bluuebunny/crossref_metadata_2025 huggingface dataset:
Pentoxifylline decreases post-operative intra-abdominal adhesion formation in an animal model
Authors: Yang Ya-Lin , Lee Meng-Tse Gabriel , Lee Chien-Chang , Su Pei-I , Chi Chien-Yu , Liu Cheng-Heng , Wu Meng-Che , Yen Zui-Shen , Chen Shyr-Chyr
Published: August 2018

Background

Intra-abdominal adhesions develop after nearly every abdominal surgery, commonly causing female infertility, chronic pelvic pain, and small bowel obstruction. Pentoxifylline (PTX) is a methylxanthine compound with immunomodulatory and antifibrotic properties. The aim of this study was to investigate whether PTX can reduce post-operative intra-abdominal adhesion formation via collagen deposition, tissue plasminogen activator (tPA) level, inflammation, angiogenesis, and fibrosis.

Methods

Seventy male BALB/c mice were randomized into one of three groups: (1) sham group without peritoneal adhesion model; (2) peritoneal adhesion model (PA group); (3) peritoneal adhesion model with PTX (100 mg/kg/day i.p.) administration was started on preoperative day 2 and continued daily (PA + PTX group). On postoperative day 3 and day 7, adhesions were assessed using the Lauder scoring system. Parietal peritoneum was obtained for histological evaluation with hematoxylin and eosin (HE) and picrosirius red staining. Fibrinolysis was analyzed by tPA protein levels in the peritoneum by ELISA. Immunohistological analysis was also conducted using markers for angiogenesis (ki67+/CD31+), inflammation (F4/80+) and fibrosis (FSP-1+ and α-SMA+). All the comparisons were made by comparing the PA group with the PTX treated PA group, and p < 0.05 was considered statistically significant.

Results

Intra-abdominal adhesions were markedly reduced by PTX treatment. Compared with the PA group, PTX treatment had lower adhesion scores than the PA group on both day 3 and day 7 (p < 0.05). Histological evaluations found that PTX treatment reduced collagen deposition and adhesion thickening. ELISA analysis showed that PTX treatment significantly increased the level of tPA in the peritoneum. In addition, in the immunohistological analysis, PTX treatment was found to significantly decrease the number of ki67+/CD31+ cells at the site of adhesion. Finally, we also observed that in the PTX treated group, there was a reduction in the expression of F4/80+, FSP-1+, and α-SMA+ cells at the site of adhesion.

Conclusion

PTX may decrease intra-abdominal adhesion formation via increasing peritoneal fibrinolytic activity, suppressing angiogenesis, decreasing collagen synthesis, and reducing peritoneal fibrosis. Our findings suggest that PTX can be used to decrease post-operative intra-abdominal adhesion formation.
АСТРОЦИТЫ КАК ПОСРЕДНИКИ ИНТЕГРАЦИОННЫХ ПРОЦЕССОВ В МОЗГЕ, "Успехи современной биологии"
Authors: Гомазков О. А.
Published: August 2018

Роль клеток астроглии оказывается намного более сложной, нежели представление об эластичном каркасе, обеспечивающем структурную и метаболическую поддержку мозга. Астроциты могут влиять на синаптические процессы, участвуя в передаче информации за счет рилизинга или модулирования активности нейротрансмиттеров. Исследования in vitro и in situ выявили широкий спектр молекул, секретируемых клетками нейроглии. Анализ закономерностей, сопровождающих секреторную функцию астроцитов, привел к понятию «глиотрансмиссия» (gliotransmission), что дало основание новому представлению о пластической регуляции синаптической функции, организации нейральной сети, памяти и когнитивных процессов. Концепция интегрирующей миссии астроглии открывает новые возможности для понимания механизмов нейродеструктивных заболеваний и идентификации новых мишеней терапии.
МЕХАНИЗМЫ ФОРМИРОВАНИЯ, РЕГУЛЯЦИИ И АДРЕСНОЙ КОРРЕКЦИИ ИММУННЫХ РАССТРОЙСТВ, "Успехи современной биологии"
Authors: Земсков А. М. , Земсков В.М. , Земскова В.А.
Published: August 2018

На основе данных литературы и собственных результатов обследования более 3000 пациентов, страдающих различными заболеваниями дифференцированного генеза и подвергнутых многовариантной иммунотерапии, при использовании формализованных аналитических подходов обсуждены, уточнены и подтверждены процессы формирования естественной и адресной регуляции иммунопатологии. Сформулирована новая концепция механизмов регуляции и адресной коррекции иммунопатологии.
Adjuvant and Antigen Systems for Malaria Transmission‐Blocking Vaccines
Authors: Huang Wei‐Chiao , Sia Zachary R. , Lovell Jonathan F.
Published: August 2018

Malaria is transmitted by protozoan parasites of the Plasmodium genus, via mosquito vectors. Highly effective vaccines could be a valuable tool to control the disease, but have remained elusive, in part due to the complex lifecycle of the parasite. Transmission‐blocking vaccines (TBVs) take the unconventional approach of targeting the mosquito stages of the parasite life cycle. TBVs are yet to be tested in large‐scale human trials, but represent a prominent area of interest for malaria vaccine research and development. Because TBVs rely on passive antibody transfer from a blood meal to the mosquito midgut, techniques to boost host antibody generation are a focus of investigation. In this review, immunostimulants and delivery systems for conjugating, self‐assembling, or coadministrating TBV antigens and adjuvants are summarized.
Abnormal Near‐Infrared Absorption in 2D Black Phosphorus Induced by Ag Nanoclusters Surface Functionalization
Authors: Hu Zehua , Li Qiang , Lei Bo , Wu Jing , Zhou Qionghua , Gu Chengding , Wen Xinglin , Wang Junyong , Liu Yanpeng , Li Shisheng , Zheng Yue , Lu Junpeng , He Jun , Wang Li , Xiong Qihua , Wang Jinlan , Chen Wei
Published: August 2018

Black phosphorus (BP), as a fast emerging 2D material, shows promising potential in near‐infrared (NIR) photodetection owing to its relatively small direct thickness‐dependent bandgaps. However, the poor NIR absorption due to the atomically thin nature strongly hinders the practical application. In this study, it is demonstrated that surface functionalization of Ag nanoclusters on 2D BP can induce an abnormal NIR absorption at ≈746 nm, leading to ≈35 (138) times enhancement in 808 (730) nm NIR photoresponse for BP‐based field‐effect transistors. First‐principles calculations reveal that localized bands are introduced into the bandgap of BP, serving as the midgap states, which create new transitions to the conduction band of BP and eventually lead to the abnormal absorption. This work provides a simple yet effective method to dramatically increase the NIR absorption of BP, which is crucial for developing high‐performance NIR optoelectronic devices.
Protein‐Corona‐by‐Design in 2D: A Reliable Platform to Decode Bio–Nano Interactions for the Next‐Generation Quality‐by‐Design Nanomedicines
Authors: Mei Kuo‐Ching , Ghazaryan Artur , Teoh Er Zhen , Summers Huw D. , Li Yueting , Ballesteros Belén , Piasecka Justyna , Walters Adam , Hider Robert C. , Mailänder Volker , Al‐Jamal Khuloud T.
Published: August 2018

Hard corona (HC) protein, i.e., the environmental proteins of the biological medium that are bound to a nanosurface, is known to affect the biological fate of a nanomedicine. Due to the size, curvature, and specific surface area (SSA) 3‐factor interactions inherited in the traditional 3D nanoparticle, HC‐dependent bio–nano interactions are often poorly probed and interpreted. Here, the first HC‐by‐design case study in 2D is demonstrated that sequentially and linearly changes the HC quantity using functionalized graphene oxide (GO) nanosheets. The HC quantity and HC quality are analyzed using NanoDrop and label‐free liquid chromatography–mass spectrometry (LC‐MS) followed by principal component analysis (PCA). Cellular responses (uptake and cytotoxicity in J774 cell model) are compared using imaging cytometry and the modified lactate dehydrogenase assays, respectively. Cellular uptake linearly and solely correlates with HC quantity (R2 = 0.99634). The nanotoxicity, analyzed by retrospective design of experiment (DoE), is found to be dependent on the nanomaterial uptake (primary), HC composition (secondary), and nanomaterial exposure dose (tertiary). This unique 2D design eliminates the size–curvature–SSA multifactor interactions and can serve as a reliable screening platform to uncover HC‐dependent bio–nano interactions to enable the next‐generation quality‐by‐design (QbD) nanomedicines for better clinical translation.
Alkynyl Pyridinium Crystals for Terahertz Generation
Authors: Valdivia‐Berroeta Gabriel A. , Heki Larry K. , McMurray Emmalee A. , Foote Lindsey A. , Nazari S. Hadi , Serafin Lorenzo Y. , Smith Stacey J. , Michaelis David J. , Johnson Jeremy A.
Published: August 2018

The design and synthesis of three organic nonlinear optical crystals is presented for terahertz (THz) generation that incorporates the optimal characteristics of known organic nonlinear optical crystals 4‐(4‐(dimethylamino)styryl)‐1‐methylpyridinium 4‐methylbenzenesulfonate (DAST) and 2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium 2,4,6‐trimethylbenzenesulfonate (HMQ‐TMS). The three crystals feature the 4‐((4‐(dimethylamino)phenyl)ethynyl)‐1‐methylpyridin‐1‐ium (4DEP) cation and three different anion combinations. Gas phase ab initio calculations of the cation show that 4DEP has a larger hyperpolarizability than cations from both DAST and HMQ‐TMS. To obtain the molecular packing needed for large nonlinear optical susceptibility and efficient THz generation, three anions are tested that result in noncentrosymmetric crystals: 4‐methylbenzenesulfonate, 3‐nitrobenzenesulfonate, and napthalene‐2‐sulfonate. After synthesis and crystallization, the crystal structure is characterized via X‐ray diffraction (XRD) analysis, and the relative THz generation efficiency for ideal crystals is predicted. 4DEP‐N2S shows a roughly 30% larger relative second‐order nonlinear optical susceptibility compared to HMQ‐TMS and DAST and, therefore, shows promise as a new advanced THz generation crystal.
Vacuum‐Ultraviolet Photovoltaic Detector with Improved Response Speed and Responsivity via Heating Annihilation Trap State Mechanism
Authors: Zheng Wei , Lin Richeng , Zhang Dan , Jia Lemin , Ji Xu , Huang Feng
Published: August 2018

Vacuum‐ultraviolet (VUV) photodetection is effective in probing the evolution and eruption of solar storms which are destructive to power transmission and communication systems. To realize real‐time monitoring of solar storms, astro‐ and solar physicists are dedicated to developing zero‐energy‐consumption VUV photovoltaic devices with high sensitivity. However, due to the lack of VUV transparent electrodes and high‐quality VUV photosensitive materials, the desired VUV photovoltaic devices with rapid temporal response are rarely reported. Here, graphene is used as the VUV transparent electrode, and a heterojunction device p‐Gr/AlN/n‐ZnO with p–i–n characteristics is fabricated. Benefitting from the lattice‐matched epitaxial growth of AlN film, the device realizes selective photovoltaic response to VUV light. More importantly, by employing a heat annihilation trap state mechanism, the response speed and responsivity of the device are increased by one order of magnitude. This strategy can also be applied to other multispectral photovoltaic devices, which provides a reference for the future development of new‐generation ultrafast monitoring space sensors.
Quinoid‐Resonant Conducting Polymers Achieve High Electrical Conductivity over 4000 S cm−1 for Thermoelectrics
Authors: Yuan Dafei , Liu Liyao , Jiao Xuechen , Zou Ye , McNeill Christopher R. , Xu Wei , Zhu Xiaozhang , Zhu Daoben
Published: August 2018

New conducting polymers polythieno[3,4‐b]thiophene‐Tosylate (PTbT‐Tos) are prepared by solution casting polymerization. Through tuning the alkyl group of TbT, the electrical conductivity can be effectively enhanced from 0.0001 to 450 S cm−1. Interestingly, the electrical conductivity of PTbT‐C1‐Tos increases significantly from 450 S cm−1 at room temperature to 4444 S cm−1 at 370 K, which is disparate from polyethylenedioxythiophene‐Tos exhibiting metallic conducting behavior. Quasi‐reversible phase transformation with temperature from 3D crystallites to lamellar‐stacking coincides with the increasing electrical conductivity of PTbT‐C1‐Tos with heating. Methyl‐substituted PTbT‐Tos with the best electrical property is further utilized for thermoelectrics and a power factor as high as 263 µW m−1 K−1 is obtained. It is believed that PTbT‐Tos will be a promising family of conducting polymers for solution‐processed organic electronics.
Mathematical Model for Predicting the Dissolution Behaviors of Hemicelluloses During Cold Caustic Extraction Process
Authors: Guan Qing‐Qing , Zhou Hua‐Jing , Peng Lin‐Cai , Chen Ke‐Li , He Liang , Chai Xin‐Sheng , Sun Bing
Published: August 2018

Significance

Cold caustic extraction (i.e., CCE) is widely used in mill practice for hemicelluloses removal, and the parameters of which can significantly affect the hemicelluloses dissolution. Therefore, the dissolution behaviors of hemicelluloses under different CCE process parameters have been investigated. The results showed that with the temperature increases, the dissolution of hemicelluloses also increases. However, the effect of alkali content showed complicated, since lower content (<9.0 wt %) was good for the swelling of fibers (i.e., good for hemicelluloses dissolution), but higher content (>9.0 wt %) would accelerate the competing hydration of sodium ions with water and thus limited the dissolution of hemicelluloses. Besides, a mathematical model has been also developed for predicting the hemicelluloses dissolution during CCE process, which can provide a good guidance for enhancing the purification efficiency in the CCE process operation. © 2018 American Institute of Chemical Engineers AIChE J, 65: 13–17, 2019
Recent Advances in Transition‐Metal‐Catalyzed Functionalization of 1‐Thiosugars
Authors: Ibrahim Nada , Alami Mouad , Messaoudi Samir
Published: August 2018

Thioglycosides are valuable glycomimetic derivatives that have attracted much attention as mimetics of O‐glycosides. Thioglycosides are among the most important glycomimetics reported to date due to their powerful activities. Owing to their importance, building up methods for their construction has drawn considerable attention. However, the classical methods of their synthesis presenting many shortcomings such as the use of harsh acidic media, and are generally limited in substrate scope. Therefore, metal‐catalyzed coupling of thiosugars with halogenated electrophiles can be a superior and highly versatile approach to the sunthesis of thioglycosides. The central objective of this Focus Review is to highlight metal‐catalyzed reactions for the creation of aromatic and heteroaromatic thioglycosides.
Facile Fabrication of Concentrated Polymer Brushes with Complex Patterning by Photocontrolled Organocatalyzed Living Radical Polymerization
Authors: Wang Chen‐Gang , Chen Chen , Sakakibara Keita , Tsujii Yoshinobu , Goto Atsushi
Published: August 2018

Photocontrolled surface‐initiated reversible complexation mediated polymerization (photo‐SI‐RCMP) was successfully applied to fabricate concentrated polymer brushes with complex patterning structures. Positive‐type patterned polymer brushes were obtained by photo‐SI‐RCMP under visible light (550(±50) nm) using photomasks. A particularly interesting finding was that negative‐type patterned polymer brushes were also obtainable in a facile manner. A nonspecial UV light (250–385 nm) enabled the preparation of pre‐patterned initiator surfaces in a remarkably short time (1 min), leading to negative‐type patterned polymer brushes. Based on this unique selectivity between visible and UV light, the combination of two patterning techniques enabled the preparation of complex patterned brushes, including diblock copolymers, binary polymers, and functional binary polymers, without multistep immobilization of one or more initiators on the surfaces.
Cobalt‐Catalyzed Reductive Dimethylcyclopropanation of 1,3‐Dienes
Authors: Werth Jacob , Uyeda Christopher
Published: August 2018

Dimethylcyclopropanes are valuable synthetic targets that are challenging to access in high yield using Zn carbenoid reagents. Herein, we describe a cobalt‐catalyzed variant of the Simmons–Smith reaction that enables the efficient dimethylcyclopropanation of 1,3‐dienes using a Me2CCl2/Zn reagent mixture. The reactions proceed with high regioselectivity based on the substitution pattern of the 1,3‐diene. The products are vinylcyclopropanes, which serve as substrates for transition‐metal‐catalyzed ring‐opening reactions, including 1,3‐rearrangement and [5+2] cycloaddition. Preliminary studies indicate that moderately activated monoalkenes are also amenable to dimethylcyclopropanation under the conditions of cobalt catalysis.
Facile Benzene Reduction by a Ca2+/AlI Lewis Acid/Base Combination
Authors: Brand Steffen , Elsen Holger , Langer Jens , Donaubauer Wolfgang A. , Hampel Frank , Harder Sjoerd
Published: August 2018

Attempted synthesis of the donor–acceptor complex (BDI)Ca+←AlI(BDI) complex by reaction of (BDI)Ca+ in the form of its B(C6F5)4− salt with (BDI)AlI in benzene led to dearomatization of the solvent and formation of (BDI)Ca+(C6H6)AlIII(BDI) (BDI=CH[C(CH3)N‐Dipp]2, Dipp=2,6‐diisopropylphenyl). The C6H62− anion is strongly puckered and its boat form features four long (ca. 1.50 Å) and two short (ca. 1.34 Å) C−C bond distances. The flagpole positions of the C6H62− anion chelate an AlIII cation giving a norbornadiene‐like fragment with Al in the 7‐position. The C=C double bonds of this alumina‐norbornadiene strongly coordinate to the Ca2+ metal ion. The complex is stable in solution up to 80 °C. Several mechanisms for its formation are discussed including a highly likely frustrated Lewis pair type mechanism in which benzene is activated by the Lewis acid (BDI)Ca+ followed by nucleophilic attack by the Lewis base (BDI)AlI.
Orally Active Peptides: Is There a Magic Bullet?
Authors: Räder Andreas F. B. , Weinmüller Michael , Reichart Florian , Schumacher‐Klinger Adi , Merzbach Shira , Gilon Chaim , Hoffman Amnon , Kessler Horst
Published: August 2018

For decades, the development of peptides as potential drugs was aimed solely at peptides with the highest affinity, receptor selectivity, or stability against enzymatic degradation. However, optimization of their oral availability is highly desirable to establish orally active peptides as potential drug candidates for everyday use. A twofold optimization process is necessary to produce orally active peptides: 1) optimization of the affinity and selectivity and 2) optimization of the oral availability. These two steps must be performed sequentially for the rational design of orally active peptides. Nevertheless, additional knowledge is required to understand which structural changes increase oral availability, followed by incorporation of these elements into a peptide without changing its other biological properties. Considerable efforts have been made to understand the influence of these modifications on oral availability. One approach is to improve the oral availability of a peptide that has been previously optimized for biological activity, as described in (1) above. The second approach is to first identify an intestinally permeable, metabolically stable peptide scaffold and then introduce the functional groups necessary for the desired biological function. Previous approaches to achieving peptide oral availability have been claimed to have general applicability but, thus far, most of these solutions have not been successful in other cases. This Review discusses diverse chemical modifications, model peptides optimized for bioavailability, and orally active peptides to summarize the state of the research on the oral activity of peptides. We explain why no simple and straightforward strategy (i.e. a “magic bullet”) exists for the design of an orally active peptide with a druglike biological function.
Chlorophyll Breakdown in a Fern—Discovery of Phyllobilin Isomers with a Rearranged Carbon Skeleton
Authors: Erhart Theresia , Vergeiner Stefan , Kreutz Christoph , Kräutler Bernhard , Müller Thomas
Published: August 2018

All structure‐based information on chlorophyll (Chl) breakdown in the higher plants relies on studies with angiosperms. Herein, the first investigation of a fern is reported, revealing a novel type of Chl catabolites (phyllobilins) in leaves of this large division of the vascular plants, and providing structural insights into an astounding metabolic process of the higher plants that appears to have played a role even in early phases of plant evolution. The tetrapyrrolic Chl catabolites in the cosmopolitan bracken fern were discovered to be phyllobilin isomers with an unprecedented skeleton, proposed to be the striking result of a rearrangement of a hypothetical phyllobilin precursor.
Novel sheet‐like bismuth subcarbonate‐zinc ferrite (Bi2O2CO3/ZnFe2O4) magnetically recyclable nanocomposites: Synthesis, characterization and enhanced catalytic performance for the reduction of nitrophenols and nitroanilines
Authors: Zarringhadam Parisa , Farhadi Saeed
Published: August 2018

Sheet–like Bi2O2CO3/ZnFe2O4 magnetic nanocomposites (denoted as BOC‐ZFO) with different amounts of magnetic ZnFe2O4 (ZFO) nanoparticles were successfully produced by a simple hydrothermal route. X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive X‐ray spectroscopy (EDX), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), vibrating sample magnetometer (VSM), and N2 adsorption–desorption examination were utilized to analyze the structure, morphology, size, phase composition, optical and magnetic properties of the synthesized nanocomposites. The results demonstrated the successful deposition of uniform ZFO nanoparticles onto the surface of sheet–like BOC nanostructures. Then, the catalytic activity of magnetic BOC/ZFO nanocamposites was investigated for the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) by using sodium borohydride (NaBH4) in hydrous solution and at room temperature. The results showed that BOC/ZFO nanocamposite with 30%wt of ZFO showed the best performance in the reduction of 4‐NP with 100% conversion into the amino derivative during 30 min. The effect of catalyst dosage was also investigated on the efficiency of reduction process. Under similar conditions, 2‐nitrophenol (2‐NP), 4‐nitroaniline (4‐NA) and 2‐nitroaniline (2‐NA) were also reduced to the amino derivatives within 16–29 min. The magnetic BOC/ZFO catalyst could be easily separated from the reaction system by an external magnet.
Molybdenum anchored on NH2‐modified spherical SiO2: A highly efficient and stable catalyst for oxidative desulfurization of fuel oil
Authors: Hu Zhen , Lu Shuxiang , Huang Xiaoqiao , Li Jianxin , Duan Yongsheng , Yan Lijun , Yao Yue , Liao Xiaoyuan
Published: August 2018

A catalyst (Mo‐NH2‐SiO2) has been synthesized via anchoring of Mo species onto the surface of 3‐aminopropyltriethoxysilane‐modified SiO2 (NH2‐SiO2) and applied in the catalytic oxidative desulfurization of fuel oil. Structure and properties of the catalyst were investigated using X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron and Fourier transform infrared spectroscopies and nitrogen adsorption–desorption measurements. The hydrophilic/hydrophobic characters of the catalyst were also studied. The results demonstrated that the synthesized catalyst possessed highly dispersed Mo species with an electron‐rich state and a strong hydrophobic character, which contributed significantly to increases of both catalytic activity and stability. Dibenzothiophene in model oil could be removed completely, and the removal of sulfur from diesel oil (21 500 ppmw) also reached 80.4% at 60°C in 60 min. Furthermore, the catalyst was recycled in ten reaction runs without obvious influence on activity. This work provides a novel way for preparing high‐activity and stable catalysts for oxidative desulfurization of fuel oil, which will have potential industrial applications.
Using fish scales (Sardina pilchardus) within ethylene‐propylene‐diene ter monomer rubber as bio‐based filler
Authors: Akbay İsmail Kutlugün , Güngör Ahmet , Özdemir Tonguç
Published: August 2018

Proper management of waste bio‐based materials is an important subject to protect the environment in a sustainable manner. In this study, ethylene‐propylene‐diene monomer (EPDM) composites with different fish scale content were prepared and properties of these composites were investigated. Mechanical tests, gel content, curing, and thermal properties were analyzed. In addition, rheological and morphological analyses were also carried out. It was seen that EPDM rubber and fish scale composite have a good compatibility. The addition of fish scale improved the mechanical properties of the final material. Moreover, an increase in gel content and in swelling ratio was obtained for the composite samples containing fish scale. Moving die rheometer tests are concluded that fish scale has acted like an agent that improves the vulcanization process. Thermal gravimetric analysis result pointed out that the thermal stability of the composite developed is higher than neat EPDM. It was concluded that 40 phr fish scale content gives best results. The kinetic study demonstrated that fish scale is compatible with the matrix and improves the vulcanization process. The results have shown that using the fish scale as a bio‐based filler is a facile and green way to accommodate the bio‐based wastes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46698.
g‐C3N4 Inverse Opals with Isotype Heterostructure for Enhanced Visible‐Light‐Driven Photocatalysis
Authors: Yu Jie , Zhou Liang , Lei Juying , Wang Lingzhi , Zhang Jinlong , Liu Yongdi
Published: August 2018

The photocatalytic activity of g‐C3N4 is limited by the low surface area and the fast recombination of photogenerated charges. In this work, a g‐C3N4 quantum dot (CNQDs) modified g‐C3N4 inverse opal (CN IO) metal‐free composite (CNQDs/CN IO) was successfully synthesized by a simple calcination method. CNQDs/CN IO exhibited outstanding photocatalytic activity in the removal of organic pollutants represented by phenol, which can be ascribed to (i) the inverse opal structure that enhances the light harvesting, facilitates mass transfer, and provides adequate surface area for photocatalytic reactions; (ii) the incorporation of CNQDs in the framework of g‐C3N4 promotes photogenerated charge separation and transfer across the interfaces between CN IO and CNQDs, leading to excellent photoelectrochemical properties. The strategy of self‐modification of g‐C3N4 with special structures provides a rational design idea to fabricate highly efficient metal‐free photocatalysts.
Heuristic policies for stochastic knapsack problem with time‐varying random demand
Authors: Lu Yingdong
Published: August 2018

In this paper, we consider the classic stochastic (dynamic) knapsack problem, a fundamental mathematical model in revenue management, with general time‐varying random demand. Our main goal is to study the optimal policies, which can be obtained by solving the dynamic programming formulated for the problem, both qualitatively and quantitatively. It is well known that, when the demand size is fixed and the demand distribution is stationary over time, the value function of the dynamic programming exhibits extremely useful first‐ and second‐order monotonicity properties, which lead to monotonicity properties of the optimal policies. In this paper, we are able to verify that these results still hold even in the case that the price distributions are time dependent. When we further relax the demand size distribution assumptions and allow them to be arbitrary, for example, in random batches, we develop a scheme for using value function of alternative unit demand systems to provide bounds to the value function. These results confirm some of the basic understandings of the stochastic knapsack problem. As a natural consequence, we propose a new class of heuristic policies, two‐dimensional switch‐over policies, and discuss numerical procedures for optimizing the parameters of the policies. Extensive numerical experiments demonstrate that these switch‐over policies can provide performances that are in a close neighborhood of the optimum statistically.
Study on fluorescence properties of HCV antiviral (velpatasvir) and its fluorimetric determination in presence of sofosbuvir; application to stability study and human plasma
Authors: Omar Mahmoud A. , Abdel‐Lateef Mohamed A. , Ali Ramadan , Derayea Sayed M.
Published: August 2018

Velpatasvir (VLP) is a new, oral, direct‐acting antiviral with potent inhibitory activity against all hepatitis C virus (HCV) genotypes. A highly sensitive, simple, fast and specific one fluorometric method for determination of VLP in the presence of sofosbuvir was developed and validated. The fluorescence behavior of VLP in different organic solvents was examined and explained. Methanol was concluded to be the best sensitizing reagent. The native fluorescence intensity of VLP was accomplished at 383 nm with 339 nm for excitation wavelength. The impacts of experimental variables included pH, various organized media, and time of stability were examined and optimized. A linear relationship was achieved between the VLP concentration and the fluorescence intensity in a range of 5 to 5 × 103 ng mL−1 with 0.70 and 0.23 ng mL−1, for quantitation and detection limits respectively. The proposed method was utilized for analyzing of VLP in human plasma and additionally expanded to examine the stability of VLP after its exposure to various stress conditions, like oxidative, alkaline, acidic, UV, daylight and sunlight conditions, according to ICH guidelines. Furthermore, the kinetics of acidic and oxidative degradations of VLP was examined. Moreover, the half‐life times of the reaction (t1/2) and the first‐order reaction rate constants were estimated. Finally, a suggestion for the degradation pathway was presented.
Steamed bread—A review of manufacturing, flour quality requirements, and quality evaluation
Authors: Huang Sidi , Miskelly Diane
Published: August 2018

Background and objectives

Steamed bread is a staple food in northern China and is also popular in the south of China and many Asian countries. It is a fermented food made from wheat flour, and the steaming process gives a product with a thin, white skin, an upright profile, and internal crumb ranging from dense and firm to open and soft, depending on the style and region.

Findings

This review presents an overview of the major manufacturing methods in commercial production and the factors influencing product quality, including processing and flour quality. Forty years of research has helped refine wheat quality requirements for the different styles of steamed bread, but there are still conflicting reports on basic wheat quality requirements and ingredient effects which hinder progress in the field.

Conclusions

In order for manufacturers to obtain the flour quality they require, all sectors of the chain must work to understand the interaction of production method and flour quality for each style of steamed bread and each region. This includes development and implementation of objective methods of steamed bread quality assessment.

Significance and novelty

By considering both the style of steamed bread and method of manufacture as described in this review, it is possible to select the most appropriate methods and quality evaluation parameters. This should enable future researchers to present conclusions which may be useful to later workers.
Photocatalysis for Hydrogen Production and CO2 Reduction: The Case of Copper‐Catalysts
Authors: Christoforidis Konstantinos C. , Fornasiero Paolo
Published: August 2018

Problems derived from climate change dictate the reestablishment of our prospective in energy production. In this direction, converting solar energy through photocatalysis into suitable fuels such as hydrogen and carbon‐based fuels by water splitting and CO2 reduction, respectively, has been established as a promising approach. Currently, the main concern in this field is the development of cost‐effective and efficient photocatalysts. Among the different systems studied, Cu‐based photocatalysts are considered attractive candidates for both applications due to their relative low‐cost, the natural abundance of the constituents and their promising reactivity. In this review, the current progress in the field of Cu‐based photoactive materials for both H2 production and CO2 reduction will be discussed. Finally, an outlook on the challenges and future research directions is given.
Catalytic Amplification of Au144 Nanocluster Collisions by Hydrogen Evolution Reaction
Authors: Zhou Min , Wang Dengchao , Mirkin Michael V.
Published: August 2018

Quantification of the charge‐transfer kinetics at single catalytic nanoparticles is both, challenging and crucial for fundamental understanding and practical application in catalysis and energy storage. We report here the quantification of catalytic activity of single Au144 nanoclusters towards hydrogen evolution reaction in mixed organic media. The electrocatalytic amplification by the proton reduction reaction was used to detect current spikes produced by collisions of single Au144 nanoclusters (1.6 nm in diameter) with a carbon ultramicroelectrode. Relatively short (ms‐scale) current spikes were recorded at the naturally hydrophilic carbon surface, while longer (seconds) collision current responses were observed at the hydrophobic carbon fibre electrode treated by acetone. The kinetics of the hydrogen evolution reaction at a single Au nanocluster was evaluated by measuring the amplitudes of current spikes at different overpotentials. The relationship between the current amplitude and the overpotential yielded a linear Tafel plot with the 114 mV/decade slope. This approach is potentially useful for quantifying the electron‐transfer kinetics at singe catalytic nanoclusters and larger nanoparticles.
Chemometrical study of spectral curve fitting constraint on self‐modelling curve resolution methods
Authors: Khodadadi Karimvand Somaiyeh , Abdollahi Hamid
Published: August 2018

Rotational ambiguity is a significant concern of chemometricians when using soft modeling methods to resolve bilinear data. Applying different types of constraints appropriate to a system under study can significantly reduce rotational ambiguity in soft models and the resulting range of feasible solutions. The first and most commonly used constraint is non‐negativity and can be applied to concentration and spectral response profiles as appropriate. Unimodality constraints, trilinearity constraints, and physical chemical modeling of concentration profiles are natural constraints that can significantly reduce rotational ambiguity in soft modeling curve resolution methods. Also, functional fitting of spectral response profiles (eg, peak shape modeling) has been used as a constraint for resolving spectroscopic data matrices. In the present work, the use of peak shape model constraints for spectral profiles was investigated using the Voigt function (a combination of Gaussian and Lorentzian functions). Mixture spectra of a simulated two‐component system and a real data set were fitted to several different Voigt models.

The results of applying peak shape models on the range of feasible solutions for simulated and real data sets and simultaneously fitting the data to different models show that spectral peak shape constraints are not effective for limiting the range of feasible bands. Indeed, the non‐specific spectral Voigt model does not provide enough information about spectra to be effective for significant reduction of rotational ambiguity. These studies show that in the absence of sufficient information, many sets of peak functions can be well‐fitted to spectra and rotational ambiguity is not improved when resolving bilinear spectroscopic data.
Diferrate [Fe2(CO)6(μ‐CO){μ‐P(aryl)2}]− as Self‐Assembling Iron/Phosphor‐Based Catalyst for the Hydrogen Evolution Reaction in Photocatalytic Proton Reduction—Spectroscopic Insights
Authors: Fischer Steffen , Rösel Arend , Kammer Anja , Barsch Enrico , Schoch Roland , Junge Henrik , Bauer Matthias , Beller Matthias , Ludwig Ralf
Published: August 2018

This work is focused on the identification and investigation of the catalytically relevant key iron species in a photocatalytic proton reduction system described by Beller and co‐workers. The system is driven by visible light and consists of the low‐cost [Fe3(CO)12] as catalyst precursor, electron‐poor phosphines P(R)3 as co‐catalysts, and a standard iridium‐based photosensitizer dissolved in a mixture of THF, water, and the sacrificial reagent triethylamine. The catalytic reaction system was investigated by operando continuous‐flow FTIR spectroscopy coupled with H2 gas volumetry, as well as by X‐ray absorption spectroscopy, NMR spectroscopy, DFT calculations, and cyclic voltammetry. Several iron carbonyl species were identified, all of which emerge throughout the catalytic process. Depending on the applied P(R)3, the iron carbonyl species were finally converted into [Fe2(CO)6(μ‐CO){μ‐P(R)2}]−. This involves a P−C cleavage reaction. The requirements of P(R)3 and the necessary reaction conditions are specified. [Fe2(CO)6(μ‐CO){μ‐P(R)2}]− represents a self‐assembling, sulfur‐free [FeFe]‐hydrogenase active‐site mimic and shows good catalytic activity if the substituent R is electron poor. Deactivation mechanisms have also been investigated, for example, the decomposition of the photosensitizer or processes observed in the case of excessive amounts of P(R)3. [Fe2(CO)6(μ‐CO){μ‐P(R)2}]− has potential for future applications.
Hybridization of Pd Nanoparticles with UiO‐66(Hf) Metal‐Organic Framework and the Effect of Nanostructure on the Catalytic Properties
Authors: Bakuru Vasudeva Rao , Velaga Bharath , Peela Nageswara Rao , Kalidindi Suresh Babu
Published: August 2018

Metal‐organic frameworks (MOFs) have emerged as a new class of supports for metal nanoparticles(NPs) in heterogeneous catalysis because of possible synergetic effects between the two components. In addition, MOFs also can be coated over metal NPs to influence the entire nanoparticle's surface. Herein, NPs were hybridized with UiO‐66(Hf) MOF possessing Brønsted acidic sites (on secondary building units) and fabricated Pd@UiO‐66 (Hf) core–shell and Pd/UiO‐66(Hf) supported catalysts. These hybrid materials exhibited enhanced catalytic properties (TOF increased up to 2.5 times) compared to individual counterparts or their physical mixture for dehydrogenation of ammonia borane(AB) in non‐aqueous medium(1,4‐dioxane). Further, nanostructure of the hybrid material had pronounced influence on the catalytic properties. The core–shell catalyst exhibited highest activity towards H2 generation from AB owing to greater contact interface between Pd and MOF. Further, phenylacetylene semi‐hydrogenation with AB over Pd@UiO‐66 (Hf) furnished styrene selectivity as high as 93.2 % at ∼100 % conversion mostly due to the regulated phenylacetylene diffusion through UiO‐66(Hf) shell.
Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy
Authors: Liu Wentan , Wang Bo
Published: August 2018

A concise synthesis of (±)‐merrilactone A has been accomplished featuring desymmetrization of a Cs‐symmetric dilactone, RhI‐catalyzed intramolecular hydroacylation of a 4‐alkynal, and TiIII‐mediated reductive radical cyclization of epoxy‐allene.
Design of a Production Process for Poly(oxymethylene) Dimethyl Ethers from Dimethyl Ether and Trioxane
Authors: Breitkreuz Christian Frederik , Schmitz Niklas , Ströfer Eckhard , Burger Jakob , Hasse Hans
Published: August 2018

Poly(oxymethylene) dimethyl ethers (OME) are promising synthetic fuels. When compared to fossil diesel fuel, OME reduce the soot formation in diesel engines. OME can be produced from the C1 platform syngas via different routes. This work investigates an OME production process via dimethyl ether and trioxane. The process is simulated and optimized using process simulation with varying model depth. As no experimental data are available on the chemical equilibrium of the reaction of dimethyl ether and trioxane, chemical equilibrium constants are partly estimated from formation data of the reactants.
Predictors of long‐term mortality with cardiac resynchronization therapy in mild heart failure patients with left bundle branch block
Authors: Biton Yitschak , Costa Jason , Zareba Wojciech , Baman Jayson R. , Goldenberg Ilan , McNitt Scott , Solomon Scott D. , Polonsky Bronislava , Kutyifa Valentina
Published: August 2018

Background

Cardiac resynchronization therapy (CRT) is highly beneficial in patients with heart failure (HF) and left bundle branch block (LBBB); however, up to 30% of patients in this selected group are nonresponders.

Hypothesis

We hypothesized that clinical and echocardiographic variables can be used to develop a simple mortality risk stratification score in CRT.

Methods

Best‐subsets proportional‐hazards regression analysis was used to develop a simple clinical risk score for all‐cause mortality in 756 patients with LBBB allocated to the CRT with defibrillator (CRT‐D) group enrolled in the multicenter automatic defibrillator implantation trial with cardiac resynchronization therapy. The score was used to assess the mortality risk within the CRT‐D group and the associations with mortality reduction with CRT‐D vs implantable cardioverter defibrillator (ICD) in each risk category.

Results

Four clinical variables comprised the risk score: age ≥ 65, creatinine ≥ 1.4 mg/dL, history of coronary artery bypass graft, and left ventricular ejection fraction (LVEF) < 26%. Every 1 point increase in the score was associated with 2‐fold increased mortality within the CRT‐D arm (P < 0.001). CRT‐D was associated with mortality reduction as compared with ICD only in patients with moderate risk: score 0 (HR = 0.80, P = 0.615), score 1 (HR = 0.54, P = 0.019), score 2 (HR = 0.54, P = 0.016), score 3‐4 risk factors (HR = 1.08, P = 0.811); however, the device by score interaction was not significant (P = 0.306). The score was also significantly predictive of left ventricular reverse remodeling (P < 0.001).

Conclusions

Four clinical variables can be used for improved mortality risk stratification in mild HF patients with LBBB implanted with CRT‐D.
The impact of clinical vs administrative claims coding on hospital risk‐adjusted outcomes
Authors: O'Brien Emily C. , Li Shuang , Thomas Laine , Wang Tracy Y. , Roe Matthew T. , Peterson Eric D.
Published: August 2018

Background

Comorbid condition and hospital risk‐adjusted outcomes prevalence were compared based on clinical registry vs administrative claims data.

Hypothesis

Risk‐adjusted outcomes will vary depending on the source of comorbidity data used.

Methods

Clinical data from hospitalized Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines (CRUSADE) non‐ST‐segment elevation myocardial infarction (NSTEMI) patients ≥65 years was linked to Medicare claims. Eight common comorbid conditions were coded and compared between registry data (derived from medical record review) and claims data; hospital‐level observed vs expected ratios and outlier status for 30‐day readmission and mortality were calculated using logistic generalized estimating equations for clinical vs claims data.

Results

Of 68 199 NSTEMI patients, 48.1% were female, 86.9% were white, and median age was 78. Degree of agreement between data sources for comorbid condition prevalence was 67.8% for myocardial infarction and 89.3% for diabetes. Overall, multivariable model performance was similar: Medicare mortality c‐statistics is 0.69 vs CRUSADE is 0.71; readmission c‐statistics is 0.59 for both. Hospital ratings were similar regardless of data source (mortality, R2 = 0.97863; readmission, R2 = 0.97858). Eighty‐two hospitals were mortality outliers in claims‐based models; of these, 70 were outliers in registry‐based models. Forty‐five hospitals were readmission outliers in claims‐based models; of these, 39 were outliers in registry‐based models.

Conclusions

There were significant differences in individual comorbid condition prevalence when derived from registries vs claims, but hospital‐level outcomes were comparable.
Effect of node centrality for IoT device selection in opportunistic networks: A comparison study
Authors: Cuka Miralda , Elmazi Donald , Bylykbashi Kevin , Spaho Evjola , Ikeda Makoto , Barolli Leonard
Published: August 2018

Opportunistic networks (Oppnets) are a subclass of delay‐tolerant networks where communication opportunities (contacts) are intermittent and there is no need to establish an end‐to‐end link between communication nodes. The Internet of Things (IoT) presents the notion of large networks of connected devices, sharing data about their environments and creating a diverse ecosystem of sensors, actuators, and computing nodes. IoT networks consist of heterogeneous collections of resource constrained nodes that closely interact with their environment. There are different issues for these networks. One of them is the selection of IoT devices to carry out a task in Oppnets. In this work, we implement and compare two fuzzy‐based systems (FBSs) for selecting the IoT device that completes the task in Oppnets. We call these systems FBSIDS1 and FBSIDS2. For FBSIDS1, we use three input parameters: IoT device storage, IoT device waiting time (IDWT), and IoT device remaining energy. The output parameter is IoT device selection decision. For FBSIDS2, we consider four input parameters by adding IoT device node centrality (IDNC) as a new parameter. Comparing the complexity of FBSIDS1 and FBSIDS2, FBSIDS2 is more complex than FBSIDS1. However, FBSIDS2 is more flexible and makes a better selection of IoT devices than FBSIDS1. The simulation results show that IoT device selection is increased up to 33% and 71% by increasing IDNC and IDWT, respectively, for FBSIDS2, and up to 46% and 61% by increasing IDWT and IDNC, respectively, for FBSIDS1.
Detecting misinformation in social networks using provenance data
Authors: Baeth Mohamed Jehad , Aktas Mehmet S.
Published: August 2018

In recent years, the credibility of information on social networks has attracted considerable of interest due to its critical role in the spread of information online. In this paper, we argue that the quality of information created on social networks can be analyzed using its provenance data. In particular, we propose an algorithm that assesses information credibility on social networks in order to detect fake or malicious information using a fuzzy analytic hierarchy process to assign proper weights to the proposed metrics. In order to test the usability of the proposed algorithm, we introduce a prototype implementation and test it on a large‐scale synthetic social provenance dataset. The initial results reveal a proportional relationship between our proposed distance from positivity algorithm and the provenance graph metrics‐based user credibility.