bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of Common Pesticides Used in Storage of Agricultural Produce within Makurdi, Benue State Nigeria
Authors: Pii Barizomdu T. , Wuana R. A. , Malu S. P. , Nwafor S. C.
Published: July 2019

The objective of the study was to survey the common pesticides used in postharvest storage of agricultural produce within Makurdi, Nigeria and to test the knowledge of the farmers and marketers on the health effects of these chemicals. The study provides information on the type of pesticides used by farmers, marketers and consumers of stored agricultural food products such as cowpea, yam chips, cassava chips, sesame seeds, maize and soybeans being major farm produces found within Makurdi and Benue State in general. Selection of 100 respondents were done using simple random sampling techniques across five major markets (Modern, Wurukum, North bank, Wadata and High level markets) through structured interview schedule. Socio-economic characteristics of the respondents were analyzed using frequency and percentages. Percentages were used to determine the common storage pesticides used within Makurdi, storage time, the frequency of customer purchase and perceived health impact of the storage pesticides. Data obtained were analyzed using descriptive statistics. The results revealed that 51% of the respondents were males with 41% between the ages of 30-39. Married respondents accounted for 52% and 48% having household sizes of 1-5, only 20% had no form of formal education and 75% were marketers. In a multiple response schedule, aluminium phosphate tablets ranked 80% for storage pesticide while dichlovos was 60%, DDT 35%. Others such as endosulfan, gamalin, carbofuran, carbendazim and permethrin were between 5-15%. Furthermore the study revealed the use of many restricted and obsolete pesticides still in use within this state and in outrageous quantities which could pose health challenge to consumers of these food products.
Validated Stability Indicating HPTLC, UHPLC and UV-Spectrophotometric Techniques for the Determination of Bepotastine Besilate in Presence of Its Oxidative Degradate
Authors: Soliman Marwa Mohammed , Darwish Manal Kamal , Abdel-Razeq Sawsan Abdel-Moneem
Published: July 2019

The study is aimed at developing methods which have a complete validation as stipulated in the ICH guidelines and to be applied for the determination of Bepotastine besilate (BB) in pure form and in pharmaceutical formulations in the presence of its oxidative degradation product. High performance thin layer chromatography (HPTLC), Ultra high performance liquid chromatography (UHPLC) and different spectrophotometric methods (first derivative, first derivative of ratio spectra and ratio difference are developed for simultaneous determination of bepotastine besilate in laboratory-prepared mixtures of bepotastine besilate with its oxidative degradate and in pharmaceutical formulations were used in the study design. Firstly, HPTLC was performed and separation occurred on silica gel 60 F254 plates, with butanol: ammonia (8:2, v/v) as a developing system. UHPLC in which separation occurred on a Kinetex C 18 column using methanol- 0.1% O-phosphoric acid - acetonitrile (70:20:10, by volume) as mobile phase, followed. And lastly was UV/Vis spectrophotometry which included first derivative determination of the drug at 252.6 nm, first derivative of ratio of peak amplitudes at 233.4, 250 and 275.6 nm and the ratio difference with the amplitude difference between (240 nm and 260 nm). Result showed that HPTLC method was applicable over the concentration range of 0.5-5 μg / band, while UHPLC method was linear over the concentration 2- 12 μg/mL and spectrophotometric methods were linear over the concentration range 20-120 μg/mL for bepotastine besilate. The proposed three techniques are quite accurate and precise. They can be used for routine analysis of bepotastine besilate in pharmaceutical formulation and stability indicating methods.
Effects of Continuous Deep-fat Frying on the Physicochemical Properties of Assorted Brands of Edible Cooking Oils Sold in Greater Metropolitan Kampala
Authors: Omara Timothy , Kigenyi Erisa , Laker Fortunate , Adokorach Monica , Otim George , Kalukusu Raymond , Musau Bashir , Kagoya Sarah , Victoria Nakabuye Brenda
Published: July 2019

Aims: To investigate the effects of continuous deep fat frying of white (Irish) potatoes on the physical and chemical attributes of ten brands of edible cooking oils: Fortune Butto, Roki, Tamu, Best Fry, Mukwano, Golden Fry (hard oils); Sunseed, Sunny, Sunvita and Sunlite (soft oils) sold in Kampala, Uganda.

Place and Duration of the Study: Oil samples of approximate manufacturing dates were obtained from Mega Standard supermarket in Greater Metropolitan Kampala, Uganda. Oil samples were also obtained from local Irish potato fryers in Makindye division of Kampala during ten deep frying cycles. Irish potatoes was procured from Nakasero market, Kampala. Physicochemical analyses were performed at the Quality Control Laboratory of Mukwano Industries Limited, Kampala Industrial area, Kampala. The research was conducted between May 2018 to December 2018.

Methodology: 400g of Irish potato slices (1cm × 1cm × 3cm) were submersed in 1500mL of oil maintained at 140°C for 6 minutes in an Electric Deep Fryer with a frying time of 10 minutes.The color value (CV) and the acidification of the oils as free fatty acid (FFA), peroxide value (POV), paraanisidine value (AnV), iodine adsorption value (IV) and total oxidation (TOTOX) value before and between ten successive frying cycles were determined using ISO and AOCS official methods.The maximum number of reuses of an oil was estimated from the frying round before its POV or AnV surpassed the maximum permissible statutory or Codex Alimentarius limit for edible oils.

Results: For fresh oils, the statistical physicochemical parameter ranges were: CV (0.4R 3.4Y-7.7R 70Y), FFA (0.0430±0.30-0.1508±0.30), POV (0.5951±0.03-6.6134±0.23 meqO2/Kg),                AnV (0.90±0.01-4.30±0.19) and IV (57.62±0.17-128.35±0.02gI2/100g). By the 10th fry, the ranges were CV (3.0R 23Y-20.4R 70Y), FFA (0.2286±0.01-0.4817±0.01), POV (11.1138±0.01-15.7525±0.01meqO2/Kg), AnV (10.31±0.03-22.16±0.01) and IV (53.66±0.01-126.03±0.02gI2/100g). Considering oxidizability as TOTOX values, frying stability of the selected brands of cooking oils during the frying cycles followed the order: Roki > Fortune Butto > Sunvita > Sunny > Sunlite > Mukwano > Tamu > Best Fry >  Golden Fry > Sunseed.

Conclusion: Reuse of the oils for continuous frying of Irish potatoes on the same day can be done only up to 7 times on average for hard oils and 6 times for soft oils with the oils still regarded as safe for human consumption. Hard oils should be preferred to soft oils for deep frying of Irish potato chips.Further research should elucidate the variation of physicochemical properties of other oil brands on the Ugandan market such as Nile, Fortune, Kimbo, Star Fry, Cow boy and Ufuta and should use other food samples such as fish, cassava, chicken, sweet plantain, dough, meat and edible grasshoppers.
Occurrence of Different Kinds of Diseases in Sesame Cultivation in Myanmar and Their Impact to Sesame Yield
Authors: Min Yu Yu , Toyota Koki
Published: July 2019

We surveyed diseases of sesame in 10 farmers’ fields at Nay Pyi Taw, Myanmar and did interviews 25 farmers for the occurrence of diseases and its impact on yield in Magway, the major sesame growing area in Myanmar. We found phyllody, charcoal rot (root and stem rot), Alternaria leaf blight, powdery mildew, and leaf curl, based on on-site symptoms and their microscopic observation in Nay Pyi Taw. The disease incidence ranged from 5% to 30% in phyllody, from 10% to 30% in charcoal rot (root and stem rot) and 10% to 40% in Alternaria blight, while leaf curl and powdery mildew were not observed abundantly. According to interviews conducted in Magway, 60% of the farmers suffered from phyllody disease symptoms, 80% from charcoal rot, 48% from Cercospora, 28% bacterial leaf spot and 24% diseases with the symptoms of leaf roll. Most farmers (84%) noticed combinations of diseases symptoms either phyllody or charcoal rot/black and stem rot or Cercospora leaf spot and/or bacterial leaf spot. Yield losses ranged from 5 to 50% by phyllody, from 10 to 75% by charcoal rot (root and stem rot), from 5 to 50% by Cercospora leaf spot, and 5% by bacterial leaf spot. Other abnormal symptoms such as discoloring of root, seedling death and leaf yellowing were also observed and the yield losses ranged from 5 to 50%.There were no significance relations between the actual yield and yield losses estimated by each disease. A half of farmers (54%) burnt the crop residues after harvest, while 45% directly buried them in their fields including plant parts infected with diseases. Although there was no difference in sesame yield between these two practices, the average yield was higher by 15% in farmers with the burnt practice. Only a few farmers applied fungicides. Potential constraints to cause yield reduction and necessary actions to increase sesame yield are discussed.
MODFLOW’s River Package: Part 2: Correction, Combining Analytical and Numerical Approaches
Authors: Morel-Seytoux Hubert J.
Published: July 2019

Most widely used integrated hydrologic models still describe the flow interaction between streams and aquifers using primitive early concepts. In the previous article the shortcomings of the methodology were shown in great details. In this second part means are presented by which improvements can be introduced into the procedures.  Accuracy and numerical efficiency will be improved. The article describes in details the proposed alternatives for both the saturated and the unsaturated connections. In the article reference is made specifically to the code MODFLOW.  Most of the other integrated hydrologic models used for large-scale regional studies apply essentially the same methodology to estimate seepage.
Conformal Printing of Graphene for Single‐ and Multilayered Devices onto Arbitrarily Shaped 3D Surfaces
Authors: Ng Leonard Wei Tat , Zhu Xiaoxi , Hu Guohua , Macadam Nasiruddin , Um Dooseung , Wu Tien‐Chun , Le Moal Frederic , Jones Chris , Hasan Tawfique
Published: July 2019

Printing has drawn a lot of attention as a means of low per‐unit cost and high throughput patterning of graphene inks for scaled‐up thin‐form factor device manufacturing. However, traditional printing processes require a flat surface and are incapable of achieving patterning onto 3D objects. Here, a conformal printing method is presented to achieve functional graphene‐based patterns onto arbitrarily shaped surfaces. Using experimental design, a water‐insoluble graphene ink with optimum conductivity is formulated. Then single‐ and multilayered electrically functional structures are printed onto a sacrificial layer using conventional screen printing. The print is then floated on water, allowing the dissolution of the sacrificial layer, while retaining the functional patterns. The single‐ and multilayer patterns can then be directly transferred onto arbitrarily shaped 3D objects without requiring any postdeposition processing. Using this technique, conformal printing of single‐ and multilayer functional devices that include joule heaters, resistive deformation sensors, and proximity sensors on hard, flexible, and soft substrates, such as glass, latex, thermoplastics, textiles, and even candies and marshmallows, is demonstrated. This simple strategy promises to add new device and sensing functionalities to previously inert 3D surfaces.
Vibration‐Induced Emission (VIE) of N,N′‐Disubstituted‐Dihydribenzo[a,c]phenazines: Fundamental Understanding and Emerging Applications
Authors: Zhang Zhiyun , Song Wenxuan , Su Jianhua , Tian He
Published: July 2019

Organic fluorophores with dual‐emission and large Stokes shifts are attracting great attention due to their importance in fundamental research and technique applications. This Progress Report gives an account on how a novel luminescence mechanism termed vibration‐induced emission (VIE) is established. The VIE mechanism is coined for the rationalization of an alterable dual emission of V‐shaped N,N′‐disubstituded‐dihydribenzo[a,c]phenazines (DHPs), which are originated from a bent‐to‐planar vibration and the reverse in the excited state. The validation of the VIE mechanism is highlighted, such as the work reporting the utilization of chemically‐locked strategy to snapshot the excited‐state planarization of DHPs, and the application of the approach of steric hindrance‐induced planarization to tune the ground‐state geometry of DHPs. Moreover, the emerging applications of this VIE concept in photoelectric and biomedical disciplines are summarized. Additionally, further development of the VIE systems as well as the remaining challenges are prospected. This report could arouse wide interest from various fields to the specific area of VIE, which would not only broaden the VIE territory but also enlarge the scope of advanced functional materials.
Multifunctional Nano‐Biointerfaces: Cytocompatible Antimicrobial Nanocarriers from Stabilizer‐Free Cubosomes
Authors: Zabara Mahsa , Senturk Berna , Gontsarik Mark , Ren Qun , Rottmar Markus , Maniura‐Weber Katharina , Mezzenga Raffaele , Bolisetty Sreenath , Salentinig Stefan
Published: July 2019

The rational design of alternative antimicrobial materials with reduced toxicity toward mammalian cells is highly desired due to the growing occurrence of bacteria resistant to conventional antibiotics. A promising approach is the design of lipid‐based antimicrobial nanocarriers. However, most of the commonly used polymer‐stabilized nanocarriers are cytotoxic. Herein, the design of a novel, stabilizer‐free nanocarrier for the human cathelicidin derived antimicrobial peptide LL‐37 that is cytocompatible and promotes cell proliferation for improved wound healing is reported. The nanocarrier is formed through the spontaneous integration of LL‐37 into novel, stabilizer‐free glycerol mono‐oleate (GMO)‐based cubosomes. Transformations in the internal structure of the cubosomes from Pn3m to Im3m‐type and eventually their transition into small vesicles and spherical micelles are demonstrated upon the encapsulation of LL‐37 into their internal bicontinuous cubic structure using small angle X‐ray scattering, cryogenic transmission electron microscopy, and light scattering techniques. Additional in vitro biological assays show the antimicrobial activity of the stabilizer‐free nano‐objects on a variety of bacteria strains, their cytocompatibility, and cell‐proliferation enhancing effect. The results outline a promising strategy for the comprehensive design of antimicrobial, cytocompatible lipid nanocarriers for the protection and delivery of bioactive molecules with potential for application as advanced wound healing materials.
Fe(III)‐Porphyrin Sonotheranostics: A Green Triple‐Regulated ROS Generation Nanoplatform for Enhanced Cancer Imaging and Therapy
Authors: Zhu Jing , Chu Chengchao , Li Dongsheng , Pang Xin , Zheng Huili , Wang Junqing , Shi Yesi , Zhang Yang , Cheng Yi , Ren En , Cheng Jingliang , Chen Xiaoyuan , Liu Gang
Published: July 2019

To address the urgent need for effective sonodynamic therapy (SDT), a facile and efficient strategy is developed for fabricating a new class of sonotheranostics. Herein, a Fe(III)‐porphyrin nano‐sonosensitizer is prepared by a one‐step coordination synthesis, and then anchored with Bis(DPA‐Zn)‐RGD and manganese superoxide dismutase (SOD2) siRNA. Benefiting from the delicate interactions of the Fe(III)‐coordinated nanoformulations, a highly potent sono/gene combinational therapy guided by fluorescence/magnetic resonance imaging is achieved. Importantly, this sonotheranostics significantly enhances the SDT effect of porphyrin through the cancer‐targeted delivery capability and enhanced reactive oxygen species production via triple‐regulated approaches, including down‐regulation of SOD2, depletion of glutathione, and generation of Fenton reaction. This work opens up new perspectives for developing versatile sonotheranostics to overcome the clinical challenges of SDT.
A New Lithium‐Ion Conductor LiTaSiO5: Theoretical Prediction, Materials Synthesis, and Ionic Conductivity
Authors: Wang Qi , Wu Jian‐Fang , Lu Ziheng , Ciucci Francesco , Pang Wei Kong , Guo Xin
Published: July 2019

Owing to the nonleakage and incombustibility, solid electrolytes are crucial for solving the safety issues of rechargeable lithium batteries. In this work, a new class of solid electrolyte, acceptor‐doped LiTaSiO5, is designed and synthesized based on the concerted migration mechanism. When Zr4+ is doped to the Ta5+ sites in LiTaSiO5, the high‐energy lattice sites are partly occupied by the introduced lithium ions, and the lithium ions at those sites interact with the lithium ions placed in the low‐energy sites, thereby favoring the concerted motion of lithium ions and lowering the energy barrier for ion transport. Therefore, the concerted migration of lithium ions occurs in Zr‐doped LiTaSiO5, and a 3D lithium‐ion diffusion network is established with quasi‐1D chains connected through interchain channels. The lithium‐ion occupation, as revealed by ab initio calculations, is validated by neutron powder diffraction. Zr‐doped LiTaSiO5 electrolytes are successfully synthesized; Li1.1Ta0.9Zr0.1SiO5 shows a conductivity of 2.97 × 10−5 S cm−1 at 25 °C, about two orders of magnitude higher than that of LiTaSiO5, and it increases to 3.11 × 10−4 S cm−1 at 100 °C. This work demonstrates the power of theory in designing new materials.
Sorption‐Enhanced Mixed Matrix Membranes with Facilitated Hydrogen Transport for Hydrogen Purification and CO2 Capture
Authors: Zhu Lingxiang , Yin Deqiang , Qin Yueling , Konda Shailesh , Zhang Shawn , Zhu Aiden , Liu Shuai , Xu Ting , Swihart Mark T. , Lin Haiqing
Published: July 2019

Mixed matrix membranes (MMMs) comprising size‐sieving fillers dispersed in polymers exhibit diffusivity selectivity and may surpass the upper bound for gas separation, but their performance is limited by defects at the polymer/filler interface. Herein, a fundamentally different approach employing a highly sorptive filler that is inherently less sensitive to interfacial defects is reported. Palladium nanoparticles with extremely high H2 sorption are dispersed in polybenzimidazole at loadings near the percolation threshold, which increases both H2 permeability and H2/CO2 selectivity. Performance of these MMMs surpasses the state‐of‐the‐art upper bound for H2/CO2 separation with polymer‐based membranes. The success of these sorption‐enhanced MMMs for H2/CO2 separation may launch a new research paradigm that taps the enormous knowledge of affinities between gases and nanomaterials to design MMMs for a wide variety of gas separations.
Transfer‐Free Synthesis of Lateral Graphene–Hexagonal Boron Nitride Heterostructures from Chemically Converted Epitaxial Graphene
Authors: Bradford Jonathan , Shafiei Mahnaz , MacLeod Jennifer , Motta Nunzio
Published: July 2019

The synthesis of lateral heterostructures of graphene and hexagonal boron nitride (h‐BN) has attracted attention due to the ability to broadly tune the electronic properties of the hybrid monolayer. Conventional synthesis methods for lateral heterostructures rely on chemical vapor deposition on metal surfaces, and application of the heterostructure in devices requires transfer of the material onto a suitable substrate during which the sample is susceptible to damage or contamination. Herein, a transfer‐free synthesis method to produce lateral heterostructures of graphene and h‐BN by chemical conversion of epitaxial graphene on 6H‐SiC(0001) is demonstrated. X‐ray photoelectron spectroscopy measurements confirm the substitution of graphene with h‐BN, while scanning tunneling microscopy reveals that the h‐BN domains reside in‐plane with graphene forming an interface along the zig‐zag direction. Raman spectroscopy measurements provide insight into the reaction mechanism in which h‐BN is substituted for graphene at defect sites thereby reducing the defect density in the lateral heterostructure. The development of scalable, transfer‐free synthesis methods for lateral heterostructures of graphene and h‐BN, as demonstrated in this work, is expected to facilitate a route toward large‐scale synthesis of 2D semiconductors and atomically thin circuitry directly on‐chip.
Atomic‐Scale Study of Metal–Oxide Interfaces and Magnetoelastic Coupling in Self‐Assembled Epitaxial Vertically Aligned Magnetic Nanocomposites
Authors: Radtke Guillaume , Hennes Marcel , Bugnet Matthieu , Ramasse Quentin M. , Weng Xiaorong , Demaille Dominique , Gobaut Benoit , Ohresser Philippe , Otero Edwige , Choueikani Fadi , Juhin Amélie , Sainctavit Philippe , Zheng Yunlin , Vidal Franck
Published: July 2019

Vertically aligned nanocomposites (VANs) of metal/oxide type have recently emerged as a novel class of heterostructures with great scientific and technological potential in the fields of nanomagnetism, multiferroism, and catalysis. One of the salient features of these hybrid materials is their huge vertical metal/oxide interface, which plays a key role in determining the final magnetic and/or transport properties of the composite structure. However, in contrast to their well‐studied planar counterparts, detailed information on the structural features of vertical interfaces encountered in VANs is scarce. In this work, high resolution scanning transmission electron microscopy (STEM) and electron energy‐loss spectroscopy (EELS) are used to provide an element selective atomic‐scale analysis of the interface in a composite consisting of ultrathin, self‐assembled Ni nanowires, vertically epitaxied in a SrTiO3/SrTiO3(001) matrix. Spectroscopic EELS measurements evidence rather sharp interfaces (6–7 Å) with the creation of metallic NiTi bonds and the absence of nickel oxide formation is confirmed by X‐ray absorption spectroscopy measurements. The presence of these well‐defined phase boundaries, combined with a large lattice mismatch between the oxide and metallic species, gives rise to pronounced magnetoelastic effects. Self‐assembled columnar Ni:SrTiO3 composites thus appear as ideal model systems to explore vertical strain engineering in metal/oxide nanostructures.
Gecko‐Effect Inspired Soft Gripper with High and Switchable Adhesion for Rough Surfaces
Authors: Tian Hongmiao , Li Xiangming , Shao Jinyou , Wang Chao , Wang Yan , Tian Yazhou , Liu Haoran
Published: July 2019

Geckos, which can walk upside down on smooth or rough surfaces, owe this ability to the hierarchical structures under their toes. These structures are responsible for substantial adhesion and, at the same time, for quick attachment/detachment by mechanical stimulus of toe muscles. Inspired by such stimuli‐responsive systems in nature, an active adhesive soft gripper for rough surfaces is proposed in this study, consisting of the mushroom‐like morphology acting as adhesive structures and the pressure controllable deformation working as toe muscles. Through tunable pressure, the adhesive force can be increased and reduced by roughly 20‐fold for a ground glass, in which it can quickly reach high adhesion with positive pressure and reduce to small adhesion under negative pressure. This gecko inspired soft gripper is tested and found successful as a pick‐up and drop‐down system for transporting a surface with different features, composed of rough acrylic plate, steel ball, flexible photo paper, heavy glass block/plate, etc., which will have great potential for applications in industrial line and daily life as well as providing a novel perspective for the design of soft grippers.
Stability and Dark Hysteresis Correlate in NiO‐Based Perovskite Solar Cells
Authors: Di Girolamo Diego , Matteocci Fabio , Kosasih Felix Utama , Chistiakova Ganna , Zuo Weiwei , Divitini Giorgio , Korte Lars , Ducati Caterina , Di Carlo Aldo , Dini Danilo , Abate Antonio
Published: July 2019

In perovskite solar cells (PSCs), the interfaces are a weak link with respect to degradation. Electrochemical reactivity of the perovskite's halides has been reported for both molecular and polymeric hole selective layers (HSLs), and here it is shown that also NiO brings about this decomposition mechanism. Employing NiO as an HSL in p–i–n PSCs with power conversion efficiency (PCE) of 16.8%, noncapacitive hysteresis is found in the dark, which is attributable to the bias‐induced degradation of perovskite/NiO interface. The possibility of electrochemically decoupling NiO from the perovskite via the introduction of a buffer layer is explored. Employing a hybrid magnesium‐organic interlayer, the noncapacitive hysteresis is entirely suppressed and the device's electrical stability is improved. At the same time, the PCE is improved up to 18% thanks to reduced interfacial charge recombination, which enables more efficient hole collection resulting in higher Voc and FF.
Mechanism by which Tungsten Oxide Promotes the Activity of Supported V2O5/TiO2 Catalysts for NOX Abatement: Structural Effects Revealed by 51V MAS NMR Spectroscopy
Authors: Jaegers Nicholas R. , Lai Jun‐Kun , He Yang , Walter Eric , Dixon David A. , Vasiliu Monica , Chen Ying , Wang Chongmin , Hu Mary Y. , Mueller Karl T. , Wachs Israel E. , Wang Yong , Hu Jian Zhi
Published: July 2019

The selective catalytic reduction (SCR) of NOx with NH3 to N2 with supported V2O5(‐WO3)/TiO2 catalysts is an industrial technology used to mitigate toxic emissions. Long‐standing uncertainties in the molecular structures of surface vanadia are clarified, whereby progressive addition of vanadia to TiO2 forms oligomeric vanadia structures and reveals a proportional relationship of SCR reaction rate to [surface VOx concentration]2, implying a 2‐site mechanism. Unreactive surface tungsta (WO3) also promote the formation of oligomeric vanadia (V2O5) sites, showing that promoter incorporation enhances the SCR reaction by a structural effect generating adjacent surface sites and not from electronic effects as previously proposed. The findings outline a method to assess structural effects of promoter incorporation on catalysts and reveal both the dual‐site requirement for the SCR reaction and the important structural promotional effect that tungsten oxide offers for the SCR reaction by V2O5/TiO2 catalysts.
Sustainable Synthesis of Pure Silica Zeolites from a Combined Strategy of Zeolite Seeding and Alcohol Filling
Authors: Wu Qinming , Zhu Longfeng , Chu Yueying , Liu Xiaolong , Zhang Changsheng , Zhang Juan , Xu Hao , Xu Jun , Deng Feng , Feng Zhaochi , Meng Xiangju , Xiao Feng‐Shou
Published: July 2019

Currently, the synthesis of pure silica zeolites always requires the presence of organic structure‐directing agents (OSDAs), which direct the assembly pathway and ultimately fill the pore space. A sustainable route is now reported for synthesizing pure silica zeolites in the absence of OSDAs from a combined strategy of zeolite seeding and alcohol filling, where the zeolite seeds direct crystallization of zeolite crystals from amorphous silica, while the alcohol is served as pore filling in the zeolites. Very importantly, the alcohol could be fully washed out from zeolite pores by water at room temperature, which completely avoids calcination at high temperature for removal of OSDAs in the synthesis of pure silica zeolites.
Mussel‐Inspired Two‐Dimensional Freestanding Alkyl‐Polydopamine Janus Nanosheets
Authors: Sheng Wenbo , Li Wei , Yu Bo , Li Bin , Jordan Rainer , Jia Xin , Zhou Feng
Published: July 2019

Mussel‐inspired two‐dimensional freestanding, alkyl‐polydopamine (alkyl‐PDA) Janus nanosheets, with a well‐controlled nanometer thickness and a lateral size of up to micrometers, have been developed. A self‐assembled octadecylamine (ODA) bilayer is used as the reactive template for the dopamine polymerization, resulting in the formation of well‐defined nanosheets. The alkyl‐PDA nanosheets show an amphiphilic nature with hydrophilic PDA and hydrophobic alkyl chains on opposing sides. The nanosheets can be used to functionalize many substrates and is dependent on the configuration of surface of the nanosheets. The nanosheets are quite stable, as the morphology is preserved after carbonization at 900 °C. Post‐modification of the nanosheets can be easily achieved because of the reactive nature of PDA. This work will provide a new strategic approach for fabricating polymeric Janus nanosheets, which can find applications for surface modifications, catalyst supports, and guided self‐assembly.
An Asymmetric Supercapacitor–Diode (CAPode) for Unidirectional Energy Storage
Authors: Zhang En , Fulik Natalia , Hao Guang‐Ping , Zhang Han‐Yue , Kaneko Katsumi , Borchardt Lars , Brunner Eike , Kaskel Stefan
Published: July 2019

A new asymmetric capacitor concept is proposed providing high energy storage capacity for only one charging direction. Size‐selective microporous carbons (w<0.9 nm) with narrow pore size distribution are demonstrated to exclusively electrosorb small anions (BF4−) but size‐exclude larger cations (TBA+ or TPA+), while the counter electrode, an ordered mesoporous carbon (w>2 nm), gives access to both ions. This architecture exclusively charges in one direction with high rectification ratios (RR=12), representing a novel capacitive analogue of semiconductor‐based diodes (“CAPode”). By precise pore size control of microporous carbons (0.6 nm, 0.8 nm and 1.0 nm) combined with an ordered mesoporous counter electrode (CMK‐3, 4.8 nm) electrolyte cation sieving and unidirectional charging is demonstrated by analyzing the device charge‐discharge response and monitoring individual electrodes of the device via in situ NMR spectroscopy.
Oxygen‐Triggered Switchable Polymerization for the One‐Pot Synthesis of CO2‐Based Block Copolymers from Monomer Mixtures
Authors: Zhao Yajun , Wang Yong , Zhou Xingping , Xue Zhigang , Wang Xianhong , Xie Xiaolin , Poli Rinaldo
Published: July 2019

Switchable polymerization provides the opportunity to regulate polymer sequence and structure in a one‐pot process from mixtures of monomers. Herein we report the use of O2 as an external stimulus to switch the polymerization mechanism from the radical polymerization of vinyl monomers mediated by (Salen)CoIII−R [Salen=N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐cyclohexanediamine; R=alkyl] to the ring‐opening copolymerization (ROCOP) of CO2/epoxides. Critical to this process is unprecedented monooxygen insertion into the Co−C bond, as rationalized by DFT calculations, leading to the formation of (Salen)CoIII−O−R as an active species to initiate ROCOP. Diblock poly(vinyl acetate)‐b‐polycarbonate could be obtained by ROCOP of CO2/epoxides with preactivation of (Salen)Co end‐capped poly(vinyl acetate). Furthermore, a poly(vinyl acetate)‐b‐poly(methyl acrylate)‐b‐polycarbonate triblock copolymer was successfully synthesized by a (Salen)cobalt‐mediated sequential polymerization with an O2‐triggered switch in a one‐pot process.
Different Modes of Anion Response Cause Circulatory Phase Transfer of a Coordination Cage with Controlled Directionality
Authors: Mihara Nozomi , Ronson Tanya K. , Nitschke Jonathan R.
Published: July 2019

Controlled directional transport of molecules is essential to complex natural systems, from cellular transport up to organismal circulatory systems. In contrast to these natural systems, synthetic systems that enable transport of molecules between several spatial locations on the macroscopic scale, when external stimuli are applied, remain to be explored. Now, the transfer of a supramolecular cage is reported with controlled directionality between three phases, based on a cage that responds reversibly in two distinct ways to different anions. Notably, circulatory phase transfer of the cage was demonstrated based on a system where the three layers of solvent are arranged within a circular track. The direction of circulation between solvent phases depended upon the order of addition of anions.
Nickel‐Catalyzed Regioselective Hydroalkylation and Hydroarylation of Alkenyl Boronic Esters
Authors: Bera Srikrishna , Hu Xile
Published: July 2019

Metal hydride catalyzed hydrocarbonation reactions of alkenes are an efficient approach to construct new carbon–carbon bonds from readily available alkenes. However, the regioselectivity of hydrocarbonation remains challenging to be controlled. In nickel hydride (NiH) catalyzed hydrocarbonation, linear selectivity is most often obtained because of the relative stability of the linear Ni–alkyl intermediate over its branched counterpart. Herein, we show that the boronic pinacol ester (Bpin) group directs a Ni‐catalyzed hydrocarbonation to occur at its adjacent carbon center, resulting in formal branch selectivity. Both alkyl and aryl halides can be used as electrophiles in this hydrocarbonation, providing access to a wide range of secondary alkyl Bpin derivatives, which are valuable building blocks in synthetic chemistry. The utility of the method is demonstrated by the late‐stage functionalization of natural products and drug molecules, the synthesis of an anticancer agent, and iterative syntheses.
Role of π‐π interactions and chain flexibility in dispersion and dynamic‐mechanical properties of nanocomposites with multiple wall carbon nanotubes
Authors: Hamester Michele Regina Rosa , Dalmolin Carla , Becker Daniela
Published: July 2019

Two polymers of same functional group were used; one with greater chain flexibility, PA 6.6, and the other with two benzene rings in the main chain, PA 6I‐6T (aPA), to evaluate how the structure influences on the nanoparticle dispersion homogeneity and on dynamic‐mechanical properties. In the aPA nanocomposites, good dispersion and homogeneous distribution were observed for all CNT concentrations. However, PA 6.6 nanocomposites showed agglomerated regions in all formulations. The interfacial energy of the aPA/CNT was five times lower than that of PA6.6/CNT, resulting in greater compatibility in this nanocomposite. An increase of up to 26% was observed with 2.5% of CNT in aPA nanocomposites storage modulus. In the samples with PA 6.6, the increase was at most 5%. Even with greater flexibility of PA 6.6 macromolecules, the π‐π interaction between the aPA aromatic rings and CNTs might be the decisive factor for dispersion improvement and positively influence on the dynamic‐mechanical properties of these nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48195.
Preparation, structure, and pervaporation performance of poly(amide–imide)‐sulfonated polyimide composites
Authors: Kononova S. V. , Sapegin D. A. , Kruchinina E. V. , Gubanova G. N. , Romashkova K. A. , Didenko A. L. , Smirnova V. E. , Popova E. N. , Saprykina N. N. , Vlasova E. N. , Svetlichnyi V. M.
Published: July 2019

Poly{[4,4′‐bisdiphenyl‐2,2′‐disulfonic acid]imide‐1,3‐bis(3,4‐dicarboxyphenoxy)benzene} was synthesized via polycondensation and subsequent thermal imidization in m‐cresol:triethylamine. The obtained polymer and its composites with aromatic poly(amide–imide) obtained through polycondensation of 4‐chloroformyl‐(N‐p‐chloroformylphenyl)phthalimide and 4,4′‐diaminodiphenyl ether were investigated by use of nuclear magnetic resonance, thermogravimetric analysis, dynamic mechanical analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray diffraction analysis. Transport properties of composite films were studied during pervaporation of water–alcohol mixtures. On the basis of the data obtained, suggestions on the structure of materials and its influence on transport and other physical properties were made. The addition of 30 wt % of sulfonated polyimide to the poly(amide–imide) matrix enhances its separation factor in the process of separation of an azeotrope water/ethanol mixture by four times while permeability remains unchanged. The methanol permeability increases with an increase of the mass fraction of sulfonated polyimide in the composite film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48197.
Hydrophobic SiO2 nanoparticle‐induced polyvinylidene fluoride crystal phase inversion to enhance permeability of thin film composite membrane
Authors: Sun Hao , Liu Yijun , Li Dan , Liu Bing , Yao Jie
Published: July 2019

Thin film composite (TFC) membrane can get rid of small molecular contaminants and salts with a very high efficiency, thus exhibiting promising potential for addressing the emerging problem of a clean water shortage. In this work, a new type of TFC membrane was prepared by interfacial polymerization of two monomers (MPD and TMC) on surface of SiO2/polyvinylidene fluoride (PVDF) substrate. The maximum flux of 3.16 L m−2 h−1 Bar−1 was achieved for the optimized hydrophobic SiO2 nanoparticles well dispersed in PVDF substrate, which is 2.6 times higher than that of 1.21 L m−2 h−1 Bar−1 for the commercial cellulose triacetate reverse osmosis membrane. The improved performance of TFC membrane could be attributed to the higher compaction resistance of SiO2/PVDF substrate. Further analysis revealed that PVDF crystal phase inversion induced by superhydrophobic SiO2 nanoparticles obviously enhanced the intramolecular and intermolecular hydrogen bonds between PVDF polymer molecules. Additionally, the narrower finger‐like pore size and thicker pore wall of SiO2/PVDF substrate also played significant roles in enhancing the compaction resistance of PVDF membrane. This work also provides a proof‐of‐concept demonstration of high permeability substrates for effective flux enhancement of TFC membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48204.
Free volume correlation with electrical conductivity of polycarbonate/reduced graphene oxide nanocomposites studied by positron annihilation lifetime spectroscopy
Authors: Zhong Jiang , Ding Yang , Gao Fei , Wen Jia , Zhou Jiyong , Zheng Wenbin , Shen Liang , Fu Changqing , Wang Bo
Published: July 2019

The reduced graphene oxide (RGO) was added to polycarbonate (PC) through solvent mixing. The influences of RGO on the free volumes and electrical conductivity of PC were systemically studied by positron annihilation lifetime spectroscopy (PALS), Fourier‐transform infrared spectroscopy, transmission electron microscope, and electrical conductivity measurements for PC/RGO nanocomposites. The nanosized effect, good conductivity of RGO, and strong interfacial interaction between RGO and PC result in the low conductive threshold of 0.36 wt %. Ten orders of magnitude increase in electrical conductivity was obtained. The results of PALS indicate the properties of free volumes fluctuate around the conductive percolation threshold. The conformational change of PC segments in the interfacial region induced by the strong interfacial interaction leads to an increase in free volume radius. The concentration of free volume decreases due to the depression of free volume holes as the introduction of RGO. Significantly, an exponential function is proposed to describe the effect of relative fractional free volume on the electrical conductivity, suggesting that free volume plays an important role in regulating electrical conductivity of PC/RGO. The physical quantity fd that refers required fractional free volume of polymer composites from insulating to conducting phase is found. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48207.
Convection, latent heating and potential temperature budget in the rapidly intensifying Typhoon Mujigae (2015)
Authors: Tang Xiba , Yang Shuai , Ping Fan , Li Mengxia , Peng Jing
Published: July 2019

Based on a 72‐hr simulation of the rapidly intensifying Typhoon Mujigae (2015), the spatiotemporal evolutions of various inner‐core convections and the associated latent heating (LH) features were investigated. Results showed two interesting turning points from the pre‐rapid intensification (RI) stage to RI onset. One was a change from convective–stratiform mixed precipitation to a convective precipitation (CP)‐dominant trend, while the other happened inside the CP. As the major contributor to LH, during the CP, the dramatic increase and radially inward movement of deep convection and associated LH release from −4 to −2 hr relative to RI, provided some useful clues for predicting the RI of a tropical cyclone (TC). But how do distinct convections act on the RI of a TC? From the potential temperature budget and flow vector intuitive display, there were upper‐ and lower‐level warm cores, fed by the centripetal transport from deep‐convection‐related LH sources and lower‐level radial inflow of weak‐to‐moderate convection‐associated LH sources. The former brought about higher heating efficiency, embodied by a higher rate (2.5 times greater) of pressure decline during RI. Thus, by comparing the LH effects of diverse convections on warm‐core formation, and the role of the warm core in the RI of a TC, the link between various convections and TC intensification can be established.
Re‐assessing effects of bromide and granular activated carbon on disinfection byproduct formation
Authors: Wang Lili , Vacs Renwick Deborah , Regli Stig
Published: July 2019

While granular activated carbon (GAC) can effectively remove disinfection byproduct (DBP) precursors, its use has raised concerns over the increased formation of some brominated DBP (Br‐DBP) species in treated water postchlorination, especially for waters with high bromide concentrations. The Information Collection Rule Treatment Study Database contains the results of the most extensive GAC studies ever conducted nationwide. Data were analyzed to assess the extent of DBP speciation changes and the overall reduction of Br‐DBPs by GAC to gain new insights into the bromide effect. Results showed that formation of three brominated trihalomethanes (collectively Br‐THM3) varied greatly depending on total organic carbon (TOC) removal and bromide concentrations. Low TOC concentrations in GAC effluents resulted in greatly reduced Br‐THM3 formation, except for a few cases where Br‐THM3 formation increased. GAC followed by chloramination were likely to better control Br‐THM3 formation for waters with high TOC and high bromide. Finally, chlorine demand reduction by GAC was quantified.
Techno‐economic and life‐cycle assessments of small‐scale biorefineries for isobutene and xylo‐oligosaccharides production: a comparative study in Portugal and Chile
Authors: Lopes Tiago F. , Carvalheiro Florbela , Duarte Luís C. , Gírio Francisco , Quintero Julián A. , Aroca Germán
Published: July 2019

This work presents a comparative simulation study involving the techno‐economic and environmental assessment of lignocellulosic‐based small‐scale biorefineries, integrated with a piggery waste‐based anaerobic digestion platform (ADB), located in Portugal and Chile. Two main products are obtained: isobutene and xylo‐oligosaccharides (XOS). The bioproduction of isobutene using a genetically engineered organism (Escherichia coli), coupled with the removal and purification of high added‐value XOS, obtained after a feedstock hydrothermal pre‐treatment, was evaluated. Two lignocellulosic agricultural wastes were used: corn stover in the Portuguese case study and wheat straw in Chilean case study. Both processes were simulated using the Aspen Plus modeling software tool, while the Aspen Process Economic Analyzer was used to carry out the economic evaluation. The simulation results were validated with experimental data from the laboratory and the literature. An economic assessment was performed considering the different locations of both biorefineries. A life‐cycle analysis (LCA) was also applied to evaluate the differences in environmental impacts on both locations. The results showed that the isobutene / XOS biorefinery concept was economically viable in both Portugal and Chile, mainly due to the high market value of XOS. The biorefinery has lower production costs for isobutene and XOS (1 US$/kg of isobutene and 1.18 US$/kg of XOS) when located in Portugal, as compared with Chile (1.14 US$/kg of isobutene and 1.56 US$/kg of XOS). Conversely, it leads to less environmental impact when located in Chile: 48.8 kgCO2eq./GJisobutene, in comparison to 60.7 kgCO2eq./GJisobutene in Portugal. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd
Spannungsumlagerungen bei ermüdungsbeanspruchten Spannbetonbalken im numerischen Modell und Versuch
Authors: Birkner Dennis , Marx Steffen
Published: July 2019

Mithilfe eines Resonanzprüfstands werden vorgespannte Betonbalken bis in den Very‐High‐Cycle‐Fatigue Bereich auf Ermüdung beansprucht. Es werden großformatige Probekörper untersucht, sodass im Vergleich zu üblichen Probekörpergrößen Effekte wie lokale Steifigkeitsänderungen und Spannungsumlagerungen abgebildet werden können, die einen positiven Einfluss auf die Lebensdauer von Beton haben. Die Ergebnisse dieser Untersuchungen werden hinsichtlich der Dehnungs‐ und Steifigkeitsänderung ausgewertet und anschließend mit numerischen Berechnungen verglichen. Das verwendete numerische Modell ist ein in einem kommerziellen Finite‐Elemente‐Programm implementierter Algorithmus, der in der Lage ist, Steifigkeitsverluste infolge Ermüdungsbeanspruchungen abzubilden und somit auch Spannungsumlagerungen darzustellen, die messtechnisch in den Versuchen nicht erfassbar sind. Die Ergebnisse zeigen eine kontinuierliche Schädigungsentwicklung mit einem dreiphasigen Verlauf, infolgedessen es zu Spannungsumlagerungen von den stärker beanspruchten Querschnittsrändern ins Balkeninnere und somit zu einer Verlängerung der Bauteillebensdauer kommt.
Combined Cell Surface Display of β‐d‐Glucosidase (BGL), Maltose Transporter (MAL11), and Overexpression of Cytosolic Xylose Reductase (XR) in Saccharomyces cerevisiae Enhance Cellobiose/Xylose Coutilization for Xylitol Bioproduction from Lignocellulosic Biomass
Authors: Guirimand Gregory G. Y. , Bamba Takahiro , Matsuda Mami , Inokuma Kentaro , Morita Kenta , Kitada Yuki , Kobayashi Yuma , Yukawa Takahiro , Sasaki Kengo , Ogino Chiaki , Hasunuma Tomohisa , Kondo Akihiko
Published: July 2019

Xylitol is a highly valuable commodity chemical used extensively in the food and pharmaceutical industries. The production of xylitol from d‐xylose involves a costly and polluting catalytic hydrogenation process. Biotechnological production from lignocellulosic biomass by micro‐organisms like yeasts is a promising option. In this study, xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae (S. cerevisiae) (YPH499‐SsXR‐AaBGL) expressing cytosolic xylose reductase (Scheffersomyces stipitis xylose reductase [SsXR]), along with a β‐d‐glucosidase (Aspergillus aculeatus β‐glucosidase 1 [AaBGL]) displayed on the cell surface. The simultaneous cofermentation of cellobiose/xylose by this strain leads to an ≈2.5‐fold increase in Yxylitol/xylose (=0.54) compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499‐XR‐ScMAL11‐BGL with a significantly improved xylitol production capacity from cellobiose/xylose coutilization. This report constitutes a promising proof of concept to further scale up the biorefinery industrial production of xylitol from lignocellulose by combining cell surface and metabolic engineering in S. cerevisiae.