ResearchPad - Organic Chemistry https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Transferrin-Modified Osthole PEGylated Liposomes Travel the Blood-Brain Barrier and Mitigate Alzheimer’s Disease-Related Pathology in APP/PS-1 Mice]]> https://www.researchpad.co/product?articleinfo=N69d6ab98-bd8d-4010-844a-59b94990e522

Introduction

Osthole (Ost) is a coumarin compound that strengthens hippocampal neurons and neural stem cells against Aβ oligomer-induced neurotoxicity in mice, and is a potential drug for the treatment of Alzheimer's disease (AD). However, the effectiveness of the drug is limited by its solubility and bioavailability, as well as by the low permeability of the blood-brain barrier (BBB). In this study, a kind of transferrin-modified Ost liposomes (Tf-Ost-Lip) was constructed, which could improve the bioavailability and enhance brain targeting.

Methods

Tf-Ost-Lip was prepared by thin-film hydration method. The ability of liposomal formulations to translocate across BBB was investigated using in vitro BBB model. And the protective effect of Tf-Ost-Lip was evaluated in APP-SH-SY5Y cells. In addition, we performed pharmacokinetics study and brain tissue distribution analysis of liposomal formulations in vivo. We also observed the neuroprotective effect of the varying formulations in APP/PS-1 mice.

Results

In vitro studies reveal that Tf-Ost-Lip could increase the intracellular uptake of hCMEC/D3 cells and APP-SH-SY5Y cells, and increase the drug concentration across the BBB. Additionally, Tf-Ost-Lip was found to exert a protective effect on APP-SH-SY5Y cells. In vivo studies of pharmacokinetics and the Ost distribution in brain tissue indicate that Tf-Ost-Lip prolonged the cycle time in mice and increased the accumulation of Ost in the brain. Furthermore, Tf-Ost-Lip was also found to enhance the effect of Ost on the alleviation of Alzheimer’s disease-related pathology.

Conclusion

Transferrin-modified liposomes for delivery of Ost has great potential for AD treatment.

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<![CDATA[Targeted Prodrug-Based Self-Assembled Nanoparticles for Cancer Therapy]]> https://www.researchpad.co/product?articleinfo=N2b0f5f7d-d5ab-49b6-9010-39c3b297e587

Background

Targeted prodrug has various applications as drug formulation for tumor therapy. Therefore, amphoteric small-molecule prodrug combined with nanoscale characteristics for the self-assembly of the nano-drug delivery system (DDS) is a highly interesting research topic.

Methods and Results

In this study, we developed a prodrug self-assembled nanoplatform, 2-glucosamine-fluorescein-5(6)-isothiocyanate-glutamic acid-paclitaxel (2DA-FITC-PTX NPs) by integration of targeted small molecule and nano-DDS with regular structure and perfect targeting ability. 2-glucosamine (DA) and paclitaxel were conjugated as the targeted ligand and anti-tumor chemotherapy drug by amino acid group. 2-DA molecular structure can enhance the targeting ability of prodrug-based 2DA-FITC-PTX NPs and prolong retention time, thereby reducing the toxicity of normal cell/tissue. The fluorescent dye FITC or near-infrared fluorescent dye ICG in prodrug-based DDS was attractive for in vivo optical imaging to study the behavior of 2DA-FITC-PTX NPs. In vitro and in vivo results proved that 2DA-FITC-PTX NPs exhibited excellent targeting ability, anticancer activity, and weak side effects.

Conclusion

This work demonstrates a new combination of nanomaterials for chemotherapy and may promote prodrug-based DDS clinical applications in the future.

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<![CDATA[Enzymatic Synthesis of Ricinoleyl Hydroxamic Acid Based on Commercial Castor Oil, Cytotoxicity Properties and Application as a New Anticancer Agent]]> https://www.researchpad.co/product?articleinfo=N2ee31eb3-084a-41f9-bd1c-0b276d684b2d

Background

New anticancer agents that rely on natural/healthy, not synthetic/toxic, components are very much needed.

Methods

Ricinoleyl hydroxamic acid (RHA) was synthesized from castor oil and hydroxylamine using Lipozyme TL IM as a catalyst. To optimize the conversion, the effects of the following parameters were investigated: type of organic solvent, period of reaction, amount of enzyme, the molar ratio of reactants and temperature. The highest conversion was obtained when the reaction was carried out under the following conditions: hexane as a solvent; reaction period of 48 hours; 120 mg of Lipozyme TL IM/3 mmol oil; HA-oil ratio of 19 mmol HA/3 mmol oil; and temperature of 40°C. The cytotoxicity of the synthesized RHA was assessed using human dermal fibroblasts (HDF), and its application towards fighting cancer was assessed using melanoma and glioblastoma cancer cells over a duration of 24 and 48 hours.

Results

RHA was successfully synthesized  and it demonstrated strong anticancer activity against glioblastoma and melanoma cells at as low as a 1 µg/mL concentration while it did not demonstrate any toxicity against HDF cells.

Conclusion

This is the first report on the synthesis of RHA with great potential to be used as a new anticancer agent.

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<![CDATA[Dual Receptor-Targeted and Redox-Sensitive Polymeric Micelles Self-Assembled from a Folic Acid-Hyaluronic Acid-SS-Vitamin E Succinate Polymer for Precise Cancer Therapy]]> https://www.researchpad.co/product?articleinfo=N0333ac7a-c329-4c80-b402-750b5176061b

Purpose

Poor site-specific delivery and insufficient intracellular drug release in tumors are inherent disadvantages to successful chemotherapy. In this study, an extraordinary polymeric micelle nanoplatform was designed for the efficient delivery of paclitaxel (PTX) by combining dual receptor-mediated active targeting and stimuli response to intracellular reduction potential.

Methods

The dual-targeted redox-sensitive polymer, folic acid-hyaluronic acid-SS-vitamin E succinate (FHSV), was synthesized via an amidation reaction and characterized by 1H-NMR. Then, PTX-loaded FHSV micelles (PTX/FHSV) were prepared by a dialysis method. The physiochemical properties of the micelles were explored. Moreover, in vitro cytological experiments and in vivo animal studies were carried out to evaluate the antitumor efficacy of polymeric micelles.

Results

The PTX/FHSV micelles exhibited a uniform, near-spherical morphology (148.8 ± 1.4 nm) and a high drug loading capacity (11.28% ± 0.25). Triggered by the high concentration of glutathione, PTX/FHSV micelles could quickly release their loaded drug into the release medium. The in vitro cytological evaluations showed that, compared with Taxol or single receptor-targeted micelles, FHSV micelles yielded higher cellular uptake by the dual receptor-mediated endocytosis pathway, thus leading to significantly superior cytotoxicity and apoptosis in tumor cells but less cytotoxicity in normal cells. More importantly, in the in vivo antitumor experiments, PTX/FHSV micelles exhibited enhanced tumor accumulation and produced remarkable tumor growth inhibition with minimal systemic toxicity.

Conclusion

Our results suggest that this well-designed FHSV polymer has promising potential for use as a vehicle of chemotherapeutic drugs for precise cancer therapy.

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<![CDATA[Recent advances in Cu-catalyzed C(sp3)–Si and C(sp3)–B bond formation]]> https://www.researchpad.co/product?articleinfo=N094cb311-3a9b-4561-85d1-3da339003c68

Numerous reactions generating C–Si and C–B bonds are in focus owing to the importance of incorporating silicon or boron into new or existing drugs, in addition to their use as building blocks in cross-coupling reactions en route to various targets of both natural and unnatural origins. In this review, recent protocols relying on copper-catalyzed sp3 carbon–silicon and carbon–boron bond-forming reactions are discussed.

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<![CDATA[Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules]]> https://www.researchpad.co/product?articleinfo=N2da8d4d5-b463-4cfc-950b-82b29801c666

This account surveys the current progress on the application of intra- and intermolecular enyne metathesis as main key steps in the synthesis of challenging structural motifs and stereochemistries found in bioactive compounds. Special emphasis is placed on ruthenium catalysts as promoters of enyne metathesis to build the desired 1,3-dienic units. The advantageous association of this approach with name reactions like Grignard, Wittig, Diels–Alder, Suzuki–Miyaura, Heck cross-coupling, etc. is illustrated. Examples unveil the generality of such tandem reactions in providing not only the intricate structures of known, in vivo effective substances but also for designing chemically modified analogs as valid alternatives for further therapeutic agents.

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<![CDATA[Synthesis of C70-fragment buckybowls bearing alkoxy substituents]]> https://www.researchpad.co/product?articleinfo=N91b13719-870a-4402-9418-dda505f93cc1

Buckybowls bearing a C70 fragment having two alkoxy groups were synthesized and their structural and optical properties were investigated by single crystal X-ray analysis and UV–vis spectroscopy. In the synthesis of dioxole derivative 5b, the regioisomer 5c was also produced. The yield of 5c was increased by increasing the reaction temperature, indicating that the rearrangement might involve the equilibrium between the Pd(IV) intermediates through C–H bond activation.

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<![CDATA[Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates]]> https://www.researchpad.co/product?articleinfo=Ne01c2aed-b6ec-4457-9394-9b87ccc5084e

Herein, we present an efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates. Each step of the synthesis was optimized to provide excellent yields. Moreover, the absolute configuration of the obtained compounds was determined by X-ray analysis, which proved the stereochemistry that was proposed based on NMR studies.

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<![CDATA[Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes]]> https://www.researchpad.co/product?articleinfo=Nc0c1d82b-a0e4-45ff-a782-c7ead1cb0a12

This paper describes the synthesis of a series of organic liquid crystals (LCs) containing selectively fluorinated cyclopropanes at their termini. The syntheses used difluorocarbene additions to olefin precursors, an approach which proved straightforward such that these liquid crystal candidates could be efficiently prepared. Their physical and thermodynamic properties were evaluated and depending on individual structures, they either displayed positive or negative dielectric anisotropy. The study gives some guidance into effective structure–property relationships for the design of LCs containing selectively fluorinated cyclopropane motifs.

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<![CDATA[Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment]]> https://www.researchpad.co/product?articleinfo=Nc7b5e36b-29ae-495a-b1d4-7ef341c9288b

The stereoselective synthesis of the (Z)-enamide fragment of chondrochloren (1) is described. A Buchwald-type coupling between amide 3 and (Z)-bromide 4 was used to generate the required fragment. The employed amide 3 comprising three chiral centers was obtained through a seven-step sequence starting from ᴅ-ribonic acid-1,4-lactone. The (Z)-vinyl bromide 4 is accessible in four steps from 4-hydroxybenzaldehyde. The pivotal cross coupling between both fragments was achieved after extensive experimentation with copper(I) iodide, K2CO3 and N,N′-dimethylethane-1,2-diamine.

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<![CDATA[Towards triptycene functionalization and triptycene-linked porphyrin arrays]]> https://www.researchpad.co/product?articleinfo=N0c82ea75-e6fc-4da6-bb30-66c3010790d0

Herein, 9,10-diethynyltriptycene is investigated for its use as a rigid isolating unit in the synthesis of multichromophoric arrays. Sonogashira cross-coupling conditions are utilized to attach various porphyrins and boron dipyrromethenes (BODIPYs) to the triptycene scaffold. While there are previous examples of triptycene porphyrin complexes, this work reports the first example of a linearly connected porphyrin dimer, linked through the bridgehead carbons of triptycene. Symmetric and unsymmetric examples of these complexes are demonstrated and single crystal X-ray analysis of an unsymmetrically substituted porphyrin dimer highlights the evident linearity in these systems. Moreover, initial UV–vis and fluorescence studies show the promise of triptycene as a linker for electron transfer studies, showcasing its isolating nature.

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<![CDATA[Sodium Bicyclo[1.1.1]pentanesulfinate: A Bench‐Stable Precursor for Bicyclo[1.1.1]pentylsulfones and Bicyclo‐ [1.1.1]pentanesulfonamides]]> https://www.researchpad.co/product?articleinfo=N2edb0d1a-4e1a-4d32-b5a0-dca7e1abafed

Abstract

Herein, we present the synthesis of the bench‐stable sodium bicyclo[1.1.1]pentanesulfinate (BCP‐SO2Na) and its application in the synthesis of bicyclo[1.1.1]pentyl (BCP) sulfones and sulfonamides. The salt can be obtained in a four‐step procedure from commercially available precursors in multigram scale without the need for column chromatography or crystallization. Sulfinates are known to be useful precursors in radical and nucleophilic reactions and are widely used in medicinal chemistry. This building block enables access to BCP sulfones and sulfonamides avoiding the volatile [1.1.1]propellane which is favorable for the extension of SAR studies. Further, BCP‐SO2Na enables the synthesis of products that were not available with previous methods. A chlorination of BCP‐SO2Na and subsequent reaction with a Grignard reagent provides a new route to BCP sulfoxides. Several products were analyzed by single‐crystal X‐ray diffraction.

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<![CDATA[Land Use, Not Stream Order, Controls N2O Concentration and Flux in the Upper Mara River Basin, Kenya]]> https://www.researchpad.co/product?articleinfo=Nb2cade8a-1394-4f7d-b436-62478769eb74

Abstract

Anthropogenic activities have led to increases in nitrous oxide (N2O) emissions from river systems, but there are large uncertainties in estimates due to lack of data in tropical rivers and rapid increase in human activity. We assessed the effects of land use and river size on N2O flux and concentration in 46 stream sites in the Mara River, Kenya, during the transition from the wet (short rains) to dry season, November 2017 to January 2018. Flux estimates were similar to other studies in tropical and temperate systems, but in contrast to other studies, land use was more related to N2O concentration and flux than stream size. Agricultural stream sites had the highest fluxes (26.38 ± 5.37 N2O‐N μg·m–2·hr–1) compared to both forest and livestock sites (5.66 ± 1.38 N2O‐N μg·m–2·hr–1 and 6.95 ± 2.96 N2O‐N μg·m–2·hr–1, respectively). N2O concentrations in forest and agriculture streams were positively correlated to stream carbon dioxide (CO2‐C(aq)) but showed a negative correlation with dissolved organic carbon, and the dissolved organic carbon:dissolved inorganic nitrogen ratio. N2O concentration in the livestock sites had a negative relationship with CO2‐C(aq) and a higher number of negative fluxes. We concluded that in‐stream chemoautotrophic nitrification was likely the main biogeochemical process driving N2O production in agricultural and forest streams, whereas complete denitrification led to the consumption of N2O in the livestock stream sites. These results point to the need to better understand the relative importance of nitrification and denitrification in different habitats in producing N2O and for process‐based studies.

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<![CDATA[Understanding ambivalence in help-seeking for suicidal people with comorbid depression and alcohol misuse]]> https://www.researchpad.co/product?articleinfo=N5bd48253-819c-499c-aeec-83c12fc90159

Help-seeking prior to a suicide attempt is poorly understood. Participants were recruited from a previous research trial who reported a history of suicidal behaviours upon follow-up. Qualitative interviews were conducted with six adults to understand their lived experience of a suicide attempt and the issues affecting help-seeking prior to that attempt. Participants described being aware of personal and professional supports available; however, were ambivalent about accessing them for multiple reasons. This paper employs an ecological systems framework to better understand the complex and multi-layered interpersonal, societal and cultural challenges to help-seeking that people with suicidal ideation can experience.

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<![CDATA[Uptake and speciation of zinc in edible plants grown in smelter contaminated soils]]> https://www.researchpad.co/product?articleinfo=N21b4cc8f-fdc5-4198-8cfa-2868c1971919

Heavy metal accumulation in edible plants grown in contaminated soils poses a major environmental risk to humans and grazing animals. This study focused on the concentration and speciation of Zn in different edible plants grown in soils contaminated with smelter wastes (Spelter, WV, USA) containing high levels of the metals Zn, Cu, Pb, Cd. Their accumulation was examined in different parts (roots, stem, and leaves) of plants and as a function of growth stage (dry seed, sprouting seed, cotyledon, and leaves) in the root vegetables radish, the leafy vegetable spinach and the legume clover. Although the accumulation of metals varied significantly with plant species, the average metal concentrations were [Zn] > [Pb] > [Cu] > [Cd]. Metal uptake studies were complemented with bulk and micro X-ray absorption spectroscopy (XAS) at Zn K-edge and micro X-ray fluorescence (μXRF) measurements to evaluate the speciation and distribution of Zn in these plant species. Dynamic interplay between the histidine and malate complexation of Zn was observed in all plant species. XRF mapping of spinach leaves at micron spatial resolution demonstrated the accumulation of Zn in vacuoles and leaf tips. Radish root showed accumulation of Zn in root hairs, likely as ZnS nanoparticles. At locations of high Zn concentration in spinach leaves, μXANES suggests Zn complexation with histidine, as opposed to malate in the bulk leaf. These findings shed new light on the dynamic nature of Zn speciation in plants.

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<![CDATA[Variation in plasma 25-hydroxyvitamin D2 and D3 in normal pregnancy with gestational age, sampling season, and complications: A longitudinal cohort study]]> https://www.researchpad.co/product?articleinfo=Ndf1a2733-e0b1-4fc7-90ad-b2bfa4368f5f

Introduction

Low levels of vitamin D in pregnancy have been associated with the risk of a variety of pregnancy outcomes. Few studies have investigated vitamin D concentrations throughout pregnancy in healthy women, and most guidelines recommend high vitamin D levels. In the present study, we investigated 25-hydroxyvitamin D concentrations in healthy Caucasian Danish women in relation to season, gestational age and possible vitamin D-linked complications.

Materials and methods

Eight hundred and one healthy Caucasian Danish women with an expected normal pregnancy were recruited among 2147 women attending first trimester screening. Seven blood samplings were planned throughout the pregnancy and delivery period. The 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3) concentrations were measured by LC-MS/MS and total 25-hydroxyvitamin D (25(OH)D) were calculated.

Results

A total of 3304 samples from 694 women were available for 25(OH)D measurements. The mean (25th-75th percentiles) concentrations of 25(OH)D, 25(OH)D3, and 25(OH)D2 were 54.6 (38.8–68.6) nmol/L, 52.2 (36.4–66.4) nmol/L, and 2.4 (2.2–2.2) nmol/L, respectively. Season was the strongest predictor of 25(OH)D concentration, with the lowest values observed in winter and spring, where only 42% and 41% of samples, respectively, were above 50 nmol/L. Nearly all women had values below the suggested optimal level of 75 nmol/L, independent of season. 25(OH)D peaked at gestational weeks 21–34. Plasma 25(OH)D2 levels were low in all seasons. Women with complications during pregnancy had higher 25(OH)D (estimated difference 9.8 nmol/L, standard error 2.7, p<0.001) than did women without complications, and women giving birth vaginally had lower 25(OH)D than did those delivering via elective (10.0 nmol/L, standard error 2.1, p<0.001) or emergency cesarean section (6.8 nmol/L, standard error 2.2, p<0.001).

Conclusion

The 25(OH)D concentrations vary with both season and gestational age. Healthy women had lower 25(OH)D concentrations than recommended, without an association with an increased risk of pregnancy complications. Guidelines for vitamin D in pregnancy may require revision.

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<![CDATA[Physicochemical and biological evaluation of JR-131 as a biosimilar to a long-acting erythropoiesis-stimulating agent darbepoetin alfa]]> https://www.researchpad.co/product?articleinfo=Na789b0ff-1b14-409c-afa6-0c7a70fc7c42

Renal anemia is predominantly caused by a relative deficiency in erythropoietin (EPO). Conventional treatment for renal anemia includes the use of recombinant human EPO (rhEPO) or a long-acting erythropoiesis-activating agent named darbepoetin alfa, which is a modified rhEPO with a carbohydrate chain structure that differs from native hEPO. We have developed a biosimilar to darbepoetin alfa designated JR-131. Here, we comprehensively compare the physicochemical and biological characteristics of JR-131 to darbepoetin alfa. JR-131 demonstrated similar protein structure to the originator, darbepoetin alfa, by peptide mapping and circular dichroism spectroscopy. Additionally, mass spectroscopic analyses and capillary zone electrophoresis revealed similar glycosylation patterns between the two products. Human bone marrow-derived erythroblasts differentiated and proliferated to form colonies with JR-131 to a similar degree as darbepoetin alfa. Finally, JR-131 stimulated erythropoiesis and improved anemia in rats similarly to darbepoetin alfa. Our data show the similarity in physicochemical and biological properties of JR-131 to those of darbepoetin alfa, and JR-131 therefore represents a biosimilar for use in the treatment of renal anemia.

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<![CDATA[Effectiveness of the Common Elements Treatment Approach (CETA) in reducing intimate partner violence and hazardous alcohol use in Zambia (VATU): A randomized controlled trial]]> https://www.researchpad.co/product?articleinfo=N3889b1ed-7187-41ba-b4d5-94f42ba3d649

Background

Both intimate partner violence (IPV) and alcohol misuse are highly prevalent, and partner alcohol misuse is a significant contributor to women’s risk for IPV. There are few evidence-based interventions to address these problems in low- and middle-income countries (LMICs). We evaluated the effectiveness of an evidence-based, multi-problem, flexible, transdiagnostic intervention, the Common Elements Treatment Approach (CETA) in reducing (a) women’s experience of IPV and (b) their male partner’s alcohol misuse among couples in urban Zambia.

Methods and findings

This was a single-blind, parallel-assignment randomized controlled trial in Lusaka, Zambia. Women who reported moderate or higher levels of IPV and their male partners with hazardous alcohol use were enrolled as a couple and randomized to CETA or treatment as usual plus safety checks (TAU-Plus). The primary outcome, IPV, was assessed by the Severity of Violence Against Women Scale (SVAWS) physical/sexual violence subscale, and the secondary outcome, male alcohol misuse, by the Alcohol Use Disorders Identification Test (AUDIT). Assessors were blinded. Analyses were intent-to-treat. Primary outcome assessments were planned at post-treatment, 12 months post-baseline, and 24 months post-baseline. Enrollment was conducted between May 23, 2016, and December 17, 2016. In total, 123 couples were randomized to CETA, 125 to TAU-Plus. The majority of female (66%) and a plurality of male (48%) participants were between 18 and 35 years of age. Mean reduction in IPV (via SVAWS subscale score) at 12 months post-baseline was statistically significantly greater among women who received CETA compared to women who received TAU-Plus (−8.2, 95% CI −14.9 to −1.5, p = 0.02, Cohen’s d effect size = 0.49). Similarly, mean reduction in AUDIT score at 12 months post-baseline was statistically significantly greater among men who received CETA compared to men who received TAU (−4.5, 95% CI −6.9 to −2.2, p < 0.001, Cohen’s d effect size = 0.43). The Data and Safety Monitoring Board recommended the trial be stopped early due to treatment effectiveness following the 12-month post-baseline assessment, and CETA was offered to control participants. Limitations of the trial included the lack of a true control condition (i.e., that received no intervention), self-reported outcomes that may be subject to social desirability bias, and low statistical power for secondary IPV outcomes.

Conclusions

Results showed that CETA was more effective than TAU-Plus in reducing IPV and hazardous alcohol use among high-risk couples in Zambia. Future research and programming should include tertiary prevention approaches to IPV, such as CETA, rather than offering only community mobilization and primary prevention.

Trial registration

The trial was registered on ClinicalTrials.gov (NCT02790827).

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<![CDATA[A compound attributes-based predictive model for drug induced liver injury in humans]]> https://www.researchpad.co/product?articleinfo=Ndeb57c49-a1cc-41d4-9618-08dc56c45dac

Drug induced liver injury (DILI) is one of the key safety concerns in drug development. To assess the likelihood of drug candidates with potential adverse reactions of liver, we propose a compound attributes-based approach to predicting hepatobiliary disorders that are routinely reported to US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Specifically, we developed a support vector machine (SVM) model with recursive feature extraction, based on physicochemical and structural properties of compounds as model input. Cross validation demonstrates that the predictive model has a robust performance with averaged 70% of both sensitivity and specificity over 500 trials. An independent validation was performed on public benchmark drugs and the results suggest potential utility of our model for identifying safety alerts. This in silico approach, upon further validation, would ultimately be implemented, together with other in vitro safety assays, for screening compounds early in drug development.

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<![CDATA[The effect of NaOH pretreatment on coal structure and biomethane production]]> https://www.researchpad.co/product?articleinfo=Nec5b1db1-34f5-4425-bec1-1f1e431a6eb6

Biogenic CBM is an important component of detected CBM, which is formed by coal biodegradation and can be regenerated by anaerobic microorganisms. One of the rate-limiting factors for microbial degradation is the bioavailability of coal molecules, especially for anthracite which is more condense and has higher aromaticity compared with low-rank coal. In this paper, NaOH solution with different concentrations and treating time was employed to pretreat anthracite from Qinshui Basin to alter the coal structure and facilitate the biodegradation. The results showed that the optimal pretreatment conditions were 1.5 M NaOH treating for 12 h, under which the biomethane production was increased by 17.65% compared with untreated coal. The results of FTIR and XRD showed that NaOH pretreatment mainly reduced the multi-substituted aromatics, increased the C-O in alcohols and aromatic ethers and the branching degree of aliphatic chain, and decreased the aromatic ring structure, resulting in the improvement of coal bioavailability and enhancement of biomethane yield. And some organics with potential to generate methane were released to filtrate as revealed by GC-MS. Our results suggested that NaOH was an effective solution for pretreating coal to enhance biogenic methane production, and anthracite after treating with NaOH could be the better substrate for methanogenesis.

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