bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Seed Weights and Sowing Media on Germination and Early Growth of Afzelia africana Smith ex Pers
Authors: Aderounmu A. F. , Asinwa I. O. , Adetunji A. O. 
Published: September 2019

Seed weight is essential in assessing seed quality traits, while sowing medium has significant role in seed germination. This study therefore assessed effect of seed weights and sowing media on germination of Afzelia africana seeds to enhancing sustainable production of the species.
Seeds of different sizes were collected, weighed and grouped into small (120), medium (120) and large (120) seeds. Each seed group was sown in three sowing media (washed river sand, decomposed sawdust, and forest top soil) replicated 4 times and arranged in Completely Randomized Design. The growth assessment comprised of 3 treatments which included seedlings from small, medium and large seeds and replicated 4 times. Plant height, leaf production and stem diameter were assessed fortnightly for twelve weeks. Biomass assessment was carried out twice (second week and twelfth week). Mean Daily Germination, Germination Percentage, Germination Energy, Peak Value, Germination value, Net Assimilation Rate and Relative Growth Rate were estimated. Data were subjected to analysis of variance (ANOVA).
Mean Daily Germination showed that large seeds sown in river sand large seed size sown in saw dust (T4 and T7) had highest value of 3.47 and 3.29 respectively with GV of 12.83.
There was significant difference (p < 0.05) in the effects of different sowing media and seed weights on the germination of A. africana. Saw dust gave the highest mean value with 52.777±0.28 while mean value of large sized seeds was highest (57.539±0.6). There was significant difference (p<0.05) in the effects of different seed weight on the height, collar diameter and leaf production.
Germination percentage of A. africana improved significantly with the sowing media and seed weight especially sawdust, river sand, and large seed size. It therefore suggested that A. africana seedling should be raised at nursery stage with river sand and Large seed size in order to increase the growth of plant and have more vigorous seedlings for plantation establishment.
MAP moving horizon estimation for threshold measurements with application to field monitoring
Authors: Battistelli Giorgio , Chisci Luigi , Forti Nicola , Gherardini Stefano 
Published: September 2019

SummaryThis paper deals with state estimation of a spatially distributed system given noisy measurements from pointwise‐in‐time‐and‐space threshold sensors spread over the spatial domain of interest. A maximum a posteriori probability (MAP) approach is undertaken and a moving horizon (MH) approximation of the MAP cost function is adopted. It is proved that, under system linearity and log‐concavity of the noise probability density functions, the proposed MH‐MAP state estimator amounts to the solution, at each sampling interval, of a convex optimization problem. Moreover, a suitable centralized solution for large‐scale systems is proposed with a substantial decrease of the computational complexity. The latter algorithm is shown to be feasible for the state estimation of spatially dependent dynamic fields described by partial differential equations via the use of the finite element spatial discretization method. A simulation case study concerning estimation of a diffusion field is presented in order to demonstrate the effectiveness of the proposed approach. Quite remarkably, the numerical tests exhibit a noise‐assisted behavior of the proposed approach in that the estimation accuracy results optimal in the presence of measurement noise with non‐null variance.
Ultimately Sensitive Organic Bioelectronic Transistor Sensors by Materials and Device Structure Design
Authors: Picca Rosaria Anna , Manoli Kyriaki , Macchia Eleonora , Sarcina Lucia , Di Franco Cinzia , Cioffi Nicola , Blasi Davide , Österbacka Ronald , Torricelli Fabrizio , Scamarcio Gaetano , Torsi Luisa 
Published: September 2019

AbstractOrganic bioelectronic sensors are gaining momentum as they can combine high‐performance sensing level with flexible large‐area processable materials. This opens to potentially highly powerful sensing systems for point‐of‐care health monitoring and diagnostics at low cost. Prominent to detect biochemical recognition events, are electrolyte‐gated organic field‐effect transistors (EGOFETs) and organic electrochemical transistors (OECTs) as they are easily fabricated and operated. EGOFETs are recently shown to be capable of label‐free single‐molecule detections, even in serum. This progress report aims to provide a critical perspective through a selected overview of the literature on both EGOFET and OECT biosensors. Attention is paid to correctly attribute them to the potentiometric and amperometric biosensor categories, which is important to set the right conditions for quantification purposes. Moreover, to deepen the understanding of the sensing mechanisms, with the support of unpublished data, focus is put on two among the most critical aspects, namely, the capacitance interplay and the role of Faradaic currents. The final aim is to provide a rationale of the functional mechanisms encompassing both EGOFET and OECT sensors, to improve materials and devices' designs taking advantage of the processes that enhance the sensing response enabling the extremely high‐performance level resulting in ultimate sensitivity, selectivity, and fast response.
Directed Pinning of Moving Water Droplets on Photoresponsive Liquid Crystal Mats
Authors: Liu Yuyun , Zhu Chongyu , Zhao Yong , Qing Xin , Wang Feng , Deng Daosheng , Wei Jia , Yu Yanlei 
Published: September 2019

AbstractCompared to conventional continuous‐flow liquid manipulation, the direct control of liquid droplets on an open surface prevents the potential cross contamination during liquid transfer, which is advantageous for biological microliquids. However, the fabrication techniques of smart surfaces and the fast manipulation of droplets remotely remain difficult, limiting its practical application. Herein, large‐scaled photoresponsive superhydrophobic mats fabricated by the electrospinning of linear liquid crystal polymer are presented. Upon the alternated irradiation of UV–vis light, these mats exhibit significant, fast, and reversible change of adhesion, while their surfaces maintain the superhydrophobicity. Therefore, the water droplets can be pinned at any directed point on the mat surface after the fast superhydrophobic adhesion switch by the remote control of light. It is expected that the active manipulation of discrete droplets on an open surface through these photoresponsive mats provides a new concept for microdroplet manipulation, allowing for minimal reactions among biological samples.
An Efficient Separator with Low Li‐Ion Diffusion Energy Barrier Resolving Feeble Conductivity for Practical Lithium–Sulfur Batteries
Authors: Lv Xiaoxue , Lei Tianyu , Wang Bojun , Chen Wei , Jiao Yu , Hu Yin , Yan Yichao , Huang Jianwen , Chu Junwei , Yan Chaoyi , Wu Chunyang , Wang Jianwei , Niu Xiaobin , Xiong Jie 
Published: September 2019

AbstractDue to unprecedented features including high‐energy density, low cost, and light weight, lithium–sulfur batteries have been proposed as a promising successor of lithium‐ion batteries. However, unresolved detrimental low Li‐ion transport rates in traditional carbon materials lead to large energy barrier in high sulfur loading batteries, which prevents the lithium–sulfur batteries from commercialization. In this report, to overcome the challenge of increasing both the cycling stability and areal capacity, a metallic oxide composite (NiCo2O4@rGO) is designed to enable a robust separator with low energy barrier for Li‐ion diffusion and simultaneously provide abundant active sites for the catalytic conversion of the polar polysulfides. With a high sulfur‐loading of 6 mg cm−2 and low sulfur/electrolyte ratio of 10, the assembled batteries deliver an initial capacity of 5.04 mAh cm−2 as well as capacity retention of 92% after 400 cycles. The metallic oxide composite NiCo2O4@rGO/PP separator with low Li‐ion diffusion energy barrier opens up the opportunity for lithium–sulfur batteries to achieve long‐cycle, cost‐effective operation toward wide applications in electric vehicles and electronic devices.
Direct numerical simulation of mass transfer in bidisperse arrays of spheres
Authors: Lu Jiangtao , Peters Elias A.J.F. , Kuipers Johannes A.M. 
Published: September 2019

AbstractIn this study, an efficient ghost cell‐based immersed boundary method is used to perform direct numerical simulations of mass‐transfer processes in bidisperse arrays. Stationary spherical particles, with a size ratio of 1.5, are homogeneously distributed in a periodic domain in the spanwise directions. Simulations are performed over a range of solids volume fractions, volume fraction ratios of small‐to‐large particles, and Reynolds numbers. Through our studies, we find that large particles have a negative influence on the overall mass‐transfer performance; however, the performance of individual particle species is independent on the relative volume fraction ratios. We propose two correlations: (a) a refitted Gunn correlation for a better description of the interfacial transfer performance based on individual particle species; (b) a fractional calculation for a simple estimation of the overall performance in bidisperse systems using characteristics of individual particle species. We also investigate how well the overall mass‐transfer coefficient can be predicted by defining an appropriate equivalent diameter.
Crystal‐State Photochromism and Dual‐Mode Mechanochromism of an Organic Molecule with Fluorescence, Room‐Temperature Phosphorescence, and Delayed Fluorescence
Authors: Huang Lili , Liu Lei , Li Xianjiang , Hu Huan , Chen Mingxing , Yang Qingyuan , Ma Zhiyong , Jia Xinru 
Published: September 2019

AbstractA D‐A‐D′ type pure organic molecule, named ODFRCZ, has unique triple‐emission character covering fluorescence, phosphorescence, and delayed fluorescence (DF). The phosphorescence of ODFRCZ has a rather long lifetime of about 350 ms at room temperature. One dimer of ODFRCZ with enhanced parallel molecular packing acts more effectively to prompt ISC processes, which further generates room‐temperature phosphorescence (RTP), owing to the larger transition dipole moment and closer energy level between S1 and Tn. ODFRCZ is a rare example of an organic RTP molecule that shows dual‐stimuli responsiveness of dual‐mode mechanochromism (fluorescence red‐shift and RTP/DF on‐off switch) and reversible crystal‐state photochromism. This work may broaden the knowledge for stimuli‐responsive RTP organic molecules and lay the foundation for their wide‐scale applications.
1,2‐Dithienyldicyanoethene‐Based, Visible‐Light‐Driven, Chiral Fluorescent Molecular Switch: Rewritable Multimodal Photonic Devices
Authors: Li Juntao , Bisoyi Hari Krishna , Lin Siyang , Guo Jinbao , Li Quan 
Published: September 2019

AbstractReported here is the first example of a 1,2‐dithienyldicyanoethene‐based visible‐light‐driven chiral fluorescent molecular switch that exhibits reversible trans to cis photoisomerization. The trans form in solution almost completely transforms into the cis form, accompanied by a 10‐fold decrease in its fluorescence intensity within 60 seconds when exposed to green light (520 nm). The reverse isomerization proceeds upon irradiation with blue light (405 nm). When doped into commercially available achiral liquid crystal hosts, this molecular switch efficiently induces luminescent helical superstructures, that is, a cholesteric phase. The intensity of the circularly polarized fluorescence as well as the selective reflection wavelength of the induced cholesteric phases can be reversibly tuned using visible light of two different wavelengths. Optically rewritable photonic devices using cholesteric films containing this molecular switch are described.
Blue LED Irradiation of Iodonium Ylides Gives Diradical Intermediates for Efficient Metal‐free Cyclopropanation with Alkenes
Authors: Chidley Tristan , Jameel Islam , Rizwan Shafa , Peixoto Philippe A. , Pouységu Laurent , Quideau Stéphane , Hopkins W. Scott , Murphy Graham K. 
Published: September 2019

AbstractA facile and highly chemoselective synthesis of doubly activated cyclopropanes is reported where mixtures of alkenes and β‐dicarbonyl‐derived iodonium ylides are irradiated with light from blue LEDs. This metal‐free synthesis gives cyclopropanes in yields up to 96 %, is operative with cyclic and acyclic ylides, and proceeds with a variety of electronically‐diverse alkenes. Computational analysis explains the high selectivity observed, which derives from exclusive HOMO to LUMO excitation, instead of free carbene generation. The procedure is operationally simple, uses no photocatalyst, and provides access in one step to important building blocks for complex molecule synthesis.
Consecutive Intermolecular Reductive Amination/Asymmetric Hydrogenation: Facile Access to Sterically Tunable Chiral Vicinal Diamines and N‐Heterocyclic Carbenes
Authors: Chen Ya , Pan Yixiao , He Yan‐Mei , Fan Qing‐Hua 
Published: September 2019

AbstractA highly enantioselective iridium‐ or ruthenium‐catalyzed intermolecular reductive amination/asymmetric hydrogenation relay with 2‐quinoline aldehydes and aromatic amines has been developed. A broad range of sterically tunable chiralN,N′‐diaryl vicinal diamines were obtained in high yields (up to 95 %) with excellent enantioselectivity (up to >99 % ee). The resulting chiral diamines could be readily transformed into sterically hindered chiral N‐heterocyclic carbene (NHC) precursors, which are otherwise difficult to access. The usefulness of this synthetic approach was further demonstrated by the successful application of one of the chiral vicinal diamines and chiral NHC ligands in a transition‐metal‐catalyzed asymmetric Suzuki–Miyaura cross‐coupling reaction and asymmetric ring‐opening cross‐metathesis, respectively.
Model Reactions Involving Ester Functional Groups during Thermo‐Oxidative Degradation of Biodiesel
Authors: Ball James C. , Anderson James E. , Sears Victoria A. , Wallington Timothy J. 
Published: September 2019

AbstractBiodiesel is a renewable fuel used in diesel engines that is typically blended with diesel fuel. However, biodiesel is susceptible to oxidation, which has the potential to produce higher molecular weight materials that may adversely impact vehicle fuel‐system performance. To investigate the chemical reactions potentially important in biodiesel oxidation, four different types of chemical reactions involving esters were studied: (1) ester formation (reactions of acids with alcohols), (2) alcoholysis (reactions of alcohols with esters), (3) acidolysis (reaction of acids with esters), and (4) ester exchange (reactions between two esters). Experiments with representative model compounds were used to evaluate these reactions at 90 °C with aeration; conditions previously used to simulate thermo‐oxidative degradation during biodiesel aging. Reactions were monitored using gas chromatography, fourier transform infrared (FTIR) spectroscopy, and total acid number (TAN). Evidence is presented suggesting that alcoholysis and ester formation (Reactions 1 and 2), catalyzed by carboxylic acids, are important reactions of esters that could lead to larger molecules. Acidolysis (Reaction 3) proceeded at a comparatively slow rate and ester exchange reaction products (Reaction 4) were not detected under these aging conditions.
Development of degradable poly(ethylene terephthalate)‐based nanocomposites with the aid of polylactic acid and graphenic materials: Thermal, thermo‐oxidative and hydrolytic degradation characteristics
Authors: Jafari Seyed Mohammad Ali , Khajavi R. , Goodarzi V. , Kalaee M. R. , Khonakdar H. A. 
Published: September 2019

ABSTRACTPoly(ethylene terephthalate)/poly(lactic acid) (PET/PLA) blends with composition of 90/10 and 75/25 (wt %/wt %) along with two types of graphenic materials, namely graphene oxide (GO) and exfoliated graphite (xGnP), were prepared through one‐step melt mixing process. The Thermal, thermo‐oxidative, and hydrolytic degradation characteristics of the developed degradable PET‐based nanocomposites were investigated. Thermal degradation studies by thermogravimetry analysis and melt rheological analysis in N2 atmosphere, revealed that unlike xGnP, the addition of GO to the blends reduced their thermal stability leading to reduction of viscosity and elasticity of the blends. The behavior was attributed to the role of GO in enhancing the chain scission reactions. In the air atmosphere, the barrier properties of the graphenic materials prevailed. Compared to xGnP, the relatively well‐dispersed GO showed better barrier against oxygen and increased the thermo‐oxidative stability of the blends. Investigation of the hydrocatalytic degradation of developed systems, at different pH of 2 and 4, over a period of 40 days at 37 °C, showed that the amount of weight loss of the GO‐containing nanocomposite systems was higher than that of xGnP. The overall results of thermal, thermo‐oxidative, and hydrocatalytic degradation studies confirmed the prominent role of GO in the development of degradable PET‐based products. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48466.
Mechanical properties and fracture behavior of high‐performance epoxy nanocomposites modified with block polymer and core–shell rubber particles
Authors: Bajpai Ankur , Wetzel Bernd , Klingler Andreas , Friedrich Klaus 
Published: September 2019

ABSTRACTThe mechanical properties, thermomechanical properties, and fracture mechanic properties of block‐copolymer (BCP), core–shell rubber (CSR) particles, and their hybrids in bulk epoxy/anhydride system were investigated at 23 °C. The results show that fracture toughness was increased by more than 268% for 10 wt % BCP, 200% for 12 wt % of CSR particles, and 100% for hybrid systems containing 3 wt % of each, BCP and CSR. The volume content of nanoparticles influences the final morphology and thus influences the tensile properties and fracture toughness of the modified systems. The toughening mechanisms induced by the BCP and CSR particles were identified as (1) localized plastic shear‐band yielding around the particles and (2) cavitation of the particles followed by plastic void growth in the epoxy polymer. These mechanisms were modeled using the Hsieh et al. approach and the values of GIc of the different modified systems were calculated. Excellent agreement was found between the predicted and the experimentally measured fracture energies. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48471.
Reflections on the Lead and Copper Rule and Lead Levels in Flint's Water
Authors: Masten Susan J. , Davies Simon H. , Haider Syed W. , McPherson Calley R. 
Published: September 2019

Key TakeawaysAfter the Flint water crisis, sampling programs were established to assess residential water lead levels.There have been differences in water lead levels for households with lead service lines versus those with copper service lines, and adding phosphate affects water lead levels.Since Flint's return to treated Lake Huron water in 2016, 90th percentile water lead levels have decreased, but they're higher than that reported in 2005–2011.
Developing an l‐threonine‐producing strain from wild‐type Escherichia coli by modifying the glucose uptake, glyoxylate shunt, and l‐threonine biosynthetic pathway
Authors: Zhu Lifei , Fang Yu , Ding Zhixiang , Zhang Shuyan , Wang Xiaoyuan 
Published: September 2019

AbstractWild‐type Escherichia coli MG1655 usually does not accumulate l‐threonine. In this study, the effects of 13 genes related to the glucose uptake, glycolysis, TCA cycle, l‐threonine biosynthesis, or their regulation on l‐threonine accumulation in E. coli MG1655 were investigated. Sixteen E. coli mutant strains were constructed by chromosomal deletion or overexpression of one or more genes of rsd, ptsG, ptsH, ptsI, crr, galP, glk, iclR, and gltA; the plasmid pFW01‐thrA*BC‐rhtC harboring the key genes for l‐threonine biosynthesis and secretion was introduced into these mutants. The analyses on cell growth, glucose consumption, and l‐threonine production of these recombinant strains showed that most of these strains could accumulate l‐threonine, and the highest yield was obtained in WMZ016/pFW01‐thrA*BC‐rhtC. WMZ016 was derived from MG1655 by deleting crr and iclR and enhancing the expression of gltA. WMZ016/pFW01‐thrA*BC‐rhtC could produce 17.98 g/L l‐threonine with a yield of 0.346 g/g glucose, whereas the control strain MG1655/pFW01‐thrA*BC‐rhtC could only produce 0.68 g/L l‐threonine. In addition, WMZ016/pFW01‐thrA*BC‐rhtC could tolerate the high concentration of glucose and produced no detectable by‐products; therefore, it should be an ideal platform strain for further development. The results indicate that manipulating the glucose uptake and TCA cycle could efficiently increase l‐threonine production in E. coli.
Production of tert‐butyl (3R,5S)‐6‐chloro‐3,5‐dihydroxyhexanoate using carbonyl reductase coupled with glucose dehydrogenase with high space–time yield
Authors: Zhang Xiao‐Jian , Zheng Ling , Wu Di , Zhou Rong , Liu Zhi‐Qiang , Zheng Yu‐Guo 
Published: September 2019

Abstracttert‐Butyl (3R,5S)‐6‐chloro‐3,5‐dihydroxyhexanoate ((3R,5S)‐CDHH) is an important chiral intermediate for the synthesis of rosuvastatin. The biotechnological production of (3R,5S)‐CDHH is catalyzed from tert‐butyl (S)‐6‐chloro‐5‐hydroxy‐3‐oxohexanoate ((S)‐CHOH) by a carbonyl reductase, and this synthetic pathway is becoming a primary route for (3R,5S)‐CDHH production due to its high enantioselectivity, mild reaction conditions, low cost, process safety, and environmental friendship. However, the requirement of the pyridine nucleotide cofactors, reduced nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) limits its economic flexibility. In the present study, a recombinant Escherichia coli strain harboring carbonyl reductase R9M and glucose dehydrogenase (GDH) was constructed with high carbonyl reduction activity and cofactor regeneration efficiency. The recombinant E. coli cells were applied for the efficient production of (3R,5S)‐CDHH with a substrate conversion of 98.8%, a yield of 95.6% and an enantiomeric excess (e.e.) of >99.0% under 350 g/L of (S)‐CHOH after 12 hr reaction. A substrate fed‐batch strategy was further employed to increase the substrate concentration to 400 g/L resulting in an enhanced product yield to 98.5% after 12 hr reaction in a 1 L bioreactor. Meanwhile, the space–time yield was 1,182.3 g L−1 day−1, which was the highest value ever reported by a coupled system of carbonyl reductase and glucose dehydrogenase.
Acyldepsipeptide Probes Facilitate Specific Detection of Caseinolytic Protease P Independent of Its Oligomeric and Activity State
Authors: Eyermann Barbara , Meixner Maximilian , Brötz‐Oesterhelt Heike , Antes Iris , Sieber Stephan A. 
Published: September 2019

AbstractCaseinolytic protease P (ClpP) is a tetradecameric peptidase that assembles with chaperones such as ClpX to gain proteolytic activity. Acyldepsipeptides (ADEPs) are small‐molecule mimics of ClpX that bind into hydrophobic pockets on the apical site of the complex, thereby activating ClpP. Detection of ClpP has so far been facilitated with active‐site‐directed probes which depend on the activity and oligomeric state of the complex. To expand the scope of ClpP labeling, we took a stepwise synthetic approach toward customized ADEP photoprobes. Structure–activity relationship studies with small fragments and ADEP derivatives paired with modeling studies revealed the design principles for suitable probe molecules. The derivatives were tested for activation of ClpP and subsequently applied in labeling studies of the wild‐type peptidase as well as enzymes bearing mutations at the active site and an oligomerization sensor. Satisfyingly, the ADEP photoprobes provided a labeling readout of ClpP independent of its activity and oligomeric state.