B2C平台买家诚信约束机制探析

我国现有的B2C电子商务平台的诚信机制,主要是用于约束卖家行为的,而对于买家行为的约束则较松散,难以从根本上遏制买家恶意评价、利用平台规则漏洞进行欺诈等各种失信行为,严重影响了平台卖家的正常交易。B2c平台买家诚信约束机制可在完善电子商务平台自身评价机制的基础上,引入第三方诚信中介机制和社会网络社区的约束机制。B2C电子商务平台可通过双向评价机制及买家身份等级设定约束买家行为;第三方诚信中介通过第三方支付、第三方质量鉴定及第三方认证等,使弱社会关系之中的信任变得可能,从而实现对买家显性声誉的约束;社会网络社区的重点在于使所有参与者以真实的身份参与平台活动,通过实名分享及购物推荐实现买家隐性声誉约束。     

ICP-AES 法测定鬼针草中硒的含量

分别采用湿法消解和微波消解处理了7月、9月和11月3个收获时期鬼针草样品,以电感耦合等离子体发射光谱仪（ICP—AES）检测样品中硒的含量．结果表明：鬼针草的硒含量分别为1．312mg／kg,1．999mg／kg,0．187mg／kg,随季节有所变化,以9月份硒含量最高．ICP—AES测定硒元素的相对标准偏差（RSD）为0．15％-1．76％,回收率在98．23％～101．2％．     

Presynaptic Membrane Receptor in Human Brain

Myasthenia gravis (MG) is an autoimmune disease that results from antibody mediated damage of Acetylcholine receptor (AChR) at the neuromuscular junction. The autoimmune character of MG and pathogenic role of AChR antibodies have been established by several workers i.e., the demonstration of anti-AChR antibodies in about 90 % of MG patients. It has been demonstrated that patients with MG also have antibodies against a second protein named presynaptic membrane receptor (PsmR), which is identified by utilizing β-Bgtx, a ligand which binds to PsmR. Using β-Bgtx Sepharose 4B affinity matrix, the PsmR was purified from different regions of human cadaver brain by affinity chromatography. Purified receptor was characterized both by biochemical and immunological procedures. PsmR purified from different regions of the brain shows a specific activity of 0.37 ± 0.01, 0.39 ± 0.02 and 0.43 ± 0.005 nM/ μg of protein in Parietal lobe, Occipital lobe and Frontal lobe respectively. The affinity purified PsmR from the brain of 87 and 68 kd (parietal lobe, occipital lobe and frontal lobe) shows immunoreactivity with myasthenic sera. These findings suggest that PsmR from brain is another antigen against which autoantibodies are developed in Myasthenia gravis patients. Upon treatment with various enzymes we concluded that PsmR from brain is a glycoprotein in which the immunoreactivity resides in the carbohydrate as well as the peptide epitopes. In conclusion the PsmR is another antigen against which autoantibodies are formed in different regions of brain. These can be used as a diagnostic tool for detecting antibodies in the sera or cerebrospinal fluid of MG patients.     

青藏高原东南部地震b值时空演化及其对区域应力场特征的启示

区域应力分布特征是地震危险性评价的重要指标之一。采用青藏高原东南部1970—2019年的地震目录数据,使用最大似然法对该区进行地震b值时空扫描,得到该区b值时空分布特征;利用地震b值与应力的负相关关系,分析青藏高原东南部主要断裂带上的应力分布及变化。研究结果显示：1）在鲜水河—小江断裂系统的中部,大凉山断裂带附近区域的b值比安宁河—则木河断裂带附近区域低,推测大凉山断裂带承担较多的应力,可能是未来地震风险较高的断裂带;2）研究区浅层（0~20 km）比深层（20~40 km）的b值高,这是与浅层区域围压低、岩石倾向脆性破裂,而深层区域围压高、岩石倾向韧性变形的特征相一致的;3）汶川地震发生前后,震源及周边区域的b值经历了降低—升高—降低的过程,揭示了区域内应力的累积—释放—累积过程;地震震级越大,震前b值降低趋势持续越久,该地震的发生对b值的影响范围越大、b值波动越明显,距震中越近的区域的b值在地震前后的波动越明显;4）龙门山断裂带及其附近地区b值较低,推测该区域应力较大。     

Pathogenic mutations of TGFBI and CHST6 genes in Chinese patients with Avellino, lattice, and macular corneal dystrophies

Objective  

To investigate gene mutations associated with three different types of corneal dystrophies (CDs), and to establish a phenotype-genotype correlation.     

Osteoinduction by Ca-P biomaterials implanted into the muscles of mice

The osteoinduction of porous biphasic calcium phosphate ceramics (BCP) has been widely reported and documented, but little research has been performed on rodent animals, e.g., mice. In this study, we report osteoinduction in a mouse model. Thirty mice were divided into two groups. BCP materials (Sample A) and control ceramics (Sample B) were implanted into the leg muscle, respectively. Five mice in each group were killed at 15, 30, and 45 d after surgery. Sample A and Sample B were harvested and used for hematoxylin and eosin (HE) staining, immunohistochemistry (IHC) staining, and Alizarin Red S staining to check bone formation in the biomaterials. Histological analysis showed that no bone tissue was formed 15 d after implantation (0/5) in either of the two groups. Newly-formed bone tissues were observed in Sample A at 30 d (5/5) and 45 d (5/5) after implantation; the average amounts of newly-formed bone tissues were approximately 5.2% and 8.6%, respectively. However, we did not see any bone tissue in Sample B until 45 d after implantation. Bone-related molecular makers such as bone morphogenesis protein-2 (BMP-2), collagen type I, and osteopontin were detected by IHC staining in Sample A 30 d after implantation. In addition, the newly-formed bone was also confirmed by Alizarin Red S staining. Because this is the report of osteoinduction in the rodent animal on which all the biotechnologies were available, our results may contribute to further mechanism research.     

Changes of paired-pulse evoked responses during the development of epileptic activity in the hippocampus

Dysfunction of inhibitory synaptic transmission can destroy the balance between excitatory and inhibitory synaptic inputs in neurons, thereby inducing epileptic activity. The aim of the paper is to investigate the effects of successive excitatory inputs on the epileptic activity induced in the absence of inhibitions. Paired-pulse orthodromic and antidromic stimulations were used to test the changes in the evoked responses in the hippocampus. Picrotoxin (PTX), γ-aminobutyric acid (GABA) type A (GABA_A) receptor antagonist, was added to block the inhibitory synaptic transmission and to establish the epileptic model. Extracellular evoked population spike (PS) was recorded in the CA1 region of the hippocampus. The results showed that the application of PTX induced a biphasic change in the paired-pulse ratio of PS amplitude. A short latency increase of the second PS (PS2) was later followed by a reappearance of PS2 depression. This type of depression was observed in both orthodromic and antidromic paired-pulse responses, whereas the GABAergic PS2 depression [called paired-pulse depression (PPD)] during baseline recordings only appeared in orthodromic-evoked responses. In addition, the depression duration at approximately 100 ms was consistent with a relative silent period observed within spontaneous burst discharges induced by prolonged application of PTX. In conclusion, the neurons may ignore the excitatory inputs and intrinsically generate bursts during epileptic activity. The depolarization block could be the mechanisms underlying the PPD in the absence of GABA_A inhibitions. The distinct neuronal responses to stimulations during different epileptic stages may implicate the different antiepileptic effects of electrical stimulation.     

Cordyceps cicadae extracts ameliorate renal malfunction in a remnant kidney model

Background and Objectives  

Chronic kidney disease (CKD) is a growing public health problem with an urgent need for new pharmacological agents. Cordyceps cicadae is widely used in traditional Chinese medicine (TCM) and has potential renoprotective benefits. The current study aimed to determine any scientific evidence to support its clinical use.