bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges of providing HIV pre-exposure prophylaxis across Australian clinics: qualitative insights of clinicians
Authors: Smith Anthony K J , Haire Bridget , Newman Christy E. , Holt Martin
Published: April 2021

Background HIV pre-exposure prophylaxis (PrEP) has been rapidly implemented in Australia, initially through restricted access in demonstration studies, and then through prescribing across sexual health clinics and general practice settings. In 2018, PrEP was publicly subsidised for people with Medicare (universal health insurance for citizens, permanent residents and those from countries with reciprocal arrangements). There is little research examining the experiences of PrEP providers in Australia, and existing research has been primarily conducted before public subsidy. Methods: In this qualitative study, we examine the challenges that have emerged for PrEP-providing clinicians after public subsidy for PrEP was introduced. We conducted 28 semi-structured interviews in 2019–20 with PrEP providers in two Australian states, and analysed data thematically. Participants included general practitioners (GPs), sexual health nurses and sexual health physicians. Results: Sexual health services have been reconfigured to meet changing patient demand, with an emphasis on ensuring equitable financial access to PrEP. Restrictions to nurse-led PrEP frustrated some participants, given that nurses had demonstrated competence during trials. GPs were believed to be less effective at prescribing PrEP, but GP participants themselves indicated that PrEP was an easy intervention, but difficult to integrate into general practice. Participants expressed discomfort with on-demand PrEP. Conclusions: Our findings indicate that supporting ways for patients without Medicare to access PrEP inexpensively, advocating for nurse-led PrEP, and developing guidelines adapted to general practice consultations could ensure that PrEP is delivered more effectively and equitably. Additionally, PrEP providers require encouragement to build confidence in providing on-demand PrEP.
Causes and predictors of mortality from lupus nephritis in Southern Hunan, China
Authors: Liu Peng , Peng Zhong , Xiang Yazhou , Duan Yingjie , Huang Hong , Peng Zhiyong , Zhang Yong , Yang Bo , Ou Jihong , He Zhangxiu
Published: April 2021

Objectives

The objective of the study was to explore the causes and predictors of mortality in a cohort of LN with LN in southern Hunan, China.

Methods

We analyzed 236 patients with biopsy-proven LN during 2010–2018. Demographic data, laboratory data, SLEDAI scores, treatment strategies, and comorbidity were collected. Cox regression analysis was carried out to determine the independent predictors of mortality.

Results

The patients had mean disease duration of 67.9 ± 28.2 months. Class IV LN was the predominant biopsy class within the cohort (38.1%). After 1 year therapy, the majority of patients achieved complete remission (72.9%) and 44 (18.6%) patients achieved partial remission. The 5- and 10-years survival rates for our cohort were 94.4 and 85.2%, respectively. There were 18 deaths (7.6%), of which the main causes were infection (50%) alone and cardiovascular diseases (27.8%). Independent predictors of mortality in our cohort were: platelet-to-neutrophil ratio (PNR) [hazard ratio (HR) 5.910; confidence interval (CI) 1.253–27.875], onset age (HR 1.090; CI 1.035–1.147), and SLEDAI scores (HR 1.258; CI 1.068–1.482).

Conclusion

We firstly revealed that PNR might be a promising predictor of mortality and reported the causes and prognostic predictors of mortality in LN from southern Hunan, China.
Tension promotes kinetochore–microtubule release by Aurora B kinase
Authors: Chen Geng-Yuan , Renda Fioranna , Zhang Huaiying , Gokden Alper , Wu Daniel Z. , Chenoweth David M. , Khodjakov Alexey , Lampson Michael A.
Published: April 2021

To ensure accurate chromosome segregation, interactions between kinetochores and microtubules are regulated by a combination of mechanics and biochemistry. Tension provides a signal to discriminate attachment errors from bi-oriented kinetochores with sisters correctly attached to opposite spindle poles. Biochemically, Aurora B kinase phosphorylates kinetochores to destabilize interactions with microtubules. To link mechanics and biochemistry, current models regard tension as an input signal to locally regulate Aurora B activity. Here, we show that the outcome of kinetochore phosphorylation depends on tension. Using optogenetics to manipulate Aurora B at individual kinetochores, we find that kinase activity promotes microtubule release when tension is high. Conversely, when tension is low, Aurora B activity promotes depolymerization of kinetochore–microtubules while maintaining attachment. Thus, phosphorylation converts a catch-bond, in which tension stabilizes attachments, to a slip-bond, which releases microtubules under tension. We propose that tension is a signal inducing distinct error-correction pathways, with release or depolymerization being advantageous for typical errors characterized by high or low tension, respectively.
Ubiquitous membrane-bound DNase activity in podosomes and invadopodia
Authors: Pal Kaushik , Zhao Yuanchang , Wang Yongliang , Wang Xuefeng
Published: April 2021

Podosomes and invadopodia, collectively termed invadosomes, are adhesive and degradative membrane structures formed in many types of cells and are well known for recruiting various proteases. However, another major class of degradative enzymes, deoxyribonuclease (DNase), remains unconfirmed and not studied in invadosomes. Here, using surface-immobilized nuclease sensor (SNS), we demonstrated that invadosomes recruit DNase to their core regions, which degrade extracellular double-stranded DNA. We further identified the DNase as GPI-anchored membrane-bound DNase X. DNase recruitment is ubiquitous and consistent in invadosomes of all tested cell types. DNase activity exhibits within a minute after actin nucleation, functioning concomitantly with protease in podosomes but preceding it in invadopodia. We further showed that macrophages form DNase-active podosome rosettes surrounding bacteria or micropatterned antigen islets, and the podosomes directly degrade bacterial DNA on a surface, exhibiting an apparent immunological function. Overall, this work reports DNase in invadosomes for the first time, suggesting a richer arsenal of degradative enzymes in invadosomes than known before.
Mechanism of mutant calreticulin-mediated activation of the thrombopoietin receptor in cancers
Authors: Venkatesan Arunkumar , Geng Jie , Kandarpa Malathi , Wijeyesakere Sanjeeva Joseph , Bhide Ashwini , Talpaz Moshe , Pogozheva Irina D. , Raghavan Malini
Published: April 2021

Myeloproliferative neoplasms (MPNs) are frequently driven by mutations within the C-terminal domain (C-domain) of calreticulin (CRT). CRTDel52 and CRTIns5 are recurrent mutations. Oncogenic transformation requires both mutated CRT and the thrombopoietin receptor (Mpl), but the molecular mechanism of CRT-mediated constitutive activation of Mpl is unknown. We show that the acquired C-domain of CRTDel52 mediates both Mpl binding and disulfide-linked CRTDel52 dimerization. Cysteine mutations within the novel C-domain (C400A and C404A) and the conserved N-terminal domain (N-domain; C163A) of CRTDel52 are required to reduce disulfide-mediated dimers and multimers of CRTDel52. Based on these data and published structures of CRT oligomers, we identify an N-domain dimerization interface relevant to both WT CRT and CRTDel52. Elimination of disulfide bonds and ionic interactions at both N-domain and C-domain dimerization interfaces is required to abrogate the ability of CRTDel52 to mediate cell proliferation via Mpl. Thus, MPNs exploit a natural dimerization interface of CRT combined with C-domain gain of function to achieve cell transformation.
O-GlcNAc modification of nuclear pore complexes accelerates bidirectional transport
Authors: Yoo Tae Yeon , Mitchison Timothy J.
Published: April 2021

Macromolecular transport across the nuclear envelope depends on facilitated diffusion through nuclear pore complexes (NPCs). The interior of NPCs contains a permeability barrier made of phenylalanine-glycine (FG) repeat domains that selectively facilitates the permeation of cargoes bound to nuclear transport receptors (NTRs). FG-repeat domains in NPCs are a major site of O-linked N-acetylglucosamine (O-GlcNAc) modification, but the functional role of this modification in nucleocytoplasmic transport is unclear. We developed high-throughput assays based on optogenetic probes to quantify the kinetics of nuclear import and export in living human cells. We found that increasing O-GlcNAc modification of the NPC accelerated NTR-facilitated transport of proteins in both directions, and decreasing modification slowed transport. Superresolution imaging revealed strong enrichment of O-GlcNAc at the FG-repeat barrier. O-GlcNAc modification also accelerated passive permeation of a small, inert protein through NPCs. We conclude that O-GlcNAc modification accelerates nucleocytoplasmic transport by enhancing the nonspecific permeability of the FG-repeat barrier, perhaps by steric inhibition of interactions between FG repeats.
Modelling the impact of electrode roughness on net charge density in polyethylene
Authors: Hoang M Q , Nguyen M Q , Vu T T N , Teyssedre G , Le Roy S
Published: April 2021

Predicting the electric field distribution under dc stress within polymeric insulations remains a challenge, as space charge behaviour is still difficult to understand in these materials. Charge generation is often thought to arise from injection at the electrodes. Hence, surface roughness should be taken into account, as it strengthens the electric field locally and therefore promotes charge generation at some points. A charge transport model has been developed in 2D to account for surface roughness. The model is first validated with the help of previous results, obtained with a one-dimensional charge transport model. Then, with simple shapes accounting for roughness, the simulated results show that surface roughness has a significant impact on the net space charge behaviour. The impact of shape, and size of protrusions are presented, as well as a more realistic case where a large surface of the electrode is considered to be rough.
An audit of published South African diagnostic reference level data
Authors: Trauernicht C J , Pitcher R D
Published: April 2021

Diagnostic reference levels (DRLs) are accepted as a dose optimisation tool for patients undergoing x-ray imaging and are required by South African (SA) legislation for 26 fluoroscopically guided procedures (FGPs). The aim of this paper is to collate all published SA data on DRLs in preparation for a project to establish national DRLs. Systematic searches were conducted of various applicable databases. All research that proposed DRLs for any imaging procedure in South Africa was included. Twenty-one works met inclusion criteria, the earliest from 2001. Two-thirds of all work reported on FGPs and five studies documented computed tomography DRLs. Three publications focussed exclusively on paediatric imaging DRLs. No studies on mammography or dental radiography were found. For clinical procedures with more than one proposed DRL, the range of proposed DRL varied by up to a factor of five. The highest proposed DRL is 373.1 Gy cm2 for endovascular aneurysm/aortic repair procedures. Data were collected in six public hospitals and two private hospital groups. Thirty-six authors contributed to the manuscripts, but only six studies had an inter-disciplinary authorship. This is the first paper to provide a comprehensive review of SA DRL data and thereby advances international radiation protection initiatives. The data suggests there is room for more interdisciplinary work and that there must be rigorous standardization of reported parameters and data collection. This audit also highlights the need for standardized terminology, particularly for FGPs.
Error analysis in measuring physical quantities using various sensors on a smartphone
Authors: Listiaji Prasetyo , Subhan Subhan , Daeni Fitri , Karmuji
Published: April 2021

In the initial topic in basic physics in school and college, the concept of analysing a measurement error needs to be understood by students. This paper proposes the use of various sensors on smartphones for statistical error analysis which usually uses the classical method with repeated measurements. The smartphone sensors used were light, acceleration, and magnetometer sensors. The data from the sensor recording fluctuations for 10 s were analysed for the simple statistical figures and error. The experiment used three different conditions, namely placing the smartphone on a stable table, holding it with your hand, and bringing it closer to a notebook that played a 650 Hz tones. The experimental findings, the experimental conditions (environmental and blunder), and the specifications of the instrument affect the error. Students also can tell that the sensor takes repeated measurements so that it shows fluctuation data. This research contributes to offering the use of the latest technology, namely smartphones, for statistical error analysis for physics students.
Data-driven respiratory phase-matched PET attenuation correction without CT
Authors: Hwang Donghwi , Kang Seung Kwan , Kim Kyeong Yun , Choi Hongyoon , Seo Seongho , Lee Jae Sung
Published: April 2021

We propose a deep learning-based data-driven respiratory phase-matched gated-PET attenuation correction (AC) method that does not need a gated-CT. The proposed method is a multi-step process that consists of data-driven respiratory gating, gated attenuation map estimation using maximum-likelihood reconstruction of attenuation and activity (MLAA) algorithm, and enhancement of the gated attenuation maps using convolutional neural network (CNN). The gated MLAA attenuation maps enhanced by the CNN allowed for the phase-matched AC of gated-PET images. We conducted a non-rigid registration of the gated-PET images to generate motion-free PET images. We trained the CNN by conducting a 3D patch-based learning with 80 oncologic whole-body 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan data and applied it to seven regional PET/CT scans that cover the lower lung and upper liver. We investigated the impact of the proposed respiratory phase-matched AC of PET without utilizing CT on tumor size and standard uptake value (SUV) assessment, and PET image quality (%STD). The attenuation corrected gated and motion-free PET images generated using the proposed method yielded sharper organ boundaries and better noise characteristics than conventional gated and ungated PET images. A banana artifact observed in a phase-mismatched CT-based AC was not observed in the proposed approach. By employing the proposed method, the size of tumor was reduced by 12.3% and SUV90% was increased by 13.3% in tumors with larger movements than 5 mm. %STD of liver uptake was reduced by 11.1%. The deep learning-based data-driven respiratory phase-matched AC method improved the PET image quality and reduced the motion artifacts.
Impurity transport in tokamak plasmas, theory, modelling and comparison with experiments
Authors: Angioni Clemente
Published: April 2021

In this paper, the theory of collisional and turbulent transport of impurities in tokamak plasmas is reviewed. The results are presented with the aim of providing at the same time a historical reconstruction of the scientific progress and a complete description of the present theoretical knowledge, with a hopefully sufficiently complete reference to the works which have been published in the field in the last decades. After a general introduction on the physics challenges offered by the problem of impurity transport and their relevance for practical nuclear fusion energy, the theory of collisional transport is presented. Here a specific section is also dedicated to the transport parallel to the magnetic field lines. A complete review of the transport mechanisms produced by turbulence follows. The corresponding comparisons between theoretical predictions and experimental observations are also presented, highlighting the influence that the validation activities had in motivating further theoretical investigations. The paper is completed by a section on the direct interactions between collisional and turbulent transport and by a final specific review dedicated to the progress in the theory–based modelling activities. In the writing of this review paper, the main goal has been to combine readability with completeness and scientific rigour, providing a comprehensive list of references for deeper documentation on specific aspects.
An efficient and facile method to develop defect-free OLED displays
Authors: Solanki Ankur , Awasthi Asha , Unni K N Narayanan , Deepak
Published: April 2021

Organic light emitting diodes (OLEDs) have captured the attention of the flat-panel display market owing to their high luminescence and versatile properties. However, substrate processing plays a critical part in the fabrication of OLED displays, demonstrated here as a passive matrix display, where plenty of defects, which appear during the processing stage, result in poor display quality and yield. Photolithography is the most common technique used to develop the electrode pattern on a transparent glass substrate. Nevertheless, poor lithography leads to display defects such as dead pixels, dark columns and bright horizontal rows. Moreover, shorts between anodes due to partial etching of the transparent conducting material or cathode lines are also common problems. Herein, we discuss a technique which drastically reduces the number of electrode shorts. Selective etching of the cathode in this technique makes the optical inspection of electrode shorts far easier due to the higher contrast ratio between Cr/glass compared to indium tin oxide/glass. Further, a focused laser beam is employed to ablate the identified shorts between two or more anode/cathode lines to make the short-free patterns. Additionally, a laser beam is also capable of isolating the burnt/dead pixels in a display, which otherwise lead to dark or bright lines during operation. Thus, our findings are very important for the display industry to develop defect-free panels and for the repair of certain operational defects to increase the production yield and lifetime.
Experimental test of fluctuation relations for driven open quantum systems with an NV center
Authors: Hernández-Gómez Santiago , Staudenmaier Nicolas , Campisi Michele , Fabbri Nicole
Published: April 2021

The experimental verification of quantum fluctuation relations for driven open quantum system is currently a challenge, due to the conceptual and operative difficulty of distinguishing work and heat. The nitrogen-vacancy (NV) center in diamond has been recently proposed as a controlled test bed to study fluctuation relations in the presence of an engineered dissipative channel, in absence of work (Hernández-Gómez et al 2020 Phys. Rev. Res.
2 023327). Here, we extend those studies to exploring the validity of quantum fluctuation relations in a driven-dissipative scenario, where the spin exchanges energy both with its surroundings because of a thermal gradient, and with an external work source. We experimentally prove the validity of the quantum fluctuation relations in the presence of cyclic driving in two cases, when the spin exchanges energy with an effective infinite-temperature reservoir, and when the total work vanishes at stroboscopic times—although the power delivered to the NV center is non-null. Our results represent the first experimental study of quantum fluctuation relation in driven open quantum systems.
Submerged wall jets on corrugated beds
Authors: Wang Lei , Diao Ming-Jun
Published: April 2021

The present study was performed to investigate the effect of jet Froude number, submergence factor, and boundary roughness on the submerged wall jets. The jet Froude number ranged from 4 to 10, the submergence factor ranged from 0.375 to 3.5, and the relative roughness ranged from 0.25 to 0.50. The results showed that the rough boundary could effectively reduce the hydraulic characteristic parameters. Compared to the smooth bed, the depression in water surface elevation at the beginning of submerged wall jet and the length scales along and vertical the flow direction over the rough bed decreased. The maximum velocity u
m of cross-section appeared farther away from the bed, and the decay of it along the distance was faster than that on the smooth bed. The decay of the ratio for the maximum velocity to the nozzle velocity u
1 had two stages along the distance x/L, where L was the longitudinal distance at which u
m = 0.5u
1. The first decay stage was like that in a plane wall jet, and the second decay stage was more and more like a free jump with the decrease of Froude number and submergence factor. While the decay of maximum velocity has good similarity using the new length scale L*, where L* was the longitudinal distance at which u
m = 0.2u
1. The shear force coefficients for submerged wall jets on corrugated beds were much smaller than those for free jumps on smooth beds, let alone for free jumps on corrugated beds.
Substituent screening effect on single-molecule photostability: comparison of three differently substituted porphycenes
Authors: Bednarz Aleksandra , Kamińska Izabela , Jamrozik Agnieszka , Zielonka Karolina , Listkowski Arkadiusz , Waluk Jacek
Published: April 2021

Photobleaching of single molecules has been studied using confocal fluorescence microscopy for porphycene, a porphyrin isomer, and its two derivatives. Fourfold substitution of porphycene with bulky tert-butyl groups leads to the enhancement of photostability, even though the spectral, photophysical, and redox parameters remain similar. We attribute this effect to the increase of the efficiency of physical quenching of the chromophore triplet state by oxygen, compared with the yield of chemical reaction that leads to photobleaching. Analysis of the observed photon fluxes from single emitters embedded in a polymer film shows that the experiment based on fluorescence is biased towards detection of molecules which have oxygen—the triplet quencher—in their vicinity. The distribution of the measured photodegradation quantum yields is very heterogeneous, suggesting that physical and chemical quenching rates exhibit different distance and orientation dependences.
Microstructural characterization and tribological behavior analysis on triethanolamine functionalized reduced graphene oxide
Authors: Wang Chenglong , Sun Jianlin , Wu Ping , Ge Chenglin , Meng Weixin
Published: April 2021

A facile and modified hydrothermal method was reported for the simultaneous reduction and functionalization of graphene oxide without any reductant. The lubrication mechanisms of nanomaterials were analyzed based on tribological experiments and molecular dynamic simulation. Tribological studies indicated that triethanolamine functionalized graphene oxide exhibited excellent friction-reducing performance and the optimal concentration was 0.15 wt.%, while 0.25 wt.% of triethanolamine functionalized graphene oxide showed best wear resistance in the pin-on-disk experiment. An anti-wear and friction-reducing coefficient τ was proposed to evaluate the tribological properties of lubricants for a uniform standard. Molecular dynamics simulation results revealed the influence of different functional groups on the anti-wear and friction-reducing performance. The sliding distance between graphene oxide layers with COOH functional groups was the longest, it was conducive to reduce the friction coefficient but decrease the wear life. The order of diffusion coefficients of graphene oxide containing different functional groups was DCOOH (4.02 × 10–11 m2 s−1) > DC-OH (1.42 × 10–11 m2 s−1) > DC–O–C (5.24 × 10–12 m2 s−1). It was proposed and verified that the structure of graphene oxide could be optimized by grafting triethanolamine molecules on the C–O–C functional groups to ameliorate the tribological properties.
A deterministic tribofilm growth model considering flash temperature and surface roughness in mixed lubrication
Authors: Yang Jialong , Pu Wei , Pei Xin
Published: April 2021

Although there have been a lot of researches about the drivers of tribofilm growth in recent years, people still argue about the real mechanism of tribofilm formation. In engineering field, plenty of mechanical components are operating under mixed lubricating condition. Therefore, it makes sense to study how tribofilm will form under mixed lubrication, which can provide further analysis on how ZDDP (Zinc dialkyl- and diaryldithiophosphates) would act as an antiwear additive to influence lubricating behavior. This paper presents a numerical model to simulate tribofilm formation process under mixed lubrication condition, considering influences of temperature and stress. In view of real surface roughness at each simulation step, the tribofilm morphology is obtained, as well as a series of lubricating parameters to study the mutual impacts between tribofilm formation and lubrication performance. It can be concluded that with the growth of tribofilm, lubricating performance will decrease to some extent, especially for low entrainment speed conditions, correlating with a noticeable shift in the Stribeck friction curve towards higher entrainment speed. Using the model developed in this paper, the assumption that tribofilm as a solid film can increase surface roughness to block the flow of lubricating fluid is evidently supported.
Experimental investigation of surface roughness and chip morphology during machining of austenitic stainless steel 303 with pvd coated (TiAlN) insert
Authors: S R Sundara Bharathi , D Ravindran , A Arul Marcel Moshi
Published: April 2021

Optimizing the influencing parameters of turning operation is a precious thing which determines the desired level of quality in Material Removal Rate (MRR) and Surface Roughness (SR). In this investigation, Taguchi based Grey Relational Analysis (GRA) has been used optimizing the effective process parameters such as depth of cut, feed rate and cutting speed on Stainless Steel 303 (SS 303) material while the specimen is turned with PVD (TiAlN) coated cutting tool. The experimental combinations have been planned based on Taguchi’s Design of Experiments technique. The optimal input parameter combination has been identified as 600 m min−1 spindle speed, 0.1 mm rev−1 feed rate and 0.2 mm depth of cut. The most influencing factor affecting the overall responses of turning process has been found out using Analysis of Variance approach as spindle speed (37.91%). Second-order mathematical models have been developed using Design Expert software for all the considered output responses, which provide the experimental values within the considered range of process parameters even without performing the actual experimentation. 3D surface plots have been generated and analyzed for interpreting the correlation between the process variables. SEM images taken on the machined surfaces and chips have been analyzed and presented in order to validate the optimization results.
In-situ observation of grain growth and phase transformation in weld zone of Ti-6Al-4V titanium alloy by laser welding with filler wire
Authors: Fang Naiwen , Guo Erjun , Xu Kai , Huang Ruisheng , Ma Yiming , Chen Yongsheng , Yang Yicheng , Xie Jilin
Published: April 2021

Through in situ observation at high temperature confocal laser scanning microscope, the microstructures and phase transformation of Ti-6Al-4V titanium alloy welded joint by laser welding with filler wire during heating, heat preservation and cooling process in simulating welding thermal cycle were studied. When the weld microstructure was heated to 380 °C, obvious grain growth was observed. After heating to 1 050 °C, weld microstructures were mostly composed of coarse β-columnar grains. During the heat preservation process of the weld metal, it could be found that the β phase boundary moved slowly. In the cooling process of weld microstructures, with the increase of the cooling rate, the transition temperature for new phase precipitation decreased gradually, and that for ending the precipitation increased gradually. The microstructures after cooling to room temperature at a rate of 0.5 °C/s and 5 °C s−1 were composed of α phases. At 20 °C s−1, acicular α′ martensite appeared in the microstructures. At 80 °C s−1, precipitated phases were all composed of acicular α′ martensite.The Ti-6Al-4V titanium alloy weld microstructure by laser welding with filler wire is completely hexagonal close packed (HCP) crystal structure.The hardness of the weld microstructures was improved with the cooling rate getting faster.
Cyanide recombination in electric arc furnace plasma
Authors: Pauna Henri , Willms Thomas , Aula Matti , Echterhof Thomas , Huttula Marko , Fabritius Timo
Published: April 2021

Cyanide, among with NO
x
, CO2, and CO, is one of the adverse compounds that form in the ironmaking and steelmaking industry. High-temperature processes are suitable environments for cyanide formation, and cyanide can form as a result of recombination in electric arc plasma. Even though the cyanides might not survive e.g. the post-combustion process, understanding the formation mechanisms of hazardous materials in the steelmaking industry is important. In this work, the recombination of cyanide in a pilot-scale AC electric arc furnace is studied with optical emissions from the CN molecule. The results show how the optical emissions from the cyanide change in different process steps. Electric input, plasma temperature, and interaction of the arc with solid charge material were observed to have an impact on the CN signal. Additionally, equilibrium composition computation highlights how different sources of carbon change the recombination rate and that the highest recombination occurs at 6821 K.
Counting zeros of Dedekind zeta functions
Authors: Hasanalizade Elchin , Shen Quanli , Wong Peng-Jie
Published: April 2021

Given a number field

K
K

of degree

n
K

n_K

and with absolute discriminant

d
K

d_K

, we obtain an explicit bound for the number

N
K

(
T
)

N_K(T)

of non-trivial zeros (counted with multiplicity), with height at most

T
T

, of the Dedekind zeta function

ζ
K

(
s
)

\zeta _K(s)

of

K
K

. More precisely, we show that for

T
≥
1

T \geq 1

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartAbsoluteValue upper N Subscript upper K Baseline left-parenthesis upper T right-parenthesis minus StartFraction upper T Over pi EndFraction log left-parenthesis d Subscript upper K Baseline left-parenthesis StartFraction upper T Over 2 pi e EndFraction right-parenthesis Superscript n Super Subscript upper K Superscript Baseline right-parenthesis EndAbsoluteValue less-than-or-equal-to 0.228 left-parenthesis log d Subscript upper K Baseline plus n Subscript upper K Baseline log upper T right-parenthesis plus 23.108 n Subscript upper K Baseline plus 4.520 comma">

|

N
K

(
T
)
−

T
π

log
⁡

(

d
K

(

T

2
π
e

)

n
K

)

|

≤
0.228
(
log
⁡

d
K

+

n
K

log
⁡
T
)
+
23.108

n
K

+
4.520
,

\begin{equation*} \Big | N_K (T) - \frac {T}{\pi } \log \Big ( d_K \Big ( \frac {T}{2\pi e}\Big )^{n_K}\Big )\Big | \le 0.228 (\log d_K + n_K \log T) + 23.108 n_K + 4.520, \end{equation*}

which improves previous results of Kadiri and Ng, and Trudgian. The improvement is based on ideas from the recent work of Bennett et al. on counting zeros of Dirichlet

L
L

-functions.
Through a Glass, Darkly: Artificial Intelligence and the Problem of Opacity
Authors: Chesterman Simon
Published: April 2021

As computer programs become more complex, the ability of non-specialists to understand how a given output has been reached diminishes. Opaqueness may also be built into programs to protect proprietary interests. Both types of systems are capable of being explained, either through recourse to experts or an order to produce information. Another class of system may be naturally opaque, however, using deep learning methods that are impossible to explain in a manner that humans can comprehend. An emerging literature describes these phenomena or specific problems to which they give rise, notably the potential for bias against specific groups. Drawing on examples from the United States, the European Union, and China, this Article develops a novel typology of three discrete regulatory challenges posed by opacity. First, it may encourage—or fail to discourage—inferior decisions by removing the potential for oversight and accountability. Second, it may allow impermissible decisions, notably those that explicitly or implicitly rely on protected categories such as gender or race in making a determination. Third, it may render illegitimate decisions in which the process by which an answer is reached is as important as the answer itself. The means of addressing some or all of these concerns is routinely said to be through transparency. Yet, while proprietary opacity can be dealt with by court order and complex opacity through recourse to experts, naturally opaque systems may require novel forms of “explanation” or an acceptance that some machine-made decisions cannot be explained—or, in the alternative, that some decisions should not be made by machine at all.
The cost of non-response to cardiac resynchronization therapy: characterizing heart failure events following cardiac resynchronization therapy
Authors: Varma Niraj , Auricchio Angelo , Connolly Allison T , Boehmer John , Bahu Marwan , Costanzo Maria Rosa , Leonelli Fabio , Yoo Dale , Singh Jagmeet , Nabutovsky Yelena , Gold Michael
Published: April 2021

Aims

The aim of this study is to quantify healthcare resource utilization among non-responders to cardiac resynchronization therapy (CRT-NR) by heart failure (HF) events and influence of comorbidities.

Methods and results

The ADVANCE CRT registry (2013–2015) prospectively identified responders/CRT-NRs 6 months post-implant using the clinical composite score. Heart failure event rates and associated cost, both overall and separated for inpatient hospitalizations, office visits, emergency room visits, and observational stays, were quantified. Costs of events were imputed from payments for similar real-world encounters in subjects with CRT-D/P devices in the MarketScan™ commercial and Medicare Supplemental insurance claims databases. Effects of patient demographics and comorbidities on event rates and cost were evaluated. Of 879 US patients (age 69 ± 11 years, 29% female, ischaemic disease 52%), 310 (35%) were CRT-NR. Among CRT-NRs vs. responders, more patients developed HF (41% vs. 11%, P < 0.001), HF event rate was higher (67.0 ± 21.7 vs. 11.4 ± 3.7/100 pt-year, P < 0.001), and HF readmission within 30 days was more common [hazard ratio 7.06, 95% confidence interval (2.1–43.7)]. Inpatient hospitalization was the most common and most expensive event type in CRT-NR. Comorbid HF was increased by diabetes, hypertension, and pulmonary disorders. Over 2 years, compared to CRT responders, each CRT-NR resulted in excess cost of $6388 ($3859–$10 483) to Medicare (P = 0.015) or $10 197 ($6161–$17 394) to private insurances (P = 0.014).

Conclusion

Healthcare expenditures associated with contemporary CRT non-response management are among the highest for any HF patient group. This illustrates an unmet need for interventions to improve HF outcomes and reduce costs among some CRT recipients.
Multiple Marker Mapping of Quantitative Trait Loci in a Cross Between Outbred Wild Boar and Large White Pigs
Authors: Knott Sara A , Marklund Lena , Haley Chris S , Andersson Kjell , Davies William , Ellegren Hans , Fredholm Merete , Hansson Ingemar , Hoyheim Bjorn , Lundström Kerstin , Moller Maria , Andersson Leif
Published: April 2021

A quantitative trait locus (QTL) analysis of growth and fatness data from a three generation pig experiment is presented. The population of 199 F2 animals was derived from a cross between wild boar and Large White pigs. Animals were typed for 240 markers spanning 23 Morgans of 18 autosomes and the X chromosome. A series of analyses are presented within a least squares framework. First, these identify chromosomes containing loci controlling trait variation and subsequently attempt to map QTLs to locations within chromosomes. This population gives evidence for a large QTL affecting back fat and another for abdominal fat segregating on chromosome 4. The best locations for these QTLs are within 4 cM of each other and, hence, this is likely to be a single QTL affecting both traits. The allele inherited from the wild boar causes an increase in fat deposition. A QTL for intestinal length was also located in the same region on chromosome 4 and could be the same QTL with pleiotropic effects. Significant effects, owing to multiple QTLs, for intestinal length were identified on chromosomes 3 and 5. A single QTL affecting growth rate to 30 kg was located on chromosome 13 such that the Large White allele increased early growth rate, another QTL on chromosome 10 affected growth rate from 30 to 70 kg and another on chromosome 4 affected growth rate to 70 kg.
Properties of Maximum Likelihood Male Fertility Estimation in Plant Populations
Authors: Morgan M T
Published: April 2021

Computer simulations are used to evaluate maximum likelihood methods for inferring male fertility in plant populations. The maximum likelihood method can provide substantial power to characterize male fertilities at the population level. Results emphasize, however, the importance of adequate experimental design and evaluation of fertility estimates, as well as limitations to inference (e.g., about the variance in male fertility or the correlation between fertility and phenotypic trait value) that can be reasonably drawn.
Position Effects of Ribosomal RNA Multigene Loci on Meiotic Recombination in Wheat
Authors: Luo Ming-Cheng , Yang Zu-Li , Dvořák Jan
Published: April 2021

Homeologous wheat chromosome arms that differ by the presence or absence of a Nor locus or greatly differ in the numbers of copies of rRNA genes per Nor locus show conspicuous differences in the distribution of recombination. To assess directly the position effects of Nor loci on recombination across chromosome arms, a Triticum monococcum Nor9 haplotype was substituted for Triticum aestivum Nor9 haplotypes on two T. aestivum 1A chromosomes in the isogenic background of cv Chinese Spring. The numbers of rRNA genes in the 1A Nor9 haplotypes are greatly reduced relative to the T. monococcum haplotype. The substitution resulted in reduced recombination rate in the vicinity of the Nor9 locus. An intra-arm compensatory increase was observed in the proximal region of the arm so that the genetic length of the chromosome arm was unchanged. These findings suggest that Nor loci suppress recombination in their vicinity and change recombination patterns in Nor-bearing chromosome arms.
Arabidopsis Mutants Define an in Vivo Role for Isoenzymes of Aspartate Aminotransferase in Plant Nitrogen Assimilation
Authors: Schultz Carolyn J , Hsu Meier , Miesak Barbara , Coruzzi Gloria M
Published: April 2021

Arabidopsis contains five isoenzymes of aspartate aminotransferase (AspAT) localized to the cytosol, chloroplast, mitochondria, or peroxisomes. To define the in vivo function of individual isoenzymes, we screened for Arabidopsis mutants deficient in either of the two major isoenzymes, cytosolic AAT2 or chloroplastic AAT3, using a native gel activity assay. In a screen of 8,000 M2 seedlings, three independent mutants deficient in cytosolic AAT2 (aat2) and two independent mutants deficient in chloroplastic AAT3 (aat3) were isolated. Mapping of aat2 and aat3 mutations and the five AspAT genes (ASP1–ASP5) established associations as follows: the mutation affecting aat2 maps with and cosegregates with ASP2, one of two expressed genes for cytosolic AspAT; the mutation affecting aat3 maps to the same location as the ASP5 gene encoding chloroplastic AspAT. Phenotypic analysis of the aat2 and aat3 mutants revealed a dramatic aspartate-related phenotype in one of the mutants deficient in cytosolic AAT2. The aat2-2 mutant displays an 80% reduction in levels of aspartate transported in the phloem of light-grown plants, and a 50% reduction in levels of asparagine transported in dark-adapted plants. These results indicate that cytosolic AAT2 is the major isoenzyme controlling aspartate synthesized for nitrogen transport in the light, and that this aspartate pool is converted to asparagine when plants are dark adapted.
A Transgene Encoding a Plasma Membrane H+-ATPase That Confers Acid Resistance in Arabidopsis thaliana Seedlings
Authors: Young Jeff C , DeWitt Natalie D , Sussman Michael R
Published: April 2021

Proton pumps (H+-ATPases) are the primary active transport systems in the plasma membrane of higher plant cells. These enzymes are encoded by a large gene family expressed throughout the plant, with specific isoforms directed to various specialized cells. While their involvement in membrane energetics has been suggested by a large body of biochemical and physiological studies, a genetic analysis of their role in plants has not yet been performed. We report here that mutant Arabidopsis thaliana plants containing a phloem-specific transgene encoding a plasma membrane H+-ATPase with an altered carboxy terminus show improved growth at low pH during seedling development. These observations provide the first genetic evidence for a role of the plasma membrane H+-ATPase in cytoplasmic pH homeostasis in plants.
Somatic Embryogenesis in Arabidopsis thaliana Is Facilitated by Mutations in Genes Repressing Meristematic Cell Divisions
Authors: Mordhorst Andreas P , Voerman Keete J , Hartog Marijke V , Meijer Ellen A , van Went Jacques , Koornneef Maarten , de Vries Sacco C
Published: April 2021

Embryogenesis in plants can commence from cells other than the fertilized egg cell. Embryogenesis initiated from somatic cells in vitro is an attractive system for studying early embryonic stages when they are accessible to experimental manipulation. Somatic embryogenesis in Arabidopsis offers the additional advantage that many zygotic embryo mutants can be studied under in vitro conditions. Two systems are available. The first employs immature zygotic embryos as starting material, yielding continuously growing embryogenic cultures in liquid medium. This is possible in at least 11 ecotypes. A second, more efficient and reproducible system, employing the primordia timing mutant (pt allelic to hpt, cop2, and amp1), was established. A significant advantage of the pt mutant is that intact seeds, germinated in 2,4-dichlorophenoxyacetic acid (2,4-D) containing liquid medium, give rise to stable embryonic cell cultures, circumventing tedious hand dissection of immature zygotic embryos. pt zygotic embryos are first distinguishable from wild type at early heart stage by a broader embryonic shoot apical meristem (SAM). In culture, embryogenic clusters originate from the enlarged SAMs. pt somatic embryos had all characteristic embryo pattern elements seen in zygotic embryos, but with higher and more variable numbers of cells. Embryogenic cell cultures were also established from seedling, of other mutants with enlarged SAMs, such as clavata (clv). pt clv double mutants showed additive effects on SAM size and an even higher frequency of seedlings producing embryogenic cell lines. pt clv double mutant plants had very short fasciated inflorescence stems and additive effects on the number of rosette leaves. This suggests that the PT and CLV genes act in independent pathways that control SAM size. An increased population of noncommitted SAM cells may be responsible for facilitated establishment of somatic embryogenesis in Arabidopsis.
Modulation of Tubulin Polypeptide Ratios by the Yeast Protein Pac10p
Authors: Alvarez Pablo , Smith Adelle , Fleming James , Solomon Frank
Published: April 2021

Normal assembly and function of microtubules require maintenance of the proper levels of several proteins, including the tubulin polypeptides themselves. For example, in yeast a significant excess of β-tubulin causes rapid microtubule disassembly and subsequent cell death. Even the modest excess of β-tubulin produced by genetic alterations such as deletion of the minor α-tubulin gene TUB3 affects cell growth and can confer microtubule phenotypes. We show here that the levels of the yeast protein Pac10p affect the relative levels of the tubulin polypeptides. Cells deleted for PAC10 have the same phenotypes as do cells that express reduced levels of α-tubulin or Rbl2p, two proteins that bind β-tubulin. Conversely, overexpression of Pac10p enhances the ability of α-tubulin or Rbl2p to suppress the lethality associated with excess β-tubulin. However, Pac10p is itself not a β-tubulin binding protein. Pac10 null cells show a 30% decrease in the ratio of α-tubulin to β-tubulin. The results suggest that Pac10p modulates the level of α-tubulin in the cell, and so influences microtubule morphogenesis and tubulin metabolism.
Mot3, a Zn Finger Transcription Factor That Modulates Gene Expression and Attenuates Mating Pheromone Signaling in Saccharomyces cerevisiae
Authors: Grishin Anatoly V , Rothenberg Michael , Downs Maureen A , Blumer Kendall J
Published: April 2021

In the yeast Saccharomyces cerevisiae, mating pheromone response is initiated by activation of a G protein- and mitogen-activated protein (MAP) kinase-dependent signaling pathway and attenuated by several mechanisms that promote adaptation or desensitization. To identify genes whose products negatively regulate pheromone signaling, we screened for mutations that suppress the hyperadaptive phenotype of wild-type cells overexpressing signaling-defective G protein β subunits. This identified recessive mutations in MOT3, which encodes a nuclear protein with two Cys2-His2 Zn fingers. MOT3 was found to be a dosage-dependent inhibitor of pheromone response and pheromone-induced gene expression and to require an intact signaling pathway to exert its effects. Several results suggested that Mot3 attenuates expression of pheromone-responsive genes by mechanisms distinct from those used by the negative transcriptional regulators Cdc36, Cdc39, and Mot2. First, a Mot3-lexA fusion functions as a transcriptional activator. Second, Mot3 is a dose-dependent activator of several genes unrelated to pheromone response, including CYC1, SUC2, and LEU2. Third, insertion of consensus Mot3 binding sites (C/A/T)AGG(T/C)A activates a promoter in a MOT3-dependent manner. These findings, and the fact that consensus binding sites are found in the 5′ flanking regions of many yeast genes, suggest that Mot3 is a globally acting transcriptional regulator. We hypothesize that Mot3 regulates expression of factors that attenuate signaling by the pheromone response pathway.
An Intragenic Suppressor of Cold Sensitivity Identifies Potentially Interacting Bases in the Peptidyl Transferase Center of Tetrahymena rRNA
Authors: Sweeney Rosemary , Yao Meng-Chao
Published: April 2021

Peptidyl transfer of a growing peptide on a ribosome-bound transfer RNA (tRNA) to an incoming amino acyl tRNA is the central step in translation, and it may be catalyzed primarily by the large subunit (LSU) ribosomal RNA (rRNA). Genetic and biochemical evidence suggests that the central loop of domain V of the LSU rRNA plays a direct role in peptidyl transfer. It was previously found that a single base change at a universally conserved site in this region of the Tetrahymena thermophila LSU rRNA confers anisomycin resistance (an-r) as well as extremely slow growth, cold sensitivity, and aberrant cell morphology. Because anisomycin specifically inhibits peptidyl transfer, possibly by interfering with tRNA binding, it is likely that this mutant rRNA is defective in efficiently completing one of these steps. In the present study, we have isolated an intragenic suppressor mutation located only three bases away from the original mutation that partially reverses the slow growth and cold-sensitive phenotypes. These data imply that the functional interaction of these two bases is necessary for normal rRNA function, perhaps for peptidyl transfer or tRNA binding. These data provide the first demonstration of a functional interaction between bases within this rRNA region.