Strain engineering and epitaxial stabilization of halide perovskites.

Strain engineering is a powerful tool with which to enhance semiconductor device performance1,2. Halide perovskites have shown great promise in device applications owing to their remarkable electronic and optoelectronic properties3-5. Although applying strain to halide perovskites has been frequently attempted, including using hydrostatic pressurization6-8, electrostriction9, annealing10-12, van der Waals force13, thermal expansion mismatch14, and heat-induced substrate phase transition15, the controllable and device-compatible strain engineering of halide perovskites by chemical epitaxy remains a challenge, owing to the absence of suitable lattice-mismatched epitaxial substrates. Here we report the strained epitaxial growth of halide perovskite single-crystal thin films on lattice-mismatched halide perovskite substrates. We investigated strain engineering of α-formamidinium lead iodide (α-FAPbI3) using both experimental techniques and theoretical calculations. By tailoring the substrate composition-and therefore its lattice parameter-a compressive strain as high as 2.4 per cent is applied to the epitaxial α-FAPbI3 thin film. We demonstrate that this strain effectively changes the crystal structure, reduces the bandgap and increases the hole mobility of α-FAPbI3. Strained epitaxy is also shown to have a substantial stabilization effect on the α-FAPbI3 phase owing to the synergistic effects of epitaxial stabilization and strain neutralization. As an example, strain engineering is applied to enhance the performance of an α-FAPbI3-based photodetector.

Blood Pressure after Successful Endovascular Therapy: A Systematic Review and Meta-Analysis of Randomized Control Trials.

OBJECTIVE: There are limited data evaluating the optimum blood pressure (BP) goal post mechanical thrombectomy (MT) and its effect on outcomes of patients with large vessel occlusions (LVO). The objective of this study was to compare the efficacy and safety of intensive versus conventional BP control after reperfusion with MT via a systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS: We searched PubMed and Embase to obtain articles related to BP control post MT through September 2023. The primary outcome was functional independence (modified Rankin Scale [mRS] 0-2) at 3 months, while secondary outcomes included excellent outcome (mRS 0-1), symptomatic intracranial hemorrhage (sICH), and mortality. RESULTS: Four RCTs with 1,566 patients (762 randomized into intensive BP control vs. 806 randomized into conventional BP control) were included. Analysis showed that there was a lower likelihood of functional independence (mRS 0-2: odds ratio [OR]: 0.68, 95% confidence interval [CI] 0.51-0.91, p = 0.009) in the more intensive treatment group compared with the conventional treatment group. There was no statistically significant difference in achieving excellent outcome (mRS0-1: OR: 0.82, 95% CI: 0.63-1.07; p = 0.15), risk of sICH or mortality. INTERPRETATION: This systematic review and meta- analysis Indicates that in patients who achieved successful MT for acute ischemic stroke with LVO, intensive BP control was associated with a lower likelihood of functional independence at 3 months without significant difference in likelihood of achieving excellent outcome, sICH risk, or mortality. ANN NEUROL 2024;95:858-865.

Deterministic switching of a perpendicularly polarized magnet using unconventional spin-orbit torques in WTe2.

Spin-orbit torque (SOT)-driven deterministic control of the magnetic state of a ferromagnet with perpendicular magnetic anisotropy is key to next-generation spintronic applications including non-volatile, ultrafast and energy-efficient data-storage devices. However, field-free deterministic switching of perpendicular magnetization remains a challenge because it requires an out-of-plane antidamping torque, which is not allowed in conventional spin-source materials such as heavy metals and topological insulators due to the system's symmetry. The exploitation of low-crystal symmetries in emergent quantum materials offers a unique approach to achieve SOTs with unconventional forms. Here we report an experimental realization of field-free deterministic magnetic switching of a perpendicularly polarized van der Waals magnet employing an out-of-plane antidamping SOT generated in layered WTe2, a quantum material with a low-symmetry crystal structure. Our numerical simulations suggest that the out-of-plane antidamping torque in WTe2 is essential to explain the observed magnetization switching.

Raman spectroscopy study of pressure-induced phase transitions in single crystal CuInP2S6.

Two-dimensional ferroic materials exhibit a variety of functional properties that can be tuned by temperature and pressure. CuInP2S6 is a layered material that is ferrielectric at room temperature and whose properties are a result of the unique structural arrangement of ordered Cu+ and In3+ cations within a (P2S6)4- anion backbone. Here, we investigate the effect of hydrostatic pressure on the structure of CuInP2S6 single crystals through a detailed Raman spectroscopy study. Analysis of the peak frequencies, intensities, and widths reveals four high pressure regimes. At 5 GPa, the material undergoes a monoclinic-trigonal phase transition. At higher pressures (5-12 GPa), we see Raman peak sharpening, indicative of a change in the electronic structure, followed by an incommensurate phase between 12 and 17 GPa. Above 17 GPa, we see evidence for bandgap reduction in material. The original state of the material is fully recovered upon decompression, showing that hydrostatic pressure could be used to tune the electronic and ferrielectric properties of CuInP2S6.

Enhancing Perpendicular Magnetic Anisotropy in Garnet Ferrimagnet by Interfacing with Few-Layer WTe2.

Engineering magnetic anisotropy in a ferro- or ferrimagnetic (FM) thin film is crucial in a spintronic device. One way to modify the magnetic anisotropy is through the surface of the FM thin film. Here, we report the emergence of a perpendicular magnetic anisotropy (PMA) induced by interfacial interactions in a heterostructure comprised of a garnet ferrimagnet, Y3Fe5O12 (YIG), and a low-symmetry, high spin-orbit coupling (SOC) transition metal dichalcogenide, WTe2. At the same time, we also observed an enhancement in Gilbert damping in the WTe2-covered YIG area. Both the magnitude of interface-induced PMA and the Gilbert damping enhancement have no observable WTe2 thickness dependence down to a single quadruple layer, indicating that the interfacial interaction plays a critical role. The ability of WTe2 to enhance the PMA in FM thin film, combined with its previously reported capability to generate out-of-plane damping like spin torque, makes it desirable for magnetic memory applications.

Catalyst discovery through megalibraries of nanomaterials.

The nanomaterial landscape is so vast that a high-throughput combinatorial approach is required to understand structure-function relationships. To address this challenge, an approach for the synthesis and screening of megalibraries of unique nanoscale features (>10,000,000) with tailorable location, size, and composition has been developed. Polymer pen lithography, a parallel lithographic technique, is combined with an ink spray-coating method to create pen arrays, where each pen has a different but deliberately chosen quantity and composition of ink. With this technique, gradients of Au-Cu bimetallic nanoparticles have been synthesized and then screened for activity by in situ Raman spectroscopy with respect to single-walled carbon nanotube (SWNT) growth. Au3Cu, a composition not previously known to catalyze SWNT growth, has been identified as the most active composition.

Risky drinking and cognitive impairment in community residents aged 50 and over.

OBJECTIVES: Alcohol misuse is known to be a risk factor for dementia. This study aimed to explore the association between risky drinking and cognitive impairment in a cohort study of middle aged and older people at risk of dementia. METHOD: The sample comprised 15,582 people aged 50 and over drawn from the PROTECT study. Risky drinking was defined according to a score of 4 or above on the Alcohol Use Disorders Identification Test (AUDIT). Cognitive function was assessed on visual episodic memory, spatial working memory, verbal working memory and verbal reasoning. RESULTS: Risky drinkers at baseline were more likely to be younger, male, white British, married, of higher educational status, current or past tobacco smokers and to have moderate to severe depression than non-risky drinkers. Risky drinkers were also more likely to be impaired on self-reported instrumental activities of daily living and subjective cognitive decline. At baseline, risky drinkers were less likely than non-risky drinkers to show impairment on verbal reasoning and spatial working memory but not on visual episodic memory or verbal working memory. Risky drinking at baseline predicted decline in cognitive function on visual episodic memory, verbal reasoning and spatial working memory at 2 year follow-up, but only verbal working memory and spatial working memory remained significant outcomes after controlling for possible confounders. CONCLUSION: Although of small effect size, the association between risky drinking and impairment on measures of working memory and visuospatial function warrants further examination; particularly given the possibility of partial reversibility in alcohol related cognitive impairment.

Identification of Parameters Controlling Peptide-Driven Graphene Exfoliation in Aqueous Media.

Bio-inspired approaches represent potentially transformational methods to fabricate and activate non-natural materials for applications ranging from biomedical diagnostics to energy harvesting platforms. Recently, bio-based methods for the exfoliation of graphene in water have been developed, resulting in peptide-capped nanosheets; however, a clear understanding of the reaction system and peptide ligand structure remains unclear, limiting the advance of such approaches. Here the effects of reaction solution conditions and peptide ligand structure were systematically examined for graphene exfoliation, identifying key parameters to optimize material production. For this, the P1 peptide, identified with affinity for graphene, was exploited to drive exfoliation of bulk graphite to generate the final materials. The peptide was modified at both the N- and C-terminus with a 10-carbon chain fatty acid to explore the effects of a hydrophobic domain on the exfoliation process. The system was examined as a function of sonication time, pH, reagent concentration, and graphite source, where the final materials were fully characterized using a suite of approaches. Collectively, these results demonstrated that maximum graphene production was achieved using the parent P1 peptide after 12 h of sonication under basic conditions. While the exfoliation efficiency was slightly lower for the fatty acid modified peptides, the graphene produced using these biomolecules had fewer defects incorporated, potentially from the wrapping of the nanosheet edge by the aliphatic domain. Such results are important to provide key reaction designs to optimize the reproducibility of graphene exfoliation using biomimetic approaches.

Zeolite Nanosheets Stabilize Catalyst Particles to Promote the Growth of Thermodynamically Unfavorable, Small-Diameter Carbon Nanotubes.

A challenge in the synthesis of single-wall carbon nanotubes (SWCNTs) is the lack of control over the formation and evolution of catalyst nanoparticles and the lack of control over their size or chirality. Here, zeolite MFI nanosheets (MFI-Ns) are used to keep cobalt (Co) nanoparticles stable during prolonged annealing conditions. Environmental transmission electron microscopy (ETEM) shows that the MFI-Ns can influence the size and shape of nanoparticles via particle/support registry, which leads to the preferential docking of nanoparticles to four or fewer pores and to the regulation of the SWCNT synthesis products. The resulting SWCNT population exhibits a narrow diameter distribution and SWCNTs of nearly all chiral angles, including sub-nm zigzag (ZZ) and near-ZZ tubes. Theoretical simulations reveal that the growth of these unfavorable tubes from unsupported catalysts leads to the rapid encapsulation of catalyst nanoparticles bearing them; their presence in the growth products suggests that the MFI-Ns prevent nanoparticle encapsulation and prologue ZZ and near-ZZ SWCNT growth. These results thus present a path forward for controlling nanoparticle formation and evolution, for achieving size- and shape-selectivity at high temperature, and for controlling SWCNT synthesis.

Thrombectomy after in-house stroke in the transfer population.

BACKGROUND: Patients with large-vessel occlusion (LVO) who initially present to a non-thrombectomy-capable center ("spoke") have worse outcomes than those presenting directly to a thrombectomy-capable center ("hub"). Furthermore, patients who suffer in-hospital strokes (IHS) suffer worse outcomes than those suffering strokes in the community. Data on patients who suffer IHS at a spoke hospital is lacking. We aim to characterize this particularly vulnerable population, define their outcomes, and compare them to patients who develop IHS at a hub institution. METHODS: We retrospectively reviewed prospectively collected data from patients suffering an IHS at a spoke hospital who were then transferred to the hub hospital for endovascular therapy (EVT). We then compared outcomes of these patients under EVT after developing IHS at the hub institution. RESULTS: A total of 108 IHS patients met inclusion criteria: 91 (84%) at a spoke facility and 17 (16%) at the hub facility. Baseline characteristics and reason for hospital admission were comparable between the two groups. Time from imaging to IV-tPA administration (17 vs. 70 min, p = 0.01) and time to EVT (120 vs. 247 min, p = 0.001) were significantly shorter in the hub group. More patients had a 90 day-mRS of 0-3 in the hub group than the spoke group (57% vs 22%, p < 0.05). CONCLUSION: Patients undergoing EVT after suffering IHS at a spoke hospital have significantly higher rates of poor outcomes compared to patients who suffer IHS at a hub hospital. Prolonged time delays in the initiation of IV-tPA and EVT represent areas of improvement.

Addressing alcohol-related dementia should involve better detection, not watchful waiting.

Alcohol-related dementia represents an underrecognised mental disorder with both clinical and public mental health aspects. There is considerable scope for improving its assessment within both mainstream and specialist mental health services, but ongoing challenges remain in ensuring its timely detection so that appropriate preventative and rehabilitative interventions can be applied. Declaration of interest None.

Refinements in the Techniques of 2-Stage Breast Reconstruction.

BACKGROUND: Two-stage breast reconstruction with tissue expanders is one of the most common plastic surgery procedures. Acellular dermal matrix (ADM) has become popular for its ability to improve expansion parameters and aesthetics, albeit with a higher complication profile. We present data that support redefining 2-stage reconstruction to include tissue expanders regardless of final reconstructive modality to act as a bridge. Furthermore, we show that cooperation with the ablative surgeon and technical refinements support ADM omission from the first stage of reconstruction. METHODS: We retrospectively reviewed charts from the senior author's (D.A.J.) private practice over a 10-year follow-up period. Inclusion criteria included all women over 18 years who underwent mastectomy and had a tissue expander placed immediately or in a delayed fashion and successfully completed tissue expansion and are finished with the second stage of reconstruction or awaiting second stage of reconstruction. Demographic data, tissue expander filling data, final reconstruction, aesthetic outcome, and complications were tabulated. RESULTS: A total of 118 women (165 breasts) met inclusion criteria. There were no statistically significant differences in initial fill volume (P = 0.094), number of visits until final expansion (P = 0.677), or final fill volume (P = 0.985) between the ADM and non-ADM cohorts. In addition, non-ADM patients had superior aesthetic scores with respect to defects other than scarring (P = 0.015), projection (P = 0.013), and inframammary fold quality (P = 0.009). Fifteen percent of women decided to change desired final reconstruction modality during the tissue expansion phase. CONCLUSIONS: This reconstructive algorithm emphasizes surgical cooperation between the ablative and reconstructive surgeon, improved technique, and patient education. This focus translates into maintained tissue expansion, aesthetically pleasing results, and allows for the omission of ADM from reconstruction.

Stroke Thrombectomy and Right Atrial Clot Aspiration in 29 Year Old Woman.

We present a case report of a previously healthy 29 year old woman who developed thromboembolic events in rapid fashion after a recent orthopedic surgery. This case highlights the importance of understanding risk factors for clot formation even in those who had no prior events, the efficacy of novel aspiration techniques to remove emboli, and how rapid triaging of acute symptoms can lead to the best outcomes. She presented to the emergency department with shortness of breath and was found to have a large bilateral pulmonary embolus. She was given intravenous thrombolysis. Shortly after, she developed aphasia and right-sided weakness and was taken emergently for mechanical thrombectomy of a left middle cerebral artery occlusion. She was later found to have a patent foramen ovale and a highly mobile right atrial thrombus which was aspirated. Further evaluation revealed right lower extremity peroneal and popliteal deep venous thrombi. She was placed on anticoagulation, made a full clinical recovery, and was discharged home. Prompt recognition of symptoms, efficient in-hospital work flow, and a multidisciplinary approach led to an outstanding outcome in this young patient.

Surgical rescue mitral valve procedure post percutaneous transluminal mitral commissurotomy-a single-center observational study.

Percutaneous transluminal mitral commissurotomy (PTMC) has become the standard of care for severe mitral stenosis with favorable anatomy. Although the complications have reduced over the years, the need for emergency surgical rescue persists. This study evaluates the outcomes of surgical rescue performed within 24 h of undergoing PTMC from 1 January 2013 to 31 December 2019. Out of 2259 PTMC patients, 22 patients (< 1%) required rescue mitral valve surgery. Out of 22 patients, 17 patients (77.27%) developed mitral regurgitation; five patients (22.7%) had cardiac tamponade. Mitral valve replacement was performed in 20 patients (90.9%), while two patients (9.1%) underwent mitral valve repair. Cardiac tamponade was secondary to injury of the left atrium (9.1%), left ventricle (4.5%), and right ventricle (9.1%). Concomitant tricuspid valve repair was done in three patients (13.6%). Intraoperatively, anterior mitral leaflet tear was seen in 68.2% while posterior mitral leaflet tear was noted in 9.1%. Postoperatively, three patients (13.6%) required prolonged ventilation, incidence of stroke was 4.5% (n = 1), and in-hospital mortality was 4.5% (n = 1). Intra-aortic balloon pump was used in three patients (13.6%), preoperatively. We conclude that post-PTMC complications are rare, but they require urgent surgical intervention.

Schizencephaly Associated With Bipolar Affective Disorder.

Schizencephaly is a rare congenital anomaly characterized by the formation of abnormal clefts in the brain. Despite the association of psychotic symptoms with various brain abnormalities or insults, their occurrence in individuals with schizencephaly is relatively infrequent. The association of bipolar disorder, with or without psychosis, with schizencephaly is rarer. A systematic search on PubMed using "Schizencephaly AND Bipolar Disorder" yielded only four case studies specifically addressing the connection between these two conditions. Here, we present a case of a 22-year-old male patient with a history of childhood seizures who developed first episode psychosis along with manic symptoms and was found to have closed-lip schizencephaly.

Association between HDL levels and stroke outcomes in the Arab population.

Low HDL levels are associated with an increased stroke incidence and worsened long-term outcomes. The aim of this study was to assess the relationship between HDL levels and long-term stroke outcomes in the Arab population. Patients admitted to the Qatar Stroke Database between 2014 and 2022 were included in the study and stratified into sex-specific HDL quartiles. Long-term outcomes included 90-Day modified Rankin Score (mRS), stroke recurrence, and post-stroke cardiovascular complications within 1 year of discharge. Multivariate binary logistic regression analyses were performed to identify the independent effect of HDL levels on short- and long-term outcomes. On multivariate binary logistic regression analyses, 1-year stroke recurrence was 2.24 times higher (p = 0.034) and MACE was 1.99 times higher (p = 0.009) in the low-HDL compared to the high-HDL group. Mortality at 1 year was 2.27-fold in the low-normal HDL group compared to the reference group (p = 0.049). Lower sex-specific HDL levels were independently associated with higher adjusted odds of 1-year post-stroke mortality, stroke recurrence, and MACE (p < 0.05). In patients who suffer a stroke, low HDL levels are associated with a higher risk of subsequent vascular complication.