Hypothesis testing for two‐stage designs with over or under enrollment

Simon's two‐stage designs are widely used in cancer phase II clinical trials for assessing the efficacy of a new treatment. However in practice, the actual sample size for the second stage is often different from the planned sample size, and the original inference procedure is no longer valid. Previous work on this problem has certain limitations in computation. In this paper, we attempt to maximize the unconditional power while controlling for the type I error for the modified second stage sample size. A normal approximation is used for computing the power, and the numerical results show that the approximation is accurate even under small sample sizes. The corresponding confidence intervals for the response rate are constructed by inverting the hypothesis test, and they have reasonable coverage while preserving the type I error. Copyright © 2015 John Wiley & Sons, Ltd.     

鱼鳞胶原提取及其热稳定性提高的研究进展

近年来,随着水产加工业的迅速发展,鱼类下脚料中胶原蛋白的提取成为人们的研究热点。鱼鳞胶原具有优于畜禽胶原的低抗原性、低过敏性等特点,且来源广泛、价格低廉。该文综述了鱼鳞胶原提取及其热稳定性改进技术方面的研究进展。     

常州市有螺环境现状调查分析

目的 调查常州市有螺环境改造现状,为螺情监测提供依据.方法 收集全市有螺环境资料,对所有有螺环境进行现场调查并进行环境分类,建立数据库分析各类环境特点,并应用Google Earth软件绘制分布图.结果 常州市有螺环境共计6 174个,面积3 911.97万m2,分布于7市(县、区)的51个乡(镇)、414个村.根据环境分类,Ⅱ类环境最多,Ⅰ、Ⅱ、Ⅲ、Ⅳ类环境面积的构成比分别为24.8％、54.4％、11.3％、9.5％.金坛市、武进区、溧阳市的有螺环境面积最大,分别占全市总面积的31.0％、24.4％、24.0％.金坛市、溧阳市、武进区、新北区以现况Ⅱ类环境居多,天宁区、钟楼区、戚墅堰区以现况Ⅰ类环境居多.Ⅳ类环境主要分布在武进区和新北区,分别占68.3％、25.9％.江湖滩、内陆和山丘3种类型流行区有螺环境面积的构成比分别为9.9％、49.8％、40.3％.3种类型流行区均以Ⅱ类环境居多,面积分别占52.3％、50.1％、60.2％,Ⅳ类环境所占比例分别为22.5％、14.1％、0.7％.结论 常州市有螺环境分布广,面积大,应重点加强对Ⅲ类、ⅣV类环境的监测.     

Bone marrow mesenchymal stem cell therapy in ischemic stroke：mechanisms of action and treatment optimization strategies

Animal and clinical studies have conifrmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction, angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action, and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke. We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.     

The best medicine? The influence of physical activity and inactivity on Parkinson's disease

The incidence of Parkinson's disease (PD) is expected to increase as our population ages and will likely strain the projected capacity of our health care system. Despite being the most common movement disorder, there have been few noninvasive therapeutic advances for people with PD since the first levodopa clinical trial in 1961. The study of PD pathogenesis, combined with an appreciation for the biochemical mechanisms by which physical activity and exercise may impact physiology, has resulted in emerging hypotheses for new modifiable risk factors for PD. Physical activity and exercise as a means of preventing PD, or maintaining the functionality of people with PD, are a promising area of investigation. Conversely, physical inactivity is implicated in many disease states, some of which are also correlated with the development of PD, such as metabolic syndrome. The primary relationship between these diseases is likely rooted in heightened inflammation and oxidative stress at the cellular level. Physical activity and exercise as a means of attenuating inflammation have led to increased interest in related potential therapeutic targets for PD. Ultimately, these findings may translate into low‐cost, universally available therapies for PD disease modification or prevention. © 2016 International Parkinson and Movement Disorder Society     

A Facile Route to Bio‐Inspired Supramolecular Oligo(Ethylene Glycol) Catecholates

A particularly facile synthetic route to mussel‐inspired oligo(ethylene glycol) catecholates is described, yielding high purity materials with minimal purification. The oligocatecholates show remarkable thermal and rheological properties for their actual chain length, suggesting the operation of non‐covalent interactions between their l ‐DOPA‐bearing chain ends. This end‐group effect is more pronounced in the shorter oligomers (M _n of ethylene glycol chain of 200 and 400 Da), where the end‐group density is higher. Various surfaces (glass, stainless steel) are modified with the oligocatecholates, using a dip‐coating approach from dilute aqueous solutions. Water contact angle measurements and X‐ray photoelectron spectroscopy confirm the presence of a hydrophilic surface coating layer. The potential of these materials for application as antifouling coatings and viscosity modifiers is highlighted.     

Systemic disruption of the homeostasis of transfer RNA isopentenyltransferase causes growth and development abnormalities in Bombyx mori

Isopentenylation at A37 (i⁶A37) of some transfer RNAs (tRNAs) plays a vital role in regulating the efficiency and fidelity of protein synthesis. However, whether insects, which are well known for their highly efficient protein synthesis machinery, employ this regulatory mechanism remains uninvestigated. In the current study, a candidate tRNA isopentenyltransferase (IPT) gene with three alternative splicing isoforms (BmIPT1–BmIPT3) was identified in Bombyx mori (silkworm). Only BmIPT1 could complement a yeast mutant lacking tRNA IPT. Phylogenetic analysis showed that silkworm tRNA IPT is conserved in the Lepidoptera. BmIPT was expressed in all B. mori tissues and organs that were investigated, but was expressed at a significantly higher level in silk glands of the fourth instar compared to the first day of the fifth instar. Interestingly, BmIPT was expressed at a significantly higher level in the domesticated silkworm, B. mori, than in wild Bombyx mandarina in multiple tissues and organs. Knock‐down of BmIPT by RNA interference caused severe abnormalities in silk spinning and metamorphosis. Constitutive overexpression of BmIPT1 using a cytoplasmic actin 4 promoter in B. mori raised its messenger RNA level more than sixfold compared with nontransgenic insects and led to significant decreases in the body weight and cocoon shell ratio. Together, these results confirm the first functional tRNA IPT in insects and show that a suitable expression level of tRNA IPT is vital for silk spinning, normal growth, and metamorphosis. Thus, i⁶A modification at position A37 in tRNA probably plays an important role in B. mori protein synthesis.