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https://www.readbyqxmd.com/read/28441772/structural-and-biochemical-properties-of-novel-self-cleaving-ribozymes
#1
REVIEW
Ki-Young Lee, Bong-Jin Lee
Fourteen well-defined ribozyme classes have been identified to date, among which nine are site-specific self-cleaving ribozymes. Very recently, small self-cleaving ribozymes have attracted renewed interest in their structure, biochemistry, and biological function since the discovery, during the last three years, of four novel ribozymes, termed twister, twister sister, pistol, and hatchet. In this review, we mainly address the structure, biochemistry, and catalytic mechanism of the novel ribozymes. They are characterized by distinct active site architectures and divergent, but similar, biochemical properties...
April 24, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28441747/associations-between-diet-and-toenail-arsenic-concentration-among-pregnant-women-in-bangladesh-a-prospective-study
#2
Pi-I D Lin, Sabri Bromage, Md Golam Mostofa, Joseph Allen, Emily Oken, Molly L Kile, David C Christiani
This prospective study evaluated the relationship between long-term dietary habits and total arsenic (As) concentration in toenail clippings in a cohort of 1616 pregnant women in the Bangladeshi administrative regions of Sirajdikhan and Pabna Sadar. Diet was assessed at Gestation Week 28 and at Postpartum Month 1, using a locally-validated dish-based semi-quantitative food-frequency questionnaire. Toenail As concentration was analyzed by microwave-assisted acid digestion and inductively coupled plasma mass spectrometry...
April 23, 2017: Nutrients
https://www.readbyqxmd.com/read/28441740/a-miniature-aerosol-sensor-for-detecting-polydisperse-airborne-ultrafine-particles
#3
Chao Zhang, Dingqu Wang, Rong Zhu, Wenming Yang, Peng Jiang
Counting and sizing of polydisperse airborne nanoparticles have attracted most attentions owing to increasing widespread presence of airborne engineered nanoparticles or ultrafine particles. Here we report a miniature aerosol sensor to detect particle size distribution of polydisperse ultrafine particles based on ion diffusion charging and electrical detection. The aerosol sensor comprises a couple of planar electrodes printed on two circuit boards assembled in parallel, where charging, precipitation and measurement sections are integrated into one chip, which can detect aerosol particle size in of 30-500 nm, number concentration in range of 5 × 10²-10⁷ /cm³...
April 22, 2017: Sensors
https://www.readbyqxmd.com/read/28441516/epoxynemanione-a-nemanifuranones-a-f-and-nemanilactones-a-c-from-nemania-serpens-an-endophytic-fungus-isolated-from-riesling-grapevines
#4
Ashraf Ibrahim, Dan Sørensen, Hilary A Jenkins, Linda Ejim, Alfredo Capretta, Mark W Sumarah
Ten polyketide specialized metabolites, epoxynemanione A, nemanifuranones A-F, and nemanilactones A-C, were isolated from the culture filtrate of Nemania serpens (Pers.) Grey (1821), an endophytic fungus from a Riesling grapevine (Vitis vinifera) found in Canada's Niagara region. Additionally, four known metabolites 2-(hydroxymethyl)-3-methoxy-benzoic acid, phyllostine, 5-methylmellein and a nordammarane triterpenoid were isolated. A related known metabolite 2,3-dihydro-2-hydroxy-2,4-dimethyl-5-trans-propenylfuran-3-one has also been included for structural and biological comparison to the nemanifuranones...
April 22, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28441501/hooked-on-cryogels-a-carbamate-linker-based-depot-for-slow-drug-release
#5
Duygu Aydin, Mehmet Arslan, Amitav Sanyal, Rana Sanyal
Poly(ethylene glycol) (PEG) based bulk hydrogels and cryogels containing activated carbonate groups as amine reactive handles to facilitate drug conjugations through carbamate linkages were fabricated and evaluated as slow releasing drug reservoirs. As an initial approach, photopolymerization of N-hydroxysuccinimide (NHS)-activated carbonate functional group containing monomer and PEG-methacrylate in the presence of a crosslinker was utilized to obtain bulk hydrogels with high gel conversions. The resultant hydrogels possessed moderate water uptake (170-340 %) which was dependent on the monomer ratios...
April 25, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28441475/2-2-spirobis-chromene-derivatives-chemistry-and-their-relation-with-the-multistate-system-of-anthocyanins
#6
Artur J Moro, A Jorge Parola, Fernando Pina, Ana-Maria Pana, Valentin Badea, Iulia Pausescu, Sergiu Shova, Liliana Cseh
The chemistry of 2,2'-spirobis[chromene] derivatives is intimately related to the one of anthocyanins and similar compounds. The 2,2'-spirobis[chromene] species plays a central role in the network of chemical reactions connecting two different flavylium-based multistate systems. In the present work, a new asymmetric 2,2'-spirobis[chromene] intermediate possessing a constrained propylenic bridge between carbons 3 and 3' was isolated and its role as a pivot in the anthocyanins-type multistate of chemical reactions was investigated by the conjugation of absorption spectroscopy, stopped-flow, NMR and X-Ray crystallography...
April 25, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28441352/high-throughput-determination-of-sodium-danshensu-in-beagle-dogs-by-the-lcms-ms-method-employing-liquid-liquid-extraction-based-on-96-well-format-plates
#7
Jingjing Jiang, Xin Zhao, Xiuxiu Li, Shengyuan Wu, Shidan Yu, Yuefen Lou, Guorong Fan
Sodium Danshensu (sodium d-(+)-β-(3,4-dihydroxyphenyl) lactate), one of the water-soluble ingredients in Salvia miltiorrhiza, exhibits potent relaxation of the coronary artery and anticoagulation effection. A high-throughput, rapid, and sensitive method combining liquid chromatography with electrospray ionization tandem mass spectrometry to determine the sodium danshensu in beagle dog plasma was developed and validated, using gallic acid as an internal standard (IS). Acidified plasma samples were extracted using 96-well liquid-liquid extraction, and were eluted on a CNW Athena C18 column (3 μm, 2...
April 25, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28441341/a-long-term-treatment-with-arachidonyl-2-chloroethylamide-combined-with-valproate-increases-neurogenesis-in-a-mouse-pilocarpine-model-of-epilepsy
#8
Marta Andres-Mach, Mirosław Zagaja, Agnieszka Haratym-Maj, Radosław Rola, Maciej Maj, Joanna Haratym, Monika Dudra-Jastrzębska, Jarogniew J Łuszczki
Rational polytherapy in the treatment of refractory epilepsy has been the main therapeutic modality for several years. In treatment with two or more antiepileptic drugs (AEDs), it is of particular importance that AEDs be selected based on their high anticonvulsant properties, minimal side effects, and impact on the formation of new neurons. The aim of the study was to conduct an in vivo evaluation of the relationship between treatments with synthetic cannabinoid arachidonyl-2'-chloroethylamide (ACEA) alone or in combination with valproic acid (VPA) and hippocampal neurogenesis in a mouse pilocarpine model of epilepsy...
April 25, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28441323/gold-nanoplates-for-a-localized-surface-plasmon-resonance-based-boric-acid-sensor
#9
Marlia Morsin, Muhamad Mat Salleh, Akrajas Ali Umar, Mohd Zainizan Sahdan
Localized surface plasmon resonance (LSPR) properties of metallic nanostructures, such as gold, are very sensitive to the dielectric environment of the material, which can simply be adjusted by changing its shape and size through modification of the synthesizing process. Thus, these unique properties are very promising, particularly for the detection of various types of chemicals, for example boric acid which is a non-permitted preservative employed in food preparations. For the sensing material, gold (Au) nanoplates with a variety of shapes, i...
April 25, 2017: Sensors
https://www.readbyqxmd.com/read/28441273/case-report-of-physiologic-phenibut-dependence-treated-with-a-phenobarbital-taper-in-a-patient-being-treated-with-buprenorphine
#10
Emily Brunner, Robert Levy
: This case report describes the development of dependence to phenibut, a gamma-aminobutyric acid-receptor type B agonist, in a patient concurrently being treated with buprenorphine. The patient experienced withdrawal symptoms which were successfully treated with a phenobarbital taper based on a protocol to treat sedative use disorder. This case report provided an example of the development of a phenibut use disorder and also brought up a public health question of whether phenibut should therefore be officially classified and monitored...
April 24, 2017: Journal of Addiction Medicine
https://www.readbyqxmd.com/read/28441229/preliminary-model-for-the-design-of-a-custom-middle-ear-prosthesis
#11
Brandon Kamrava, Jonathan A Gerstenhaber, Mamta Amin, Yah-El Har-El, Pamela C Roehm
HYPOTHESIS: Custom prostheses could be used to recreate the ossicular chain and improve hearing. BACKGROUND: Ossicular discontinuity or fixation occurs in 55% of cases of conductive hearing loss, with most cases involving the incus. Reconstruction has been achieved by a variety of methods; however, there has been little improvement in hearing outcomes in decades. METHODS: Precise measurements of anatomic dimensions, weight, and center of gravity were taken from 19 cadaveric incudes...
April 24, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28441015/-bottom-up-construction-of-multi-polyprodrug-arm-hyperbranched-amphiphiles-for-cancer-therapy
#12
Pei Sun, Dong Chen, Hongping Deng, Nan Wang, Ping Huang, Xin Jin, Xinyuan Zhu
Despite of great advantages of polymer-drug conjugates (PDC) in cancer therapy, the controlling of drug loading site and degree via a facile approach remains a great challenge. Herein, combination the controllability of the "bottom-up" strategy and the stability of multi-arm hyperbranched amphiphiles, we have developed a novel multi-polyprodrug-arm hyperbranched amphiphiles (H40-star-(PHCPTMA-b-PMPC), hPCM) via reversible addition-fragmentation chain transfer (RAFT) polymerization for cancer therapy. The hPCM was constructed via two-step polymerization of an acid-labile prodrug monomer and a zwitterionic monomer, respectively...
April 25, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28440871/effects-of-different-salt-treatments-on-the-fermentation-metabolites-and-bacterial-profiles-of-kimchi
#13
Dong Wook Kim, Bo-Min Kim, Hyeon-Jeong Lee, Gwang-Ju Jang, Seong Hwa Song, Jae-In Lee, Sang Bong Lee, Jae Min Shim, Kang Wook Lee, Jeong Hwan Kim, Kyung-Sik Ham, Feng Chen, Hyun-Jin Kim
The effects of purified salt (PS) and mineral-rich sea salt (MRS), both with different mineral profiles, on kimchi fermentation were studied using a culture-dependent 16S rRNA sequencing technique and mass-based metabolomic analysis. The different mineral profiles in the fermentation medium caused changes in the bacterial profiles of the 2 kimchi products. An increase of Leuconostoc species in MRS-kimchi decreased the Lactobacillus/Leuconostoc ratio, which led to changes in metabolites (including sugars, amino acids, organic acids, lipids, sulfur compounds, and terpenoids) associated with kimchi quality...
April 25, 2017: Journal of Food Science
https://www.readbyqxmd.com/read/28440836/controllable-hydrothermal-synthesis-of-ni-h-bea-with-a-hierarchical-core-shell-structure-and-highly-enhanced-biomass-hydrodeoxygenation-performance
#14
Bing Ma, Huimei Cui, Darui Wang, Peng Wu, Chen Zhao
Ni based catalysts are wildly used in catalytic industrial processes due to their low costs and high activities. The design of highly hierarchical core-shell structured Ni/HBEA is achieved using a sustainable, simple, and easy-tunable hydrothermal synthesis approach using combined NH4Cl and NH3·H2O as a co-precipitation agent at 120 °C. Starting from a single-crystalline hierarchical H(+)-exchanged beta polymorph zeolite (HBEA), the adjustment of the precipitate conditions shows that mixed NH4Cl and NH3·H2O precipitates with proper concentrations are vital in the hydrothermal synthesis for preserving a good crystalline morphology of HBEA and generating abundant highly-dispersed Ni nanoparticles (loading: 41 wt%, 5...
April 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28440830/organocatalytic-decarboxylative-aldol-reaction-of-%C3%AE-ketoacids-with-%C3%AE-ketophosphonates-en-route-to-the-enantioselective-synthesis-of-tertiary-%C3%AE-hydroxyphosphonates
#15
Ganga B Vamisetti, Raghunath Chowdhury, Sunil K Ghosh
The first example of an asymmetric organocatalyzed decarboxylative aldol reaction of β-ketoacids (aroylacetic acids) with α-ketophosphonates that produces a quaternary chiral centre has been developed. A quinidine based bifunctional urea derivative was identified as the preferred catalyst affording γ-aroyl tertiary α-hydroxyphosphonates in good yield and enantioselectivity. The (31)P NMR spectroscopic study was performed to shed light on the reaction mechanism.
April 25, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28440819/amphiphilic-carbon-dots-as-versatile-vectors-for-nucleic-acid-and-drug-delivery
#16
Hai-Jiao Wang, Xi He, Tian-Ying Luo, Ji Zhang, Yan-Hong Liu, Xiao-Qi Yu
Carbon dot (CD)-based multifunctional delivery systems have shown great potential in both drug/gene delivery and bio-imaging. In this work, we present a strategy to simply construct amphiphilic CDs (ACDs) by conjugating hydrophobic alkyl epoxide to the surface amino groups of PEI 600-derived CDs. ACDs could well dissolve in water or organic solvents and emit bright fluorescence both in solutions and cells. (1)HNMR also suggested that ACDs may form micelle-like structures in water, and their CMC could be determined...
April 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28440732/expression-of-microrna-let-7a-positively-correlates-with-hepatitis-b-virus-replication-in-hepatocellular-carcinoma-tissues
#17
Dongni Qiu, Jian Chen, Jie Liu, Zhongguang Luo, Weiru Jiang, Jianping Huang, Zhibing Qiu, Wenjie Yue, Lijun Wu
Let-7a miRNA is downregulated in various cancers. However, in hepatocellular carcinoma (HCC) patients infected with hepatitis B virus (HBV), the relationship between let-7a and HBV replication has not been fully elucidated. Liver specimens were collected from 23 HCC patients with chronically active HBV. The serum levels of the HBV antigens hepatitis B surface antigen (HBsAg) and hepatitis B virus e antigen (HBeAg), and the HBV antibodies, anti-HBs, anti-HBe and anti-hepatitis B core antigen (anti-HBc) were measured using the microparticle enzyme immunoassay...
May 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28440708/towards-in-vitro-to-in-vivo-translation-of-monoclonal-antibody-pharmacokinetics-application-of-a-neonatal-fc-receptor-mediated-transcytosis-assay-to-understand-the-interplaying-clearance-mechanisms
#18
Claudia A Castro Jaramillo, Sara Belli, Anne-Christine Cascais, Sherri Dudal, Martin R Edelmann, Markus Haak, Marie-Elise Brun, Michael B Otteneder, Mohammed Ullah, Christoph Funk, Franz Schuler, Silke Simon
Monoclonal antibodies (mAbs) are a rapidly growing drug class for which great efforts have been made to optimize certain molecular features in order to achieve the desired pharmacokinetic (PK) properties. One approach is to engineer the interactions of the mAb with the neonatal Fc receptor (FcRn) by introducing specific amino acid sequence mutations, and to assess their effect on the PK profile with in vivo studies. Indeed, FcRn protects mAbs from intracellular degradation, thereby prolongs antibody circulation time in plasma and modulates its systemic clearance...
April 25, 2017: MAbs
https://www.readbyqxmd.com/read/28440624/acid-base-catalysis-in-glycosidations-a-nature-derived-alternative-to-the-generally-employed-methodology
#19
Peng Peng, Richard R Schmidt
Inverting glycosyltransferases enforce in the active site an intramolecular, acid-base catalyzed glycosidation that, due to proximity of the donor anomeric carbon and the acceptor hydroxyl group, follows an SN2-type reaction. Spacers, tethering donor and acceptor via nonreacting functional groups, led in intramolecular glycosidations to excellent yields and, independent of the donor anomeric configuration, to either the α- or the β-anomer. The requirement of a demanding protecting group pattern confines the application of this efficient method...
April 25, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28440619/collagen-membranes-with-ribonuclease-inhibitors-for-long-term-stability-of-electrochemical-aptamer-based-sensors-employing-rna
#20
Mirelis Santos-Cancel, Ryan J White
Electrochemical aptamer-based (E-AB) sensors offer advantageous analytical detection abilities on account of their rapid response time (sec to min), specificity to a target, and selectivity to function in complex media. Ribonucleic acid (RNA) aptamers employed in this class of sensor offer favorable binding characteristics resulting from the ability of RNA to form stable tertiary folds aided by long-range intermolecular interactions. As a result, RNA aptamers can fold into more complex three-dimensional structures than their DNA counterparts, and consequently, exhibit better binding ability to target analytes...
April 25, 2017: Analytical Chemistry
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