bluuebunny/crossref_metadata_2025 huggingface dataset:
The heart of a hibernator: EGFR and MAPK signaling in cardiac muscle during the hibernation of thirteen-lined ground squirrels,Ictidomys tridecemlineatus
Authors: Childers Christine L. , Tessier Shannon N. , Storey Kenneth B.
Published: September 2019

Background

Thirteen-lined ground squirrels (Ictidomys tridecemlineatus)experience dramatic changes in physiological and molecular parameters during winter hibernation. Notably, these animals experience reduced blood circulation during torpor, which can put numerous stresses on their hearts. The present study evaluates the role played by the epidermal growth factor receptor (EGFR) in signal transduction during hibernation at low body temperature to evaluate signaling mechanisms. By investigating the regulation of intracellular mitogen activated protein kinase (MAPK) pathway responses, anti-apoptosis signals, downstream transcription factors, and heat shock proteins in cardiac muscle we aim to determine the correlation between upstream tyrosine phosphorylation events and downstream outcomes.

Methods

Protein abundance of phosphorylated EGFR, MAPKs and downstream effector proteins were quantified using immunoblotting and Luminex®multiplex assays.

Results

Monitoring five time points over the torpor/arousal cycle, EGFR phosphorylation on T654, Y1068, Y1086 was found to increase significantly compared with euthermic control values particularly during the arousal process from torpor, whereas phosphorylation at Y1045 was reduced during torpor. Phosphorylation of intracellular MAPK targets (p-ERK 1/2, p-JNK, p-p38) also increased strongly during the early arousal stage with p-p38 levels also rising during prolonged torpor. However, of downstream MAPK effector kinases that were measured, only p-Elk-1 levels changed showing a decrease during interbout arousal (IA). Apoptosis markers revealed a strong reduction of the pro-apoptotic p-BAD protein during entrance into torpor that remained suppressed through torpor and IA. However, active caspase-9 protein rose strongly during IA. Levels of p-AKT were suppressed during the transition phases into and out of torpor. Of four heat shock proteins assessed, only HSP27 protein levels changed significantly (a 40% decrease) during torpor.

Conclusion

We show evidence of EGFR phosphorylation correlating to activation of MAPK signaling and downstream p-ELK1 suppression during hibernation. We also demonstrate a reduction in p-BAD mediated pro-apoptotic signaling during hibernation with active caspase-9 protein levels increasing only during IA.I. tridecemlineatushas natural mechanisms of tissue protection during hibernation that is largely due to cellular regulation through phosphorylation-mediated signaling cascade. We identify a possible link between EGFR and MAPK signaling via p-ERK, p-p38, and p-JNK in the cardiac muscle of these hibernating mammals that correlates with an apparent reduction in caspase-9 apoptotic signaling. This reveals a piece of the mechanism behind how these mammals are resilient to cardiac stresses during hibernation that would otherwise be damaging.
Assessing the Source of Thallium Contamination in Ground and Surface Waters in the Locality of Yamtenga (Burkina-Faso): Correlation with Some Heavy Metal Ions
Authors: Kam Ollé Rodrigue , Bakouan Corneille , Zongo Inoussa , Guel Boubié
Published: September 2019

Thallium (Tl) is a non-essential element for human being and is considered as a highly toxic trace element at a concentration above 2 µg/L. To assess the source of thallium contamination in ground and surface waters in the locality of Yamtenga village (11°43'35.1'' N and 00°11'50.8'' W, Burkina Faso), chemical analyzes of thallium concentrations in the soils of Yamtenga village along with geological descriptions (geological map and hydrographic watershed map of the studied area) were undertaken. We found thallium concentrations in this area ranging from 1.61 mg / kg to 404.75 mg / kg. A zoned mineralization in thallium, due to the geological structure of the locality, was established in the soils, suggesting that the source of thallium contamination in ground and surface waters in the locality of Yamtenga village is of natural origin. The concentration of some heavy metals (Pb, Zn, Cd, Cu and Mn) were also evaluated in the soils of Yamtenga village and their concentration relationships with thallium were analyzed by the Pearson correlation coefficient based on matrix correlation. Moderate (0.554), low (0.408) and significant (0.999) correlations coefficients were obtained between thallium and lead, zinc, manganese respectively. Significant correlation coefficients (0.788 and 0.791) were also noted between thallium and copper, cadmium respectively. Thallium concentrations in ground and surface waters in this locality are mainly related to the interactions between water and source rocks, thallium being released following some alteration processes with other heavy metals elements especially manganese.
Acute and Subacute Toxicity of Oxalis barrelieri (Oxalidaceae) Aqueous Aerial Parts Extract
Authors: Mezui Christophe , Amang André Perfusion , Mbomo Rigobert Espoir Ayissi , Teukam Mimosette Mesmine Kuissu , Lontsi-Nolah Merveille-Celeste , Toungainbo Yolande Mossebo , Tan Paul Vernyuy
Published: September 2019

Aims: The present study was carried out to investigate the toxic effects of the Oxalis barrelieri aqueous aerial parts extract.

Place and Duration of Study: Department of Biological Sciences (Animal Physiology Laboratory), Higher Teachers’ Training College, University of Yaoundé I. Between April 2017 and June 2018.

Materials and Methods: Acute toxicity using a single dose of 2000 mg/kg was administered to mice and effects were observed for 14 days. In sub-acute toxicity, the experimental rats (males and females) received aqueous extract of Oxalis barrelieri at doses of 200 mg/kg, 400 mg/kg and 800 mg/kg daily for 28 days while the control and satellite control groups received distilled water and satellite test group received extract at the dose of 800 mg/kg. The physical parameters were evaluated throughout the treatment, while the haematological, biochemical and histological parameters were evaluated at the end of the treatment.

Results: In acute toxicity, the results obtained show no death and no significant variation (p>0.05) in behavioral and morphological parameters. In sub-acute toxicity assay, few modifications were observed in haematological and biochemical parameters. At the higher dose of extract (800 mg/kg),the rate of red blood cells decreased significantly (p<0.05) two weeks after treatment in male rats , there were a significant increase (P˂0.001) in ASAT activity in male and female rats two weeks after extract administration, and a reversible significant increase (P˂0.05) in triglyceride level in male rats only. Histopathology showed a reversible slight dose dependent structural alteration of the kidney and reversible vascular congestion in liver.

Conclusion:  The aqueous aerial parts extract of Oxalis barrelieri could possess moderate toxicity at high doses and adequate caution should be exercised in its use in ethnomedicine.
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.
Deciphering the specific interaction between the acyl carrier protein IacP and the T3SS‐major hydrophobic translocator SipB from Salmonella
Authors: Canestrari Mickaël J. , Serrano Bastien , Bartoli Julia , Prima Valérie , Bornet Olivier , Puppo Rémy , Bouveret Emmanuelle , Guerlesquin Françoise , Viala Julie P.
Published: September 2019

Salmonella is a facultative intracellular pathogen that invades epithelial cells of the intestine using the SPI‐1 Type 3 secretion System (T3SS). Insertion of the SPI‐1 T3SS translocon is facilitated by acylation of the translocator SipB, which involves a protein–protein interaction with the acyl carrier protein IacP. Using nuclear magnetic resonance and biological tests, we identified the residues of IacP that are involved in the interaction with SipB. Our results suggest that the 4′‐phosphopantetheine group that functionalizes IacP participates in the interaction. Its solvent exposition may rely on two residues highly conserved in acyl carrier proteins associated with T3SS. This study is the first to address the specificity of acyl carrier proteins associated with T3SS.
MAP moving horizon estimation for threshold measurements with application to field monitoring
Authors: Battistelli Giorgio , Chisci Luigi , Forti Nicola , Gherardini Stefano
Published: September 2019

This 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

Organic 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

Compared 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

Due 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

In 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.
A Community's Response to Adverse Childhood Experiences: Building a Resilient, Trauma‐Informed Community
Authors: Matlin Samantha L. , Champine Robey B. , Strambler Michael J. , O'Brien Caitlin , Hoffman Erin , Whitson Melissa , Kolka Laurie , Tebes Jacob Kraemer
Published: September 2019

Highlights

Adverse Childhood Experience (ACEs) may be mitigated by trauma‐informed social environments.

However, there is little empirical evidence that show how community approaches can address ACEs.

A participatory change process was implemented by a community coalition in response to ACEs.

Data was used to track implementation, generate hypotheses and guide a community response to ACEs.

Results show how one community initiated steps to build a resilient, trauma‐informed community.
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

A 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

Reported 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

A 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

A 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.
Fe3O4 – Glutathione stabilized Ag nanoparticles: A new magnetically separable robust and facile catalyst for aqueous phase reduction of nitroarenes
Authors: Kumari Mitlesh , Gupta Ragini , Jain Yachana
Published: September 2019

The heterostructured Ag nanoparticles decorated Fe3O4 Glutathione (Fe3O4‐Glu‐Ag) nanoparticles (NPs) were synthesized by sonicating glutathione (Glu) with magnetite and further surface immobilization of silver NPs on it. The ensuing magnetic nano catalyst is well characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA). The prepared Fe3O4‐Glu‐Ag nanoparticles have proved to be an efficient and recyclable nanocatalyst with low catalyst loading for the reduction of nitroarenes and heteronitroarenes to respective amines in the presence of NaBH4 using water as a green solvent which could be easily separated at the end of a reaction using an external magnet and can be recycled up to 5 runs without any significant loss in catalytic activity. Gram scale study for the reduction of 4‐NP has also being carried out successfully and it has been observed that this method can serve as an efficient protocol for reduction of nitroarenes on industrial level.
Molybdenum (VI)‐functionalized UiO‐66 provides an efficient heterogeneous nanocatalyst in oxidation reactions
Authors: Afzali Niloufar , Kardanpour Reihaneh , Zadehahmadi Farnaz , Tangestaninejad Shahram , Moghadam Majid , Mirkhani Valiollah , Mechler Adam , Mohammadpoor‐Baltork Iraj , Bahadori Mehrnaz
Published: September 2019

A novel heterogeneous nanocatalyst was established by supporting molybdenum (VI) on Zr6 nodes in the structure of the well‐known UiO‐66 metal–organic framework (MOF). The structure of the UiO‐66 before and after Mo (VI) immobilization was confirmed with XRD, DR‐FTIR and UV–vis spectroscopy, and the presence and amount of Mo (VI) was identified by X‐ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. TEM imaging confirmed the absence of Mo clusters on the MOF surface, while SEM confirmed that the appearance of the MOF has not changed upon immobilizing the Mo (VI) catalyst. BET adsorption measurements were used to confirm the porosity of the catalyst. The catalytic activity of this heterogeneous catalyst was investigated in oxidation of sulfides with H2O2 in acetonitrile and oxidative desulfurization of dibenzothiophene. Easy work up, convenient and steady reuse and high activity and selectivity are prominent properties of this new hybrid material.
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

Biodiesel 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

Poly(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

The 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 Takeaways

After 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

Wild‐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

tert‐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

Caseinolytic 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.
The “Double‐Whammy”: How Cuts in State Appropriations and Federal Pell Grants Harm Rural Community College Students and the Institutions That Serve Them
Authors: Koh Jonathan P. , Katsinas Stephen G. , Bray Nathaniel J. , Hardy David E.
Published: September 2019

This chapter reviews multiple variables across all public community colleges, and unveils marked disparities in public funding between and within the states at community colleges of different sizes and geographical settings.
Side‐by‐side comparison of composition and structural properties of wheat, rye, oat, and maize bran and their impact on in vitro fermentability
Authors: Roye Chiara , Bulckaen Karen , De Bondt Yamina , Liberloo Inge , Van De Walle Davy , Dewettinck Koen , Courtin Christophe M.
Published: September 2019

Background and objectives

Compared to wheat bran, less information on physicochemical characteristics and health‐related effects is available for bran from other cereals and results are often confounded by residual endosperm. Therefore, the objective of this study was to compare structure and composition of endosperm‐depleted bran of wheat, rye, oat, and maize, and link these characteristics to fecal fermentation characteristics.

Findings

Compared to wheat, endosperm‐depleted rye bran contained twice the amount of fructan (8.0% dm) and water‐extractable arabinoxylan (1.4% dm). Oat bran had a more open structure and was rich in (1,3:1,4)‐β‐glucan (17.0% dm). For rye and oat bran, and to a lesser extent wheat bran, fermentation with fecal microbiota resulted in short chain fatty acid production, with full metabolization of fructan and β‐glucan after 2 and 24 hr of fecal fermentation, respectively. For maize bran, a less accessible structure containing over 70% of arabinoxylan and cellulose was coupled to a lower degree of fecal fermentation.

Conclusion

Removal of endosperm as a confounding factor when studying bran properties allowed us to obtain more accurate estimates of the composition, structure, and some physicochemical characteristics of bran of wheat, rye, oat, and maize. Bran fecal fermentation characteristics were mainly determined by composition and to a lesser extent by accessibility of the structure.

Significance and novelty

This is the first study that compares composition, structure, and fecal fermentation characteristics of wheat, rye, oat, and maize bran, after eliminating endosperm as a confounding factor. The knowledge obtained will allow a more goal‐oriented choice of bran type for incorporation into food products, depending on targeted physiological effects and nutritional impact.
Formation of the CuII–Phenoxyl Radical by Reaction of O2 with a CuII–Phenolate Complex via the CuI–Phenoxyl Radical
Authors: Suzuki Takashi , Oshita Hiromi , Yajima Tatsuo , Tani Fumito , Abe Hitoshi , Shimazaki Yuichi
Published: September 2019

Reaction of Cu(ClO4)2⋅6 H2O with a tripodal 2N2O ligand, H2Me2NL, having a p‐(dimethylamino)phenol moiety, in CH2Cl2/MeOH (1:1 v/v) under basic conditions under an inert gas atmosphere gave [Cu(Me2NL)(H2O)] (1). The same reaction carried out under aerobic conditions gave [Cu(Me2NL)(MeOH)]ClO4 (2), which could be obtained also from the isolated complex 1 by reaction with O2 in CH2Cl2/MeOH. The X‐ray crystal structures of 1 and 2 revealed similar square‐pyramidal structures, but 2 showed the (dimethylamino)phenoxyl radical features. Complex 1 exhibits characteristic CuII EPR signals of the d
ground state in CH2Cl2/MeOH at 77 K, whereas 2 is EPR‐silent. The EPR and X‐ray absorption fine structure (XAFS) results suggest that 2 is assigned to the CuII–(dimethylamino)phenoxyl radical. However, complex 1 showed different features in the absence of MeOH. The EPR spectrum of the CH2Cl2 solution of 1 exhibits distortion from the d
ground state and a temperature‐dependent equilibrium between the CuII–(dimethylamino)phenolate and the CuI–(dimethylamino)phenoxyl radical. From these results, CuII–phenoxyl radical complex 2 is concluded to be formed by the reaction of 1 with O2 via the CuI–phenoxyl radical species.
A Solvent‐Exposed Cysteine Forms a Peculiar NiII‐Binding Site in the Metallochaperone CooT from Rhodospirillum rubrum
Authors: Alfano Marila , Veronesi Giulia , Musiani Francesco , Zambelli Barbara , Signor Luca , Proux Olivier , Rovezzi Mauro , Ciurli Stefano , Cavazza Christine
Published: September 2019

In Rhodospirillum rubrum, the maturation of carbon monoxide dehydrogenase (CODH) requires three nickel chaperones, namely RrCooC, RrCooT and RrCooJ. Recently, the biophysical characterisation of the RrCooT homodimer and the X‐ray structure of its apo form revealed the existence of a solvent‐exposed NiII‐binding site at the dimer interface, involving the strictly conserved Cys2. Here, a multifaceted approach that used NMR and X‐ray absorption spectroscopies, complemented with structural bio‐modelling methodologies, was used to characterise the binding mode of NiII in RrCooT. This study suggests that NiII adopts a square‐planar geometry through a N2S2 coordinating environment that comprises the two thiolate and amidate groups of both Cys2 residues at the dimer interface. The existence of a diamagnetic mononuclear NiII centre with bis‐amidate/bis‐thiolate ligands, coordinated by a single‐cysteine motif, is unprecedented in biology and raises the question of its role in the activation of CODH at the molecular level.
Dearomatizing and Derivatizing a Mesityl Group on Boron by One‐Pot Photoisomerization and [4+2] Diels–Alder Addition
Authors: Deng Billy , Wang Xiang , Wang Suning
Published: September 2019

Boron compounds having a conjugated chelate backbone (N,C‐chelate or C,C‐chelate) and two mesityl substituents on boron have been found to undergo a facile one‐pot transformation/reaction with dienophiles, which leads to the dearomatization of one mesityl ring and its [4+2] Diels–Alder addition with the dienophile. Photochemical activation is the key in this transformation of the aryl ring.
Atroposelective Total Synthesis of the Fourfold ortho‐Substituted Naphthyltetrahydroisoquinoline Biaryl O,N‐Dimethylhamatine
Authors: Slack Eric D. , Seupel Raina , Aue Donald H. , Bringmann Gerhard , Lipshutz Bruce H.
Published: September 2019

A stereoselective total synthesis of O,N‐dimethylhamatine, an analogue of an axially chiral naphthylisoquinoline natural biaryl product from tropical Ancistrocladus lianas, is reported. The route features a late‐stage atropo‐diastereoselective biaryl bond formation. Generation of this especially challenging, sterically hindered tetra‐ortho‐substituted array was achieved by using Nolan's (IPr*NHC)PdCinCl pre‐catalyst under mild Negishi coupling conditions. Discussion is offered regarding the selectivity obtained experimentally and predicted from DFT calculations on the key biaryl coupling step that leads to the desired M‐diastereomer.
Pulmonary metastasis of cribriform‐morular variant of thyroid carcinoma mimicking primary adenocarcinoma of the lung: A potential pitfall
Authors: Laforga Juan B. , Pedro Teresa , Gasent Joan M.
Published: September 2019

Cribriform‐morular variant of papillary thyroid carcinoma (CMV‐TC) shows a peculiar mixture of follicular, cribriform, papillary, trabecular, and solid patterns with squamoid morules. Ocassionally, lung metastasis may be interpreted incorrectly as primary lung adenocarcinoma. We illustrate a case of pulmonary meastasis of CMV‐TC mimicking a primary adenocarcinoma, 7 years after diagnosis of CMV‐TC. The lung metastases may be easily missed if the pathologist is unaware of the patient's prior history and a limited immunohistochemical panel (CK7 and TTF‐1) is used. The histologic and immunohistochemical (β‐catenin+, ER+, PR+, TTF‐1 +, and CK7+) findings were diagnostic of CMV‐TC and ensured adequate treatment.
Mating dynamics and multiple paternity in a long‐lived vertebrate
Authors: Zajdel Joshua , Lance Stacey L. , Rainwater Thomas R. , Wilkinson Phillip M. , Hale Matthew D. , Parrott Benjamin B.
Published: September 2019

Multiple paternity is relatively common across diverse taxa; however, the drivers and implications related to paternal and maternal fitness are not well understood. Several hypotheses have been offered to explain the occurrence and frequency of multiple paternity. One set of hypotheses seeks to explain multiple paternity through direct and indirect benefits including increased genetic diversity or enhanced offspring fitness, whereas another set of hypotheses explains multiple paternity as a by‐product of sexual conflict and population‐specific parameters such as density. Here, we investigate mating system dynamics in a historically studied population of the American alligator (Alligator mississippiensis) in coastal South Carolina. We examine parentage in 151 nests across 6 years and find that 43% of nests were sired by multiple males and that male reproductive success is strongly influenced by male size. Whereas clutch size and hatchling size did not differ between singly sired and multiply sired nests, fertility rates were observed to be lower in multiply sired clutches. Our findings suggest that multiple paternity may exert cost in regard to female fitness, and raise the possibility that sexual conflict might influence the frequency of multiple paternity in wild alligator populations.
Predicting species occurrences with habitat network models
Authors: Ortiz‐Rodríguez Damian O. , Guisan Antoine , Holderegger Rolf , van Strien Maarten J.
Published: September 2019

Biodiversity conservation requires modeling tools capable of predicting the presence or absence (i.e., occurrence‐state) of species in habitat patches. Local habitat characteristics of a patch (lh), the cost of traversing the landscape matrix between patches (weighted connectivity [wc]), and the position of the patch in the habitat network topology (nt) all influence occurrence‐state. Existing models are data demanding or consider only local habitat characteristics. We address these shortcomings and present a network‐based modeling approach, which aims to predict species occurrence‐state in habitat patches using readily available presence‐only records.

For the tree frogHyla arboreain the Swiss Plateau, we delineated habitat network nodes from an ensemble habitat suitability model and used different cost surfaces to generate the edges of three networks: one limited only by dispersal distance (Uniform), another incorporating traffic, and a third based on inverse habitat suitability. For each network, we calculated explanatory variables representing the three categories (lh,wc, andnt). The response variable, occurrence‐state, was parametrized by a sampling intensity procedure assessing observations of comparable species over a threshold of patch visits. The explanatory variables from the three networks and an additional non‐topological model were related to the response variable with boosted regression trees.

The habitat network models had a similar fit; they all outperformed the non‐topological model. Habitat suitability index (lh) was the most important predictor in all networks, followed by third‐order neighborhood (nt). Patch size (lh) was unimportant in all three networks.

We found that topological variables of habitat networks are relevant for the prediction of species occurrence‐state, a step‐forward from models considering only local habitat characteristics. For any habitat patch, occurrence‐state is most prominently influenced by its habitat suitability and then by the number of patches in a wide neighborhood. Our approach is generic and can be applied to multiple species in different habitats.