bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicene/ZnI2 van der Waals heterostructure: tunable structural and electronic properties
Authors: Hassan Md. Sakib , Islam Md. Sherajul , Park Jeongwon 
Published: April 2021

Abstract
By utilizing ab initio density functional theory, the structural and electronic properties of novel silicene/ZnI2 heterobilayers (HBLs) were investigated. Constructing HBLs with ZnI2 in different stacking configurations leads to direct bandgap opening of silicene at K point, which ranges from 138.2 to 201.2 meV. By analyzing the projected density of states and charge density distribution, we found that the predicted HBLs conserve the electronic properties of silicene and ZnI2 can serve as a decent substrate. The tunability of electronic properties can be achieved by enforcing biaxial strain and by varying interlayer distance where bandgap can get as low as zero to as high as 318.8 meV and 290.7 meV, respectively depending on the stacking patterns. Maintenance of the remarkable features of silicene, high mobility of charge carriers, and fine-tuning of bandgap pave the way to construct new nanoelectronic devices using these novel silicene/ZnI2 HBLs.
The adaptation and investigation of cone-beam CT reconstruction algorithms for horizontal rotation fixed-gantry scans of rabbits
Authors: Gardner Mark , Dillon Owen , Shieh Chun-Chien , O’Brien Ricky , Debrot Emily , Barber Jeffrey , Ahern Verity , Bennett Peter , Heng Soo-Min , Corde Stéphanie , Jackson Michael , Keall Paul 
Published: April 2021

Abstract
Fixed-gantry radiation therapy has been proposed as a low-cost alternative to the conventional rotating-gantry radiation therapy, that may help meet the rising global treatment demand. Fixed-gantry systems require gravitational motion compensated reconstruction algorithms to produce cone-beam CT (CBCT) images of sufficient quality for image guidance. The aim of this work was to adapt and investigate five CBCT reconstruction algorithms for fixed-gantry CBCT images. The five algorithms investigated were Feldkamp–Davis–Kress (FDK), prior image constrained compressed sensing (PICCS), gravitational motion compensated FDK (GMCFDK), motion compensated PICCS (MCPICCS) (a novel CBCT reconstruction algorithm) and simultaneous motion estimation and iterative reconstruction (SMEIR). Fixed-gantry and rotating-gantry CBCT scans were acquired of 3 rabbits, with the rotating-gantry scans used as a reference. Projections were sorted into rotation bins, based on the angle of rotation of the rabbit during image acquisition. The algorithms were compared using the structural similarity index measure root mean square error, and reconstruction time. Evaluation of the reconstructed volumes showed that, when compared with the reference rotating-gantry volume, the conventional FDK algorithm did not accurately reconstruct fixed-gantry CBCT scans. Whilst the PICCS reconstruction algorithm reduced some motion artefacts, the motion estimation reconstruction methods (GMCFDK, MCPICCS and SMEIR) were able to greatly reduce the effect of motion artefacts on the reconstructed volumes. This finding was verified quantitatively, with GMCFDK, MCPICCS and SMEIR reconstructions having RMSE 17%–19% lower and SSIM 1% higher than a conventional FDK. However, all motion compensated fixed-gantry CBCT reconstructions had a 56%–61% higher RMSE and 1.5% lower SSIM than FDK reconstructions of conventional rotating-gantry CBCT scans. The results show that motion compensation is required to reduce motion artefacts for fixed-gantry CBCT reconstructions. This paper further demonstrates the feasibility of fixed-gantry CBCT scans, and the ability of CBCT reconstruction algorithms to compensate for motion due to horizontal rotation.
Sparse-domain regularized stripe decomposition combined with guided-image filtering for ring artifact removal in propagation-based x-ray phase-contrast CT
Authors: Li Yimin , Zhao Yuqing , Ji Dongjiang , Lv Wenjuan , Xin Xiaohong , Zhao Xinyan , Liu Dayong , Ouyang Zhaoguang , Hu Chunhong 
Published: April 2021

Abstract
Propagation-based x-ray phase-contrast computed tomography (PB-PCCT) images often suffer from severe ring artifacts. Ring artifacts are mainly caused by the nonuniform response of detector elements, and they can degrade image quality and affect the subsequent image processing and quantitative analyses. To remove ring artifacts in PB-PCCT images, a novel method combined sparse-domain regularized stripe decomposition (SDRSD) method with guided image filtering (GIF) was proposed. In this method, polar coordinate transformation was utilized to convert the ring artifacts to stripe artifacts. And then considering the directional and sparse properties of the stripe artifacts and the continuity characteristics of the sample, the SDRSD method was designed to remove stripe artifacts. However, for the SDRSD method, the presence of noise may destroy the edges of the stripe artifacts and lead to incomplete decomposition. Hence, a simple and efficient smoothing technique, namely GIF, was employed to overcome this issue. The simulations and real experiments demonstrated that the proposed method could effectively remove ring artifacts as well as preserve the structures and edges of the samples. In conclusion, the proposed method can serve as an effective tool to remove ring artifacts in PB-PCCT images, and it has high potential for promoting the biomedical and preclinical applications of PB-PCCT.
Deep learning-based photoplethysmography classification for peripheral arterial disease detection: a proof-of-concept study
Authors: Allen John , Liu Haipeng , Iqbal Sadaf , Zheng Dingchang , Stansby Gerard 
Published: April 2021

Abstract

Objective. A proof-of-concept study to assess the potential of a deep learning (DL) based photoplethysmography PPG (‘DLPPG’) classification method to detect peripheral arterial disease (PAD) using toe PPG signals. Approach. PPG spectrogram images derived from our previously published multi-site PPG datasets (214 participants; 31.3% legs with PAD by ankle brachial pressure index (ABPI)) were input into a pretrained 8-layer (five convolutional layers + three fully connected layers) AlexNet as tailored to the 2-class problem with transfer learning to fine tune the convolutional neural network (CNN). k-fold random cross validation (CV) was performed (for k = 5 and k = 10), with each evaluated over k training/validation runs. Overall test sensitivity, specificity, accuracy, and Cohen’s Kappa statistic with 95% confidence interval ranges were calculated and compared, as well as sensitivities in detecting mild-moderate (0.5 ≤ ABPI < 0.9) and major (ABPI < 0.5) levels of PAD. Main results. CV with either k = 5 or 10 folds gave similar diagnostic performances. The overall test sensitivity was 86.6%, specificity 90.2% and accuracy 88.9% (Kappa: 0.76 [0.70–0.82]) (at k = 5). The sensitivity to mild-moderate disease was 83.0% (75.5%–88.9%) and to major disease was 100.0% (90.5%–100.0%). Significance. Substantial agreements have been demonstrated between the DL-based PPG classification technique and the ABPI PAD diagnostic reference. This novel automatic approach, requiring minimal pre-processing of the pulse waveforms before PPG trace classification, could offer significant benefits for the diagnosis of PAD in a variety of clinical settings where low-cost, portable and easy-to-use diagnostics are desirable.
A conformally flat generalized Ricci recurrent spacetime in F(R)-gravity
Authors: De Avik , Loo Tee-How , Solanki Raja , Sahoo P K 
Published: April 2021

Abstract
In the present paper we study a conformally flat generalized Ricci recurrent perfect fluid spacetime with constant Ricci scalar as a solution of modified F(R)-gravity theory. We show that a Robertson-Walker spacetime is generalized Ricci Recurrent if and only if it is Ricci symmetric. The perfect fluid type matter is shown to have EoS ω = −1. Some energy conditions are analyzed with couple of popular toy models of F(R)-gravity, like F(R) = R + α
R

m
where α, m are constants and

F
(
R
)
=
R
+
β
R
ln
R

where β is constant. In harmony with the recent observational studies of accelerated expansion of the Universe, both cases exhibit that the null, weak, and dominant energy conditions fulfill their requirements whereas the strong energy condition is violated.
Rainfall Threshold of Citarum River Flood for Early Warning on Urban Area
Authors: Safarina Ariani Budi , Chairunnisa  , Lestari Novita Dwi , Aprilianingsih Devi , Syahrullah Fathulhuda Muhammad , Sadidah Muthiah 
Published: April 2021

Abstract
Floods in Bandung basin located in the upper Citarum river resulted in huge losses because they occurred in industrial areas and densely populated settlements. Disaster risk reduction can be done with flood early warning in residential areas. The purpose of this study is to determine the rainfall threshold that causes inundation in residential areas in seven districts located on the floodplain of the Citarum river. The method used is the analysis of the rainfall-runoff model to obtain the Citarum river unit hydrograph. Flows in the rivers are assumed to be one-dimensional unsteady flow whereas overflow is assumed to be overland flow. Threshold rainfall is determined based on the deconvolution method, with the drainage coefficient calculated based on the land use map. The results of the study are the capacity discharge and the load discharge of the Citarum river in the seven sub-districts, which the most upstream is the Majalaya sub-district and the downstream is Katapang sub-district. The lowest threshold rainfall has occurred in the sub-district Bojongsoang that is 54.34 mm that produced the flood water level as high as 662 m MSL. and the evacuation time for early warning is 5.5 hours.
Influence of Temperature and Reaction Time on the Performance of Thermal Pyrolysis of Compact Polystyrene Waste
Authors: Palmay P , Nuñez R , Donoso C , Bruno J 
Published: April 2021

Abstract
The purpose of this study is to determine the influence of the temperature and reaction time on the thermal pyrolysis process of compact polystyrene residues based on the percentage of liquid obtained at a heating cup of 15 C min-1 and cooling system for the condensation of pyrolytic gases at 10 ° C. It worked with temperatures between 375 and 425 °C and times of 5 and 10 minutes. The results showed that the reaction time has no representative influence on the liquid fraction, while the temperature has a great importance in the liquid yield reaching a maximum contribution at 400 °C, after this the percentage of liquid oils tends to decrease by guiding the formation of the gas fraction. The maximum production was 81.4% with a kinematic viscosity of 1,026 mm2 s-1, relative density 0.9352, flash point 24 °C and a caloric power of 48.5 MJ kg-1. The mixture of aromatic hydrocarbons obtained, with carbon chains between C6 and C20, are present in 75% by mass.
National trends in prescription drug expenditures and projections for 2021
Authors: Tichy Eric M , Hoffman James M , Suda Katie J , Rim Matthew H , Tadrous Mina , Cuellar Sandra , Clark John S , Wiest Michelle D , Matusiak Linda M , Schumock Glen T 
Published: April 2021

Abstract

Purpose
To report historical patterns of pharmaceutical expenditures, to identify factors that may influence future spending, and to predict growth in drug spending in 2021 in the United States, with a focus on the nonfederal hospital and clinic sectors.

Methods
Historical patterns were assessed by examining data on drug purchases from manufacturers using the IQVIA National Sales Perspectives database. Factors that may influence drug spending in hospitals and clinics in 2021 were reviewed—including new drug approvals, patent expirations, and potential new policies or legislation. Focused analyses were conducted for biosimilars, cancer drugs, generics, coronavirus disease 2019 (COVID-19) pandemic influence, and specialty drugs. For nonfederal hospitals, clinics, and overall (all sectors), estimates of growth of pharmaceutical expenditures in 2021 were based on a combination of quantitative analyses and expert opinion.

Results
In 2020, overall pharmaceutical expenditures in the United States grew 4.9% compared to 2019, for a total of $535.3 billion. Utilization (a 2.9% increase) and new drugs (a 1.8% increase) drove this increase, with price changes having minimal influence (a 0.3% increase). Adalimumab was the top drug in 2020, followed by apixaban and insulin glargine. Drug expenditures were $35.3 billion (a 4.6% decrease) and $98.4 billion (an 8.1% increase) in nonfederal hospitals and clinics, respectively. In clinics, growth was driven by new products and increased utilization, whereas in hospitals the decrease in expenditures was driven by reduced utilization. Several new drugs that will influence spending are expected to be approved in 2021. Specialty and cancer drugs will continue to drive expenditures along with the evolution of the COVID-19 pandemic.

Conclusion
For 2021, we expect overall prescription drug spending to rise by 4% to 6%, whereas in clinics and hospitals we anticipate increases of 7% to 9% and 3% to 5%, respectively, compared to 2020. These national estimates of future pharmaceutical expenditure growth may not be representative of any particular health system because of the myriad of local factors that influence actual spending.
High level of conservation and diversity among the endophytic seed bacteriome in eight alpine grassland species growing at the Qinghai Tibetan Plateau
Authors: Liang Danni , Guo Jianxiu , Hou Fujiang , Bowatte Saman 
Published: April 2021

ABSTRACT
Seed borne microorganisms play an important role in plant biology. Concerns have recently been raised about loss of seed microbial diversity by seed treatments, crop domestication and plant breeding. Information on the seed microbiomes of native plants growing in natural ecosystems is beneficial as they provide the best settings to detect indigenous plant microbe interactions. Here, we characterized the seed bacterial community of 8 native alpine grassland plants. First, seed bacterial diversity was examined using Illumina DNA sequencing, then 28 cultivable bacteria were isolated and potential functions were explored. Across 8 plant species, 343 different bacterial genera were identified as seed endophytes, 31 of those were found in all plant species, indicating a high level of conservation. Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes and Chloroflexi were the top five dominant phyla. Plant species identity was a key determinant shaping the seed endophytic bacteriome. ACC deaminase activity, siderophores production and secretion of lytic enzymes were common functions shown by isolated bacteria. Our results demonstrate that highly diverse and beneficial bacterial populations are hosted by seeds of alpine grassland species to ensure the establishment of best bacterial symbionts for the next generation. This information is useful for crop improvement by reinstating beneficial seed microbial diversities for high-quality forage and crop seeds.
MONOSOMIC ANALYSIS OF FATTY ACID COMPOSITION IN EMBRYO LIPIDS OF ZEA MAYS L
Authors: Plewa Michael J , Weber David F 
Published: April 2021

ABSTRACT
The effects of monosomy of specific chromosomes on the fatty acid composition of maize embryos were studied. A novel technique was developed to obtain fatty acid profiles of single embryos without reducing the viability of the sampled kernels. Monosomic 2 embryos had significantly more oleic acid and significantly less linoleic acid than diploid control embryos. Since the conversion of oleic acid to linoleic acid is a single-enzyme-mediated reaction, we suggest that a gene involved in linoleic acid biosynthesis is located on chromosome 2. Additional consistent variations were found in other monosomic types. This study demonstrates that monosomic analysis can be used to study gene dosage effects at the biochemical level.
GENETIC CONTROL OF QUERCETIN FORMATION IN THE ALEURONE TISSUE OF MAIZE
Authors: Reddy A R , Reddy G M 
Published: April 2021

ABSTRACT
The genes C, C2, R, A, A2, Bz, Bz2 and Pr are required for the formation of purple anthocyanin in the aleurone tissue of maize, and the recessive gene(s) result in non-purple (red, bronze and colorless). Aleurone extracts of recessive a and certain double recessive combinations were analyzed by paper chromatography, absorption spectra in the ultraviolet (UV) and infrared, mass spectra, and other analytical techniques. Homozygous recessive a tissue accumulates the flavonol, quercetin, while the double combinations a c and a r lack it, suggesting that dominant genes C and R are required for its formation and act prior to A in the synthesis of flavonols, as in the gene action sequence for anthocyanin synthesis. Dominant C-I inhibits the formation of quercetin, whereas Bz, Bz2 and In do not affect its formation. These results suggest a close biogenetic relationship between quercetin and cyanidin-3-glucoside and also independently confirm the position of A in both sequences.
THE GENE ACTION AND FUNCTION OF TWO DOPA OXIDASE POSITIVE MELANOCYTE MUTANTS OF THE FOWL
Authors: Brumbaugh J A , Lee K W 
Published: April 2021

ABSTRACT
Ultrastructural and autoradiographic analysis revealed the developmental genetic differences between the dopa oxidase positive pk and I mutations of the fowl. The differences were revealed by the results of five measurements involving homozygous mutant melanocytes, heterozygous melanocytes, and standard melanocytes at each of the loci. The measurements were: ultrastructural comparisons of melanosomes in pigmented epithelial (PE) and neural crest derived (NC) melanocytes, the number of 3H-dopa and 3H-leucine grains/µ2 of melanosome, the 3H-dopa/3H-leucine ratio, and the percentage of cytoplasmic 3H-leucine grains that were melanosomal. The pk mutation altered both PE and NC melanosomes. +/pk melanocytes were characterized by suppressed 3H-dopa/µ2 and 3H-dopa/3H-leucine values. +/pk cells, however, had the same percentage of melanosomal 3H-leucine grains as the "pk" standard. The I mutation altered only NC melanosomes. +/I melanocytes were characterized by 3H-dopa/µ2 and 3H-dopa/3H-leucine values similar to the "I" standard. +/I cells had a lower percentage of melanosomal 3H-leucine grains than the "I" standard, however. These data suggest that pk is a structural mutation affecting melanin binding to the premelanosome, while I seems to be a control gene mutation partially suppressing the production of premelanosomal components in NC melanocytes.
GENETIC ANALYSIS OF THE 5S RNA GENES IN DROSOPHILA MELANOGASTER
Authors: Procunier James D , Tartof Kenneth D 
Published: April 2021

ABSTRACT
The 5S RNA genes of Drosophila melanogaster in either an isogenic wild-type or a multiply inverted (SM1) chromosome 2 increase their multiplicity when opposite a deficiency for the 5S gene site. This is analogous to the compensation phenomenon previously described for the 18S and 28S ribosomal RNA genes of the X chromosome nucleolus organizer region. Molecular hybridization of 5S RNA to DNA containing various doses of the 56F1-9 region of chromosome 2 demonstrates that most, if not all, of the 5S genes reside in or near this region. Also, a deficiency missing approximately one-half of the wild-type number of 5S genes was isolated and genetically localized. This mutant has a phenotype like that of bobbed, a mutant known to be partially deficient in 18S and 28S ribosomal RNA genes. Finally, we report the existence of a chromosomal rearrangement which splits the second chromosome into two segments, each containing 5S DNA.
ADAPTIVE SIGNIFICANCE OF VEGETATIVE INCOMPATIBILITY IN NEUROSPORA CRASSA
Authors: Hartl Daniel L , Dempster Everett R , Brown Spencer W 
Published: April 2021

ABSTRACT
Certain features reminiscent of sexuality occur in the vegetative life cycle of some filamentous fungi such as Neurospora crassa. Hyphal fusions can occur between genetically different individuals, thereby endowing the new composite mycelium, a heterokaryon, with some of the advantages of heterozygosity usually associated with diploid organisms. In N. crassa, however, there are a number of incompatibility loci which prevent formation of heterokaryons unless the alleles at the incompatibility loci are identical in the two mycelia. The selection pressures that maintain incompatibility polymorphisms are not known. We suggest here that they are maintained because they prevent a kind of exploitation of heterokaryons by nuclei that are nonadaptive in homokaryons but that enjoy a proliferative advantage over other nuclei in heterokaryons. A mathematical model that abstracts the major features of the vegetative life cycle of Neurosopra crassa has been developed, and the action of selection in this model and various extensions of it is such as to maintain polymorphisms of vegetative incompatibility factors.
FURTHER STUDIES ON THE BALANCE BETWEEN Adh1 AND Adh2 IN MAIZE: GENE COMPETITIVE PROGRAMS
Authors: Freeling Michael 
Published: April 2021

ABSTRACT
Two unlinked genes which specify alcohol dehydrogenase (ADH) enzymes in maize are coordinately regulated by competition for a factor which limits the rate of total ADH expression during anaerobiosis. The "gene competition hypothesis" and the existence of organ-specific competitive programs, as proposed by Schwartz (1971), is further supported. The potential balance of expression between these two genes appears to be organ-specific and may be "locked-in" and inherited via meristematic growth. The actual expression of these two genes is dependent on the mode of ADH induction. The discussion examines alternative hypotheses explaining gene competition and reinterprets extant data on the adaptive significance of maize ADH polymorphism.
THE SYNTHESIS OF 5S RNA AND ITS RELATIONSHIP TO 18S AND 28S RIBOSOMAL RNA IN THE BOBBED MUTANTS OF DROSOPHILA MELANOGASTER
Authors: Mohan Jag 
Published: April 2021

ABSTRACT
Ribosomes contain one molecule each of 5S, 18S and 28S RNA. In Drosophila melanogaster although the genes for 18S+28S are physically separated from the 5S RNA genes, the multiplicity of various ribosomal RNA genes is roughly the same. Thus a coordinate synthesis of these three molecules might seem feasible. This problem has been approached by determining the molar ratios of various RNA's in ovaries and in adult flies. In ovaries there is a slight excess of 5S RNA molecules over other rRNA's, but in adult flies no such differences exist. Bobbed mutants also have the same molar ratios as wild-type flies. Results on 5S RNA synthesis in both in vitro and in vivo studies show that it is reduced in coordination with 18S+28S rRNA in the bobbed mutants of Drosophila melanogaster. Various possibilities are discussed in considering the implications of these results.
CYTOPLASMIC STERILITY FACTORS IN VICIA FABA L
Authors: Edwardson J R , Bond D A , Christie R G 
Published: April 2021

ABSTRACT
Tissues of cytoplasmic male sterile, maintainer, restorer, and restored lines, and sterile plants which reverted to fertility in Vicia faba were examined in ultrathin sections. Cytoplasmic spherical bodies (CSB), ca. 70 nm in diameter, were observed in tissues of all sterile plants but not in tissues of maintainer, restorer or restored sterile plants. No CSB were observed in a reverted fertile branch of a tiller-sterile plant, nor in 5 of 6 reverted fertile plants. One reverted fertile plant contained CSB in ovules. It is proposed that the CSB are the sites of, or possibly, products of, sterility factors in Vicia faba.