A Hierarchically Organized Photoelectrode Architecture for Highly Efficient CdS/CdSe‐Sensitized Solar Cells

A form of photoelectrode architecture suitable for inorganic semiconductor solar cells is reported. The developed architecture consists of hierarchically organized TiO₂ nanostructures with several tens of nanometer‐sized particles that have a large surface area and open channels with several hundred‐nanometer‐gaps perpendicular to the substrate. These are tailored by controlling the kinetic energy of the ablated species during pulsed laser deposition (PLD). To fabricate the solar cells, CdS and CdSe inorganic sensitizers are assembled onto the architecture by successive ionic layer adsorption and reaction and polysulfide solution is used as an electrolyte with lead sulfide counter‐electrodes. The inorganic semiconductor solar cells using the developed architecture (PLD‐TiO₂) show high energy conversion efficiencies of 5.57% compared to a conventional mesoporous TiO₂ film(NP‐TiO₂) (3.84%) with an optical mask at 1 sun of illumination. The improved cell performance of PLD‐TiO₂ is attributed to greater light‐harvesting ability, which results in the enhancement of the J_sc value. PLD‐TiO₂ absorbs more CdS/CdSe because of its larger surface area and excellent adhesion properties with fluorine‐doped tin oxide (FTO) substrates. Additionally, due to its unique channel‐shaped architecture, PLD‐TiO₂ has a longer electron lifetime compared to NP‐TiO₂.     

A novel phosphorescence sensor for Co2+ ion based on Mn‐doped ZnS quantum dots

N‐acetyl‐l ‐cysteine‐capped Mn‐doped ZnS quantum dots (QDs) were prepared by hydrothermal methods. It could emit phosphorescence at 583 nm with the excitation wavelength at 315 nm. The phosphorescence intensity of QDs could be quenched dramatically by increasing the concentration of Co²⁺ ion. The novel phosphorescence sensor based on N‐acetyl‐l ‐cysteine‐capped QDs was developed for detecting Co²⁺ ion with a linear dynamic range of 1.25 × 10^–6–3.25 × 10^–5 m . The limit of detection and RSD were 6.0 × 10^–8 m and 2.3%, respectively. Interference experiments showed excellent selectivity over numerous cations such as alkali, alkaline earth and transitional metal ions. The possible quenching mechanism was also examined by phosphorescence decays. The proposed phosphorescence method was further applied to the trace determination of Co²⁺ ion in tap and pond water samples with recoveries of 97.75–103.32%. Copyright © 2013 John Wiley & Sons, Ltd.     

Modification of Sialylation Mediates the Invasive Properties and Chemosensitivity of Human Hepatocellular Carcinoma

Aberrant sialylation is closely associated with malignant phenotypes of tumor cells, including invasiveness and metastasis. This study investigated sialylation with regard to the modification of invasive properties and chemosensitivity in human hepatocellular carcinoma (HCC) cell lines and the association between the sialyltransferase gene family and clinicopathological characteristics in HCC patients. Using mass spectrometry analysis, we found that the composition profiling of sialylated N-glycans differed between MHCC97H and MHCC97L cells with different metastatic potential. The expressional profiles of 20 sialyltransferase genes showed differential expression in two cell lines, transitional and tumor tissues, from the same patients. Two genes, ST6GAL1 and ST8SIA2, were detected as overexpressed in MHCC97H and MHCC97L cells. The altered expression levels of ST6GAL1 and ST8SIA2 corresponded to a changed invasive phenotype and chemosensitivity of MHCC97H and MHCC97L cells both in vitro and in vivo. Further data indicated that manipulation of the expression of the two genes led to altered activity of the phosphoinositide-3 kinase (PI3K)/Akt signaling pathway. Targeting the PI3K/Akt pathway by its specific inhibitor wortmannin or by Akt RNA interference resulted in a reduced capacity for invasion and chemoresistance of MHCC97H cells. Our results imply that sialylation may function as an internal factor, regulating the invasion and chemosensitivity of HCC, probably through ST6GAL1 or ST8SIA2 regulation of the activity of the PI3K/Akt pathway.Metastasis of tumor cells and the development of resistance to antitumor therapies are the major causes of death in cancer patients. Specific changes in the glycosylation patterns of cell surface glycoproteins have been shown to enhance the metastatic efficiency of tumor cells, in particular that of terminal sialylation (1). It is well known that alterations in cell surface sialylated antigens affect many cellular properties—for example, cell–cell adhesion, cell–extracellular matrix adhesion, immune defense, cell metastasis, and invasion abilities (2–5). Sialyltransferases catalyze the transfer of sialic acid from cytidine 5′-monophospho-N-acetylneuraminic acid to terminal positions of glycoprotein and glycolipid carbohydrate groups (6).The sialyltransferase (ST)¹ family is a family of anabolic enzymes consisting of 20 members that are divided into three subfamilies (7). α-2,3-sialyltransferases mediate the transfer of sialic acid with an α-2,3-linkage to it with terminal Gal residues (ST3GalI-VI). α-2,6-sialyltransferases mediate the transfer of sialic acid with an α-2,6-linkage to it with terminal Gal (ST6GalI-II) (8, 9) or GalNAc residues (ST6GalNAcI-VI). α-2,8-sialyltransferases mediate the transfer of sialic acid with an α-2,8-linkage (ST8SiaI-VI). Changes in specific sialyltransferase expression in several tumors have been reported. ST3GalIII modulates pancreatic cancer cell motility and adhesion in vitro and enhances its metastatic potential in vivo (10). The high expression of ST3GalIV is associated with the malignant behavior of gastric cancer cells (11). ST6GalI is up-regulated in colon adenocarcinoma, and its expression is positively correlated with tumor cell invasiveness and metastasis (12–14). ST6GalNAcI expression is sufficient to enhance the tumorigenicity of MDA-MB-231 breast cancer cells (15). Overexpression of ST6GalNAcII has been correlated with poor patient survival (16). ST6GalNAcV has recently been reported to mediate brain metastasis of breast cancer cells (17). ST8Sia I is also overexpressed in neuroectoderm-derived malignant tumors such as melanoma, glioblastoma, and neuroblastoma, as well as in estrogen receptor negative breast cancer, where it plays a role in cell proliferation, migration, adhesion, and angiogenesis (18).The phosphoinositide 3 kinase (PI3K)/Akt pathway is involved in many cellular processes, including proliferation, differentiation, apoptosis, cell cycle progression, cell motility, tumorigenesis, tumor growth, and angiogenesis (19, 20). In addition, several reports highlight that the PI3K/Akt pathway is responsible for the proliferation, invasion, metastasis, and drug resistance of hepatocellular carcinoma (HCC), and targeting PI3K/AKT inhibits the proliferation and tumorigenesis of HCC cells (21, 22). MicroRNA-7 plays a substantial role in inhibiting the tumorigenesis and reversing the metastasis of HCC through the PI3K/Akt/mTOR signaling pathway in vitro and in vivo (23). The proliferation and invasion of HCC cells are inhibited by lipocalin 2 through the blockade of PI3K/Akt signaling (24). Activation of the PI3K/Akt pathway mediates rapamycin and sorafenib resistance in HCC cells (25, 26). However, little is known about the ST family and its signaling pathway in relation to malignant phenotypes of human HCC.Therefore, the aims of the present study were to determine sialylated oligosaccharide alteration and expression levels of ST genes among the MHCC97H and MHCC97L cell lines and HCC patient cells by using MS and real-time PCR. In addition, we investigated whether the ST gene family participates in the regulation of tumor invasion and chemosensitivity via the PI3K/Akt pathway and the possible mechanisms.     

Enhanced Specificity of TPMT*2 Genotyping Using Unidirectional Wild-Type and Mutant Allele-Specific Scorpion Primers in a Single Tube

Genotyping of thiopurine S-methyltransferase (TPMT) is recommended for predicting the adverse drug response of thiopurines. In the current study, a novel version of allele-specific PCR (AS-PCR), termed competitive real-time fluorescent AS-PCR (CRAS-PCR) was developed to analyze the TPMT*2 genotype in ethnic Chinese. This technique simultaneously uses wild-type and mutant allele-specific scorpion primers in a single reaction. To determine the optimal conditions for both traditional AS-PCR and CRAS-PCR, we used the Taguchi method, an engineering optimization process that balances the concentrations of all components using an orthogonal array rather than a factorial array. Instead of running up to 264 experiments with the conventional factorial method, the Taguchi method achieved the same optimization using only 16 experiments. The optimized CRAS-PCR system completely avoided non-specific amplification occurring in traditional AS-PCR and could be performed at much more relaxed reaction conditions at 1% sensitivity, similar to traditional AS-PCR. TPMT*2 genotyping of 240 clinical samples was consistent with published data. In conclusion, CRAS-PCR is a novel and robust genotyping method, and the Taguchi method is an effective tool for the optimization of molecular analysis techniques.     

油蒿群落不同演替阶段某些群落特征的研究

 本文就鄂尔多斯高原毛乌素沙地油蒿群落不同演替阶段的特征进行了研究。结果表明：流动沙地质地疏松,植物种类少、稀疏,群落冠层温度变化剧烈,相对湿度低,油蒿生长旺盛,其叶的含水量、水势、蒸腾强度高;固定沙地,植物种类增多、覆盖度大、生物量高,缓冲气象因子的能力强。但蒸腾失水量大,致使土壤含水量低,在某种程度上限制了油蒿生长;具结皮的固定沙地,植物种类最多,密度最大,但土壤紧实,油蒿生长微弱,其叶的含水量、水势最低,但蒸腾最大,加速失水。其演替趋势为流动沙地→流动沙地油蒿群落→固定沙地油蒿群落→具结皮的固定沙地油蒿+本氏针茅群落→本氏针茅群落。     

Identification of miRNAs and their targets from Brassica napus by high-throughput sequencing and degradome analysis

ABSTRACT: BACKGROUND: MicroRNAs (miRNAs) are endogenous regulators of a broad range of physiological processes and act by either degrading mRNA or blocking its translation. Oilseed rape (Brassica napus) is one of the most important crops in China, Europe and other Asian countries with publicly available expressed sequence tags (ESTs) and genomic survey sequence (GSS) databases, but little is known about its miRNAs and their targets. To date, only 46 miRNAs have been identified in B. napus. RESULTS: Forty-one conserved and 62 brassica-specific candidate B. napus miRNAs, including 20 miRNA* sequences, were identified using Solexa sequencing technology. Furthermore, 33 non-redundant mRNA targets of conserved brassica miRNAs and 19 new non-redundant mRNA targets of novel brassica-specific miRNAs were identified by genome-scale sequencing of mRNA degradome. CONCLUSIONS: This study describes large scale cloning and characterization of B. napus miRNAs and their potential targets, providing the foundation for further characterization of miRNA function in the regulation of diverse physiological processes in B. napus.     

关节镜下有限清理术治疗膝关节骨性关节炎的体会

目的:探讨关节镜下有限清理术治疗膝关节骨性关节炎的疗效。方法:自2005年6月至2009年10月对62例81膝膝关节骨性关节炎患者进行关节镜下有限清理术,对其临床疗效进行分析。结果:本组病例均获随访,时间12~36个月。优28膝,良39膝,可10膝,差4膝,优良率82.7%。结论:关节镜下有限清理术治疗膝关节骨性关节炎可以有效改善病人的症状,明显改善生活质量。