Manipulating single excess electrons in monolayer transition metal dihalide

Polarons are entities of excess electrons dressed with local response of lattices, whose atomic-scale characterization is essential for understanding the many body physics arising from the electron-lattice entanglement, yet difficult to achieve. Here, using scanning tunneling microscopy and spectroscopy (STM/STS), we show the visualization and manipulation of single polarons in monolayer CoCl₂, that are grown on HOPG substrate via molecular beam epitaxy. Two types of polarons are identified, both inducing upward local band bending, but exhibiting distinct appearances, lattice occupations and polaronic states. First principles calculations unveil origin of polarons that are stabilized by cooperative electron-electron and electron-phonon interactions. Both types of polarons can be created, moved, erased, and moreover interconverted individually by the STM tip, as driven by tip electric field and inelastic electron tunneling effect. This finding identifies the rich category of polarons in CoCl₂ and their feasibility of precise control unprecedently, which can be generalized to other transition metal halides.

Preventing the Burnout Syndrome by Creating a Healthy & Healing Environment

Occupational burnout is a significant global problem that has impacted clinical outcomes, patient safety, and patient-centered care across healthcare settings (World Health Organization) [WHO], 2019. The classic definition of burnout, as defined by Dr. Christina Maslach, is “a psychologic syndrome involving emotional exhaustion, depersonalization, and a diminished sense of personal accomplishment (Maslach & Jackson, 1982). Burnout affects cognitive, behavioral and emotional aspects of human behavior. It also interferes with how individuals process and interact with others at an individual and organizational level. Others have noted that burn-out individuals tend to focus on negative things rather than positive emotions (Bianchi & Laurent, 2015). Nurse and physician burnout was recognized before the COVID-19 pandemic as a growing problem. Evidence now suggests that more than 50% of nurses, physician assistants and physicians report syndromes of burnout. The problem has become even more pronounced when the work environment contributes stressors associated with technological advancements, EMRs, increased patient acuity, and financial cost cutting measures. It is now recognized that individuals and organizations burnout. As a public health issue, burnout and well-being are multifactorial and recognize that individuals and organizations contribute significant factors to the burnout syndrome. It appears that burnout rates are rising across specialties and settings resulting in increase of costs to individuals and organizations (National Academy of Medicine [NAM]), 2018. What is needed is a clear map to make decisions on clinical burnout. Healthcare workers (HCW) need confidential access to wellness activities, support systems and mental health consultation. A new model is needed to further refine the work-life balance and create a caring corporate culture. Healthcare leaders need to rethink how to support employees across disciplines when it comes to burnout and well-being.

The National Lung Cancer Audit: The Impact of COVID-19

Since 2014, the National Lung Cancer Audit (NLCA) has been evaluating the performance of the UK NHS lung cancer services against established standards of care. Prior to the onset of the COVID-19 pandemic, the NLCA's annual reports revealed a steady stream of improvements in early diagnosis, access to surgery, treatment with anti-cancer therapies, input from specialist nursing and survival for patients with lung cancer in the NHS. In January 2022, the NLCA reported on the negative impact COVID-19 has had on all aspects of the lung cancer diagnosis and treatment pathway within the NHS. This article details the fundamental changes made to the NLCA data collection and analysis process during the COVID-19 pandemic and details the negative impact COVID-19 had on NHS lung cancer patient outcomes during 2020.

Collapse of Healthcare Providers-medical and Paramedical-healthcare Staff after last Three Years of Pandemics and War Conflicts

This Editorial dispatch focuses on absolute shortage of healthcare workers and their psychical and physical exhaustion with devastation consequences on healthcare providers and management of pandemics and health destruction within ongoing armed conflicts in Europe and Middle East,focusing on non prioritizing HCW versus healthcare infrastructure, vaccines medications, but putting both to the same level of priority.

Prediction of Effective Photoelectron and Hole Separation in Type-I MoS2/PtSe2 van der Waals Junction

Understanding the dynamics of charge transfer at vertical heterostructures of transition metal dichalcogenide monolayers is fundamentally important for future technological applications, given the unique feature of van der Waals interactions at the interface. Here, we employ time-dependent density functional theory formalism combined with molecular dynamics to investigate photoexcited electrons and holes in the type-I MoS₂/PtSe₂ van der Waals heterobilayer. While type-I junctions have been traditionally viewed as being ineffective in photocarrier separation, we show that here a different mechanism from type-II is at play, which effectively separates photoelectrons from photoholes. The key is the phonon bottleneck, arising from the characteristically different dynamic band alignments in the valence and conduction bands, respectively, which only affects the transfer of holes but not electrons. The disparity between electron and hole transfer rates offers a new direction for effective control of charge separation at interfaces.

Devastation Consequences of Pandemia and War Conflicts in Health and Social Security

This current issue of Clinical Social Work and Health Intervention(1) reflects to some extent on two previous issues of this interdisciplinary Journal dealing within the last 2 years with two groups of catastrophic effects on civil society, social security, healthcare and finally to economics worldwide l. Pandemic, declared by WHO and most states authorities worldwide, due to the potentially deadly virus COVID-19, may be followed by another endemic disease e.g. zoonotic influenza, monkey pox and hepatitis X. 2. At least four War conflicts: Azerbaijan versus Armenia; Yemen versus Saudi Forces; Afghanistan versus NATO; and recently the Russian Federation & Belarus versus Ukraine.

Ligand-Assisted Charge-Transfer Mechanism: The Case of CdSe/Cysteine/MoS2 Heterostructures

Molecular linkers, such as cysteine, are used to stabilize colloidal quantum dots (QDs) and anchor them. Despite the typically large molecular HOMO/LUMO gap of linkers, they can increase the quantum yield and provide an effective charge-transfer channel. Through first-principles calculations, we investigate the ligand binding and the implications for charge transfer using a prototypical CdSe-Cysteine-MoS₂ three-way heterostructure. We find that the deprotonated ligand interacts with both sides of the heterostructure, which allows for successful self-passivation of the cysteine ligand molecule and the formation of dative bonds with a greatly reduced molecular gap compared with the gas phase. This leads to the formation of a charge-transfer state that is delocalized across the ligand and can directly assist electron transfer from the conduction band of colloidal CdSe QDs to the underlying MoS₂ substrate, which is a mechanism that could extend far beyond 0D-2D hybrid systems.

354 Thoracic Complex Case Review Meeting (CCRM): A Multidisciplinary Approach to Improving Patient Care and Service Efficiency

Objectives

The profile of thoracic patients and the indications for surgery are becoming increasingly complex. A multidisciplinary perioperative approach can optimise patients, improve outcomes and prevent high-risk patients being inappropriately declined surgery. We aim to retrospectively review the first 100 patients discussed at the CCRM in 2016-17 with a primary outcome of number of on-the-day cancellations. Secondary outcomes include unplanned critical care (HDU) admissions, 30 and 90-day morbidity and mortality.

Method

Data was collected retrospectively for demographics, co-morbidities, lung-function and dynamic testing, diagnosis and proposed surgical approach. CCRM outcomes included need for HDU, requiring further optimisation, change in surgical strategy or patient deemed too high risk.

Results

Average age was 69 years (IQR 12.5) (65 M: 35 F). American Society of Anaesthesiologists’ classification of 3 with predicted of mortality of 2 % (IQR 0.8). Maximal oxygen uptake (VO2 max) was 18.6ml/kg/min (SD ± 4.2). 24 patients were recommended for optimisation and 34 to proceed with HDU. 14 were deemed too high-risk and 30 had a change in surgical strategy. Only 1 patient was cancelled on-the-day due to a recent deterioration in health. 30 and 90-day mortality rates were 1% and 2% respectively, and 2 patients required unplanned HDU.

Conclusions

CCRM is a simple approach to optimise high-risk patients and minimise unplanned HDU. No patients were cancelled on-the-day due to inadequate optimisation or unexpected need for HDU. Mortality was acceptable and lower than predicted. Our study established CCRM as a safe and effective way of selecting high-risk patients for further optimisation and appropriate perioperative care.

Emerging Wake-up Call before next Pandemics as Apart of Medicine and Technology: We terribly need Social and Healthcare Workers

Thousands of healthcare and social workers (HCSW) died or lost their ability to work in their field after Covid pandemics in all three waves, and thousands left their profession due to burnout syndrome. Despite development of vaccines took 6- 18 months and refreshment of old molecules for treatment weeks, many countries paid a very high price for this pandemics not due to lack of medications or ventilator assistance devices but due to the increasing lack of trained HCSW.

Remote Passivation in Two-Dimensional Materials: The Case of the Monolayer-Bilayer Lateral Junction of MoSe2

Two-dimensional (2D) monolayer-bilayer (ML-BL) lateral junctions (LJs) have recently attracted attention due to their straightforward synthesis and resulting clean interface. Such systems consist of an extended ML with a secondary layer present only over half of the system, leading to an interface that is associated with the terminating edge of the secondary half layer. Our first-principles calculations reveal that the edges of the half layer completely lack reconstruction in the presence of unintentional dopants, in this case, Re. This observation is in startling contrast to the known physics of three-dimensional (3D) semiconductor surfaces where reconstruction has been widely observed. Herein, the electrostatics of the reduced dimensionality allows for greater separation between compensating defects, enabling dopants to remotely passivate edge states without needing to directly participate in the chemistry.

Orientation-Controlled Large-Area Epitaxial PbI2 Thin Films with Tunable Optical Properties

Lead iodide (PbI₂) as a layered material has emerged as an excellent candidate for optoelectronics in the visible and ultraviolet regime. Micrometer-sized flakes synthesized by mechanical exfoliation from bulk crystals or by physical vapor deposition have shown a plethora of applications from low-threshold lasing at room temperature to high-performance photodetectors with large responsivity and faster response. However, large-area centimeter-sized growth of epitaxial thin films of PbI₂ with well-controlled orientation has been challenging. Additionally, the nature of grain boundaries in epitaxial thin films of PbI₂ remains elusive. Here, we use mica as a model substrate to unravel the growth mechanism of large-area epitaxial PbI₂ thin films. The partial growth leading to uncoalesced domains reveals the existence of inversion domain boundaries in epitaxial PbI₂ thin films on mica. Combining the experimental results with first-principles calculations, we also develop an understanding of the thermodynamic and kinetic factors that govern the growth mechanism, which paves the way for the synthesis of high-quality large-area PbI₂ on other substrates and heterostructures of PbI₂ on single-crystalline graphene. The ability to reproducibly synthesize high-quality large-area thin films with precise control over orientation and tunable optical properties could open up unique and hitherto unavailable opportunities for the use of PbI₂ and its heterostructures in optoelectronics, twistronics, substrate engineering, and strain engineering.

Realization of AlSb in the Double-Layer Honeycomb Structure: A Robust Class of Two-Dimensional Material

Exploring two-dimensional (2D) van der Waals (vdW) systems is at the forefront of materials of physics. Here, through molecular beam epitaxy on graphene-covered SiC(0001), we report successful growth of AlSb in the double-layer honeycomb (DLHC) structure, a 2D vdW material which has no direct analogue to its 3D bulk and is predicted to be kinetically stable when freestanding. The structural morphology and electronic structure of the experimental 2D AlSb are characterized with spectroscopic imaging scanning tunneling microscopy and cross-sectional imaging scanning transmission electron microscopy, which compare well to the proposed DLHC structure. The 2D AlSb exhibits a band gap of 0.93 eV versus the predicted 1.06 eV, which is substantially smaller than the 1.6 eV of bulk. We also attempt the less-stable InSb DLHC structure; however, it grows into bulk islands instead. The successful growth of a DLHC material here demonstrates the feasibility for the realization of a large family of 2D DLHC traditional semiconductors with characteristic excitonic, topological, and electronic properties.

Switchable electronic and enhanced magnetic properties of CrI3 edges

Owing to its novel electronic and magnetic properties, two-dimensional CrI₃ has great potential in the application of spintronic devices. However, as an inevitable line defect, the properties of the edges of CrI₃ remain elusive. Here, via first-principles calculations with spin-orbit coupling, we investigated the thermodynamic stabilities, electronic and magnetic properties of thirteen CrI₃ edges with different structures. We showed that zigzag edges are more stable than armchair edges, and a CrI₃ nanoribbon can be either metallic or insulating depending on its chemical growth conditions. The edge stability and associated electronic properties can be understood in terms of the octahedron ligand field and electron counting model. In most cases, both the magnetic moment and Curie temperature can be enhanced by edges, which are in startle contrast to the surfaces of three-dimensional ferromagnetic materials, where a magnetic dead layer is often observed.

Epitaxial Growth of Two-Dimensional Insulator Monolayer Honeycomb BeO

The emergence of two-dimensional (2D) materials launched a fascinating frontier of flatland electronics. Most crystalline atomic layer materials are based on layered van der Waals materials with weak interlayer bonding, which naturally leads to thermodynamically stable monolayers. We report the synthesis of a 2D insulator composed of a single atomic sheet of honeycomb structure BeO (h-BeO), although its bulk counterpart has a wurtzite structure. The h-BeO is grown by molecular beam epitaxy (MBE) on Ag(111) thin films that are also epitaxially grown on Si(111) wafers. Using scanning tunneling microscopy and spectroscopy (STM/S), the honeycomb BeO lattice constant is determined to be 2.65 Å with an insulating band gap of 6 eV. Our low-energy electron diffraction measurements indicate that the h-BeO forms a continuous layer with good crystallinity at the millimeter scale. Moiré pattern analysis shows the BeO honeycomb structure maintains long-range phase coherence in atomic registry even across Ag steps. We find that the interaction between the h-BeO layer and the Ag(111) substrate is weak by using STS and complementary density functional theory calculations. We not only demonstrate the feasibility of growing h-BeO monolayers by MBE, but also illustrate that the large-scale growth, weak substrate interactions, and long-range crystallinity make h-BeO an attractive candidate for future technological applications. More significantly, the ability to create a stable single-crystalline atomic sheet without a bulk layered counterpart is an intriguing approach to tailoring 2D electronic materials.

Carrier Dynamics and Transfer across the CdS/MoS2 Interface upon Optical Excitation

Carrier dynamics across the interface of heterostructures have important technological, photovoltaic, and catalytic implications. Using first-principles time-dependent density functional theory, we have systematically investigated the charge transfer of excited carriers from CdS to MoS₂ and found that two interdependent mechanisms are responsible for the transfer, one slow and one fast. While the slower process may be attributed to typical electron-phonon coupling, the interfacial dipole resulting from this transfer enables a fast secondary process involving a level crossing of the excited carrier state in CdS with receiving states in MoS₂. An analysis based on the interfacial binding energy reveals that the Cd-terminated (001) interface is by far the most energetically favorable, which in addition to its calculated fast resonant electron transfer suggests it is a good candidate to explain the experimentally observed charge transfer between CdS and MoS₂.

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2 As2

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd₂ As₂ . As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time-reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c-axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.

iPSC modeling of young-onset Parkinson's disease reveals a molecular signature of disease and novel therapeutic candidates

Young-onset Parkinson's disease (YOPD), defined by onset at <50 years, accounts for approximately 10% of all Parkinson's disease cases and, while some cases are associated with known genetic mutations, most are not. Here induced pluripotent stem cells were generated from control individuals and from patients with YOPD with no known mutations. Following differentiation into cultures containing dopamine neurons, induced pluripotent stem cells from patients with YOPD showed increased accumulation of soluble α-synuclein protein and phosphorylated protein kinase Cα, as well as reduced abundance of lysosomal membrane proteins such as LAMP1. Testing activators of lysosomal function showed that specific phorbol esters, such as PEP005, reduced α-synuclein and phosphorylated protein kinase Cα levels while increasing LAMP1 abundance. Interestingly, the reduction in α-synuclein occurred through proteasomal degradation. PEP005 delivery to mouse striatum also decreased α-synuclein production in vivo. Induced pluripotent stem cell-derived dopaminergic cultures reveal a signature in patients with YOPD who have no known Parkinson's disease-related mutations, suggesting that there might be other genetic contributions to this disorder. This signature was normalized by specific phorbol esters, making them promising therapeutic candidates.

Visual Immunoprecipitate Assay (VIP) for Listeria monocytogenes and Related Listeria Species Detection in Selected Foods: Collaborative Study

Six foods representing a variety of food products were analyzed by the Assurance Listeria polyclonal enzyme immunoassay (EIA) and by either the Bacteriological Analytical Manual or the U.S. Department of Agriculture culture method for detecting Listeria monocytogenes and related Listeria species. Samples of each food type, at each inoculation level, were analyzed simultaneously by both methods. A total of 19 laboratories representing federal government agencies and private industry in the United States and Canada participated. Food types were inoculated with Listeria species including L. monocytogenes, with the exception of 3 lots of green beans, which were naturally contaminated. During this study, 1764 samples and controls were analyzed and confirmed, of which 492 were positive and 947 were negative by both methods. There were 159 samples that were positive by culture method but negative by the EIA and 188 that were negative by culture method but positive by EIA. Twenty-two samples were negative by EIA and by culture method but confirmed positive when Assurance selective enrichment broths were subcultured to selective agar. The Assurance polyclonal EIA for detecting L. monocytogenes and related Listeria species in foods has been adopted first action by AOAC INTERNATIONAL.

Assurance Enzyme Immunoassay for Detection of Enterohemorrhagic Escherichia coli 0157:H7 in Selected Foods: Collaborative Study

Five foods types were analyzed by the Assurance EHEC (Escherichia coli 0157:H7) enzyme immunoassay (EIA) and by the Bacteriological Analytical Manual (BAM) culture method. Each sample of each food type at each inoculation level was simultaneously analyzed by both methods. A total of 21 laboratories representing state and federal government agencies and private industry in the United States and Canada participated. Samples were inoculated with E. coli 0157:H7, except for one lot of poultry that was naturally contaminated. A total of 1304 samples and controls were analyzed and confirmed, of which 473 were positive and 818 were negative by both methods. Thirteen samples were positive by BAM but negative by EIA. Because of the study design, it was not possible for the BAM method to produce false-negative or falsepositive results. The Assurance method for detection of E. coli OI57:H7 in selected foods has been adopted first action by AOAC INTERNATIONAL.