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Directed Evolution

Chong Chen, Kun Liu, Yupeng Xu, Pengwei Zhang, Yan Suo, Yi Lu, Wenyuan Zhang, Li Su, Qing Gu, Huamao Wang, Jianren Gu, Zonghai Li, Xun Xu
Anti-vascular endothelial growth factor (VEGF) therapies are widely used for the treatment of neovascular fundus diseases such as diabetic retinopathy. However, these agents need to be injected intravitreally, because their strong hydrophilicity and high molecular weight prevent them from penetrating cell membranes and complex tissue barriers. Moreover, the repeated injections that are required can cause infection and tissue injury. In this study, we used in vivo-directed evolution phage display technology to identify a novel dodecapeptide, named CC12, with the ability to penetrate the ocular barrier in a noninvasive (via conjunctival sac instillation) or minimally invasive (via retrobulbar injection) manner...
September 30, 2016: Biomaterials
Fengjiao Chen, Qishan Zhu, Yeyun Wang, Wei Cui, Xiaodong Su, Yanguang Li
Increasing attention has now been focused on the photoelectrochemical (PEC) hydrogen evolution as a promising route to transform solar energy into chemical fuels. Silicon is one of the most studied PEC electrode materials, but its performance is still limited by its inherent PEC instability and electrochemical inertness toward water splitting. To achieve significant PEC activities, silicon-based photoelectrodes usually have to be coupled with proper cocatalysts, and thus formed semiconductor/cocatalyst interface represents a critical structural parameter in the rational design of efficient PEC devices...
October 21, 2016: ACS Applied Materials & Interfaces
Shashidhara Marathe, Xianbo Shi, Michael J Wojcik, Albert T Macrander, Lahsen Assoufid
A procedure for a technique to measure the transverse coherence of synchrotron radiation X-ray sources using a single phase grating interferometer is reported. The measurements were demonstrated at the 1-BM bending magnet beamline of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). By using a 2-D checkerboard π/2 phase-shift grating, transverse coherence lengths were obtained along the vertical and horizontal directions as well as along the 45° and 135° directions to the horizontal direction...
October 11, 2016: Journal of Visualized Experiments: JoVE
Pierre E Affaticati, Shao-Bo Dai, Panwajee Payongsri, Helen C Hailes, Kai Tittmann, Paul A Dalby
The S385Y/D469T/R520Q variant of E. coli transketolase was evolved previously with three successive smart libraries, each guided by different structural, bioinformatical or computational methods. Substrate-walking progressively shifted the target acceptor substrate from phosphorylated aldehydes, towards a non-phosphorylated polar aldehyde, a non-polar aliphatic aldehyde, and finally a non-polar aromatic aldehyde. Kinetic evaluations on three benzaldehyde derivatives, suggested that their active-site binding was differentially sensitive to the S385Y mutation...
October 21, 2016: Scientific Reports
Yanling Zhang, Aizhi Liu, Changyin Sun
For large quantities of spatial models, the multi-strategy selection under weak selection is the sum of two competition terms: the pairwise competition and the competition of multiple strategies with equal frequency. Two parameters σ1 and σ2 quantify the dependence of the multi-strategy selection on these two terms, respectively. Unlike previous studies, we here do not require large populations for calculating σ1 and σ2, and perform the first quantitative analysis of the effect of migration on them in group-structured populations of any finite sizes...
October 21, 2016: Scientific Reports
Sampada Chitale, Joshua S Derasp, Bashir Hussain, Kashif Tanveer, André M Beauchemin
Directed hydration of α-amino nitriles was achieved under mild conditions using simple carbohydrates as catalysts exploiting temporary intramolecularity. A broadly applicable procedure using both formaldehyde and NaOH as catalysts efficiently hydrated a variety of primary and secondary susbtrates, and allowed the hydration of enantiopure substrates to proceed without racemization. This work also provides a rare comparison of the catalytic activity of carbohydrates, and shows that the simple aldehydes at the basis of chemical evolution are efficient organocatalysts mimicking the function of hydratase enzymes...
October 20, 2016: Chemical Communications: Chem Comm
Bratindranath Mukherjee, Swagotom Sarker, Eric Crone, Pawan Pathak, Vaidyanathan Ravi Subramanian
This work presents a hitherto unreported approach to assemble a 1D oxide-1D chalcogenide heterostructured photoactive film. As a representative system, bismuth (Bi), a low melting point catalyst, facilitated 1D CdSe nanowires are directly grown on anodized 1D-TiO2 nanotube (T_NT). A combination of the reductive successive-ionic-layer-adsorption-reaction (R-SILAR) and the solution-liquid-solid (S-L-S) approach is implemented towards the assembly of this heterostructure, reported in this 1D-1D form for the first time...
October 20, 2016: ACS Applied Materials & Interfaces
Michael Y Ni, Tom K Li, Herbert Pang, Brandford H Y Chan, Betty Y Yuan, Ichiro Kawachi, C Mary Schooling, Gabriel M Leung
Despite the extensive history of social movements around the world, the evolution of population mental health before, during, and after a social movement remains sparsely documented. We sought to assess over time the prevalence of depressive symptoms during and after the Occupy Central movement in Hong Kong and to examine the associations of direct and indirect exposures to Occupy Central with depressive symptoms. We longitudinally administered interviews to 909 adults who were randomly sampled from the population-representative FAMILY Cohort at 6 time points from March 2009 to March 2015: twice each before, during, and after the Occupy Central protests...
October 19, 2016: American Journal of Epidemiology
Jostein Gohli, Kjetil L Voje
BACKGROUND: Bergmann's rule proposes that animals in cold habitats will be larger than those in warm habitats. This prediction has been tested thoroughly at the intraspecific level, but few studies have investigated the hypothesis with interspecific data using phylogenetic comparative approaches. Many clades of mammals have representatives in numerous distinct biomes, making this order highly suitable for a large-scale interspecific assessment of Bergmann's rule. Here, we evaluate Bergmann's rule within 22 mammalian families-with a dataset that include ~35 % of all described species-using a phylogenetic comparative approach...
October 19, 2016: BMC Evolutionary Biology
Chenyi Cai, Min Kuang, Xiling Chen, Hao Wu, Hongtao Ge, Gengfeng Zheng
The development of efficient and robust electrocatalyst has been the central of the solar water splitting-based hydrogen fuel acquisition. In this work, we reported the use of cow milk, with addition of tetraethyl orthosilicate (TEOS) and melamine, for the synthesis of nitrogen-doped mesoporous carbon microspheres. Due to the large surface and enhanced charge transport behavior, the obtained samples enabled low overpotentials and a small Tafel slope toward oxygen evolution reaction, which were close or comparable to the best OER catalysts of carbon materials reported previously...
October 12, 2016: Journal of Colloid and Interface Science
Su Lui, Xiaohong Joe Zhou, John A Sweeney, Qiyong Gong
Unlike neurologic conditions, such as brain tumors, dementia, and stroke, the neural mechanisms for all psychiatric disorders remain unclear. A large body of research obtained with structural and functional magnetic resonance imaging, positron emission tomography/single photon emission computed tomography, and optical imaging has demonstrated regional and illness-specific brain changes at the onset of psychiatric disorders and in individuals at risk for such disorders. Many studies have shown that psychiatric medications induce specific measurable changes in brain anatomy and function that are related to clinical outcomes...
November 2016: Radiology
Maurine Neiman, Amy Krist
Why some species and lineages are more likely to be invasive than others is one of the most important unanswered questions in basic and applied biology. In particular, the relative contributions to the invasion process of factors like pre-adaptation to invasiveness in the native range, evolution post-colonization, and random vs. non-random sampling of colonist lineages remain unclear. We use a powerful common garden approach to address the potential for a role for sensitivity to nutrient limitation in determining the invasiveness of particular lineages of Potamopyrgus antipodarum, a New Zealand freshwater snail that has become globally invasive...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Honglin Li, Ke Yu, Zheng Tang, Zi-Qiang Zhu
Electrochemically splitting water for hydrogen evolution has attracted a lot attention and developed as a promising approach to produce hydrogen energy. Searching for high-activity and economical electrocatalysts to replace Pt-based catalysts remains a great challenge. In this paper, we reported a concise and effective strategy to fabricate the novel MoWS2 composite for using as the electrocatalyst through hydrothermal method for the first time. The final obtained MoWS2 composite demonstrated a well-defined hierarchical structure and that the densely stacked nanopetals act as the active sites to participate the corresponding hydrogen evolution reaction (HER) processes...
October 18, 2016: ACS Applied Materials & Interfaces
Cristóbal Ovidio Muñoz, Diego Restrepo, Doris Cardona
Objective Characterize the theoretical models that have underpinned empirical research on the concept of positive mental health from the time it first emerged in the field of health up to the present. Methods A systematic search of the literature was conducted in PubMed, EBSCO (including Academic Search Complete, ERIC, Academic Source, MasterFILE Premier, MedicLatina, MEDLINE, and the Psychology and Behavioral Sciences Collection), Science Direct, Psicodoc, Springer Link, Taylor & Francis, Wiley Online Library, Directory of Open Access Journals (DOAJ), Redalyc, SciELO, Ovid, Embase, and ProQuest (including Health and Medical Complete, the Nursing and Allied Health Source, Psychology Journals, and Social Science Journals)...
March 2016: Revista Panamericana de Salud Pública, Pan American Journal of Public Health
Irene Folaron, Monica Lovasz
Retention standards and policies applied to active duty members in the U.S. military who identify as transgender have recently been in evolution. The Secretary of Defense recently released a new directive allowing transgender members to serve openly with the option to transition gender while in active duty, abrogating the old policy disqualifying transgender members from continued service. There is a reasonable expectation that some may pursue medical and surgical options toward gender transition. The clinical pathway for gender transition relies heavily on Mental Health and Endocrinology services...
October 2016: Military Medicine
Liang Hu, Yao Huang, Wenyu Chen, Xin Fu, Haibo Xie
The morphology and dynamics of the pendant drops attached to the chemically patterned surfaces (pattern-pinned pendant drop) with different hydrophilic/hydrophobic contrast are investigated experimentally and numerically. During the experiments, the evolution of the contact angle and the maximum drop volume is found to be different from the traditional pendant drops whose contact line pinned on the edge of the tips (tip-pinned pendant drop), and the deviation is related both to the pattern radius and the wettability contrast...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Ming Jiang, Hao Wang, Yingjie Li, Haichuan Zhang, Guoxin Zhang, Zhiyi Lu, Xiaoming Sun, Lei Jiang
Constructing a nanostructured electrode with superaerophobic surface property (i.e., superlow adhesion to gas bubbles) has been strikingly highlighted as an advanced technology to minimize the energy loss during various electrochemical gas evolution reactions. Herein, aiming at enhancing the performance of chlorine evolution reaction (ClER), which holds the key for chlor-alkali industry as well as water treatment, a nanostructured RuO2 @TiO2 electrode is demonstrated to overcome the bubble shielding effect, thereby maximizing the working area and offering a robust working condition...
October 18, 2016: Small
Carola Becker, Gerhard Scholtz
Female reproductive systems are important characters for understanding the evolution of Brachyura and resolving its phylogenetic relationships. We herein investigate a podotreme brachyuran reproductive system comprehensively for the first time studying spermathecae and gonopores of Homoloidea with histological methods, micro-computer tomography and scanning electron microscopy. Our results show that spermathecal apertures are species-specific and their shape corresponds closely to that of male copulatory organs...
October 17, 2016: Journal of Morphology
Bishoy M Faltas, Davide Prandi, Scott T Tagawa, Ana M Molina, David M Nanus, Cora Sternberg, Jonathan Rosenberg, Juan Miguel Mosquera, Brian Robinson, Olivier Elemento, Andrea Sboner, Himisha Beltran, Francesca Demichelis, Mark A Rubin
Chemotherapy-resistant urothelial carcinoma has no uniformly curative therapy. Understanding how selective pressure from chemotherapy directs the evolution of urothelial carcinoma and shapes its clonal architecture is a central biological question with clinical implications. To address this question, we performed whole-exome sequencing and clonality analysis of 72 urothelial carcinoma samples, including 16 matched sets of primary and advanced tumors prospectively collected before and after chemotherapy. Our analysis provided several insights: (i) chemotherapy-treated urothelial carcinoma is characterized by intra-patient mutational heterogeneity, and the majority of mutations are not shared; (ii) both branching evolution and metastatic spread are very early events in the natural history of urothelial carcinoma; (iii) chemotherapy-treated urothelial carcinoma is enriched with clonal mutations involving L1 cell adhesion molecule (L1CAM) and integrin signaling pathways; and (iv) APOBEC-induced mutagenesis is clonally enriched in chemotherapy-treated urothelial carcinoma and continues to shape the evolution of urothelial carcinoma throughout its lifetime...
October 17, 2016: Nature Genetics
Oliver Sartor
Radiopharmaceuticals used in the treatment of castrate-resistant prostate cancer are reviewed herein with an emphasis on sequential and combination therapies. Four bone-seeking radiopharmaceuticals had been approved in the United States. Three of these are β-emitters (phosphorus-32, strontium-89, samarium-153-ethylenediaminetetramethylene-phosphonic acid) that are approved for palliative purposes. One α-emitter (radium-223 [Ra]) is approved for prolongation of survival in bone metastatic castrate-resistant prostate cancer...
September 2016: Cancer Journal
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