinicians, researchers, and policy makers.     

Characterizing Emergency Department Use in Assisted Living

ObjectivesLittle is known about emergency department (ED) utilization among the nearly 1 million older adults residing in assisted living (AL) settings. Unlike federally regulated nursing homes, states create and enforce AL regulations with great variability, which may affect the quality of care provided. The objective of this study was to examine state variability in all-cause and injury-related ED use among residents in AL.DesignObservational retrospective cohort study.Setting and ParticipantsWe identified a cohort of 293,336 traditional Medicare beneficiaries residing in larger AL communities (25+ beds).MethodsWith Medicare enrollment and claims data, we identified ED visits and classified those because of injury. We present rates of all-cause and injury-related ED use per 100 person-years in AL, by state, adjusting for age, sex, race, dual-eligibility, and chronic conditions.ResultsRisk-adjusted state rates of all-cause ED visits ranged from 100.9 visits/100 AL person-years [95% confidence interval (CI) 92.8, 109.9] in New Mexico to 162.3 visits/100 AL person-years (95% CI 154.0, 174.7) in Rhode Island. The risk-adjusted rate of injury-related ED visits ranged from 18.7 visits/100 AL person-years (95% CI 17.2, 20.3) in New Mexico to 35.7 visits/100 AL person-years (95% CI 34.7, 36.8) in North Carolina.Conclusions and ImplicationsWe observed significant variability among states in all-cause and injury-related ED use among AL residents. There is an urgent need to better understand why this variability is occurring to prevent avoidable visits to the ED.