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1. chinaXiv:201711.00169 [pdf]

Syntheses, Crystal Structures, and Fluorescence Properties of Three Coordination Polymers Constructed Based on Benzoic Acid and Its Derivatives

LIU Guang-Zeng; CHEN Hong-Tai; ZHANG Xiu-Tang[1]
Subjects: Chemistry >> Physical Chemistry

Three new different dimensional coordination polymers, namely, [Zn(BA-)2(4,4?-bib)1.5]n (1), [Zn(4-BrBA-)2(1,4-bmb)]n (2) and [Mn(4-BrBA-)2(4,4?-bib)]n (3) have been assembled through the mixed-ligand synthetic strategy (4-HBrBA = 4-bromobenzoic acid, HBA = benzoic acid, 1,4-bmb = 1,4-bis(1H-imidazol-4-yl)benzene, 4,4?-bib = 4,4?-bis(imidazolyl)biphenyl). Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses (EA), powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Single-crystal X-ray diffraction analysis reveals that the crystals of complexes 1~3 are all in triclinic systems, space group P. Complexes 1 and 2 are 0D binuclear structures, and 3 is a 1D chain. Moreover, the solid state fluorescence properties of 1 and 2 have been investigated

submitted time 2017-11-05 From cooperative journals:《结构化学》 Hits1184Downloads710 Comment 0

2. chinaXiv:201706.00763 [pdf]

Numerical Investigation of the Effects of ITD Length on Low Pressure Nozzle

Liu, Guang; Liu, Jun; Liu, Hongrui; Wang, Pei; Du, Qiang
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics

The advantage of high efficiency, low SFC (Specific Fuel Consumption), ultra-high bypass ratio turbofan engine attracts more and more attention in modern commercial engine. The intermediate turbine duct (ITD), which connects high pressure turbine (HPT) with low pressure turbine (LPT), has a critical impact on the overall performance of turbine by guiding flow coming from HPT to LPT without too much loss. Therefore, it becomes more and more urgent to master the technique of designing aggressive, even super-aggressive ITD. Much more concerns have been concentrated on the duct. However, in order to further improve turbine, LPT nozzle is arranged into ITD to shorten low pressure axle. With such design concept, it is obvious that LPT nozzle flow field is easily influenced by upstream duct structure, but receives much less interests on the contrary. In this paper, numerical method is used to investigate the effects of length of ITD with upstream swirl blades on LPT nozzle. Nine models with the same swirl and nozzle blades, while the length of ITD is the only parameter to be changed, will be discussed. Finally, several conclusions and advices for designers are summarized. After changing axial length of ducts, inlet and outlet flow field of nozzle differs, correspondingly. On the other hand, the shearing stress on nozzle blade (suction and pressure) surface presents individual feature under various inlet flow. In addition to that, "Clocking-like effect" is described in this paper, which will contribute much to the pressure loss and should be paid enough attention.

submitted time 2017-06-26 From cooperative journals:《热科学学报》 Hits1503Downloads866 Comment 0

3. chinaXiv:201703.00310 [pdf]

A broadband KU-band microstrip reflectarray antenna using single-layer fractal elements

Xue, Fei; Wang, Hong-Jian; Yi, Min; Liu, Guang
Subjects: Geosciences >> Space Physics

A novel single-layer microstrip reflectarray element with fractal structure is proposed. Ansoft HFSS is used to analyze the reflect phase for the fractal element in honeycomb lattice. A 469-element prime focus microstrip reflectarray antenna composed of the proposed fractal elements is designed, manufactured, and measured. The measured gain level of 29.8 dB is obtained at the center frequency of 13.58 GHz with 1-dB gain bandwidth of 15.3%.

submitted time 2017-03-10 Hits17044Downloads2012 Comment 0

4. chinaXiv:201605.01735 [pdf]

PTEN deficiency reprogrammes human neural stem cells towards a glioblastoma stem cell-like phenotype

Duan, Shunlei; Yuan, Guohong; Ren, Ruotong; Xu, Xiuling; Fu, Lina; Li, Ying; Yang, Jiping; Zhang, Weiqi; Liu, Guang-Hui; Liu, Xiaomeng; Li, Jingyi; Tang, Fuchou; Ren, Ruotong; Bai, Ruijun; Liu, Guang-Hui; Ren, Ruotong; Bai, Ruijun; Qu, Jing; Zhang, Weizhou; Wu, Jun
Subjects: Biology >> Biophysics

PTEN is a tumour suppressor frequently mutated in many types of cancers. Here we show that targeted disruption of PTEN leads to neoplastic transformation of human neural stem cells (NSCs), but not mesenchymal stem cells. PTEN-deficient NSCs display neoplasm-associated metabolic and gene expression profiles and generate intracranial tumours in immunodeficientmice. PTEN is localized to the nucleus in NSCs, binds to the PAX7 promoter through association with cAMP responsive element binding protein 1 (CREB)/CREB binding protein (CBP) and inhibits PAX7 transcription. PTEN deficiency leads to the upregulation of PAX7, which in turn promotes oncogenic transformation of NSCs and instates 'aggressiveness' in human glioblastoma stem cells. In a large clinical database, we find increased PAX7 levels in PTEN-deficient glioblastoma. Furthermore, we identify that mitomycin C selectively triggers apoptosis in NSCs with PTEN deficiency. Together, we uncover a potential mechanism of how PTEN safeguards NSCs, and establish a cellular platform to identify factors involved in NSC transformation, potentially permitting personalized treatment of glioblastoma.

submitted time 2016-05-15 Hits4169Downloads1898 Comment 0

5. chinaXiv:201605.01529 [pdf]

A Werner syndrome stem cell model unveils heterochromatin alterations as a driver of human aging

Zhang, Weiqi; Wang, Ping; Zhou, Junzhi; Ren, Ruotong; Xu, Xiuling; Yuan, Tingting; Yang, Jiping; Li, Ying; Guan, Dee; Pan, Huize; Duan, Shunlei; Ding, Zhichao; Chen, Chang; Yang, Fuquan; Liu, Guang-Hui; Li, Jingyi; Liu, Xiaomeng; Tang, Fuchou; Suzuki, Keiichiro; Ocampo, Alejandro
Subjects: Biology >> Biophysics

Werner syndrome (WS) is a premature aging disorder caused by WRN protein deficiency. Here, we report on the generation of a human WS model in human embryonic stem cells (ESCs). Differentiation of WRN-null ESCs to mesenchymal stem cells (MSCs) recapitulates features of premature cellular aging, a global loss of H3K9me3, and changes in heterochromatin architecture. We show that WRN associates with heterochromatin proteins SUV39H1 and HP1 alpha and nuclear lamina-heterochromatin anchoring protein LAP2 beta. Targeted knock-in of catalytically inactive SUV39H1 in wild-type MSCs recapitulates accelerated cellular senescence, resembling WRN-deficient MSCs. Moreover, decrease in WRN and heterochromatin marks are detected in MSCs from older individuals. Our observations uncover a role for WRN in maintaining heterochromatin stability and highlight heterochromatin disorganization as a potential determinant of human aging.

submitted time 2016-05-12 Hits2647Downloads1438 Comment 0

6. chinaXiv:201605.01464 [pdf]

Regenerative medicine: targeted genome editing in vivo

Wang, Lixia; Liu, Guang-Hui; Wu, Jun; Belmonte, Juan Carlos Izpisua; Fang, Weiwei; Liu, Guang-Hui; Liu, Guang-Hui
Subjects: Biology >> Biophysics >> Cell Biology

The CRISPR/Cas system has proven to be a powerful gene editing tool both in vitro and in vivo. A recent flurry of studies of in vivo gene editing using the CRISPR/Cas system bring bright prospects in creating animal models and targeted gene therapy of human genetic diseases.

submitted time 2016-05-12 Hits2411Downloads1378 Comment 0

7. chinaXiv:201605.01385 [pdf]

CRISPR/Cas9 and TALE: beyond cut and paste

Deng, Liping; Ren, Ruotong; Liu, Guang-Hui; Wu, Jun; Suzuki, Keiichiro; Belmote, Juan Carlos Izpisua; Liu, Guang-Hui; Liu, Guang-Hui
Subjects: Biology >> Biophysics >> Cell Biology

Nuclease-based genome editing has proven to be a powerful and promising tool for disease modeling and gene therapy. Recent advances in CRISPR/Cas and TALE indicate that they could also be used as a targeted regulator of gene expression, as well as being utilized for illuminating specific chromosomal structures or genomic regions.

submitted time 2016-05-12 Hits1829Downloads1046 Comment 0

8. chinaXiv:201605.01375 [pdf]

Characterization of a novel mouse model with genetic deletion of CD177

Xie, Qing; Li, Xiangrui; Xie, Qing; Parlet, Corey; Borcherding, Nicholas; Kolb, Ryan; Li, Wei; Tygrett, Lorraine; Waldschmidt, Thomas; Olivier, Alicia; Zhang, Weizhou; Klesney-Tait, Julia; Keck, Kathy; Chen, Songhai; Liu, Guang-Hui; Liu, Guang-Hui
Subjects: Biology >> Biophysics >> Cell Biology

Neutrophils play an essential role in the innate immune response to infection. Neutrophils migrate from the vasculature into the tissue in response to infection. Recently, a neutrophil cell surface receptor, CD177, was shown to help mediate neutrophil migration across the endothelium through interactions with PECAM1. We examined a publicly available gene array dataset of CD177 expression from human neutrophils following pulmonary endotoxin instillation. Among all 22,214 genes examined, CD177 mRNA was the most upregulated following endotoxin exposure. The high level of CD177 expression is also maintained in airspace neutrophils, suggesting a potential involvement of CD177 in neutrophil infiltration under infectious diseases. To determine the role of CD177 in neutrophils in vivo, we constructed a CD177-genetic knockout mouse model. The mice with homozygous deletion of CD177 have no discernible phenotype and no significant change in immune cells, other than decreased neutrophil counts in peripheral blood. We examined the role of CD177 in neutrophil accumulation using a skin infection model with Staphylococcus aureus. CD177 deletion reduced neutrophil counts in inflammatory skin caused by S. aureus. Mechanistically we found that CD177 deletion in mouse neutrophils has no significant impact in CXCL1/KC- or fMLP-induced migration, but led to significant cell death. Herein we established a novel genetic mouse model to study the role of CD177 and found that CD177 plays an important role in neutrophils.

submitted time 2016-05-12 Hits1922Downloads1115 Comment 0

9. chinaXiv:201605.01363 [pdf]

Selective Elimination of Mitochondrial Mutations in the Germline by Genome Editing

Reddy, Pradeep; Ocampo, Alejandro; Suzuki, Keiichiro; Luo, Jinping; Sugawara, Atsushi; Okamura, Daiji; Wu, Jun; Lam, David; Esteban, Concepcion Rodriguez; Sancho-Martinez, Ignacio; Belmonte, Juan Carlos Izpisua; Bacman, Sandra R.; Williams, Sion L.; Moraes, Carlos T.; Tsunekawa, Yuji; Xiong, Xiong; Zhao, Huimin; Montserrat, Nuria; Liu, Guang-Hui; Liu, Guang-Hui
Subjects: Biology >> Biophysics >> Biochemistry & Molecular Biology

Mitochondrial diseases include a group of maternally inherited genetic disorders caused by mutations in mtDNA. In most of these patients, mutated mtDNA coexists with wild-type mtDNA, a situation known as mtDNA heteroplasmy. Here, we report on a strategy toward preventing germline transmission of mitochondrial diseases by inducing mtDNA heteroplasmy shift through the selective elimination of mutated mtDNA. As a proof of concept, we took advantage of NZB/BALB heteroplasmic mice, which contain two mtDNA haplotypes, BALB and NZB, and selectively prevented their germline transmission using either mitochondria-targeted restriction endonucleases or TALENs. In addition, we successfully reduced human mutated mtDNA levels responsible for Leber's hereditary optic neuropathy (LHOND), and neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP), in mammalian oocytes using mitochondria-targeted TALEN (mito-TALENs). Our approaches represent a potential therapeutic avenue for preventing the trans-generational transmission of human mitochondrial diseases caused by mutations in mtDNA.

submitted time 2016-05-12 Hits2879Downloads1088 Comment 0

10. chinaXiv:201605.00772 [pdf]

Modeling xeroderma pigmentosum associated neurological pathologies with patients-derived iPSCs

Fu, Lina; Xu, Xiuling; Ren, Ruotong; Zhang, Weiqi; Yang, Jiping; Ren, Xiaoqing; Wang, Si; Zhao, Yang; Liu, Guang-Hui; Ren, Ruotong; Zhang, Weiqi; Liu, Guang-Hui; Qu, Jing; Wu, Jun; Belmonte, Juan Carlos Izpisua; Wu, Jun; Sun, Liang; Yang, Ze; Yu, Yang; Qiao, Jie
Subjects: Biology >> Biophysics >> Cell Biology

Xeroderma pigmentosum (XP) is a group of genetic disorders caused by mutations of XP-associated genes, resulting in impairment of DNA repair. XP patients frequently exhibit neurological degeneration, but the underlying mechanism is unknown, in part due to lack of proper disease models. Here, we generated patient-specific induced pluripotent stem cells (iPSCs) harboring mutations in five different XP genes including XPA, XPB, XPC, XPG, and XPV. These iPSCs were further differentiated to neural cells, and their susceptibility to DNA damage stress was investigated. Mutation of XPA in either neural stem cells (NSCs) or neurons resulted in severe DNA damage repair defects, and these neural cells with mutant XPA were hyper-sensitive to DNA damage-induced apoptosis. Thus, XP-mutant neural cells represent valuable tools to clarify the molecular mechanisms of neurological abnormalities in the XP patients.

submitted time 2016-05-05 Hits1918Downloads1074 Comment 0

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