35 research outputs found

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Social development of 21st century and reform of China’s elementary education

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    Seawater carbonate chemistry and growth rate, C fixation rate, cellular Fe uptake rates and growth Fe use efficiency of Phaeodactylum tricornutum

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    Light affects iron (Fe) growth requirements in marine phytoplankton while CO2 can influence energy allocation and light sensitivity. Therefore, ongoing increases in seawater CO2 concentrations could impact the growth of Fe- and light-limited phytoplankton. In this study, Phaeodactylum tricornutum was used as a model diatom to examine the interactive effects of Fe, light, and CO2 on photosynthesis, growth, and protein expression in marine phytoplankton. Low concentration of biologically available inorganic iron (Fe) and low-light intensity decreased specific rates of carbon (C)-fixation and growth, and the two together had an even greater effect, indicating a co-limitation. Increased partial pressure of CO2 from its current value (400 μatm) to 750 μatm had no effect at growth sufficient levels of Fe and light, but increased C-fixation and growth rate under Fe or light limitation, and had an even greater effect in Fe and light co-limited cells. The results suggest that ongoing increases in CO2 may increase C-fixation rates in Fe- and light-limited and co-limited regions, which cover at least 30% of the ocean. Measurements of photosynthetic proteins in photosystems II and I, and transcripts of proteins involved in CO2 concentrating mechanisms (CCMs), photorespiration, and antioxidant protection, suggest that the benefit of increased CO2 in the Fe- and light-limited cells was from a downregulation of CCMs and resultant decreased demands for energy supplied from photosynthesis, and from decreased rates of photorespiration, which consumes photosynthetically produced ATP and NADPH. A decrease in oxidative stress with increased CO2 also contributed

    Association between age at first birth and postpartum depression: A two-sample mendelian randomization analysis

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    Background: Previous observational research has documented an association between age at first childbirth (AFB) and postpartum depression (PPD). However, the causal relationship remains unclear. This study aimed to assess the causal effects of AFB on PPD using a two-sample Mendelian randomization (MR) analysis. Methods: Three sets of instrumental variables were obtained from the United Kingdom Biobank (UK Biobank), Neale Lab consortium and a meta-analysis of genome-wide association studies (GWAS). Single-nucleotide polymorphisms (SNPs) associated with the PPD phenotype were obtained from the Finngen consortium, which included 13,657 cases and 236,178 controls. Inverse variance weighted (IVW), weighted median, weighted mode, and MR-Egger methods to evaluate causal effects. Heterogeneity was assessed using Cochran's Q test and funnel plots. Horizontal pleiotropy and sensitivity were assessed using the MR-Egger intercept test and “leave-one-out” analysis, respectively. Further meta-analysis was performed to validate the robustness of this relationship. Additionally, the potential mediating effects of risk factors associated with PPD were analyzed. Results: Strong causal effects between AFB and PPD was found in both IVW and weighted median methods, which was further supported by meta-analysis (IVW, odds ratio [OR] 0.59 [95% confidence interval (CI) 0.36–0.96, p = 0.03]; weighted median, OR 0.59 [95% CI 0.37–0.95, p = 0.03]). The power of the MR supports the robustness of the findings. Heterogeneity or horizontal pleiotropy was not observed. Major depressive disorders, family income levels, and marital stress were identified as potential mediating factors in the causal relationships. Conclusion: Results of MR analysis supported the causal effect of increased AFB in reducing the risk for PPD

    A Fast-Response Ultraviolet Phototransistor with a PVK QDs/ZnO Nanowire Heterostructure and Its Application in Pharmaceutical Solute Detection

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    The sensitivity and photoelectric noise of UV photodetectors are challenges that need to be overcome in pharmaceutical solute detection applications. This paper presents a new device concept for a CsPbBr3 QDs/ZnO nanowire heterojunction structure for phototransistors. The lattice match of the CsPbBr3 QDs and ZnO nanowire reduces the generation of trap centers and avoids carrier absorption by the composite center, which greatly improves the carrier mobility and high detectivity (8.13 × 1014 Jones). It is worth noting that by using high-efficiency PVK quantum dots as the intrinsic sensing core, the device has a high responsivity (6381 A/W) and responsivity frequency (300 Hz). Thus, a UV detection system for pharmaceutical solute detection is demonstrated, and the type of solute in the chemical solution is estimated by the waveform and the size of the output 2f signals

    Growth mechanism of Ag(TCNQ) nanocrystal whiskers

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    A series of one-dimensional nanostructured organometallic complex, Ag(TCNQ), were prepared at a fairly low temperature using vacuum saturated vapor reaction. The composition and crystal structure of the obtained nanostructure were characterized by powder X-ray diffraction (XRD). Scanning electron microscopy (SEM) were employed to monitor the microstructure in the growth processes, and its images show that the formation of the Ag(TCNQ) nanocrystal whiskers includes three steps, i.e. co-melting, crystallization and directional growth. The growth mechanism was further explained with the Vapor-Liquid-Solid (VLS) model

    Targeting 3-phosphoinositide-dependent protein kinase 1 associated with drug-resistant renal cell carcinoma using new oridonin analogs.

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    The current agents used for renal cell carcinoma (RCC) only exhibit the moderate response rate among patients. Development of drug resistance eventually fuels the need of either more potent drugs or new drugs to target the resistant pathways. Oridonin is a diterpenoid isolated from the Chinese medicinal herb Rabdosia rubescens and has been shown to have antitumor activities in many cancers. We previously developed new synthetic methodologies to modify structurally diversified diterpenoids and designed a series of nitrogen-enriched oridonin analogs. In this study, we screened a variety of oridonin analogs based on their cytotoxicity using MTT assay and identify the most potent candidate, namely, CYD-6-17. CYD-6-17 exhibited a high potency to inhibit the in vitro growth of several drug-resistant RCC cells as well as endothelial cells stimulated by tumor cells at nanomolar range. Delivery of CYD-6-17 significantly inhibited RCC tumor growth using xenograft model. Mechanistically, it targeted the 3-phosphoinositide-dependent protein kinase 1 gene that appeared to be a potent regulator of AKT and was associated with patient survival after targeted therapies. This offers a new rational therapeutic regimen of CYD-6-17 to drug-resistant RCC based on its novel mechanism of action.115sciescopu

    Targeting XBP1-mediated β-catenin expression associated with bladder cancer with newly synthetic Oridonin analogues

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    Conventional chemotherapy is commonly used for advanced stages of transitional cell carcinoma (TCC) with modest success and high morbidity; however, TCC eventually develops resistance. Muscle invasive bladder cancer (MIBC) is recognized as a lethal disease due to its poor response to traditional chemotherapy. Numerous studies have implicated beta-catenin, a critical effector in Wnt-mediated pathway associated with epithelial-mesenchymal transition and cancer stem cell, is involved in TCC progression, and furthermore closely associated with chemo-resistance. In this study, we discovered a novel natural product analogue CYD 6-17 that has a potent inhibitory effect on TCC cells exhibiting drug resistance to various chemotherapeutics, with an IC50 at nM range. Delivery of CYD 6-17 significantly inhibited the tumor growth using xenograft model but without detectable side effects. Mechanistically, it targeted beta-catenin gene transcription by decreasing the binding of XBP1 to the promoter region, which appeared to be a new regulatory mechanism for beta-catenin gene expression. Clinically, XBP1 expression correlated with the poor overall survival of patients. Overall, this study unveils unique mechanism of beta-catenin gene regulation in advanced TCC and also offers a potential rational therapeutic regimen to MIBC.118sciescopu

    A nephrotoxicity-free, iron-based contrast agent for magnetic resonance imaging of tumors

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    Gadolinium-based contrast agents (GBCAs) are the most widely used T1 contrast agents for magnetic resonance imaging (MRI) and have achieved remarkable success in clinical cancer diagnosis. However, GBCAs could cause severe nephrogenic systemic fibrosis to patients with renal insufficiency. Nevertheless, GBCAs are quickly excreted from the kidneys, which shortens their imaging window and prevents long-term monitoring of the disease per injection. Herein, a nephrotoxicity-free T1 MRI contrast agent is developed by coordinating ferric iron into a telodendritic, micellar nanostructure. This new nano-enabled, iron-based contrast agent (nIBCA) not only can reduce the renal accumulation and relieve the kidney burden, but also exhibit a significantly higher tumor to noise ratio (TNR) for cancer diagnosis. In comparison with Magnevist (a clinical-used GBCA), Magnevist induces obvious nephrotoxicity while nIBCA does not, indicating that such a novel contrast agent may be applicable to renally compromised patients requiring a contrast-enhanced MRI. The nIBCA could precisely image subcutaneous brain tumors in a mouse model and the effective imaging window lasted for at least 24 h. The nIBCA also precisely highlights the intracranial brain tumor with high TNR. The nIBCA presents a potential alternative to GBCAs as it has superior biocompatibility, high TNR and effective imaging window
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