bluuebunny/crossref_metadata_2025 huggingface dataset:
Rnf220/Zc4h2-mediated monoubiquitylation of Phox2 is required for noradrenergic neuron development
Authors: Song Ning-Ning , Ma Pengcheng , Zhang Qiong , Zhang Lei , Wang Huishan , Zhang Longlong , Zhu Liang , He Chun-Hui , Mao Bingyu , Ding Yu-Qiang
Published: February 2020

Noradrenaline belongs to the monoamine system and is involved in cognition and emotional behaviors. Phox2a and Phox2b play essential but non-redundant roles during development of the locus coeruleus (LC), the main noradrenergic (NA) neuron center in the mammalian brain. The ubiquitin E3 ligase Rnf220 and its cofactor Zc4h2 participate in ventral neural tube patterning by modulating Shh/Gli signaling, and ZC4H2 mutation is associated with intellectual disability, although the mechanisms for this remain poorly understood. Here, we report that Zc4h2 and Rnf220 are required for the development of central NA neurons in the mouse brain. Both Zc4h2 and Rnf220 are expressed in developing LC-NA neurons. Although properly initiated at E10.5, the expression of genes associated with LC-NA neurons is not maintained at the later embryonic stages in mice with a deficiency of either Rnf220 or Zc4h2. In addition, we show that the Rnf220/Zc4h2 complex monoubiquitylates Phox2a/Phox2b, a process required for the full transcriptional activity of Phox2a/Phox2b. Our work reveals a role for Rnf220/Zc4h2 in regulating LC-NA neuron development, and this finding may be helpful for understanding the pathogenesis of ZC4H2 mutation-associated intellectual disability.
Lamellipodin tunes cell migration by stabilizing protrusions and promoting adhesion formation
Authors: Dimchev Georgi , Amiri Behnam , Humphries Ashley C. , Schaks Matthias , Dimchev Vanessa , Stradal Theresia E. B. , Faix Jan , Krause Matthias , Way Michael , Falcke Martin , Rottner Klemens
Published: February 2020

Efficient migration on adhesive surfaces involves the protrusion of lamellipodial actin networks and their subsequent stabilization by nascent adhesions. The actin-binding protein lamellipodin (Lpd) is thought to play a critical role in lamellipodium protrusion, by delivering Ena/VASP proteins onto the growing plus ends of actin filaments and by interacting with the WAVE regulatory complex, an activator of the Arp2/3 complex, at the leading edge. Using B16-F1 melanoma cell lines, we demonstrate that genetic ablation of Lpd compromises protrusion efficiency and coincident cell migration without altering essential parameters of lamellipodia, including their maximal rate of forward advancement and actin polymerization. We also confirmed lamellipodia and migration phenotypes with CRISPR/Cas9-mediated Lpd knockout Rat2 fibroblasts, excluding cell type-specific effects. Moreover, computer-aided analysis of cell-edge morphodynamics on B16-F1 cell lamellipodia revealed that loss of Lpd correlates with reduced temporal protrusion maintenance as a prerequisite of nascent adhesion formation. We conclude that Lpd optimizes protrusion and nascent adhesion formation by counteracting frequent, chaotic retraction and membrane ruffling.

This article has an associated First Person interview with the first author of the paper.
A novel benzodiazepine derivative that suppresses microtubule dynamics and impairs mitotic progression
Authors: Pirani Vittoria , Métivier Mathieu , Gallaud Emmanuel , Thomas Alexandre , Ku Siou , Chretien Denis , Ettari Roberta , Giet Regis , Corsi Lorenzo , Benaud Christelle
Published: February 2020

A novel 2,3-benzodiazepine-4 derivative, named 1g, has recently been shown to function as an anti-proliferative compound. We now show that it perturbs the formation of a functional mitotic spindle, inducing a spindle assembly checkpoint (SAC)-dependent arrest in human cells. Live analysis of individual microtubules indicates that 1g promotes a rapid and reversible reduction in microtubule growth. Unlike most anti-mitotic compounds, we found that 1g does not interfere directly with tubulin or perturb microtubule assembly in vitro. The observation that 1g also triggers a SAC-dependent mitotic delay associated with chromosome segregation in Drosophila neural stem cells, suggests that it targets a conserved microtubule regulation module in humans and flies. Altogether, our results indicate that 1g is a novel promising anti-mitotic drug with the unique properties of altering microtubule growth and mitotic spindle organization.
AKT but not MYC promotes reactive oxygen species-mediated cell death in oxidative culture
Authors: Zheng Dongqing , Sussman Jonathan H. , Jeon Matthew P. , Parrish Sydney T. , MacMullan Melanie A. , Delfarah Alireza , Graham Nicholas A.
Published: February 2020

Oncogenes can create metabolic vulnerabilities in cancer cells. We tested how AKT (herein referring to AKT1) and MYC affect the ability of cells to shift between respiration and glycolysis. Using immortalized mammary epithelial cells, we discovered that constitutively active AKT, but not MYC, induced cell death in galactose culture, where cells rely on oxidative phosphorylation for energy generation. However, the negative effects of AKT were temporary, and AKT-expressing cells recommenced growth after ∼15 days in galactose. To identify the mechanisms regulating AKT-mediated cell death, we used metabolomics and found that AKT-expressing cells that were dying in galactose culture had upregulated glutathione metabolism. Proteomic profiling revealed that AKT-expressing cells dying in galactose also upregulated nonsense-mediated mRNA decay, a marker of sensitivity to oxidative stress. We therefore measured levels of reactive oxygen species (ROS) and discovered that galactose-induced ROS exclusively in cells expressing AKT. Furthermore, ROS were required for galactose-induced death of AKT-expressing cells. We then confirmed that galactose-induced ROS-mediated cell death in breast cancer cells with upregulated AKT signaling. These results demonstrate that AKT but not MYC restricts the flexibility of cancer cells to use oxidative phosphorylation.

This article has an associated First Person interview with the first author of the paper.
Drosophila Prp40 localizes to the histone locus body and regulates gene transcription and development
Authors: Prieto-Sánchez Silvia , Moreno-Castro Cristina , Hernández-Munain Cristina , Suñé Carlos
Published: February 2020

In eukaryotes, a large amount of histones need to be synthesized during the S phase of the cell cycle to package newly synthesized DNA into chromatin. The transcription and 3′ end processing of histone pre-mRNAs are controlled by the histone locus body (HLB), which is assembled on the shared promoter for H3 and H4. Here, we identified the Drosophila Prp40 pre-mRNA processing factor (dPrp40, annotated as CG3542) as a novel HLB component. We showed that dPrp40 is essential for Drosophila development, with functionally conserved activity in vertebrates and invertebrates. We observed that dPrp40 is fundamental in endocycling cells, highlighting a role for this factor in mediating replication efficiency in vivo. The depletion of dPrp40 from fly cells inhibited the transcription, but not the 3′ end processing, of histone mRNA in a H3- and H4-promoter-dependent manner. Our results establish that dPrp40 is an essential protein for Drosophila development that can localize to the HLB and might participate in histone mRNA biosynthesis.
Kinesin KIF18A is a novel PUM-regulated target promoting mitotic progression and survival of a human male germ cell line
Authors: Smialek Maciej Jerzy , Kuczynska Bogna , Ilaslan Erkut , Janecki Damian Mikolaj , Sajek Marcin Piotr , Kusz-Zamelczyk Kamila , Jaruzelska Jadwiga
Published: February 2020

Regulation of proliferation, apoptosis and cell cycle is crucial for the physiology of germ cells. Their malfunction contributes to infertility and germ cell tumours. The kinesin KIF18A is an important regulator of those processes in animal germ cells. Post-transcriptional regulation of KIF18A has not been extensively explored. Owing to the presence of PUM-binding elements (PBEs), KIF18A mRNA is a potential target of PUM proteins, where PUM refers to Pumilio proteins, RNA-binding proteins that act in post-transcriptional gene regulation. We conducted RNA co-immunoprecipitation combined with RT-qPCR, as well as luciferase reporter assays, by applying an appropriate luciferase construct encoding wild-type KIF18A 3′-UTR, upon PUM overexpression or knockdown in TCam-2 cells, representing human male germ cells. We found that KIF18A is repressed by PUM1 and PUM2. To study how this regulation influences KIF18A function, an MTS proliferation assay, and apoptosis and cell cycle analysis using flow cytometry, was performed upon KIF18A mRNA siRNA knockdown. KIF18A significantly influences proliferation, apoptosis and the cell cycle, with its effects being opposite to PUM effects. Repression by PUM proteins might represent one of mechanisms influencing KIF18A level in controlling proliferation, cell cycle and apoptosis in TCam-2 cells.
Carpatho-Rusyn Scholarship in America, 1988-2019
Authors: Rusinko Elaine , Horbal Bogdan
Published: February 2020

Karpackorusińskie badania naukowe w Ameryce, 1988-2019 Współczesne amerykańskie badania karpackorusińskie rozpoczęły się na początku lat siedemdziesiątych XX w. Począwszy od 1988 r. i kontynuując do 2019 r., badacze karpackorusińscy regularnie uczestniczyli w amerykańskim świecie naukowym, w tym w panelach i okrągłych stołach podczas corocznych konferencji Stowarzyszenia Studiów Słowiańskich, Wschodnioeuropejskich i Eurazjatyckich (Association for Slavic, East European, and Eurasian Studies) oraz Stowarzyszenia do Badań Narodowości (the Association for the Study of Nationalities). Niniejszy artykuł analizuje historię i rozwój badań karpackorusińskich w Stanach Zjednoczonych poprzez analizę prezentacji przedstawionych na tych konferencjach od 1988 roku. Ewolucja badań karpackorusińskich w ciągu ostatnich trzydziestu lat pokazuje rozwój tej dziedziny tak pod względem ilości, jak i specyfikacji naukowej: od ogólnych tematów w panelach organizowanych przez inne grupy etniczne, po szczegółowe prezentacje w panelach z konkretnymi tematami karpackorusińskimi, a ostatnio w prezentacjach, które stosują nowe perspektywy i metodologie badań w wieloetnicznych, multidyscyplinarnych panelach i okrągłych stołach. Do artykułu dołączono listę paneli i prezentacji na karpackorusińskie tematy, które przedstawiono na konferencji Stowarzyszenia Studiów Słowiańskich, Wschodnioeuropejskich i Eurazjatyckich w latach 1988-2019.
Чым є література менша?
Authors: Делез Жіль , Гуатарі Фелікс
Published: February 2020

-
Do Accelerators Work? If So, How?
Authors: Hallen Benjamin L. , Cohen Susan L. , Bingham Christopher B.
Published: February 2020

Accelerators are entrepreneurial programs that attempt to help ventures learn, often utilizing extensive consultation with mentors, program directors, customers, guest speakers, alumni, and peers. Although accelerators have rapidly emerged as prominent players in the entrepreneurial ecosystem, entrepreneurs, policy makers, and academics continue to raise questions about their efficacy. Moreover, relevant organizational literature suggests that, even if accelerators are associated with better venture outcomes, results could be due to mechanisms other than learning, such as sorting or signaling. Drawing on mixed empirical methods that include proprietary data on the ventures accepted and “almost accepted” to a set of top accelerators, we find evidence that some, but not all, of the early accelerators we study substantially aid and accelerate venture development. We also find some evidence of sorting dynamics. These findings are corroborated using an auxiliary quantitative data set constructed from publicly observable data. Complementary qualitative fieldwork suggests a key driver of these accelerator effects is a novel learning mechanism we label broad, intensive, and paced consultation. The implication of these insights is that the practices of early accelerators represent a beneficial and likely replicable form of intervention that may also have relevance for independent entrepreneurs, educational programs, and corporate innovation.
Reconciling the Firm Size and Innovation Puzzle
Authors: Knott Anne Marie , Vieregger Carl
Published: February 2020

There is a prevailing view in both the academic literature and the popular press that firms need to behave more entrepreneurially. This view is reinforced by a stylized fact in the innovation literature that research and development (R&D) productivity decreases with size. A second stylized fact in the innovation literature is that R&D investment increases with size. Taken together, these stylized facts create a puzzle of seemingly irrational behavior by large firms—they are increasing spending despite decreasing returns. There have been a number of proposals to resolve the puzzle. However, to date none of these proposals has been fully validated, so the puzzle remains. Accordingly, this paper empirically tests the proposals to see whether any resolves the puzzle. We found one proposal (use of alternative measures) was able to resolve the puzzle. When using a recent measure of firms’ R&D productivity, RQ, we found that both R&D spending and R&D productivity increase with firm size. Thus, large firms seem to be acting rationally in their increasing R&D investments, as one would expect.
Transaction Costs in Resource Redeployment for Multiniche Firms
Authors: Giarratana Marco S. , Santaló Juan
Published: February 2020

Transaction costs strongly influence diversification dynamics, as predicted by resource theory. A mainstream view links the profitability of diversification with the existence of transaction costs that prevent a firm from trading in fungible, scale-free resources. This study applies a neo-Penrosian perspective to transaction costs, with the notion that diversification may be driven by the redeployment of non-scale-free resources. An empirical analysis, using tax changes in the drink sector as a measure of exogenous demand variation, offers results consistent with the prediction that redeployment is particularly relevant when retailing is concentrated and single-product competition within a focal product niche (e.g., beer) is fragmented. This study also measures redeployment across a portfolio of a multiniche firm when changes in its sales-growth rates for a particular product niche might imply contrasting changes in other product niches. The resulting evidence is consistent with predictions that demand uncertainty, and transaction costs create viable redeployment opportunities for multiniche companies.
Propagation properties of the radially polarized Airy vortex beams in a chiral medium
Authors: Yang Qian , Gong Yangyang , Huang Zhancheng , Luo Zhiming , Li Hongyu , Deng Dongmei
Published: February 2020

We study the propagation of the radially polarized Airy vortex beams (RPAiVBs) in a chiral medium analytically. The RPAiVBs split into the left circular polarization of the RPAiVBs (LCPRPAiVBs) and the right circular polarization of the RPAiVBs (RCPRPAiVBs). We mainly discuss the effects of the vortex and the chiral parameter on the propagation properties of the RPAiVBs, involving the intensity distributions and the radiation forces. It is shown that with the chiral parameter increasing, the intensity focusing position of the RCPRPAiVBs is further from 

z

=
0
Zr

, while that of the LCPRPAiVBs is opposite. Besides, the maximum radiation forces of the RCPRPAiVBs are stronger than those of the LCPRPAiVBs. It is significant that we can control the acceleration, the intensity focusing position, and the radiation forces of the RPAiVBs by varying the vortex order and the chiral parameter.
High-power, ultra-broadband supercontinuum light generated in a single-mode fiber pumped with a nanosecond passively Q-switched microchip laser
Authors: Huang Xiaowei , Pan Zhanghao , Hu Aimin , Dong Jun
Published: February 2020

The compact, high-power, broadband continuum sources are extremely needed for developing portable instruments for various applications such as optical coherence tomography, high-resolution spectroscopy, and so on. Here, we develop a compact high-power, ultra-broadband supercontinuum (SC) light source in a single-mode fiber (SMF) pumped with a

Y
b

:

Y
A
G

/

C
r

4
+

:

Y
A
G

passively

Q

-switched microchip laser oscillating at 1030 nm. The spectral bandwidth of the SC light is over 1150 nm covering from 600 to 1750 nm. The maximum average output power is 181.8 mW at an input pump power of 880 mW. The optical efficiency is 20.6%, and the net conversion efficiency is as high as 51.6% with respect to the pump power coupled into the fiber. The ultra-broadband spectrum of the SC generated in the SMF is caused by the intermodal four-wave mixing (IMFWM) and cascade stimulated Raman scattering effects. Various transverse modes have been experimentally observed in SC beam generated in the SMF. Wavelength-dependent transverse modes propagating in the SMF participating in the IMFWM process dramatically expand the spectral range in the visible region. The experimental results are basically consistent with the theoretical simulations of broadband SC generated in the SMF through the IMFWM process.
Femtosecond pulse delivery around 1560  nm in large-core inhibited-coupling fibers: erratum
Authors: Dobrakowski Dominik , Rampur Anupamaa , Stępniewski Grzegorz , Pysz Dariusz , Zhao Luming , Stepanenko Yuriy , Buczyński Ryszard , Klimczak Mariusz
Published: February 2020

This erratum reports a correction to the Figs. 8 and 9 of
J. Opt. Soc. Am.
B 36, 3030
(2019)JOBPDE0740-322410.1364/JOSAB.36.003030. Information
regarding the camera used to register a mode profile
is also clarified.
Fast calculation of tightly focused random electromagnetic beams: controlling the focal field by spatial coherence
Authors: Tong Ruihuan , Dong Zhen , Chen Yahong , Wang Fei , Cai Yangjian , Setälä Tero
Published: February 2020

Focusing of a vectorial (electromagnetic) optical beam through a high numerical aperture can be investigated by means of the Richards–Wolf diffraction integral. However, such an integral extends from two-dimensional to four-dimensional, greatly increasing the computation time and therefore limiting the applicability, when light with decreased spatial coherence is considered. Here, we advance an effective protocol for the fast calculation of the statistical properties of a tightly focused field produced by a random electromagnetic beam with arbitrary state of spatial coherence and polarization. The novel method relies on a vectorial pseudo-mode representation and a fast algorithm of the wave-vector space Fourier transform. The procedure is demonstrated for several types of radially (fully) polarized but spatially partially coherent Schell-model beams. The simulations show that the computation time for obtaining the focal spectral density distribution with 512 × 512 spatial points for a low coherence beam is less than 100 seconds, while with the conventional quadruple Richards–Wolf integral more than 100 hours is required. The results further indicate that spatial coherence can be viewed as an effective degree of freedom to govern both the transverse and longitudinal components of a tightly focused field with potential applications in reverse shaping of focal fields and optical trapping control.
Imaging high-speed moving targets with a single-pixel detector
Authors: Jiang Wenjie , Li Xianye , Peng Xinglei , Sun Baoqing
Published: February 2020

Single-pixel imaging (SPI) has recently been intensively studied as an alternative to the traditional focal plane array (FPA) technology. However, limited by the refresh rate of spatial light modulators (SLM) and inherent reconstruction mechanism, SPI is inappropriate for high-speed moving targets. To break through this limitation, we propose a novel SPI scheme for high-speed moving targets. In our scenario, the spatial encoding for the target is done by the movement of the target relative to a static pseudo-random illumination pattern. In this process, a series of single-pixel signals are generated that corresponds to the overlap between the target and certain parts of the illumination structure. This correspondence can be utilized for image reconstruction in the same way as normal SPI. In addition, compressive sensing and deep learning algorithms are used for reconstruction, respectively. Reasonable reconstructions can be obtained with a sampling ratio of only 6%. Experimental verification together with theoretical analysis has shown that our scheme is able to image high-speed moving targets that could be alternatively achieved by a fast FPA camera. Our scheme keeps the inherent advantages of SPI and meanwhile extend its application to moving targets. It is believed that this technology will have wide application in many situations.
Autofocusing of ring Airy beams embedded with off-axial vortex singularities
Authors: Zhang Xiang , Li Peng , Liu Sheng , Wei Bingyan , Qi Shuxia , Fan Xinhao , Wang Shouheng , Zhang Yuan , Zhao Jianlin
Published: February 2020

We report the autofocusing behaviors of ring Airy beams (RABs) embedded with two kinds of off-axial vortex singularities. The influences of embedded positions and topological charges of point and r vortices on the autofocusing dynamic are numerically and experimentally investigated. The results show that, for the first-order vortex, the embedded position significantly affects the focal field, and once the singularity is located on the main ring of RAB, the symmetric Bessel profile of the focal field will be broken, otherwise the Bessel-like focus can self-heal at the focal plane. However, for the higher-order vortex embedded near the main ring, it will split into several fundamental vortices and then separate with each other along the radial direction under the interaction with the RAB background. Our results hold potential for the practical application of RABs in the atmosphere and other propagation systems with perturbation and even singularities.
High-repetition-rate 100  W level sodium beacon laser for a multi-conjugate adaptive optics system
Authors: Bian Qi , Bo Yong , Zuo Jun-wei , Feng Lu , Gao Hong-wei , Yuan Lei , Cui Da-fu , Peng Qin-jun , Chen Hong-bin , Xu Zu-yan
Published: February 2020

A 100 W level kilohertz repetition-rate microsecond (µs)-pulse all-solid-state sodium beacon laser at 589 nm is demonstrated for the first time, to the best of our knowledge, via combining two independent µs-pulsed lasers. Each beamlet is generated by the sum-frequency mixing of pulsed 1064 and 1319 nm lasers in a lithium triborate (LBO) crystal, which operate at 500 Hz pulse repetition frequency with 61 W

p

-polarized and 53 W

s

-polarized output, respectively. An incoherent sequence combining technology of polarized laser beams is employed to add the two beamlets. The average power of the combined beam is up to 107.5 W with a combining efficiency of 94.3%. The combined beam has a 1 kHz repetition rate with

∼

120

µ

s

pulse duration and beam quality

M
2

=

1.41

. The central wavelength with a linewidth of

∼

0.3

G
H
z

is locked to a sodium

D

2
a

absorption line. To the best of our knowledge, this is a record-high power operating at kilohertz for µs-pulsed solid-state sodium beacon lasers.
Photothermal switch of sub-microsecond response: a monolithic-integrated ring resonator and a metasurface absorber in silicon photonic crystals
Authors: Yu Honghao , Wang Hong , Xiong Qing , Mei Junjie , Zhang Ye , Wang Yi , Lai Jianjun , Chen Changhong
Published: February 2020

Here, we demonstrate an all-silicon photonic switch, working at an infrared communication wavelength and pumped by spatial light, where a ring resonator and a metasurface absorber are both designed in photonic crystals and monolithically integrated on a silicon-on-insulator wafer. Through selective doping, the absorber gets a pump absorption completely different from near zero of the resonator. Based on the thermo-optical effect, the device is capable of tuning the wavelength of the guided mode by

∼

341

p
m

/

m
W

and switching in time

<

1.0

µ

s

to the pump response. The high responsivity and switching speed as well as all-silicon processing techniques make the design potentially for free-space optical communication and detection.
Analytical model for diffuse reflectance in single fiber reflectance spectroscopy
Authors: Faber Dirk J. , Post Anouk L. , Sterenborg Henricus J. C. M. , Van Leeuwen Ton G.
Published: February 2020

Cancer progression leads to changing scattering properties of affected tissues. Single fiber reflectance (SFR) spectroscopy detects these changes at small spatial scales, making it a promising tool for early in situ detection. Despite its simplicity and versatility, SFR signal modeling is hugely complicated so that, presently, only approximate models exist. We use a classic approach from geometrical probability to derive accurate analytical expressions for diffuse reflectance in SFR that shows a strong improvement over existing models. We consider the case of limited collection efficiency and the presence of absorption. A Monte Carlo light transport study demonstrates that we adequately describe the contribution of diffuse reflectance to the SFR signal. Additional steps are required to include semi-ballistic, non-diffuse reflectance also present in the SFR measurement.
Coherent acousto-optic tomography with diffuse light
Authors: Chung Francis J. , Hoskins Jeremy G. , Schotland John C.
Published: February 2020

We propose a method to reconstruct the optical properties of a highly scattering medium from acousto-optic measurements. The method is based on solving an inverse problem with internal data for a system of diffusion equations.
Broadband amplitude, frequency, and polarization splitter for terahertz frequencies using parallel-plate waveguide technology
Authors: Hernandez-Serrano A. I. , Mittleman Daniel M. , Pickwell-MacPherson Emma
Published: February 2020

In this Letter, we report a broadband frequency/polarization demultiplexer based on parallel-plate waveguides (PPWGs) for terahertz (THz) frequencies. The fabrication and experimental validation of this polarization sensitive demultiplexer is demonstrated for the range from 0.2 to 1 THz. Upgrading the demultiplexer by adding a second demultiplexer stage, a fifty-fifty amplitude splitter is also demonstrated in the same frequency range. The multiplexer is based on a stainless-steel traveling-wave antenna, exhibiting strong mechanical robustness. This unique device exhibits three splitting mechanisms in the same device: amplitude, polarization, and frequency splitting. This is a significant improvement for the next generation of THz passive components for communication purposes.
Amino Acid Imbalance in Atherosclerosis
Authors: Karavay P.A. , Nefyodov L.I. , Karavay N.L.
Published: February 2020

A mini-review of literature data on the mechanisms of formation of the stock of free amino acids and their derivatives in atherosclerosis and methods for correcting metabolic imbalance.
Chitin and Chitinases: Biomedical And Environmental Applications of Chitin and its Derivatives
Authors: Rameshthangam Palanivel , Solairaj Dhanasekaran , Arunachalam Gnanapragasam , Ramasamy Palaniappan
Published: February 2020

Disposal of chitin wastes from crustacean shell can cause environmental and health hazards. Chitin is a well known abundant natural polymer extracted after deproteinization and demineralization of the shell wastes of shrimp, crab, lobster, and krill. Extraction of chitin and its derivatives from waste material is one of the alternative ways to turn the waste into useful products. Chitinases are enzymes that degrade chitin. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications. The presence of surface charge and multiple functional groups make chitin as a beneficial natural polymer. Due to the reactive functional groups chitin can be used for the preparation of a spectrum of chitin derivatives such as chitosan, alkyl chitin, sulfated chitin, dibutyryl chitin and carboxymethyl chitin for specific applications in different areas. The present review is aimed to summarize the efficacy of the chitinases on the chitin and its derivatives and their diverse applications in biomedical and environmental field. Further this review also discusses the synthesis of various chitin derivatives in detail and brings out the importance of chitin and its derivatives in biomedical and environmental applications.
Using A “Superrooting”Cultivar of Taxus Chinensis Var. Mairei to Unravel Antioxidative Enzymes’ and Micrornas’ Role on Adventitious Rooting
Authors: Tang Wei , Tang Wei , Fei Yongjun
Published: February 2020

Rooting of cuttings is very important for production of economically important plants. We produced thousands of plantlets in Taxus chinensisvar. mairei using the technology of rooting of cuttings and identified two types of rooted cuttings, one with low rate of root formation and another with high rate of root formation. To determine the physiological role of antioxidative enzymes and microRNAs during the process of rooting, we measured the levels of these antioxidative enzymes and microRNAs in the stem portion, needles, roots, and basal portion of cuttings. Compared to the cuttings with low rate of root formation, cuttings with high rate of root formation had higher expression of polyphenoloxidase (PPO), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APOX), glutathione reductase (GR), and superoxide dismutase (SOD) in the adventitious roots and basal portion of the rooted cuttings 77 days after planting. In the basal portion of cuttings, the content of thiobarbituric acid reactive substances (TBARS) and total phenols were decreased and the content of antioxidants was increased, but they did not changed in the needles of cuttings during planting. Analysis of microRNAs by quantitative realtime PCR demonstrated that expression of miR162, miR408, and miR857 increases in the basal portion of cuttings, but not in the stem portion of cuttings, 77 days after planting. Expression of miR408 and miR857 were also increased in the needles of cuttings 77 days after planting. Changes of these antioxidative enzymes and microRNAs associated with the rooting features of T. chinensisvar. maireicuttings and their functions have been discussed.
Perspective for Methicillin-resistant Staphylococcus Aureus colonization, Antibiotic Susceptibility Patterns and Risk factors for Colonization among People Living with HIV at Nyenga Hospital, Buikwe District, in Central Uganda
Authors: Ssenyonga Benedict , Mwebaze Sarah , Atuhairwe Christine , MugishaTaremwa Ivan
Published: February 2020

Background
Colonization with methicillin-resistant Staphylococcus aureus (MRSA) is recognized as an association towards development of infections that may cause of morbidity among people living with Human Immunodeficiency Virus (PLWHIV). We report on the prevalence, antibiotic susceptibility pattern and risk factors associated with MRSA carriage among PLWHIV at Nyenga hospital, Buikwe district in central Uganda.

Materials and Methods
We conducted a cross-sectional study among PLWHIV attending Nyenga hospital anti-retroviral therapy (ART) clinic. Nasopharyngeal swab was collected from each participant, cultured to isolate Staphylococcus aureus, and drug susceptibility testing (DST) performed. Sociodemographic data and medical history was recorded.

Results
We enrolled 219 PLWHIV; of these, 58.4% (N=128) were females. The majority of participants (95.0%) were on ART. Ninety-eight (44.75%) of the nasopharyngeal swabs had growth, of which 41 (41.84%) were S. aureus. Of these, 11 (5.02%, 95% confidence interval: 3.67-7.02) were MRSA. Of 41 isolated S. aureus strains, only 8 (19.51%) were susceptible to all antibiotics tested. A total of three (7.32%) were multi-drug resistant (MDR), while one1 (2.43%) was a possible extensively drug resistant (XDR) strain. Deteriorating immunologic state as indicated by a low CD4 count showed a significant association with the MRSA colonization.

Conclusion
These results are reassuring that MRSA colonization is high among PLWHIV. As most of the antibiotics in use were resistant, it raises concerns of intricate clinical management in a low resource set up.
Surgical Site Infection in Cesarean Section Operation: Risk and Management
Authors: Younes Riad N. , Farias Tayna F. , Sardenberg Rodrigo A.S.
Published: February 2020

Cesarean sections (CS) are one of the most commonly performed surgical procedures worldwide. There is great variability in the percentage of cesarean sections between countries, varying from 3% to 42.9%5. In the US, approximately 32% of deliveries occur through a cesarean section. Overall, a drastic increase in cesarean section rate has been reported reaching its highest level at the present time.

In Brazil, considering the types of births by live births from 2006 to 2016, the national percentage of cesarean section was 52.37%. The variability in this percentage can still be perceived within Brazilian territory. The highest cesarean rate occurred in the Southern region, representing 58.33% of births, while the lowest rate occurred in the Northern region, with 41.79%. It is possible to see the steady increase in the percentage of CS over time, from 45.01% in 2006 to 55.39% in 2016.
Conflictividades interculturales
Authors: Briones Claudia
Published: February 2020

Fake news, populismos, peligros ambientales por el antropoceno irradian en los últimos años señales de crisis desconcertantes. ¿Qué otras preguntas habría que hacer para encarar los desconciertos y preocupaciones que nos abren? ¿Qué nuevos enfoques están ensayándose en las Ciencias Sociales para afrontar los desafíos que se nos plantean? ¿Dónde buscar definiciones más certeras y alternativas? Este ensayo explora el devenir de las demandas indígenas en América Latina como ámbitos de diagnóstico que indican fallos en las convivencias y sugieren preguntas y caminos para repensar los tiempos que nos toca vivir.
One step Purification and Characterisation of Abrin Toxin from Abrus Precatorius Seeds
Authors: Banger Swati , Singh Rita , Tripathi Nagesh , Pal Vijai , Goel Ajay Kumar
Published: February 2020

Abrin is a plant toxin obtained from Abrus precatorius seeds. It belongs to the type II ribosomal inactivating proteins (RIPs) consisting of two chains namely, catalytically active A chain and sugar binding B chain linked by a single disulphide bond.  Due to high toxicity of abrin, its exposure or consumption can lead to serious public health problems. In the present work, we have extracted and purified the abrin toxin from Abrus precatorius seeds. The toxin was purified using a single step anion exchange chromatography. The purified protein was characterized by SDS-PAGE and MALDI- TOF to confirm its purity. The toxicity of purified abrin toxin was also confirmed by injecting the toxin in mice.  The purified protein was further used to raise antibodies in mice and characterized by indirect Enzyme Linked Immunosorbent Assay. The results of present study established the use of single step ion exchange chromatography to purify abrin toxin for further development of its detection system.
Nutritional and Anti Oxidant Potential of Commonly Growing Plant Foods from Southern India
Authors: Rajendran C. , KirtanaKirtana S. , Venkatesh Rashmi , Yadav Pooja , Raghavan Anilakumar Kandankath
Published: February 2020

Certain varieties of plants are abundantly available with rich in nutrients, but the complete sets of nutritional composition studies have not been carried out. Among them, the matured leaves of Murrya keonigii; seeds and leaves of Moringa oleifera, and fruit pulp of Aegle marmelos were chosen. The proximate analysed for above samples showed that the moisture varies from 2.4% -8.2%, crude proteins from 18.75%- 34.57 %, fat content from 5.6% -19.6%, ash content from 3.87%-15.6% and carbohydrate from 28.65% - 41.23%, respectively. Estimation of mineral contents revealed that the leaves and seeds of moringa had higher concentrations than others. Determination of total antioxidant (total flavonoid) was higher (63.550 μg (RU)/ml of samples) in matured curry leaves than others. Determination of in vitro antioxidant activity with FRAP revealed highest activity in curry leaves (174.5μg) to a least activity with seeds of moringa (45.725 μg), whereas the DPPH revealed highest activity for fruit pulp of bael (1680.6μg ascorbic acid) to the least in leaves of moringa (263.15 μg ascorbic acid equivalent/mg). The ABTS showed IC50 value of 210.52 ±0.5774 for curry leaf, 487.8 ±0.3347 and 205.36 moringa seeds and leaves and 513.24 IC50 μg for pulp of bael fruit. Quantitative analysis of water soluble vitamins such as thiamine (B1) varied from 2.172 -5.558 mg; riboflavin (B2) from 2.201 -11.354 mg; pyridoxine (B6) from 4.608 -194.001 mg; biotin (B7) from 36.864 -153.027 mg, respectively. Further, the vitamin C (ascorbic acid) varied from 6.733 -23.142 mg /100g of oven dried samples, respectively. Therefore, the above foods are well intended to be included in routine diet regime and may also be willing to utilise for food supplementation with other suitable diets to manage the conditions such as malnutrition and nutrient deficiencies.
Distribution, Host Range and Bionomics of Rhopalosiphum nymphaeae (Linnaeus, 1761) a Polyphagous Aphid in Aquatic Vegetables
Authors: Halder Jaydeep , Rai A. B. , Chakrabarti Samiran , Dey Debjani
Published: February 2020

The present study records the occurrence of water lily aphid, Rhopalosiphum nymphaeae (Linn, 1971) on different aquatic plants from Varanasi and adjoining regions, Uttar Pradesh, India for the fi rst time. Both nymphs and adults prefer to feed on petiole, leaf lamina and buds towards terminal portion of different aquatic plants. They suck the cell sap resulting in curling of leaves, stunted plant growth with lower number of fruits in water chestnut. Further, the honey dew deposited on the leaves favours the development of black sooty-mould and hinders the normal photosynthetic activity of the plants. Infestation of aphid started in the region on water chestnut during last week of October (1.35 aphids leaf-1) coinciding with the initiation of winter in the region and gradually increased with highest peak (21.95 aphids leaf-1) during fourth week of January. Amongst the different aquatic host plants under study in the region, olfactometer study showed significantly highest number of R. nymphaeae (28%) attraction towards lotus followed by of water chestnut (21.3%) and water lily (20%) and the least was with water hyacinth (4%). Amongst the biopesticides tested, L. lecanii @ 5 g lit-1was found most promising with lowest median lethal time (31.09 h) followed by neem oil (1%) (41.59 h) and M. anisopliae (43.95 h).
Personality as a Predictor of Occupational Stress General Health and Job Satisfaction among IT Professionals
Authors: Bansal Dolly , Pathak Vijendra Nath
Published: February 2020

The study aims to highlight Personality as a Predictor of Occupational Stress, General Health, and Job Satisfaction among IT Professionals (government and private). Four hundred fifty respondents of IT professional (Government and private sector in India) (Male=298, Female=152), having at least 3 years of experience in IT sector from Delhi-NCR, Bangalore, and Pune. The age ranged from 22 - 49 year (Mean Age 25). Stratified random sampling was used. A total six hundred respondents were collected out of which 150 were not appropriate for the study (unfulfilled data). The psychometrically standardized questionnaires were used i.e. Occupational Stress Indicator – OSI, General Health Questionnaire 12, NEO Five-Factor Inventory and Minnesota Job Satisfaction Questionnaire. The result revealed that there was no significant difference between males and females on job satisfaction and general health. Further, there was a significant difference between the private and government sectors of IT professional’s on job satisfaction and occupational stress. The coefficient of correlation indicated a significantly positive correlation between occupational stress and personality. Regression analysis revealed that the level of job satisfaction depends upon negative affectivity. These findings indicated that negative affectivity has emerged as one of the important contributing factors to general health and job satisfaction on IT professionals. Preventive measures are suggested based on findings on how to reduce occupational stress of IT employees which would contribute to maintain a satisfied and contented staff.
Location Size and Orientation Effect of Semi elliptical Surface Crack on the Fracture of a Type 3 Composite Pressure Vessel using J integral Method
Authors: Çetin Muzaffer , Yaman Kemal
Published: February 2020

In this study, structural design and analysis of a type-3 composite over wrapped pressure vessel used in a military satellite propulsion system is presented. The aim is to design a composite tank lighter than all metal fuel tanks having the same volume. Moreover, necessary design stages have been revealed for similar composite over wrapped pressure vessels. ANSYS® is used to perform the stress-strain analysis of both metal and composite parts, to determine the optimum winding angle, tank Autofrettage and fracture characteristic for the metal liner considering the crack morphology. Tsai-Hill, Tsai-Wu and Hashin theories have been implemented to investigate the various failure modes of the composite vessel. Location, size and orientation angle of semi-elliptical surface crack has a pronounced effect on fracture characteristic of the liner. In fracture investigation J-integral method is used. It is foreseen that even in the most critical crack, the crack will not propagate and there will be no burst in the tank for proposed loading conditions. Numerical results are good agreement with the experimental results.
A study on the GA-BP neural network model for surface roughness of basswood-veneered medium-density fiberboard
Authors: Wu Xizhi , Niu Han , Li Xian-Jun , Wu Yiqiang
Published: February 2020

Roughness is an important property of wood surface and has a significant influence on the interface bonding strength and surface coating quality. However, there are no theoretical models for basswood-veneered medium-density fiberboard (MDF) by fine sanding from existing research work. In this paper, the basswood-veneered MDF was fine sanded with an air drum. Orthogonal experiment was implemented to study the effects of abrasive granularity, feed rate, belt speed, air drum deformation and air drum pressure on the surface roughness of basswood-veneered MDF. The simulation models of the parallel-grain roughness and the vertical-grain roughness of the sanded surface were conducted based on the BP (error back propagation) neural network, which was optimized by a genetic algorithm (GA) (GA-BP neural network), and these models were verified by extensive experimental data. The results showed that the influence of sanding parameters on parallel-grain roughness was similar to that on vertical-grain roughness. The order of influence was that: abrasive granularity > belt speed > feed speed > air drum deformation and air drum pressure. Based on the work, the parallel-grain roughness and vertical-grain roughness of basswood-veneered MDF could be well predicted by the GA-BP neural network. The average relative errors on parallel-grain roughness and vertical-grain roughness were 3.4% and 1.9%, respectively.
Lyapunov Stability of a Fractionally Damped Oscillator with Linear (Anti-)Damping
Authors: Hinze Matthias , Schmidt André , Leine Remco I.
Published: February 2020

In this paper, we develop a Lyapunov stability framework for fractionally damped mechanical systems. In particular, we study the asymptotic stability of a linear single degree-of-freedom oscillator with viscous and fractional damping. We prove that the total mechanical energy, including the stored energy in the fractional element, is a Lyapunov functional with which one can prove stability of the equilibrium. Furthermore, we develop a strict Lyapunov functional for asymptotic stability, thereby opening the way to a nonlinear stability analysis beyond an eigenvalue analysis. A key result of the paper is a Lyapunov stability condition for systems having negative viscous damping but a sufficient amount of positive fractional damping. This result forms the stepping stone to the study of Hopf bifurcations in fractionally damped mechanical systems. The theory is demonstrated on a stick-slip oscillator with Stribeck friction law leading to an effective negative viscous damping.
A Vygotskian approach to mediating learner intercultural competence during study abroad
Authors: Poehner Matthew E. , Pasterick Michelle L.
Published: February 2020

This study examines learner interaction with mediating resources designed to promote their intercultural competence (Byram, 2009; Deardorff, 2009) during study abroad that were made available to them through an online instructional space. In this way, the project offers a response to the challenges of students attempting to navigate a new cultural context without affordances characteristic of formal learning environments (i. e. an instructor, assigned readings, organized discussions). Undergraduate learners from a U. S. university foreign language program were enrolled in an online course organized according to principles of Vygotskian theory (2012), specifically the importance of abstract concepts and models for mediating thinking. Selected readings introduced learners to an intercultural communicative framework and discussions guided learners to reflect upon and interpret their experiences in light of ideas presented in the readings. Analysis of participant reflections and discussions reveal participant intercultural competence and ways in which it was mediated through the online course.
Influence of different surface treatment techniques on properties of rice husk incorporated polymer composites
Authors: Ezenkwa Obinna Emmanuel , Hassan Azman , Samsudin Sani Amril
Published: February 2020

Rice husk natural fiber remains a highly abundant, eco-friendly and low-cost reinforcement filler for plastic composites fabrication. Hampered by its low aspect ratio and incompatibility with non-polar polymers, its utilization in reinforcing polymer composites often results in decreased composite properties such as decreased tensile strength, impact strength, percentage elongation, and flexural strength. However, stiffness increases. Various surface treatment techniques such as mercerization, compatibilization, acetylation, electron beam irradiation and plasma surface modification have been employed to improve its compatibility with non-polar matrix polymers. This article critically reviews the influence of these surface modification techniques on the resulting composite properties. Based on the analysis of reinforcing efficiencies of these techniques, their strengths, weaknesses, opportunities, and threats, the authors, therefore, project plasma treatment as the most efficient and eco-friendly technique with prospects for high technological application of rice husk plastic composites.
High-performance pervaporation chitosan-based membranes: new insights and perspectives
Authors: Castro-Muñoz Roberto , González-Valdez José , Ahmad M. Zamidi
Published: February 2020

Today, the need of replacing synthetic polymers in the membrane preparation for diverse pervaporation (PV) applications has been recognized collectively and scientifically. Chitosan (CS), a bio-polymer, has been studied and proposed to achieve this goal especially in specific azeotropic water-organic, organic-water, and organic-organic separations, as well as in assisting specific processes (e.g. seawater desalination and chemical reactions). Different concepts of CS-based membranes have been developed, which include material blending and composite and mixed matrix membranes which have been tested for different separations. Hereby, the goal of this review is to provide a critical overview of the ongoing CS-based membrane developments, paying a special attention to the most relevant findings and results in the field. Furthermore, future trends of CS-based membranes in PV technology are presented, as well as concluding remarks and suggested strategies for the new scientist in the field.