bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bacteria- and host-derived extracellular vesicles – two sides of the same coin?
Authors: Schorey Jeffrey S. , Cheng Yong , McManus William R. 
Published: June 2021

ABSTRACT
Intracellular bacterial pathogens spend portions of their life cycle both inside and outside host cells. While in these two distinct environments, they release or shed bacterial components, including virulence factors that promote their survival and replication. Some of these components are released through extracellular vesicles, which are either derived from the bacteria themselves or from the host cells. Bacteria- and host-derived vesicles have been studied almost exclusively in isolation from each other, with little discussion of the other type of secreted vesicles, despite the fact that both are generated during an in vivo infection and both are likely play a role in bacterial pathogenesis and host immunity. In this Review, we aim to bridge this gap and discuss what we know of bacterial membrane vesicles in their generation and composition. We will compare and contrast this with the composition of host-derived vesicles with regard to bacterial components. We will also compare host cell responses to the different vesicles, with a focus on how these vesicles modulate the immune response, using Mycobacterium, Listeria and Salmonella as specific examples for these comparisons.
Mechanistic Studies into Visible Light-Driven Carboxylation of Aryl Halides/Triflates by the Combined Use of Palladium and Photoredox Catalysts
Authors: Toriumi Naoyuki , Shimomaki Katsuya , Caner Joaquim , Murata Kei , Martin Ruben , Iwasawa Nobuharu 
Published: June 2021

Abstract
The reaction mechanism of palladium-catalyzed visible light-driven carboxylation of aryl halides and triflates with a photoredox catalyst was examined in detail. Experimental and theoretical studies indicated that the active species for photoredox-catalyzed reduction was cationic ArPd(II)+ species to generate nucleophilic ArPd(I) or its further reduced ArPd(0)− species, which reacted with CO2 to give carboxylic acids. Hydrodehalogenated compounds, main byproducts in this carboxylation, were thought to be generated by protonation of these reduced species.
Muscle Metaboreflex Control of Sympathetic Activity Is Preserved after Acute Intermittent Hypercapnic Hypoxia
Authors: SHAFER BROOKE M. , INCOGNITO ANTHONY V. , VERMEULEN TYLER D. , NARDONE MASSIMO , TEIXEIRA ANDRÉ L. , BENBARUJ JENNA , MILLAR PHILIP J. , FOSTER GLEN E. 
Published: June 2021

ABSTRACT

Purpose
In normotensive patients with obstructive sleep apnea (OSA), the muscle sympathetic nerve activity (MSNA) response to exercise is increased while metaboreflex control of MSNA is decreased. We tested the hypotheses that acute intermittent hypercapnic hypoxia (IHH) in males free from OSA and associated comorbidities would augment the MSNA response to exercise but attenuate the change in MSNA during metaboreflex activation.

Methods
Thirteen healthy males (age = 24 ± 4 yr) were exposed to 40 min of IHH. Before and after IHH, the pressor response to exercise was studied during 2 min of isometric handgrip exercise (at 30% maximal voluntary contraction), whereas the metaboreflex was studied during 4 min of postexercise circulatory occlusion (PECO). Mean arterial pressure (MAP), heart rate (HR), and fibular MSNA were recorded continuously. MSNA was quantified as burst frequency (BF) and total activity (TA). Mixed effects linear models were used to compare the exercise pressor and metaboreflex before and after IHH.

Results
As expected, IHH led to significant increases in MSNA BF, TA, and MAP at baseline and throughout exercise and PECO. However, during handgrip exercise, the change from baseline in MAP, HR, MSNA BF, and TA was similar before and after IHH (All P > 0.31). During PECO, the change from baseline in MSNA BF and TA was similar after IHH, whereas the change from baseline in MAP (Δ14 mm Hg, 95% CI = 7–19, vs Δ16 mm Hg, 95% CI = 10–21; P < 0.01) was modestly increased.

Conclusion
After acute IHH, MSNA response to handgrip exercise and metaboreflex activation were preserved in healthy young males despite overall increases in resting MSNA and MAP. Chronic IHH and comorbidities often associated with OSA may be required to modulate the exercise pressor reflex and metaboreflex.
Factors affecting students’ entrepreneurial intentions and their differences based on gender, tribe, and parents’ occupation: a cross-sectional study
Authors: Hutasuhut Saidun , Thamrin Thamrin , Aditia Reza 
Published: June 2021

Background: This study examines the impact of entrepreneurial knowledge and self-efficacy in increasing students' entrepreneurial intentions and their self-efficacy. Differences were analyzed in entrepreneurial intentions based on gender, tribe, and parents’ occupation. Methods: The data used in this research was collected from a survey, done by distributing questionnaires electronically to students of the Economics Education Study Program, Faculty of Economics, State University of Medan in the semesters 3, 5, and 7, (n = 307), with a response from 260 individuals. The analytical test used was the PLS-SEM and nonparametric Mann-Whitney and Kruskal Wallis tests. Results: Entrepreneurial knowledge and self-efficacy positively and significantly increased entrepreneurial intentions. Self-efficacy was not proven to act as a moderating variable, and there was no difference in entrepreneurial intentions between genders, tribes and parents’ occupations. Conclusions: There is a need to enhance the role of the family, so that women's entrepreneurial intentions will not fall lower than men’s. It should be noted, however, the role of the family was not discussed in this study. This research implies that it is necessary to embrace innovative entrepreneurship education, so as to increase the entrepreneurial intentions of women and reduce gender inequality in entrepreneurial activities. Further research needs to be conducted on the role of culture-based families in preparing their sons and daughters to become entrepreneurs.
Regional disparities and their contribution to the coverage of the tetanus toxoid vaccine among women aged 15–49 years in Indonesia
Authors: Arifin Hidayat , Widiasih Restuning , Pradipta Rifky Octavia , Kurniawati Yulia 
Published: June 2021

Background: The prevention of Clostridium tetani bacterial infection through the administration of the tetanus toxoid (TT) vaccine in women is important. The purpose of this study was to determine the regional disparities and factors associated with TT vaccine coverage in women aged 15–49 years in Indonesia. Methods: The Indonesian Demographic Health Survey (IDHS) 2017 data was used in this study. A total of 36,028 women, aged 15–49 years were recruited using the two-stage stratified cluster sampling technique. The questionnaire used was based on the DHS Questionnaire Phase 7. Chi-squared and binary logistic regression were used in this study as part of the analysis. Results: We found that the TT vaccine coverage was 75.32% and that the majority were spread across several provinces. The provinces of Bali and Nusa Tenggara, the richer respondents, living in a rural area, visiting the health facility, having health insurance, and those currently working were factors making it more likely that the women would receive the TT vaccine. The respondents aged 15–24 years with a primary education level and the respondents who were divorced were less likely to receive the TT vaccine. Conclusion: The coverage of the TT vaccine among women can be increased by considering the regional disparities in Indonesia and the socio-economic demographic details of the respondents. Strengthening the policies from the central government in the local governments can improve the screening process and vaccine delivery outcomes. In addition, the importance of giving the TT vaccine to women needs to be relayed through health education in collaboration between health workers and the public.
Hyperspectral Estimation of Apple Canopy Chlorophyll Content Using an Ensemble Learning Approach
Authors: Bai Xueyuan , Song Yingqiang , Yu Ruiyang , Xiong Jingling , Peng Yufeng , Jiang Yuanmao , Yang Guijun , Li Zhenhai , Zhu Xicun 
Published: June 2021

HighlightsMonitored the canopy chlorophyll content of apple trees using hyperspectral reflectance information.Constructed support vector machine combination regression model (C-SVR) based on five-fold cross validation and support vector machine regression approach.Compared estimation accuracy of ensemble learning models (C-SVR, RF), machine learning models (SVR, ANN), and PLSR models for apple canopy chlorophyll content.Abstract. Rapidly and effective monitoring of the canopy chlorophyll content (CCC) of apple trees is of great significance for crop stress monitoring in precision agriculture. This study attempted to use hyperspectral vegetation indices (VIs) to estimate the CCC of apple trees based on ensemble learning approach. In this study, vegetation indices combined by any two wavelengths from 400 to 1100 nm were constructed to calculate the correlation coefficient with the CCC in apple. We constructed a partial least squares regression model (PLSR), artificial neural network regression model (ANN), support vector machine regression (SVR), random forest regression (RF) model and support vector machine combination regression model (C-SVR) based on combinations of VIs to improve the estimation accuracy in apple CCC. The results showed that the correlation coefficients between NDVI (949,695), OSAVI (828,705), RDVI (741,725), RVI (716,707), DVI (572,532), and apple CCC were all above 0.76. The CCC estimation model using the RF and C-SVR approach constructed by the NDVI (949,695), OSAVI (828,705), RDVI (741,725), RVI (716,707), and DVI (572,532) achieved the better estimation results, and the R2V, RMSEV, and RPDV values of models were 0.76, 0.131(mg . g-1), 2.04 and 0.78, 0.127(mg . g-1), 2.12, respectively. Compared with the PLSR, ANN, and SVR model, the R2V and RPDV values of C-SVR model were increased by 4%, 1.2%, 3.8%, and 5.0%, 28.4%, 7.1%, respectively. The results show that using C-SVR approach to estimating the apple CCC can realize high accuracy of quantitative estimation. Ensemble learning approach is an effective method for monitoring the nutrient status of fruit trees based on hyperspectral technique. Keywords: Apple tree canopy, Chlorophyll content, Crop stress monitoring, Ensemble learning, Hyperspectral, Vegetation index.
Chemical Components and Antioxidant and Antimicrobial Activities of Hedysarum Polybotrys Hand.-Mazz. Leaves and Root: A Comparative Study
Authors: Yang Doudou , Chen Yuan , Guo Fengxia , Jin Jianqin , Zhang Biquan , Jiao Xusheng 
Published: June 2021

HighlightsHedysarum polybotrys leaves have high levels of bioactive chemicals.H. polybotrys leaves have much stronger antioxidant activity than the root.The leaves may have a bright future if used as bioactive resources and antioxidants.The leaves should be a good material used in other fields with health and economic benefits.Abstract. Hedysarum polybotrys Hand.-Mazz. is a valuable plant that is usually used in food and medicine. The dry roots are important materials for chemical and medicinal applications, only a few researchers were concerned about the above-ground part though they contain various chemicals and nutrients. In this work, the chemical components and antioxidant and antimicrobial activities of the leaves were analyzed and compared with those of the roots. The results showed that compared to the roots the leaves contained much higher levels of polyphenol (13.11%), flavonoids (15.68%), and protein (26.49%) than the root (0.94%, 1.39%, 18.52%); higher levels of some important minerals, especially Fe (106.00 mg/kg) and Mn (20.40 mg/kg) than the root (88.80 mg/kg, 7.64 mg/kg); higher ratios of some essential fatty acids (alpha-linoleic acid); in particular, exhibited much stronger DPPH and ABTS radicals scavenging abilities and reducing power activities than HR. Therefore, the leaves contain various chemical components and much stronger antioxidant and broader antimicrobial activities than the roots, which indicates that they functioned as bioactive resources and antioxidants might have abundant health and economic benefits. The leaves and root extracts may have commercial potentials used by the food industry. Keywords: Antioxidant, Chemical components, Hedysarum polybotrys, Leaves.
Laboratory Scale of Seed Damage of Coarse-Grain Depending on Groove Diameter and Depth in Roller Devices
Authors: Kus Emrah , Yildirim Yildiran 
Published: June 2021

HighlightsThe rate of damage to the bean seed by the grooved roller planter was determinedThe effects of planting speed, seed rate, groove diameter, and groove depth on seed damageThe most suitable groove diameter and depth were determined in bean plantingAbstract. Grooved roller planters can be used in the planting of small and large seeds when they are produced in the appropriate groove diameter and groove depth depending on the seed dimensions. In this study, the rate of damage to the dry bean seeds of the grooved roller device, which was modified and placed on the bottom of the warehouse of a grain planter, was investigated. Nine grooved rollers manufactured in different groove diameters (18, 20, and 22 mm) and groove depths (5, 8, and 11 mm) were tested at 80, 120, and 160 kg ha-1 seed rates and 8, 13, and 18 min-1 feed shaft rotation speeds. Breakage, crushing, and cracking in dry bean seeds were considered as damaged seeds. According to the results, the increase in the seed rate, feed shaft rotation speed, and groove depth reduced the seed damage rate. The increase in groove diameter increased the rate of seed damage. The lowest seed damage rate values were obtained at 160 kg ha-1 seed rate, 2 m s-1 forward speed, 18 mm groove diameter, and 11 mm groove depth. Keywords: Active groove length, Dry bean seed, Forward speed, Grooved roller, Seed rate.
Resolution acuity and spatial summation of chromatic mechanisms in the peripheral retina
Authors: Zlatkova Margarita B. , Racheva Kalina , Totev Tsvetalin , Mihaylova Milena , Hristov Ivan , Anderson Roger S. 
Published: June 2021

Green stimuli are more difficult to detect than red stimuli in the retinal periphery, as reported previously. We examined the spatial characteristics of chromatic mechanisms using stimuli, modulated from an achromatic background to each pole of the “red–green” cardinal axis in DKL space at 20 deg eccentricity. The “blue–yellow” cardinal axis was also studied for comparison. By measuring both grating discrimination at the resolution limit (resolution acuity) and spatial summation, assessed by the Michaelis–Menten function, we demonstrated a marked “red–green” asymmetry. The resolution acuity was worse and spatial summation more extended for “green” compared to “red” stimuli, while showing significant individual variations. Ricco’s area was also measured, but not determined for “green” spots because of the poor small stimuli detection. These results cannot be explained by differences in L- and M-cone numerosity and/or spatial arrangement, but rather have postreceptoral origin, probably at the cortical level.
Highly efficient terahertz photoconductive metasurface detectors operating at microwatt-level gate powers
Authors: Hale Lucy L. , Harris C. Thomas , Luk Ting Shan , Addamane Sadhvikas J. , Reno John L. , Brener Igal , Mitrofanov Oleg 
Published: June 2021

Despite their wide use in terahertz (THz) research and technology, the application spectra of photoconductive antenna (PCA) THz detectors are severely limited due to the relatively high optical gating power requirement. This originates from poor conversion efficiency of optical gate beam photons to photocurrent in materials with sub-picosecond carrier lifetimes. Here we show that using an ultra-thin (160 nm), perfectly absorbing low-temperature grown GaAs metasurface as the photoconductive channel drastically improves the efficiency of THz PCA detectors. This is achieved through perfect absorption of the gate beam in a significantly reduced photoconductive volume, enabled by the metasurface. This Letter demonstrates that sensitive THz PCA detection is possible using optical gate powers as low as 5 µW—three orders of magnitude lower than gating powers used for conventional PCA detectors. We show that significantly higher optical gate powers are not necessary for optimal operation, as they do not improve the sensitivity to the THz field. This class of efficient PCA THz detectors opens doors for THz applications with low gate power requirements.
Room temperature mid-infrared fiber lasing beyond 5  µm in chalcogenide glass small-core step index fiber
Authors: Nunes J. J. , Sojka Ł. , Crane R. W. , Furniss D. , Tang Z. Q. , Mabwa D. , Xiao B. , Benson T. M. , Farries M. , Kalfagiannis N. , Barney E. , Phang S. , Seddon A. B. , Sujecki S. 
Published: June 2021

This Letter, to the best of our knowledge, reports mid-infrared fiber lasing beyond 5 µm at room temperature for the first time,

C
e

3
+

-doped, chalcogenide glass, step index fiber employed in-band pumping with a 4.15 µm quantum cascade laser. The lasing fiber is was 64 mm long, with a calculated numerical aperture of 0.48 at the lasing wavelengths. The core glass was

G
e

15

A
s

21

G
a

1

S
e

63

atomic % (at. %), doped with 500 parts-per-million-by-weight Ce, with a 9 µm core diameter. The cladding glass was

G
e

21

S
b

10

S
e

69

at. % with a 190 µm outer diameter. As pump power increases continuous wave lasing corresponding to the

2

F

7

/

2

→
2

F

5

/

2

, transition in the

C
e

3
+

ion occurs at 5.14 µm, 5.17 µm, and 5.28 µm.
The human immune response to saliva of Phlebotomus alexandri, the vector of visceral leishmaniasis in Iraq, and its relationship to sand fly exposure and infection
Authors: Lakhal-Naouar Ines , Mukbel Rami , DeFraites Robert F. , Mody Rupal M. , Massoud Lina N. , Shaw Dutchabong , Co Edgie M. , Sherwood Jeffrey E. , Kamhawi Shaden , Aronson Naomi E. 
Published: June 2021

BackgroundSand fly saliva exposure plays an important role in immunity against leishmaniasis where it has mostly been associated with protection.Phlebotomus (Ph.) alexandritransmitsLeishmania (L.) infantum, the causative agent of visceral leishmaniasis (VL), in Iraq. Our group recently demonstrated that 20% of Operation Iraqi Freedom (OIF) deployers had asymptomatic VL (AVL) indicative of prior infection by the parasiteL.infantum. Little is known aboutPh.alexandrisaliva, and the human immune response to it has never been investigated. Here, we characterize the humoral and cellular immune response to vector saliva in OIF deployers naturally exposed to bites ofPh.alexandriand characterize their immunological profiles in association to AVL.Methodology/Principal findingsThe humoral response toPh.alexandrisalivary gland homogenate (SGH) showed that 64% of 200 OIF deployers developed an antibody response. To assess the cellular immune response to saliva, we selected a subcohort of subjects based on their post-travel (median 4 months; range 1–22 months) antibody response (SGH Antibody [Ab] positive or negative) as well as their AVL status; ten never-traveled controls were also included. Banked peripheral blood mononuclear cells (PBMC), collected ~10 years after end of deployment, were stimulated with SGH for 96 hours. The levels of IFN- γ, IL-6, IL-10, IL-13 and IL-17 were determined by ELISA. Our findings indicate that OIF deployers mounted a cellular response to SGH where the anti-SGH+ asymptomatic subjects developed the highest cytokine levels. Further, stimulation with SGH produced a mixture of pro-inflammatory and anti-inflammatory cytokines. Contrary to our hypothesis, we observed no correlation between the cellular immune response toPh.alexandriSGH and prevention from asymptomatic infection withL.infantum.Conclusions/SignificanceAs we found, although all infected deployers demonstrated persistent disease control years after deployment, this did not correlate with anti-saliva systemic cellular response. More exposure to this vector may facilitate transmission of theL.infantumparasite. Since exposure to saliva ofPh.alexandrimay alter the human immune response to bites of this vector, this parameter should be taken into consideration when considering the VL risk.
Epidemiological investigation and physician awareness regarding the diagnosis and management of Q fever in South Korea, 2011 to 2017
Authors: Kim Yong Chan , Jeong Hye Won , Kim Dong-Min , Huh Kyungmin , Choi Sang-Ho , Lee Hee Young , Jung Yunjung , Seong Yeol Jung , Kim Eun Jin , Choi Young Hwa , Heo Jung Yeon 
Published: June 2021

Background
In South Korea, the number of Q fever cases has rapidly increased since 2015. Therefore, this study aimed to characterize the epidemiological and clinical features of Q fever in South Korea between 2011 and 2017.

Methods/Principal findings
We analyzed the epidemiological investigations and reviewed the medical records from all hospitals that had reported at least one case of Q fever from 2011 to 2017. We also conducted an online survey to investigate physicians’ awareness regarding how to appropriately diagnose and manage Q fever. The nationwide incidence rate of Q fever was annually 0.07 cases per 100,000 persons. However, there has been a sharp increase in its incidence, reaching up to 0.19 cases per 100,000 persons in 2017. Q fever sporadically occurred across the country, with the highest incidences in Chungbuk (0.53 cases per 100,000 persons per year) and Chungnam (0.27 cases per 100,000 persons per year) areas. Patients with acute Q fever primarily presented with mild illnesses such as hepatitis (64.5%) and isolated febrile illness (24.0%), whereas those with chronic Q fever were likely to undergo surgery (41.2%) and had a high mortality rate (23.5%). Follow-up for 6 months after acute Q fever was performed by 24.0% of the physician respondents, and only 22.3% of them reported that clinical and serological evaluations were required after acute Q fever diagnosis.

Conclusions
Q fever is becoming an endemic disease in the midwestern area of South Korea. Given the clinical severity and mortality of chronic Q fever, physicians should be made aware of appropriate diagnosis and management strategies for Q fever.