bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trehalose-deficient Acinetobacter baumannii exhibits reduced virulence by losing capsular polysaccharide and altering membrane integrity
Authors: Crippen Clay S , Glushka John , Vinogradov Evgeny , Szymanski Christine M 
Published: August 2021

Abstract
Acinetobacter baumannii has become a leading cause of bacterial nosocomial infections, in part, due to its ability to resist desiccation, disinfection and antibiotics. Several factors contribute to the tenacity and virulence of this pathogen, including production of a broad range of surface glycoconjugates, secretory systems and efflux pumps. We became interested in examining the importance of trehalose in A. baumannii after comparing intact bacterial cells by high-resolution magic angle spinning nuclear magnetic resonance and by noting high levels of this disaccharide, obscuring all other resonances in the spectrum. Since this was observed under normal growth conditions, we speculated that trehalose must serve additional functions beyond osmolyte homeostasis. Using the virulent isolate A. baumannii AB5075 and mutants in the trehalose synthesis pathway, osmoregulatory trehalose synthesis proteins A and B (△otsA and △otsB), we found that the trehalose-deficient △otsA showed increased sensitivity to desiccation, colistin, serum complement and peripheral blood mononuclear cells, while trehalose-6-phosphate producing △otsB behaved similar to the wild-type. The △otsA mutant also demonstrated increased membrane permeability and loss of capsular polysaccharide. These findings demonstrate that trehalose deficiency leads to loss of virulence in A. baumannii AB5075.
Wave Asymptotics for Waveguides and Manifolds with Infinite Cylindrical Ends
Authors: Christiansen T J , Datchev K 
Published: August 2021

Abstract
We describe wave decay rates associated to embedded resonances and spectral thresholds for waveguides and manifolds with infinite cylindrical ends. We show that if the cut-off resolvent is polynomially bounded at high energies, as is the case in certain favorable geometries, then there is an associated asymptotic expansion, up to a $O(t^{-k_0})$ remainder, of solutions of the wave equation on compact sets as $t \to \infty $. In the most general such case we have $k_0=1$, and under an additional assumption on the infinite ends we have $k_0 = \infty $. If we localize the solutions to the wave equation in frequency as well as in space, then our results hold for quite general waveguides and manifolds with infinite cylindrical ends. To treat problems with and without boundary in a unified way, we introduce a black box framework analogous to the Euclidean one of Sjöstrand and Zworski. We study the resolvent, generalized eigenfunctions, spectral measure, and spectral thresholds in this framework, providing a new approach to some mostly well-known results in the scattering theory of manifolds with cylindrical ends.
Albanese Maps and Fundamental Groups of Varieties With Many Rational Points Over Function Fields
Authors: Javanpeykar Ariyan , Rousseau Erwan 
Published: August 2021

Abstract
We investigate properties of the Albanese map and the fundamental group of a complex projective variety with many rational points over some function field and prove that every linear quotient of the fundamental group of such a variety is virtually abelian, as well as that its Albanese map is surjective, has connected fibres, and has no multiple fibres in codimension one.
Population pharmacokinetics of cefazolin in maternal and umbilical cord plasma, and simulated exposure in term neonates
Authors: Elkayal Omar , Allegaert Karel , Spriet Isabel , Smits Anne , Seghaye Marie-Christine , Charlier Corinne , Dreesen Erwin 
Published: August 2021

Abstract

Background
Intra-partum cefazolin is used to prevent group B Streptococcus (GBS) vertical transmission in mothers allergic to penicillin without a history of anaphylaxis.

Objectives
To investigate the maternal cefazolin dose–exposure relationship and subsequent maternal and neonatal target attainment at delivery.

Methods
Data were obtained from 24 healthy, GBS-colonized pregnant women (20–41 years), undergoing vaginal delivery (gestational age ≥37 weeks). During labour, all women received a 2 g cefazolin IV infusion. Eight hours later, eight women received another 1 g in the event of delayed (&gt;8 h) delivery. Next to maternal plasma concentrations (up to 10 per dosing interval, until delivery), venous and arterial umbilical cord concentrations were determined at delivery. Target attainment in maternal/neonatal plasma was set at 1 mg/L for 60% of the dosing interval (unbound cefazolin, worst-case clinical breakpoint). A population pharmacokinetic (popPK) model was built (NONMEM 7.4). ClinicalTrials.gov Identifier: NCT01295606.

Results
At delivery, maternal blood and arterial umbilical cord unbound cefazolin concentrations were &gt;1 mg/L in 23/24 (95.8%) and 11/12 (91.7%), respectively. The popPK of cefazolin in pregnant women was described by a two-compartment model with first-order elimination. Two additional compartments described the venous and arterial umbilical cord concentration data. Cefazolin target attainment was adequate in the studied cohort, where delivery occurred no later than 6.5 h after either the first or the second dose. PopPK simulations showed adequate maternal and umbilical cord exposure for 12 h following the first dose.

Conclusions
PopPK simulations showed that standard pre-delivery maternal cefazolin dosing provided adequate target attainment up to the time of delivery.
Comparative Analyses of Three Point-of-Care Urine Drug Test Devices’ Performance Characteristics for Use in Ambulatory Clinic Settings
Authors: Waggoner Derek C , Delaney Sarah R , Korpi-Steiner Nichole L 
Published: August 2021

Abstract

Background
Urine drug testing (UDT) is a standard practice used for monitoring controlled and illicit substances in ambulatory care patients. Point-of-care (POC) UDTs are useful tools that allow for drug identification within minutes, providing rapid and objective diagnostic assistance for clinicians. The objective of this study was to evaluate the performance characteristics of 3 different POC UDT devices compared to reference methods.

Methods
A total of 106 residual urine specimens were collected to evaluate the 3 POC UDT devices: the Profile®-V MEDTOX Scan® drugs of abuse test, Quidel Triage® TOX Drug screen, and Quidel Triage Rapid OXY-BUP-MDMA panel. Device performance was assessed by their ability to identify drug classes/compounds compared to manufacturer and reference method (mass spectrometry) cutoffs.

Results
The results from quantitative mass spectrometry showed that 77% (84/106) of the samples were positive for one or more drugs. Each device had variable performance across each drug class. Overall, the specificity of the Profile-V MEDTOX Scan test was 90.1%, while the Quidel Triage TOX Drug Screen and Rapid OXY-BUP-MDMA devices had specificities of 89.0% and 50.0% using their respective manufacturer-stated cutoffs. Overall sensitivity was determined to be 98.6%, 97.0%, and 100% for the Profile-V MEDTOX Scan, Quidel Triage TOX Drug Screen, and Rapid OXY-BUP-MDMA, respectively.

Conclusions
Of the 3 POC UDT devices evaluated, the Profile-V MEDTOX Scan demonstrated the best overall sensitivity and specificity compared to reference methods. False positive and negative results are possible with UDTs, ultimately the best device may depend on patient population and drugs of interest.
Robust K-means algorithm with weighted window for seismic facies analysis
Authors: Song Chengyun , Li Lin , Li Lingxuan , Li Kunhong 
Published: August 2021

Abstract
Seismic facies analysis can generate a map to describe the spatial distribution characteristics of reservoirs, and therefore plays a critical role in seismic interpretation. To analyse the characteristics of the horizon of interest, it is usually necessary to extract seismic waveforms along the target horizon using a selected time window. The inaccuracy of horizon interpretation often produces some inconsistent phases and leads to inaccurate classification. Therefore, the developed adaptive phase K-means algorithm proposed a sliding time window to extract seismic waveforms. However, setting the maximum offset of the sliding window is difficult in a real data application. A value that is too large may cause the cross-layer problem, whereas a value that is too small reduces the flexibility of the algorithm. To address this disadvantage, this paper proposes a robust K-means (R-K-means) algorithm with a Gaussian-weighted sliding window for seismic waveform classification. The used weights punish those windows distant from the interpretation horizon in the objective function, consequently producing a smaller range of horizon adjustments even when using relatively large maximum offsets and benefitting the generation of stable and reliable seismic facies maps. The application of real seismic data from the F3 block proves the effectiveness of the proposed algorithm.
Morphological components detection for super-depth-of-field bio-micrograph based on deep learning
Authors: Du Xiaohui , Wang Xiangzhou , Xu Fan , Zhang Jing , Huo Yibo , Ni Guangmin , Hao Ruqian , Liu Juanxiu , Liu Lin 
Published: August 2021

AbstractAccompanied with the clinical routine examination demand increase sharply, the efficiency and accuracy are the first priority. However, automatic classification and localization of cells in microscopic images in super depth of Field (SDoF) system remains great challenges. In this paper, we advance an object detection algorithm for cells in the SDoF micrograph based on Retinanet model. Compared with the current mainstream algorithm, the mean average precision (mAP) index is significantly improved. In the experiment of leucorrhea samples and fecal samples, mAP indexes are 83.1% and 88.1%, respectively, with an average increase of 10%. The object detection model proposed in this paper can be applied to feces and leucorrhea detection equipment, and significantly improve the detection efficiency and accuracy.
Masses and compositions of three small planets orbiting the nearby M dwarf L231-32 (TOI-270) and the M dwarf radius valley
Authors: Van Eylen V , Astudillo-Defru N , Bonfils X , Livingston J , Hirano T , Luque R , Lam K W F , Justesen A B , Winn J N , Gandolfi D , Nowak G , Palle E , Albrecht S , Dai F , Estrada B Campos , Owen J E , Foreman-Mackey D , Fridlund M , Korth J , Mathur S , Forveille T , Mikal-Evans T , Osborne H L M , Ho C S K , Almenara J M , Artigau E , Barragán O , Barros S C C , Bouchy F , Cabrera J , Caldwell D A , Charbonneau D , Chaturvedi P , Cochran W D , Csizmadia S , Damasso M , Delfosse X , De Medeiros J R , Díaz R F , Doyon R , Esposito M , Fűrész G , Figueira P , Georgieva I , Goffo E , Grziwa S , Guenther E , Hatzes A P , Jenkins J M , Kabath P , Knudstrup E , Latham D W , Lavie B , Lovis C , Mennickent R E , Mullally S E , Murgas F , Narita N , Pepe F A , Persson C M , Redfield S , Ricker G R , Santos N C , Seager S , Serrano L M , Smith A M S , Mascareño A Suárez , Subjak J , Twicken J D , Udry S , Vanderspek R , Osorio M R Zapatero 
Published: August 2021

Abstract
We report on precise Doppler measurements of L231-32 (TOI-270), a nearby M dwarf (d = 22 pc, M⋆ = 0.39 M⊙, R⋆ = 0.38 R⊙), which hosts three transiting planets that were recently discovered using data from the Transiting Exoplanet Survey Satellite (TESS). The three planets are 1.2, 2.4, and 2.1 times the size of Earth and have orbital periods of 3.4, 5.7, and 11.4 days. We obtained 29 high-resolution optical spectra with the newly commissioned Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) and 58 spectra using the High Accuracy Radial velocity Planet Searcher (HARPS). From these observations, we find the masses of the planets to be 1.58 ± 0.26, 6.15 ± 0.37, and 4.78 ± 0.43 M⊕, respectively. The combination of radius and mass measurements suggests that the innermost planet has a rocky composition similar to that of Earth, while the outer two planets have lower densities. Thus, the inner planet and the outer planets are on opposite sides of the ‘radius valley’ — a region in the radius-period diagram with relatively few members, which has been interpreted as a consequence of atmospheric photo-evaporation. We place these findings into the context of other small close-in planets orbiting M dwarf stars, and use support vector machines to determine the location and slope of the M dwarf (Teff &lt; 4000 K) radius valley as a function of orbital period. We compare the location of the M dwarf radius valley to the radius valley observed for FGK stars, and find that its location is a good match to photo-evaporation and core-powered mass loss models. Finally, we show that planets below the M dwarf radius valley have compositions consistent with stripped rocky cores, whereas most planets above have a lower density consistent with the presence of a H-He atmosphere.
The origins of low-luminosity supernovae: the case of SN 2016bkv
Authors: Deckers Maxime , Groh Jose H , Boian Ioana , Farrell Eoin J 
Published: August 2021

ABSTRACT
We investigate the low-luminosity supernova SN 2016bkv and its peculiar early-time interaction. For that, we compute radiative transfer models using the cmfgen code. Because SN 2016bkv shows signs of interaction with material expelled by its progenitor, it offers a great opportunity to constrain the uncertain evolutionary channels leading to low-luminosity supernovae. Our models indicate that the progenitor had a mass-loss rate of (6.0 ± 2.0) × 10−4$\mathit {\rm M}_{\odot }\,{\rm yr}^{-1}$(assuming a velocity of 150 ${\rm km\, s^{-1}}$). The surface abundances of the progenitor are consistent with solar contents of He and CNO. If SN 2016bkv’s progenitor evolved as a single star, it was an odd red supergiant that did not undergo the expected dredge up for some reason. We propose that the progenitor more likely evolved through binary interaction. One possibility is that the primary star accreted unprocessed material from a companion and avoided further rotational and convective mixing until the SN explosion. Another possibility is a merger with a lower mass star, with the primary remaining with low N abundance until core collapse. Given the available merger models, we can only put a loose constraint on the pre-explosion mass around 10–20 $\mathit {\rm M}_{\odot }$, with lower values being favoured based on previous observational constraints from the nebular phase.
Polo-like kinase 1 (Plk1) regulates DNA replication origin firing and interacts with Rif1 in Xenopus
Authors: Ciardo Diletta , Haccard Olivier , Narassimprakash Hemalatha , Cornu David , Guerrera Ida Chiara , Goldar Arach , Marheineke Kathrin 
Published: August 2021

Abstract
The activation of eukaryotic DNA replication origins needs to be strictly controlled at multiple steps in order to faithfully duplicate the genome and to maintain its stability. How the checkpoint recovery and adaptation protein Polo-like kinase 1 (Plk1) regulates the firing of replication origins during non-challenged S phase remained an open question. Using DNA fiber analysis, we show that immunodepletion of Plk1 in the Xenopus in vitro system decreases replication fork density and initiation frequency. Numerical analyses suggest that Plk1 reduces the overall probability and synchrony of origin firing. We used quantitative chromatin proteomics and co-immunoprecipitations to demonstrate that Plk1 interacts with firing factors MTBP/Treslin/TopBP1 as well as with Rif1, a known regulator of replication timing. Phosphopeptide analysis by LC/MS/MS shows that the C-terminal domain of Rif1, which is necessary for its repressive action on origins through protein phosphatase 1 (PP1), can be phosphorylated in vitro by Plk1 on S2058 in its PP1 binding site. The phosphomimetic S2058D mutant interrupts the Rif1-PP1 interaction and modulates DNA replication. Collectively, our study provides molecular insights into how Plk1 regulates the spatio-temporal replication program and suggests that Plk1 controls origin activation at the level of large chromatin domains in vertebrates.
An emerging picture of FANCJ’s role in G4 resolution to facilitate DNA replication
Authors: Brosh Robert M , Wu Yuliang 
Published: August 2021

Abstract
A well-accepted hallmark of cancer is genomic instability, which drives tumorigenesis. Therefore, understanding the molecular and cellular defects that destabilize chromosomal integrity is paramount to cancer diagnosis, treatment and cure. DNA repair and the replication stress response are overarching paradigms for maintenance of genomic stability, but the devil is in the details. ATP-dependent helicases serve to unwind DNA so it is replicated, transcribed, recombined and repaired efficiently through coordination with other nucleic acid binding and metabolizing proteins. Alternatively folded DNA structures deviating from the conventional anti-parallel double helix pose serious challenges to normal genomic transactions. Accumulating evidence suggests that G-quadruplex (G4) DNA is problematic for replication. Although there are multiple human DNA helicases that can resolve G4 in vitro, it is debated which helicases are truly important to resolve such structures in vivo. Recent advances have begun to elucidate the principal helicase actors, particularly in cellular DNA replication. FANCJ, a DNA helicase implicated in cancer and the chromosomal instability disorder Fanconi Anemia, takes center stage in G4 resolution to allow smooth DNA replication. We will discuss FANCJ’s role with its protein partner RPA to remove G4 obstacles during DNA synthesis, highlighting very recent advances and implications for cancer therapy.
Metal-organic frameworks bonded with metal N-heterocyclic carbenes for efficient catalysis
Authors: He Chang , Liang Jun , Zou Yu-Huang , Yi Jun-Dong , Huang Yuan-Biao , Cao Rong 
Published: August 2021

Abstract
Metal N-heterocyclic carbenes (M-NHCs) on the pore walls of a porous metal-organic framework (MOF) can be used as active sites for efficient organic catalysis. Traditional approaches that need strong alkaline reagents or insoluble Ag2O are not, however, suitable for the incorporation of NHCs on the backbones of MOFs because such reagents could destroy their frameworks or result in low reactivity. Accordingly, development of facile strategies toward functional MOFs with covalently bound M-NHCs for catalysis is needed. Herein, we describe the development of a general and facile approach to preparing MOFs with covalently linked active M-NHC (M = Pd, Ir) single-site catalysts by using a soluble Ag salt AgOC(CF3)3 as the source and subsequent transmetalation. The well-defined M-NHC-MOF (M = Pd, Ir) catalysts obtained in this way have shown excellent catalytic activity and stability in Suzuki reactions and hydrogen transfer reactions. This provides a general and facile strategy for anchoring functional M-NHC single-site catalysts onto functionalized MOFs for different reactions.
Ten Years of Diphtheria Toxin Testing and Toxigenic Cutaneous Diphtheria Investigations in Alberta, Canada: A Highly Vaccinated Population
Authors: Marshall Natalie C , Baxi Maulik , MacDonald Clayton , Jacobs Angela , Sikora Christopher A , Tyrrell Gregory J 
Published: August 2021

Abstract

Background
Respiratory diphtheria is a potentially fatal toxin-mediated disease that is rare among highly vaccinated populations. Cutaneous infections with toxigenic Corynebacterium diphtheriae are most commonly linked to travel to an endemic region. Corynebacterium ulcerans has emerged as a predominant, locally acquired cause of respiratory and cutaneous diphtheria in Western Europe. Recently, public health agencies from several highly vaccinated regions expanded their guidelines to investigate toxigenic cutaneous diphtheria regardless of travel history. With relatively unknown epidemiology of C diphtheriae in North America, and increasing diphtheria toxin testing over the last decade, this change could lead to substantial increases in public health investigations with unclear benefits.

Methods
This study examined the diagnostic and public health benefits of toxigenic cutaneous diphtheria investigations in the highly vaccinated population of Alberta, Canada, where travel history is not required for cutaneous diphtheria investigations. All C diphtheriae isolates collected between 2010 and 2019 were reviewed for specimen source, toxigenicity, biovar, and associated clinical and public health data.

Results
Of these, 5% of C diphtheriae isolates were toxigenic and 82% were isolated from cutaneous sites. Three cases of toxigenic cutaneous disease were identified, none from patients with recent travel. Contact tracing identified asymptomatic C diphtheriae colonization among 0%–26% of close contacts, with identical isolate profiles among colonized contacts and primary cases.

Conclusions
Cutaneous diphtheria in nonendemic regions warrants public health investigation regardless of travel history and overall vaccination levels. This study underscores the importance of including C ulcerans in public health guidelines to assess the overall prevalence and epidemiology of toxigenic corynebacteria.
ASSESSMENT OF RADIATION DOSE OF MOBILE COMPUTED TOMOGRAPHY IN INTENSIVE CARE UNITS
Authors: Kim Eunhye , Choi Yoonseok , Park Hyemin , Na Chanyoung , Kim Jungmin , Kim Jungsu , Han Taeho 
Published: August 2021

Abstract
Intra-hospital transport is associated with fatal risks for the occupants of an intensive care unit (ICU). Thus, mobile CT is used in ICUs. In this study, two-dimensional equivalent dose distribution data were expanded using the inverse square law of distance to identify the potential exposure of radiologic technologists and public and the maximum number of possible daily CT procedures. The exposure dose at 1.5 m from the isocentre of the mobile CT was 2.260 μSv. Based on the dose limitation (5 mSv/yr for controlled area and 1 mSv/yr for uncontrolled area) as per National Council on Radiation Protection and Measurement report, the number of possible scans per day was 9 for radiologic technologists and 2 for public. When using the radiation shielding partition with a lead equivalent of 0.3 mmPb, the exposure dose reduced as 0.399 μSv. Therefore, mobile CT can be used in ICUs when appropriate shielding is provided.
Immigrant-Biased Technological Change: The Effect of New Technology Implementation on Native and Non-Western Immigrant Employment in the Netherlands
Authors: ten Berge Jannes , Tomaskovic-Devey Donald 
Published: August 2021

Abstract
This study examines how workplace technological innovation is associated with individual-level employment turnover. We advance the literature by studying how the impact of technology differs for Dutch native workers and workers with non-Western immigrant backgrounds. Furthermore, we examine the disparate impacts of organizational context, as indexed by the proportion of workers with non-Western immigrant backgrounds and workplace job volatility, as well as industry-level unionization. Using large-scale Dutch matched employer–employee longitudinal data for the period 2001–2014, we find technology implementation to decrease chances of job ending, but this innovation protection is smaller and sometimes absent for workers with non-Western immigrant backgrounds than for native Dutch workers. This pattern is most marked for first-generation immigrants and immigrants from non-Dutch-speaking countries. We also find evidence of organization-level ethnic competition effects among low and middle educated workers, but not for workers with tertiary degrees. Among lower educated workers technological displacement is exaggerated in workplaces that employ many workers with immigrant backgrounds, although unionization mutes this effect. Among middle educated workers technological displacement is exaggerated in high-turnover workplaces.