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Abstract Two-dimensional (2D) materials can be effectively functionalized by chemically modified using doping. Very recently, a flat AgSe monolayer was successfully prepared through direct selenization of the Ag(111) surface. Besides, the results indicate that the AgSe monolayer like CuSe, has a honeycomb lattice. Motivated by the experimental outcomes, in this work, employing first-principles calculations, we systematically investigate the electronic and optical properties of AgSe and CuSe monolayers, as well as the impact of alkali metals (Li, Na and K). Without functionalization, both the CuSe and AgSe monolayers exhibit metallic characteristics. The Li (Na)-CuSe and Na (K)-AgSe systems are dynamically stable while, the K- and Li-CuSe and Li-AgSe are dynamically unstable. Interestingly, the functionalized CuSe system with Li and Na atom as well as AgSe with K and Na atom, can open the band gaps, leading to the actualization of metal to semiconductor transitions. Our results show that, the electronic characteristics of the Na-CuSe/AgSe system can be modulated by adjusting the adsorption heights, which gives rise to the change in the electronic properties and the band gap may be controlled. Furthermore, from the optical properties we can find that the K-AgSe system is the best candidate monolayer to absorb infrared radiation and visible light. Consequently, our findings shed light on the functionalization of 2D materials based CuSe and AgSe monolayers and can potentially enhance and motivate studies in producing these monolayers for current nanodevices and future applications.

In the last two decades, significant efforts have been particularly invested in two-dimensional (2D) hexagonal boron carbon nitride h-BxCyNz because of its unique physical and chemical characteristics. The presence of the carbon atoms lowers the large gap of its cousin structure, boron nitride (BN), making it more suitable for various applications. Here, we use density functional theory to study the structural, electronic, and magnetic properties of Pt-doped BC6N (Pt-BC6N, as well as its adsorption potential of small molecular gases (NO, NO2, CO2, NH3). We consider all distinct locations of the Pt atom in the supercell (B, N, and two C sites). Different adsorption locations are also considered for the pristine and Pt-doped systems. The formation energies of all Pt-doped structures are close to those of the pristine system, reflecting their stability. The pristine BC6N is semiconducting, so doping with Pt at the B and N sites gives a diluted magnetic semiconductor while doping at the C1 and C2 sites results in a smaller gap semiconductor. We find that all doped structures exhibit direct band gaps. The studied molecules are very weakly physisorbed on the pristine structure. Pt doping leads to much stronger interactions, where NO, NO2, and NH3 chemisorb on the doped systems, and CO2 physiorb, illustrating the doped systems’ potential for gas purification applications. We also find that the adsorption changes the electronic and magnetic properties of the doped systems, inviting their consideration for spintronics and gas sensing.

Abstract In this work, novel two-dimensional BC $$_2$$ 2 X (X = N, P, As) monolayers with X atoms out of the B–C plane, are predicted by means of the density functional theory. The structural, electronic, optical, photocatalytic and thermoelectric properties of the BC $$_2$$ 2 X monolayers have been investigated. Stability evaluation of the BC $$_2$$ 2 X single-layers is carried out by phonon dispersion, ab-initio molecular dynamics (AIMD) simulation, elastic stability, and cohesive energies study. The mechanical properties reveal all monolayers considered are stable and have brittle nature. The band structure calculations using the HSE06 functional reveal that the BC $$_2$$ 2 N, BC $$_2$$ 2 P and BC $$_2$$ 2 As are semiconducting monolayers with indirect bandgaps of 2.68 eV, 1.77 eV and 1.21 eV, respectively. The absorption spectra demonstrate large absorption coefficients of the BC $$_2$$ 2 X monolayers in the ultraviolet range of electromagnetic spectrum. Furthermore, we disclose the BC $$_2$$ 2 N and BC $$_2$$ 2 P monolayers are potentially good candidates for photocatalytic water splitting. The electrical conductivity of BC $$_2$$ 2 X is very small and slightly increases by raising the temperature. Electron doping may yield greater electric productivity of the studied monolayers than hole doping, as indicated by the larger power factor in the n-doped region compared to the p-type region. These results suggest that BC $$_2$$ 2 X (X = N, P, As) monolayers represent a new promising class of 2DMs for electronic, optical and energy conversion systems.

Hybrid structures often possess superior properties to those of their component materials. This arises from changes in the structural or physical properties of the new materials. Here, we investigate the structural, electronic, and gas-adsorption properties of hybrid structures made from graphene/hexagonal boron nitride and 2H-molybdenum disulfide (G/BN@MoS2) monolayers. We consider hybrid systems in which the G/BN patch is at the Mo plane (model I) and the S plane (model II). We find that the implanted hexagon of G or BN in MoS2 alters its electronic properties: G@MoS2 (I,II) are metallic, while BN@MoS2 (I) is an n-type conducting and BN@MoS2 (II) is semiconducting. We study the molecular adsorption of some diatomic gases (H2, OH, N2, NO, CO), triatomic gases (CO2, NO2, H2S, SO2), and polyatomic gases (COOH, CH4, and NH3) on our hybrid structures while considering multiple initial adsorption sites. Our results suggest that the hybrid systems may be suitable materials for some applications: G@MOS2 (I) for oxygen reduction reactions, BN@MoS2 (I,II) for NH3-based hydrogen production, and G@MoS2 (I) and BN@MoS2 (I,II) for filtration of No, Co, SO2, H2S, and NO2.

Recent advances in experimental techniques allow for the fabrication of hybrid structures. Here, we study the electronic and molecular adsorption properties of the graphene (G)/hexagonal boron nitride (h-BN)-MXenes (Mo2C) hybrid nanosheets. We use first-principles calculations to explore the structure and electronic properties of the hybrid structures of G-2H-Mo2C and h-BN-2H-Mo2C with two different oxygen terminations of the Mo2C surface. The embedding of G or h-BN patches creates structural defects at the patch-Mo2C border and adds new states in the vicinity of the Fermi energy. Since this can be utilized for molecular adsorption and/or sensing, we investigate the ability of the G-M-O1 and BN-M-O1 hybrid structures to adsorb twelve molecules. Generally, the adsorption on the hybrid systems is significantly higher than on the pristine systems, except for N2 and H2, which are weakly adsorbed on all systems. We find that OH, NO, NO2, and SO2 are chemisorbed on the hybrid systems. COOH may be chemisorbed, or it may dissociate depending on its location at the edge between the G/h-BN and the MXene. NH3 is chemisorbed/physisorbed on the BN/G-M-O1 systems. CO, H2S, CO2, and CH4 are physisorbed on the hybrid systems. Our results indicate that the studied hybrid systems can be used for molecular filtration/sensing and catalysis.

Abstract Growing experience with engineered chimeric antigen receptor (CAR)‐T cells has revealed some of the challenges associated with developing patient‐specific therapy. The promising clinical results obtained with CAR‐T therapy nevertheless demonstrate the urgency of advancements to promote and expand its uses. There is indeed a need to devise novel methods to generate potent CARs, and to confer them and track their anti‐tumor efficacy in CAR‐T therapy. A potentially effective approach to improve the efficacy of CAR‐T cell therapy would be to exploit the benefits of nanotechnology. This report highlights the current limitations of CAR‐T immunotherapy and pinpoints potential opportunities and tremendous advantages of using nanotechnology to 1) introduce CAR transgene cassettes into primary T cells, 2) stimulate T cell expansion and persistence, 3) improve T cell trafficking, 4) stimulate the intrinsic T cell activity, 5) reprogram the immunosuppressive cellular and vascular microenvironments, and 6) monitor the therapeutic efficacy of CAR‐T cell therapy. Therefore, genetic and functional modifications promoted by nanotechnology enable the generation of robust CAR‐T cell therapy and offer precision treatments against cancer.

Abstract Background The objective of this study was to determine whether patients infected with extended-spectrum beta-lactamase (ESBL)-producing organisms are colonized at multiple body sites. Methods This was a prospective cohort study at a tertiary care center in Beirut, Lebanon. Hospitalized patients with infections caused by ESBL-producing organisms were included. Cultures were obtained from the primary site of infection as well as from other sites (skin, nasopharynx, urine, rectum). Molecular analysis was performed on isolates to determine clonal relatedness. Results One hundred patients were included in the study. Only 22 patients had positive cultures from sites other than the primary site of infection. The most common ESBL gene was CTX-M-15 followed by TEM-1. In 11 of 22 patients, isolates collected from the same patient were 100% genetically related, while in the remaining patients, genomic relatedness ranged from 42.9% to 97.1%. Conclusions Colonization at sites other than the primary site of infection was not common among our patient population infected with ESBL-producing organisms. The dynamics of transmission of these bacterial strains should be studied in further prospective studies to determine the value of routine active surveillance and the need for expanded precautions in infected and colonized patients.

Objective: To assess the level of control and prevalence of type 2 diabetes in King Abdulaziz Housing City (Iskan) population of Saudi Arabia. Materials and Methods: Retrospective cross-sectional study conducted in a primary-care setting. All Type 2 diabetics referred to our diabetes center between January 2011 and January 2015 were identified, and their computerized records reviewed. Glycated hemoglobin levels (HbA1c), low-density lipoprotein (LDL), blood pressure (BP), and the albumin-creatinine ratio (ACR) were noted and the patients categorized accordingly. Demographic data (age and gender) were also documented. Inactive patients (not seen for more than 2 years) were excluded. Results: The overall prevalence of type 2 diabetes for all age groups in ISKAN population was 3.25%. About 56% of the diabetics were female and 70% were aged between 18 and 59 years. The rate of uncontrolled diabetes was 59.3%. Males were more likely to have uncontrolled diabetes (odds ratio: 1.44, CI: 1.17-1.76, P = 0.0004). Forty percent of the diabetics had an LDL above target (≥2.6 mmol/l) while 25.9% had uncontrolled hypertension (BP ≥ 140/90 mmHg). Of those who had an ACR test done within the last year (59.3%), the rate of micro- and macro-albuminuria was 8.8% and 2.5%, respectively. Conclusions: The overall prevalence of type 2 diabetes in our community seems lower than the previously reported national figures. An alarming number of diabetics in our population have an uncontrolled disease. More stringent diabetes annual review and recall program is needed to control diabetes and reduce complications.

H7 subtype avian influenza viruses have caused outbreaks in poultry, and even human infection, for decades in both Eurasia and North America. Although effective vaccines offer the best protection against avian influenza viruses, antigenically distinct Eurasian and North American lineage subtype H7 viruses require the development of cross-protective vaccine candidates. In this study, a methodology called computationally optimized broadly reactive antigen (COBRA) was used to develop four consensus H7 antigens (CH7-22, CH7-24, CH7-26, and CH7-28). In vitro experiments confirmed the binding of monoclonal antibodies to the head and stem domains of cell surface-expressed consensus HAs, indicating display of their antigenicity. Immunization with DNA vaccines encoding the four antigens was evaluated in a mouse model. Broadly reactive antibodies against H7 viruses from Eurasian and North American lineages were elicited and detected by binding, inhibition, and neutralizing analyses. Further infection with Eurasian H7N9 and North American H7N3 virus strains confirmed that CH7-22 and CH7-24 conferred the most effective protection against hetero-lethal challenge. Our data showed that the consensus H7 vaccines elicit a broadly reactive, protective response against Eurasian and North American lineage H7 viruses, which are suitable for development against other zoonotic influenza viruses.

Due to their characteristic geometry, TiO _2 nanotubes (TNTs), suitably doped by metal-substitution to enhance their photocatalytic properties, have a high potential for applications such as clean fuel production. In this context, we present a detailed investigation of the magnetic, electronic, and optical properties of transition-metal doped TNTs, based on hybrid density functional theory. In particular, we focus on the 3 d , the 4 d , as well as selected 5 d transition-metal doped TNTs. Thereby, we are able to explain the enhanced optical activity and photocatalytic sensitivity observed in various experiments. We find, for example, that Cr- and W-doped TNTs can be employed for applications like water splitting and carbon dioxide reduction, and for spintronic devices. The best candidate for water splitting is Fe-doped TNT, in agreement with experimental observations. In addition, our findings provide valuable hints for future experimental studies of the ferromagnetic/spintronic behavior of metal-doped titania nanotubes.

The magnetic and transport properties of the metal phthalocyanine (MPc) and F _16 MPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of molecules in contact with S–Au wires are investigated by density functional theory within the local density approximation, including local electronic correlations on the central metal atom. The magnetic moments are found to be considerably modified under fluorination. In addition, they do not depend exclusively on the configuration of the outer electronic shell of the central metal atom (as in isolated MPc and F _16 MPc) but also on the interaction with the leads. Good agreement between the calculated conductance and experimental results is obtained. For M = Ag, a high spin filter efficiency and conductance is observed, giving rise to a potentially high sensitivity for chemical sensor applications.

The electronic and optical properties of vertical heterostructures (HTSs) and lateral heterojunctions (HTJs) between (B,N)-codoped graphene (dop@Gr) and graphene (Gr), C3N, BC3 and h-BN monolayers are investigated using van der Waals density functional theory calculations. We have found that all the considered HTSs are energetically and thermally feasible at room temperature, and therefore they can be synthesized experimentally. The dop@Gr/Gr, BC3/dop@Gr and BN/dop@Gr HTSs are semiconductors with direct bandgaps of 0.1 eV, 80 meV and 1.23 eV, respectively, while the C3N/dop@Gr is a metal because of the strong interaction between dop@Gr and C3N layers. On the other hand, the dop@Gr-Gr and BN-dop@Gr HTJs are semiconductors, whereas the C3N-dop@Gr and BC3-dop@Gr HTJs are metals. The proposed HTSs can enhance the absorption of light in the whole wavelength range as compared to Gr and BN monolayers. The applied electric field or pressure strain changes the bandgaps of the HTSs and HTJs, indicating that these HTSs are highly promising for application in nanoscale multifunctional devices. [ABSTRACT FROM AUTHOR]

Small-sized nanoparticles are widely used in applications such as catalysis, nanoelectronics, and hydrogen storage. However, the small size causes a common problem: agglomeration on the support template. One solution is to use templates that limit the mobility of the nanoparticles. Graphene nanomeshes (GNMs) are two dimensional porous structures with controllably passivated pores. In this work, we employ first principles calculations to investigate the potential for using GNMs as support templates for Ni clusters and, at the same time, study their magnetic and hydrogen storage properties. We consider two Ni clusters (Ni6 and Ni13) and two GNMs (O-terminated and N-terminated), comparing our results to those of isolated Ni clusters and those of Ni clusters on graphene. High stability of the Ni clusters is found on the N-GNM in contrast to the O-GNM. We quantify the hydrogen storage capacity by calculating the adsorption energy for multiple H2 molecules. The values on Nix/N-GNM are significantly reduced as compared to the corresponding isolated Nix clusters, but a high hydrogen storage capacity is maintained. The fact that Nix/N-GNM hosts spin polarization is interesting for spintronic applications. [ABSTRACT FROM AUTHOR]

The magnetic and transport properties of the metal phthalocyanine (MPc) and F16MPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of molecules in contact with S–Au wires are investigated by density functional theory within the local density approximation, including local electronic correlations on the central metal atom. The magnetic moments are found to be considerably modified under fluorination. In addition, they do not depend exclusively on the configuration of the outer electronic shell of the central metal atom (as in isolated MPc and F16MPc) but also on the interaction with the leads. Good agreement between the calculated conductance and experimental results is obtained. For M = Ag, a high spin filter efficiency and conductance is observed, giving rise to a potentially high sensitivity for chemical sensor applications. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial resistance is an emerging problem worldwide, endangering antimicrobials efficacy and resulting in high rates of morbidity and mortality. It is one of the major concerns that health care facilities are facing nowadays. Mainly, extended-spectrum beta-lactamases (ESBL)-producing Enterobacterales play a role in hydrolyzing β-lactams, specifically the third-generation cephalosporins. This study aimed to investigate the prevalence of fecal carriage and molecular characterization of ESBL-producing Enterobacterales among Lebanese elderly residents in a long-term care facility (Dar Al-Ajaza Al Islamia Hospital)., Methods: Rectal culture swab specimens were collected from 132 patients at Dar Al Ajaza Al Islamia hospital between January 2019 till June 2020. The phenotype of ESBL producers was confirmed by a modified double disc synergy test and antibiotic susceptibility was determined using the Kirby-Bauer disk diffusion method. Genotypically, multiplex polymerase chain reaction was used to detect the ESBL genes., Results: The main Enterobacterales strain observed was E coli (90.15%) followed by Klebsiella pneumoniae (4.54%) and Klebsiella oxytoca (3.80%). It has been found that the ESBL percentage rate has decreased when compared to a study conducted previously at the same hospital. Moreover, the predominant ESBL gene was CTX-M (cefotaximase)., Conclusions: This study is the first to demonstrate the improved current status of ESBL in one long-term care facility. In addition, the CTX-M is still the major type in ESBL-producing organisms., (Copyright © 2023 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

Introduction: Antimicrobial resistance (AMR) is a worldwide problem that threatens treatment effectiveness against the most serious bacterial infections. AMR in Enterobacterales is highly prevalent in Lebanon. However, recent reports regarding the distribution of Enterobacterales and related antimicrobial susceptibility are scarce., Methodology: In this retrospective study at the Lebanese Hospital Geitaoui Medical Center in Lebanon, all data regarding culture specimens from urine, blood, sputum, deep tracheal aspirate, broncho-alveolar lavage, wounds, surgical sites, tissue, body fluids, and central venous catheter that were positive for at least one of the 4 bacterial isolates (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Proteus mirabilis) were collected. All susceptibility testing was performed according to the Clinical and Laboratory Standards Institute guidelines., Results: A total of 4283 non-duplicate Enterobacterales were isolated during the study period (January 2017 to December 2020). Urine was the most common site of infection. E. coli was the most detected isolate as well as the leading pathogen in urine, wounds and surgical sites, and blood. Regarding antimicrobial susceptibility, the mean susceptibility to third generation cephalosporins was 55.53% and a mean extended-spectrum β-lactamases production of 31.2% was measured in E. coli. Mean carbapenem susceptibility was the lowest in K. pneumoniae and E. cloacae. The lowest mean susceptibility to fluoroquinolones was detected in E. coli isolates., Conclusions: This study identified the predominance of E. coli among Enterobacterales in Lebanese patients, with the urinary tract being the most common site of infection and underlined the high rates of AMR in Enterobacterales in Lebanon., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2023 Mahdi Fadlallah, Elie Salem Sokhn.)

Carbapenem-resistant Enterobacterales (CRE) pathogens have been increasingly isolated and reported in Lebanon. Several studies have been published over the last two decades about the CRE situation in the country. However, compared to the worldwide data, those studies are scarce and mostly restricted to single center studies. In this review, we aim to present a comprehensive and reliable report illustrating the current situation regarding CRE in Lebanon. Variable studies have shown an increasing pattern of carbapenem resistance in Enterobacterales since the first reports of CRE isolates in 2007 and 2008. Escherichia coli and Klebsiella pneumoniae were the most detected ones. The OXA-48 class D carbapenemases were the most prevalent carbapenemases among CRE isolates. Moreover, the emergence of other carbapenemases like the NDM class B carbapenemase has been noticed. Strict infection control measures in hospitals, including the identification of CRE carriers, are needed in Lebanese hospitals since carriage is a potential risk for the spread of CRE in healthcare settings. The dissemination of CRE in the community is noticed and attributed to multiple causes, such as the refugee crisis, water contamination, and antimicrobial misuse. In conclusion, strict infection control measures in healthcare settings, in addition to accurate antimicrobial stewardship program implementation, are urgently needed., Competing Interests: The authors declare that there are no conflicts of interest., (Copyright © 2023 Mahdi Fadlallah et al.)

Background: CMV infection prevalence in kidney transplant recipients (KTR) is reported to be high in the literature, reaching rates of over 80%., Objectives: The primary endpoints were the evaluation of the prevalence, the risks factors, and the effects of CMV infection on graft function and survival, as well as patient survival at three years after kidney transplantation., Material and Methods: We retrospectively reviewed the medical records of 288 kidney transplant patients operated in three Lebanese transplant centers between 1998 and 2017 with three years of follow-up. The patients were divided into two groups: those free of any CMV infection (271 patients (94%); Group I) and those who suffered from CMV infection (17 patients (6%); Group II)., Results: Baseline demographics of the two groups were similar, including recipient and donor gender and age, cause of renal disease, recipient body mass index, pre-transplant fasting blood sugar and dialysis duration, HLA matching between donor and recipient, degree of sensitization in the recipient, type of CMV prophylaxis, maintenance immunosuppression and immunological characteristics. The prevalence of CMV infection is 5.9% among KTR. There were significant differences between the two groups concerning the type of induction therapy and the duration of anti-CMV prophylaxis. The rate of infected patients and infectious episodes were significantly higher in Group II. At 3-years, graft function and survival, patient survival, and the rate of new-onset diabetes were similar between the two groups., Conclusion: The present study is the first to explore the incidence and risk factors of CMV in kidney transplant patients in Lebanon. Comprehensive nationwide studies are therefore necessary to determine the epidemiology and risk factors of CMV infection after kidney transplantation in Lebanon., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: To examine the auditory function in a group of children with type 1 diabetes, and to study the association between hearing impairment and duration of illness, metabolic control and diabetic complication., Methods: Sixty-three diabetic patients below the age of 18 attending the university hospital in Khartoum, Sudan were investigated together with 63 age and sex matched non-diabetic controls. Pure-tone audiometric tests were performed using an Amplaid 300 clinical audiometer in a soundproof room. Both air and bone conduction were tested at frequencies between 250-8000 Hz and 250-4000 Hz respectively. Hearing impairment was noted at auditory threshold above 25 dB in any frequency and the magnitude of hearing loss was assessed according to auditory threshold in conversational frequencies only., Results: The hearing acuity was lower in the diabetic patients than in the control subjects in all tested frequencies, but the differences achieve statistical significance only at middle and high frequencies. The hearing loss was symmetrical, generally mild, and affects both sexes equally. Duration of diabetes, HbA1c concentration, and angiopathic complications showed positive correlation with the increased hearing thresholds; while, age at onset, insulin dose per day, presence of neuropathy, and frequency of DKA and hypoglycaemic episodes were not associated., Conclusion: Hearing loss occurs early in diabetic children and is related to the duration of the disease and the degree of metabolic control. Strict glycemic control might prevent or delay this complication.