Influence of land use and topography on distribution and bioaccumulation of potentially toxic metals in soil and plant leaves: A case study from Sekhukhuneland, South Africa

Potentially toxic metal (PTM) enrichment of the soil-plant system in ultramafic and mining regions is a global concern as it affects the food chain. With expanding mining industry, it is important to assess if anthropogenic factors (i.e., land use practices) have a greater influence in this regard compared to natural factors (i.e., topography). Localities in Sekhukhuneland, South Africa, were selected along an altitudinal gradient (i.e., topography: upper slope, footslope, valley and valley bottom) and a land use profile (i.e., rangelands, gardens, tailings and wastelands) to investigate the distribution of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sr and Zn of natural (i.e., ultramafic geology) and anthropogenic (i.e., mining) origin in surface soil and plant leaf tissue. Plant life form was considered as an additional factor to evaluate PTM accumulation in leaves. Findings revealed a wider distribution range for Cr and Ni in the surface soil. Co, Cu, Mg, Mo, Sr and Zn were accumulated (bioaccumulation factor, BAF > 1) in leaf tissue of 74% of the evaluated plants of which 83% were indigenous. Grasses, forbs, dwarf shrubs and shrubs showed the highest accumulation levels. Despite an observed trend in the distribution of PTMs in soils and plant leaves along the altitudinal gradient, no significant differences were determined among the topographic positions. Land use practices, however, differed significantly indicating anthropogenic interference as a predominant determinant of PTM enrichment of soil-plant systems. Metal tolerant dominant plants in Sekhukhuneland could be classified as metallophytes. Indigenous species, accumulators and excluders, showed prospects for phytoremediation and rehabilitation of metal contaminated sites, respectively. Concentrations of Cr and Co in food and medicinal plant leaves exceeded the international permissible limits, which highlighted the necessity to estimate human health risks for PTMs in metalliferous sites.

Energy transfer in reconnection and turbulence

Reconnection and turbulence are two of the most commonly observed dynamical processes in plasmas, but their relationship is still not fully understood. Using 2.5D kinetic particle-in-cell simulations of both strong turbulence and reconnection, we compare the cross-scale transfer of energy in the two systems by analyzing the generalization of the von Kármán Howarth equations for Hall magnetohydrodynamics, a formulation that subsumes the third-order law for steady energy transfer rates. Even though the large scale features are quite different, the finding is that the decomposition of the energy transfer is structurally very similar in the two cases. In the reconnection case, the time evolution of the energy transfer also exhibits a correlation with the reconnection rate. These results provide explicit evidence that reconnection dynamics fundamentally involves turbulence-like energy transfer.

G-quadruplex DNA structures in human stem cells and differentiation

The establishment of cell identity during embryonic development involves the activation of specific gene expression programmes and is underpinned by epigenetic factors including DNA methylation and histone post-translational modifications. G-quadruplexes are four-stranded DNA secondary structures (G4s) that have been implicated in transcriptional regulation and cancer. Here, we show that G4s are key genomic structural features linked to cellular differentiation. We find that G4s are highly abundant in human embryonic stem cells and are lost during lineage specification. G4s are prevalent in enhancers and promoters. G4s that are found in common between embryonic and downstream lineages are tightly linked to transcriptional stabilisation of genes involved in essential cellular functions as well as transitions in the histone post-translational modification landscape. Furthermore, the application of small molecules that stabilise G4s causes a delay in stem cell differentiation, keeping cells in a more pluripotent-like state. Collectively, our data highlight G4s as important epigenetic features that are coupled to stem cell pluripotency and differentiation.

Awareness and Knowledge of Glaucoma and their Associated Factors among People Visiting a Tertiary Level Hospital in Central Nepal

Background Glaucoma is one of the major causes of irreversible blindness globally. Almost 60 million people globally are affected by glaucoma making it the second leading cause of blindness worldwide. Diagnosis of glaucoma early on is vital for timely management and prevention of blindness. However, it is challenging to diagnose it early because it is asymptomatic in the initial stage, and there is also the dearth of appropriate screening tools. Awareness, knowledge, and beliefs are believed to influence the treatment-seeking behavior of people as well as their uptake of services. Objective To assess the awareness and knowledge about glaucoma among general patients and patient attendants visiting Dhulikhel Hospital. Method We conducted a cross sectional quantitative study among general patients visiting Dhulikhel Hospital. We collected data using face-to-face interviews with semistructured questionnaires. We analyzed data in R version 4.0.3 (2020-10-10). We presented numerical variables as mean and standard deviation whereas categorical variables as frequency and percentage. We determined factors associated with awareness and knowledge of glaucoma using logistic regression analysis and estimated adjusted odds ratio (AOR) with 95% confidence interval. Result Of 379 participants, a total of 214 (56.5%) participants had heard about glaucoma. Out of the participants who heard about glaucoma, the mean knowledge score was 48.3±21.7 and 53.3% had good knowledge on glaucoma. The odds of having heard about glaucoma were two percent lower (AOR=0.98; 95%CI: 0.97-0.99; p-value 0.036) in the older participants compared to one year younger participant, 1.98 (95%CI:1.01-3.86; p-value 0.046) times higher among literates and 2.79 (95%CI: 1.76- 4.41; p-value < 0.001) times among participants with previous ocular examination. The odds of having good knowledge was 1.94 (95%CI: 1.10-3.42; p value 0.021) times among participants with previous ocular examinations. Conclusion The knowledge and awareness regarding glaucoma in a hospital-visiting population in central Nepal was low. Half of the participants were unaware of the disease glaucoma and half of the participants who heard of the glaucoma had poor knowledge on glaucoma.

Preterm Birth, Exasperation to the South Asian Countries

When a child is born before 37 weeks or 259 days of pregnancy, it is termed as preterm birth. Pre-term birth is prevalent in both developed and developing country. However, difference lies in their survival. In lower and middle income countries, most preterm babies die due to lack of even simple interventions. India ranks top in the world for deaths due to complications of preterm birth. Similarly, other South Asian countries, Pakistan, Bangladesh, Afghanistan and Nepal rank 3rd, 6th, 9th and 20th in the same. The aim of this review paper is to provide a landscape analysis on the burden of pre-term birth and challenges in the context of South Asian region. Databases such as PubMed, Scopus and Google Scholar were searched from 2000 to 2020 and 27 articles are included in the study. It was found that pre-term birth causes huge burden in the form of morbidity, mortality as well as socio economic losses. Preterm birth was associated with increased sepsis, cardiovascular disease, respiratory illness, hypothermia, neurological and gastrointestinal complications. South Asian countries have distinct challenges in eliminating or reducing preterm births which are: poor quality health surveillance data, inadequate trained health workforce, insufficient finance and funding, service delivery and other methodological challenges. Ending pre-term birth is important as it is directly related to Sustainable Development Goal 3. Therefore, there should be increase in priority given to increase financing, quality data gathering, adopting innovative measures as well as joint efforts of all the sectors to control the pre-term birth.

Development and Characterization of Novel Conductive Sensing Fibers for In Vivo Nerve Stimulation

Advancements in electrode technologies to both stimulate and record the central nervous system’s electrical activities are enabling significant improvements in both the understanding and treatment of different neurological diseases. However, the current neural recording and stimulating electrodes are metallic, requiring invasive and damaging methods to interface with neural tissue. These electrodes may also degrade, resulting in additional invasive procedures. Furthermore, metal electrodes may cause nerve damage due to their inherent rigidity. This paper demonstrates that novel electrically conductive organic fibers (ECFs) can be used for direct nerve stimulation. The ECFs were prepared using a standard polyester material as the structural base, with a carbon nanotube ink applied to the surface as the electrical conductor. We report on three experiments: the first one to characterize the conductive properties of the ECFs; the second one to investigate the fiber cytotoxic properties in vitro; and the third one to demonstrate the utility of the ECF for direct nerve stimulation in an in vivo rodent model.

Tobacco Users among the Patients who Visited Dental Outpatient Department of a Tertiary Care Hospital: A Descriptive Cross-sectional Study

Introduction: Smoked and smokeless forms of tobacco is a preventable cause of morbidity and mortality with inevitable effects on the oral cavity as well. The aim of the study was to find out the prevalence of tobacco users among the patients who visited dental outpatient departments of a tertiary care hospital. Methods: A descriptive cross-sectional study was carried out among 255 patients visiting the dental outpatient department of a tertiary care hospital over the duration of six months. Data collection was done through personal interviews and clinical examinations. History of tobacco use was taken and patients were divided into current users, never users and ever users. Clinical examination was done using Decayed Missing Filled Teeth index, community periodontal index modified and loss of attachment. Point estimate at 95% confidence interval was calculated along with frequency and proportion for binary data. Results: Among 255 patients, 91 (35.69%) (95% Confidence Interval = 29.81-41.57) patients used tobacco. Among them, 72 (28.2%) were current users, who had taken tobacco at least once during the past 30 days and 19 (7.5%) were ever users who had taken tobacco but not during the past 30 days. Conclusions: The prevalence of tobacco use among our study participants is similar in comparison to that of the general population. Our study shows greater prevalence of the use of a smokeless form of tobacco than the smoked form of tobacco.

Mortality and long-term outcomes of palliative inotropes in ischemic and non-ischemic cardiomyopathy

Background

Palliative inotropes are frequently utilized for symptom management in patients with end stage heart failure who are unable to undergo durable advanced heart failure therapies. With the advent of improved medical management and early intervention, palliative inotropes may allow for improved patient outcomes than seen previously. In this study, we aim to investigate the survival and outcomes of palliative inotrope therapy and its impacts on ischemic versus non-ischemic cardiomyopathy.

Methods

We retrospectively analyzed 220 patients with American Heart Association Stage D heart failure who were discharged with palliative inotrope therapy after January 1, 2010. Patients who underwent mechanical circulatory support (MCS) or those who underwent heart transplant were excluded. Those with a history of coronary artery disease, myocardial infarction, history of percutaneous intervention, or coronary artery bypass grafting were assigned to ischemic cardiomyopathy (ICM), while patients without these findings were assigned to non-ischemic cardiomyopathy (NICM). Statistical analysis was completed using Chi-Square and Student's t-tests, wherein p&lt;0.05 was considered statistically significant.

Results

Of the 220 patients, 87 had NICM as opposed to 133 with ICM. Mean age was found to be higher among patients with ICM (70 [62–79]) compared to NICM (65 [55–72], p-value &lt;0.01). No significant difference was seen in total days on inotrope therapy (p=0.6). While more patients in both groups were placed on milrinone as opposed to dobutamine, there was no difference between patients with ischemic and NICM (p=0.66 and 0.51 respectively). Although a greater number of patients with NICM had been lost to follow up, admitted to hospice, or expired at 2 years (p&lt;0.01), survival at 3 months, 1 year, and 2 years showed no difference between both groups. No difference was seen in number of hospitalizations or clinic visits in one year. Both groups had similar complication rates with intravenous-access related PICC line infections and new arrhythmias. (See Table).

Conclusion

Despite more frequent use of durable mechanical support devices, many patients who are deemed unsuitable for invasive measures are treated with palliative inotrope therapy. We have found that there is no significant difference in survival, complications, and outcomes of patients on palliative inotropes among ischemic and NICM. These findings show the versatility of palliative inotrope therapy in end stage heart failure. Further studies with larger populations need to be evaluated.

Funding Acknowledgement

Type of funding sources: None.

Epidermoid Cyst of the Ear Lobule in Adult

An epidermoid cyst is one of the most common benign cysts of the skin. The cyst is filled with keratin flakes and its wall is composed of keratinized, stratified, squamous epithelium. Epidermoid cysts can occur anywhere on the body, usually along the lines of embryonic fusion and mostly on the face, scalp, neck, chest, and upper back. Around 80% of the epidermoid cysts are seen in ovaries and testicles whereas, in the head and neck, they account for only about 7% and 1.6% of epidermoid cysts are reported in the oral cavity. The condition can be congenital or acquired. Congenital causes are rare and may be caused by the entrapment of ectodermal elements intradermally or subcutaneously during embryogenesis. Acquired causes of an epidermoid cyst may result from traumatic or iatrogenic implantation of epithelial cells into the dermal layer or from obstruction of a pilosebaceous unit in the hair follicle. Surgical excision completes the treatment.

Knowledge and Practices of Child Protection among the School Health Nurses of Nepal

Background Child protection is burning issues in developing countries including Nepal. Child protection is one of the key works of the school health nurses. Objective To find out about the existing knowledge and practices of child protection among the school health nurses. Method This descriptive cross-sectional study was conducted among 130 school health nurses working in different schools throughout Nepal. The participants were selected using purposive sampling technique and were invited to participate via various online networks. Self-administered questionnaire was used to collect data. Duration of data collection was 20 December 2020 to 10 February 2021. Descriptive statistics was used to analyze and interpret the data. Result Among the 130 Participants, 88.5% belonged to less than 29 years age group and 67.7% had Proficiency Certificate Level in Nursing education. None of them has received training related to child protection recognition and response and 90.8% had work experience of less than 5 years. Eighty percent and 96.9% participants had knowledge regarding the meaning of child right and child abuse respectively. But 45.4% had knowledge on meaning of child neglect; 53.1% and 72.3% had the knowledge of physical abuse and noncontact sexual abuse respectively. Majority (86.9%) of the participants reported as relatives were the abuser and 63.8% replied as home is the common place for abuse. Similarly, 85.4% had received the information regarding child protection via television radio and newspaper. Only 36.1% has already been involved in child protection. The participants who went to local government (Palika), police and Non-government Organizations for coordination for child right issues were 9(19.1%), 7(14.8%) and 8(17.0%) respectively. Conclusion Most of the school health nurses are young without having experience of childhood abuse and received any child protection training before joining the job. They have good knowledge of child right, physical, sexual abuse except child neglect and existing legal arrangements. There is gap in knowledge and practice.

Presenting Clinico-laboratory Characteristics, Hospital Course and Outcomes of Admitted Children with COVID19 in a Tertiary Pediatric Hospital of Nepal

BACKGROUND

COVID-19 pandemic hit all age group with different presentations and outcome. This study aimed at exploring the clinical characteristics, investigational findings, hospital outcome along with 90 days follow up of COVID-19 infection in children.

METHODS

This was longitudinal descriptive study among hospital admitted children with COVID-19 RT-PCR positive during first wave of Pandemic with 90 days telephonic follow up. Demographic and clinical characteristics, comorbidities, SPO2, investigations, need of oxygen , PICU admission, need of ventilator, outcome (improved and discharged, death) and duration of hospital stay were recorded and 90 days telephonic follow up was performed for any illness and hospital admission.

RESULTS

Out of 65 children admitted, male 44 (67.7%) and female 21 (32.3%), median age was 23 months ( IQR 6 days -14 years) with 52( 80.0%) without any comorbid conditions. The common signs were Fever 40(61.5%) vomiting 15 (23.1%) and Cough 11(16.9%).Thirteen (20.0%) children has platelets count less than 150000 and 16(24.6%) had C - reactive protein Positive .Mean duration of hospital stay 8 days (Range 1 -44 days), 20( 30.8% ) needed oxygen , 20(30.8%) needed Pediatric intensive care unit (PICU)admission and 6 (9.2%), needed ventilator. Forty seven (72.3%) recovered and discharged with death of 6.2% (n=4). Fifty six children (75.4%) has not experienced any problem after COVID -19 and only 2 children needed hospital admission in 90 days telephone follow up.

CONCLUSIONS

In the first wave of the pandemic, Respiratory and Gastrointestinal symptoms were common presentation with few Severe and critical cases. Majority had good outcome. Majority has no other related illness till 90 days after discharge.

Self-interaction-corrected Kohn-Sham effective potentials using the density-consistent effective potential method

Density functional theory (DFT) and beyond-DFT methods are often used in combination with photoelectron spectroscopy to obtain physical insights into the electronic structure of molecules and solids. The Kohn-Sham eigenvalues are not electron removal energies except for the highest occupied orbital. The eigenvalues of the highest occupied molecular orbitals often underestimate the electron removal or ionization energies due to the self-interaction (SI) errors in approximate density functionals. In this work, we adapt and implement the density-consistent effective potential method of Kohut, Ryabinkin, and Staroverov [J. Chem. Phys. 140, 18A535 (2014)] to obtain SI-corrected local effective potentials from the SI-corrected Fermi-Löwdin orbitals and density in the Fermi-Löwdin orbital self-interaction correction scheme. The implementation is used to obtain the density of states (photoelectron spectra) and HOMO-LUMO gaps for a set of molecules and polyacenes. Good agreement with experimental values is obtained compared to a range of SI uncorrected density functional approximations.

Chemical profiling of DNA G-quadruplex-interacting proteins in live cells

DNA-protein interactions regulate critical biological processes. Identifying proteins that bind to specific, functional genomic loci is essential to understand the underlying regulatory mechanisms on a molecular level. Here we describe a co-binding-mediated protein profiling (CMPP) strategy to investigate the interactome of DNA G-quadruplexes (G4s) in native chromatin. CMPP involves cell-permeable, functionalized G4-ligand probes that bind endogenous G4s and subsequently crosslink to co-binding G4-interacting proteins in situ. We first showed the robustness of CMPP by proximity labelling of a G4 binding protein in vitro. Employing this approach in live cells, we then identified hundreds of putative G4-interacting proteins from various functional classes. Next, we confirmed a high G4-binding affinity and selectivity for several newly discovered G4 interactors in vitro, and we validated direct G4 interactions for a functionally important candidate in cellular chromatin using an independent approach. Our studies provide a chemical strategy to map protein interactions of specific nucleic acid features in living cells.

Anxiety, Depression and Functional Impairment among Health Care Workers during COVID-19 Pandemic: A Crosssectional Online Survey

Background COVID-19 is an infectious disease caused by a newly discovered coronavirus. The number of cases and dramatic loss of human life worldwide created psychological problems among general public, including health care workers. Objective To determine the burden of anxiety, depression, and functional impairment among health care workers in the early days of lockdown during the first wave of COVID-19 outbreak in Nepal. Method A hospital-based cross-sectional study was carried out among all the employees of Hospital for Children Eye ENT and Rehabilitation Services, Bhaktapur during the COVID-19 pandemic lockdown from April 3, 2020 to May 2, 2020 using an online questionnaire. The tools used were adopted from Nepali version of Hospital Anxiety and Depression scale (HADS) and Nepali version of WHO Disability Assessment Schedule (WHODAS 2.0). Result The mean age (SD) of the participants (n=86) was 32.53 (7.92) years. Male and female participants were equal in number. The point prevalence of anxiety and depression was 25.6% and 14.0%, respectively. Females had a higher prevalence of both anxiety (39.5% vs 11.6%, p < 0.01) and depression (18.6% vs 9.3%, p=0.351). Clinical and nonclinical staff both had a higher prevalence of both anxiety (31.0% and 20.5%, p=0.265) and depression (16.7% and 11.4%, p=0.478). The mean functional impairment score (WHODAS 2.0) among all participants and participants with anxiety and depression was 19.47 (95% CI: 18.13-20.80), 21.27 (95% CI: 18.08-24.46), and 19.92 (95% CI: 15.28- 24.56), respectively. Conclusion Anxiety and depression during the first lockdown due to COVID-19 pandemic were highly prevalent in clinical and non-clinical employees. Besides controlling the outbreak, special consideration should be given to mental health.

The eigenbuckling analysis of hexagonal lattices: closed-form solutions

Elastic instability such as the buckling of cellular materials plays a pivotal role in their analysis and design. Despite extensive research, the quantifi- cation of critical stresses leading to elastic instabi- lities remains challenging due to the inherent nonlinearities. We develop an analytical approach considering the spectral decomposition of the elasticity matrix of two-dimensional hexagonal lattice materials. The necessary and sufficient condition for the buckling is established through the zeros of the eigenvalues of the elasticity matrix. Through the analytical solution of the eigenvalues, the conditions involving equivalent elastic properties of the lattice were directly connected to the mathematical requirement of buckling. The equivalent elastic properties are expressed in closed form using geometric properties of the lattice and trigonometric functions of a non-dimensional axial force parameter. The axial force parameter was identified for four different stress cases, namely, compressive stress in the longitudinal and transverse directions separately and together and torsional stress. By solving the resulting nonlinear equations, we derive exact analytical expressions of critical eigenbuckling stresses for these four cases. Crucial parameter combinations leading to minimum buckling stresses are derived analytically. The exact closed-form analytical expressions derived in the paper can be used for quick engineering design calculations and benchmarking related experimental and numerical studies.

Quantitative live-cell PALM reveals nanoscopic Faa4 redistributions and dynamics on lipid droplets during metabolic transitions of yeast

Lipid droplets (LDs) are dynamic organelles for lipid storage and homeostasis. Cells respond to metabolic changes by regulating the spatial distribution of LDs and enzymes required for LD growth and turnover. The small size of LDs precludes the observation of their associated enzyme densities and dynamics with conventional fluorescence microscopy. Here we employ quantitative photo-activated localization microscopy to study the density of the fatty acid (FA) activating enzyme Faa4 on LDs in live yeast cells with single-molecule sensitivity and 30 nm resolution. During the log phase LDs colocalize with the endoplasmic reticulum (ER) where their emergence and expansion are mediated by the highest observed Faa4 densities. During transition to the stationary phase, LDs with a ∼2-fold increased surface area translocate to the vacuolar surface and lumen and exhibit a ∼2.5-fold increase in Faa4 density. The increased Faa4 density on LDs further suggests its role in LD expansion, is caused by its ∼5-fold increased expression level, and is specific to exogenous FA chain-lengths. When lipolysis is induced by refreshed medium, Faa4 shuttles through ER- and lipophagy to the vacuole, where it may activate FAs for membrane expansion and degrade Faa4 to reset its cellular abundance to levels in the log phase.

Nepal at the edge of sword with two edges: The COVID-19 pandemics and sustainable development goals

Humanity has been threatened by pandemics since several decades with devastating effects on all human activities including the economy, and environment. Currently, the world is reeling from the COVID-19 pandemic. The COVID-19 pandemic has been a major threat to the livelihood of billions of people worldwide. Nepal is not an exception to this and has been seriously threatened by the COVID-19 pandemic. The thousands of the peoples who depend on daily wages to join hand to mouth has been under the brunt of the COVID-19 pandemic because of job loss, disruption in the food supply chain. Also, the COVID-19 pandemic has thwarted Nepal's targets to achieve UN Sustainable Development Goals including an unprecedented state of vulnerability to hunger and poverty in the country. Though some informal shreds of evidence have reported the negative impacts of COVID-19 on Sustainable Development Goals, none of the scientific literature has been available regarding such impacts in Nepal yet. This review aims to synthesize extant literature that reports the effects of COVID-19 on the Nepalese economy and implications for achieving UN Sustainable Development Goals.We found that the COVID-19 pandemic has created unprecedented challenges to achieve the country's committed United Nation's Sustainable Development Goals for Nepal. Further, the COVID-19 pandemic has created a unique "income shock" that is supposed to precipitate household food insecurity in developing economy like Nepal. Our review indicated that the percentage of populations below poverty could rise even more than the present national reported value of 18% in the post-pandemic era. We emphasized generating employment and income-earning opportunities to build a resilient food system. Further, we urged to build international consensus to reset and rethink the course of sustainable development goals.

Promoter G-quadruplex folding precedes transcription and is controlled by chromatin

BACKGROUND

Four-stranded G-quadruplexes (G4s) are DNA secondary structures in the human genome that are primarily found in active promoters associated with elevated transcription. Here, we explore the relationship between the folding of promoter G4s, transcription and chromatin state.

RESULTS

Transcriptional inhibition by DRB or by triptolide reveals that promoter G4 formation, as assessed by G4 ChIP-seq, does not depend on transcriptional activity. We then show that chromatin compaction can lead to loss of promoter G4s and is accompanied by a corresponding loss of RNA polymerase II (Pol II), thus establishing a link between G4 formation and chromatin accessibility. Furthermore, pre-treatment of cells with a G4-stabilising ligand mitigates the loss of Pol II at promoters induced by chromatin compaction.

CONCLUSIONS

Overall, our findings show that G4 folding is coupled to the establishment of accessible chromatin and does not require active transcription.

G-quadruplexes are transcription factor binding hubs in human chromatin

BACKGROUND

The binding of transcription factors (TF) to genomic targets is critical in the regulation of gene expression. Short, double-stranded DNA sequence motifs are routinely implicated in TF recruitment, but many questions remain on how binding site specificity is governed.

RESULTS

Herein, we reveal a previously unappreciated role for DNA secondary structures as key features for TF recruitment. In a systematic, genome-wide study, we discover that endogenous G-quadruplex secondary structures (G4s) are prevalent TF binding sites in human chromatin. Certain TFs bind G4s with affinities comparable to double-stranded DNA targets. We demonstrate that, in a chromatin context, this binding interaction is competed out with a small molecule. Notably, endogenous G4s are prominent binding sites for a large number of TFs, particularly at promoters of highly expressed genes.

CONCLUSIONS

Our results reveal a novel non-canonical mechanism for TF binding whereby G4s operate as common binding hubs for many different TFs to promote increased transcription.

Observation of Beam Spin Asymmetries in the Process ep→e^{'}π^{+}π^{-}X with CLAS12

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function G_{1}^{⊥}. A clear sign change is observed around the ρ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark.

Describing adsorption of benzene, thiophene, and xenon on coinage metals by using the Zaremba-Kohn theory-based model

Semilocal (SL) density functional approximations (DFAs) are widely applied but have limitations due to their inability to incorporate long-range van der Waals (vdW) interaction. Non-local functionals (vdW-DF, VV10, and rVV10) or empirical methods (DFT+D, DFT+vdW, and DFT+MBD) are used with SL-DFAs to account for such missing interaction. The physisorption of a molecule on the surface of the coinage metals (Cu, Ag, and Au) is a typical example of systems where vdW interaction is significant. However, it is difficult to find a general method that reasonably describes both adsorption energy and geometry of even the simple prototypes of cyclic and heterocyclic aromatic molecules such as benzene (C₆H₆) and thiophene (C₄H₄S), respectively, with reasonable accuracy. In this work, we present an alternative scheme based on Zaremba-Kohn theory, called DFT+vdW-dZK. We show that unlike other popular methods, DFT+vdW-dZK and particularly SCAN+vdW-dZK give an accurate description of the physisorption of a rare-gas atom (xenon) and two small albeit diverse prototype organic molecules on the (111) surfaces of the coinage metals.

Photoproduction of the f_{2}(1270) Meson Using the CLAS Detector

The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π^{+}π^{-}, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π^{0}π^{0}p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f_{2}(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.

Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

A first measurement of the longitudinal beam spin asymmetry A_{LU} in the semi-inclusive electroproduction of pairs of charged pions is reported. A_{LU} is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A_{LU}^{sinϕ_{R}} moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.