AAV9-based PMM2 gene replacement augments PMM2 expression and improves glycosylation in primary fibroblasts of patients with phosphomannomutase 2 deficiency (PMM2-CDG)

Inherited deficiency of phosphomannomutase 2 (PMM2) (aka PMM2-CDG) is the most common congenital disorders of glycosylation (CDG) and has no cure. With debilitating morbidity and significant mortality, it is imperative to explore novel, safe, and effective therapies for the disease. Our Proof-of-Concept study showed that AAV9-PMM2 infection of patient fibroblasts augmented PMM2 expression and improved glycosylation. Thus, AAV9-PMM2 gene replacement is a promising therapeutic strategy for PMM2-CDG patients.

Electrostatic moiré potential from twisted hexagonal boron nitride layers

Moiré superlattices host a rich variety of correlated electronic phases. However, the moiré potential is fixed by interlayer coupling, and it is dependent on the nature of carriers and valleys. In contrast, it has been predicted that twisted hexagonal boron nitride (hBN) layers can impose a periodic electrostatic potential capable of engineering the properties of adjacent functional layers. Here, we show that this potential is described by a theory of electric polarization originating from the interfacial charge redistribution, validated by its dependence on supercell sizes and distance from the twisted interfaces. This enables controllability of the potential depth and profile by controlling the twist angles between the two interfaces. Employing this approach, we further demonstrate how the electrostatic potential from a twisted hBN substrate impedes exciton diffusion in semiconductor monolayers, suggesting opportunities for engineering the properties of adjacent functional layers using the surface potential of a twisted hBN substrate.

Visualization of Mesoscopic Conductivity Fluctuations in Amorphous Semiconductor Thin-Film Transistors

Charge transport in amorphous semiconductors is considerably more complicated than the process in crystalline materials due to abundant localized states. In addition to device-scale characterization, spatially resolved measurements are important to unveiling electronic properties. Here, we report gigahertz conductivity mapping in amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors by microwave impedance microscopy (MIM), which probes conductivity without Schottky barrier's influence. The difference between the dc and microwave conductivities reflects the efficacy of the injection barrier in an accumulation-mode transistor. The conductivity exhibits significant nanoscale inhomogeneity in the subthreshold regime, presumably due to trapping and release from localized states. The characteristic length scale of local fluctuations, as determined by the autocorrelation analysis, is about 200 nm. Using a random-barrier model, we can simulate the spatial variation of the potential landscape, which underlies the mesoscopic conductivity distribution. Our work provides an intuitive way to understand the charge transport mechanism in amorphous semiconductors at the microscopic level.

Implementation of a Systematic, Digital Oncology Workflow for Patient Distress Screening in a National, Multi-Site Radiotherapy Outpatient Setting

PURPOSE/OBJECTIVE(S)

Distress screening is recommended as standard of care in oncology to improve the quality of personalized care for patients, however previously reported barriers have led to poor uptake and reporting of clinician follow up and interventions. Our purpose was to improve the quality of personalized care for patients with high patient participation rate (>50%), clinical and nurse workflow compliance rate (>70%) and create structured data for practice improvement. To achieve this purpose, an in-house systematic digital screen and templated well-being plan (WBP) workflow was implemented across 33 outpatient Radiation Oncology sites in a multi-institutional center.

MATERIALS/METHODS

An in-house digital version of the NCCN Distress Thermometer and Problem Checklist (DT) was built in the integrated web-based portal for patients to complete at home or in a clinic setting. A digital workflow was co-designed with clinicians with automatic integration of the DT PDF document into the Electronic Medical Record (EMR), assigned for doctor review. Nurses subsequently recorded screening actions in the WBP. An extensive engagement, education and support program was completed nationally with phased implementation after an initial pilot at 3 sites. Staff and patient feedback were documented and presented with the collated data for review.

RESULTS

The program was successfully implemented at 33 centers across Australia in the multi-site organization between March and October 2022. A total of 7788 distress screening forms were submitted with an uptake rate of 78% at baseline and 53% at end of treatment (EOT). DT document approval rates by doctors varied (41%-98%), and WBP was completed for 48-100% of patients, with variations of rates and use noted between states and individuals for both. Referrals were recorded in the WBP for 3% of patients, however, as up to 52% of documentation was not in a WBP (for some states), true referral numbers require further manual analysis. Pairwise analysis of screening scores between time points saw 42% of scores reduced, 34% increased and 24% with no change. Analysis of a subset of patients with increased or no change in score showed 57% had some change in categories of distress, 22% had complete change and 10% had no change.

CONCLUSION

With an increasing global focus on improving patient centered care, implementation of a systematic digital workflow for distress screening and supportive care was achieved resulting in patient identified stressors being addressed as standard of care. Key barriers reported, include confidence discussing screening results with patients and manual workflows at EOT. The provision of a rich data set can also highlight opportunities for clinical practice improvement, cohort-based focus, clinical quality indicators, benchmarking and reporting.

Cocaine screening in patients undergoing nasal reconstructive surgery: a cross-sectional, survey-based study of UK rhinology consultants

OBJECTIVE

This study aimed to explore the current practices of the UK rhinology consultant body in regard to cocaine screening in nasal reconstructive surgery.

METHOD

A 12-question online survey was distributed to rhinology consultants (October 2021 to February 2022) currently practising in the UK.

RESULTS

A total of 55 consultants responded. Fifty-three per cent asked patients about cocaine use prior to consideration of surgery, and 45 per cent performed cocaine testing prior to consideration of surgery. Of these, the majority employed urine testing alone (60 per cent), with hair testing being less common as a single screening modality (4 per cent). Sixteen per cent opted for both urine and hair testing. The most common reasons for not performing cocaine testing included patient history or clinical examination that was not suggestive of cocaine use (44 per cent), lack of formal guidelines (33 per cent) and lack of testing availability (27 per cent). Sixty-four per cent were in favour of a national policy for cocaine screening.

CONCLUSION

There is marked variation in cocaine screening practices for nasal reconstructive surgery among UK rhinologists.

CREB3L2 Regulates Hemidesmosome Formation during Epithelial Sealing

The long-term success rate of dental implants can be improved by establishing a favorable biological sealing with a high-quality epithelial attachment. The application of mesenchymal stem cells (MSCs) holds promise for facilitating the soft tissue integration around implants, but the molecular mechanism is still unclear and the general application of MSC sheet for soft tissue integration is also relatively unexplored. We found that gingival tissue-derived MSC (GMSC) sheet treatment significantly promoted the expression of hemidesmosome (HD)-related genes and proteins in gingival epithelial cells (GECs). The formation of HDs played a key role in strengthening peri-implant epithelium (PIE) sealing. Further, high-throughput transcriptome sequencing showed that GMSC sheet significantly upregulated the PI3K/AKT pathway, confirming that cell adhesion and HD expression in GECs were regulated by GMSC sheet. We observed that the expression of transcription factor CREB3L2 in GECs was downregulated. After treatment with PI3K pathway inhibitor LY294002, CREB3L2 messenger RNA and protein expression levels were upregulated. Further experiments showed that overexpression or knockdown of CREB3L2 could significantly inhibit or promote HD-related genes and proteins, respectively. We confirmed that CREB3L2 was a transcription factor downstream of the PI3K/AKT pathway and participated in the formation of HDs regulated by GMSC sheet. Finally, through the establishment of early implant placement model in rats, we clarified the molecular function of CREB3L2 in PIE sealing as a mechanical transmission molecule in GECs. The application of GMSC sheet-implant complex could enhance the formation of HDs at the implant-PIE interface and decrease the penetration distance of horseradish peroxidase between the implant and PIE. Meanwhile, GMSC sheet reduced the length of CREB3L2 protein expression on PIE. These findings elucidate the potential function and molecular mechanism of MSC sheet regulating the epithelial sealing around implants, providing new insights and ideas for the application of stem cell therapy in regenerative medicine.

Assessing the Compliance and Accuracy of a National Australian Head and Neck Cancer (HNC) Database

PURPOSE/OBJECTIVE(S)

Accurate cancer databases enable auditing of patient management, and this knowledge facilitates optimizing care. A multi-institutional organization, the largest single provider of radiation oncology services in Australia, has developed its own national database (ND). All patients are entered on the ND as a prerequisite for generating a radiotherapy prescription. A significant component of the ND is automated, but manual input from the treating radiation oncologist (RO) is also required. The purpose of this study was to assess the compliance and accuracy of the data entered on this ND for head and neck cancer (HNC) patients.

MATERIALS/METHODS

We included all HNC patients with either oral cavity cancer or oropharynx cancer (ICD-10 coding) treated between September 2021 and September 2022 to assess compliance. We randomly selected 25% of these cases and assigned them to 3 HNC ROs to manually review the accuracy of all clinical data points.

RESULTS

There were 166 HNC patients, 139 oropharynx and 27 oral cavity. Compliance in the 166 patients was excellent (94% or higher) for the majority of data points - age, gender, diagnosis ICD code, diagnosis date, laterality, TNM classification, radiotherapy dose, fractionation and technique and start and completion dates. Compliance was good (85% or more) for smoking history, use of chemotherapy, and p16 status (oropharynx). Compliance was poor (43%) for specific chemotherapy regimens. Accuracy was high (92% or higher) for diagnosis ICD code, smoking history, use of chemotherapy; good (87% or higher) for p16 status (oropharynx), laterality and histopathology; and poor for date of diagnosis (75%), TNM classification (62%) and specific chemotherapy regimens (29%).

CONCLUSION

The ND is a powerful tool for assessing patient care. Overall, compliance was very good. Accuracy was very good for most items, and we have highlighted areas where improvements can be made. This study shows that a compliant and accurate ND is achievable and supports the next goal of additional items to be included in the ND, specifically patient outcome data.

Vitamin D and smell impairment: a systematic literature review

OBJECTIVE

Smell impairment affects 60-80 per cent of individuals aged over 80 years. This review aimed to identify any association between vitamin D deficiency and smell impairment, and determine the efficacy of vitamin D to treat smell impairment.

METHODS

A literature search was conducted across four databases between the years 2000 and 2022. The literature screen was performed by two independent reviewers.

RESULTS

Seven articles were included in this review. Four studies examined the association between vitamin D deficiency and smell impairment, with three studies identifying a significant relationship. Three studies investigated the use of vitamin D as treatment for smell impairment, which found complete resolution or significant symptom improvement after vitamin D deficiency was treated.

CONCLUSION

This review identified limited studies on this topic. As vitamin D supplementation is relatively cost-efficient, further large-scale studies should be carried out to investigate the efficacy of vitamin D for treating anosmia.

AAV-based gene therapy prevents and halts the progression of dilated cardiomyopathy in a mouse model of phosphoglucomutase 1 deficiency (PGM1-CDG)

Phosphoglucomutase 1 (PGM1) deficiency is recognized as the third most common N-linked congenital disorders of glycosylation (CDG) in humans. Affected individuals present with liver, musculoskeletal, endocrine, and coagulation symptoms; however, the most life-threatening complication is the early onset of dilated cardiomyopathy (DCM). Recently, we discovered that oral D-galactose supplementation improved liver disease, endocrine, and coagulation abnormalities, but does not alleviate the fatal cardiomyopathy and the associated myopathy. Here we report on left ventricular ejection fraction (LVEF) in 6 individuals with PGM1-CDG. LVEF was pathologically low in most of these individuals and varied between 10% and 65%. To study the pathobiology of the cardiac disease observed in PGM1-CDG, we constructed a novel cardiomyocyte-specific conditional Pgm2 gene (mouse ortholog of human PGM1) knockout (Pgm2 cKO) mouse model. Echocardiography studies corroborated a DCM phenotype with significantly reduced ejection fraction and left ventricular dilation similar to those seen in individuals with PGM1-CDG. Histological studies demonstrated excess glycogen accumulation and fibrosis, while ultrastructural analysis revealed Z-disk disarray and swollen/fragmented mitochondria, which was similar to the ultrastructural pathology in the cardiac explant of an individual with PGM1-CDG. In addition, we found decreased mitochondrial function in the heart of KO mice. Transcriptomic analysis of hearts from mutant mice demonstrated a gene signature of DCM. Although proteomics revealed only mild changes in global protein expression in left ventricular tissue of mutant mice, a glycoproteomic analysis unveiled broad glycosylation changes with significant alterations in sarcolemmal proteins including different subunits of laminin-211, which was confirmed by immunoblot analyses. Finally, augmentation of PGM1 in KO mice via AAV9-PGM1 gene replacement therapy prevented and halted the progression of the DCM phenotype.

Implementing microwave impedance microscopy in a dilution refrigerator

We report the implementation of a dilution refrigerator-based scanning microwave impedance microscope with a base temperature of ∼100 mK. The vibration noise of our apparatus with tuning-fork feedback control is as low as 1 nm. Using this setup, we have demonstrated the imaging of quantum anomalous Hall states in magnetically (Cr and V) doped (Bi, Sb)2Te3 thin films grown on mica substrates. Both the conductive edge modes and topological phase transitions near the coercive fields of Cr- and V-doped layers are visualized in the field-dependent results. Our study establishes the experimental platform for investigating nanoscale quantum phenomena at ultralow temperatures.

Single-crystalline van der Waals layered dielectric with high dielectric constant

The scaling of silicon-based transistors at sub-ten-nanometre technology nodes faces challenges such as interface imperfection and gate current leakage for an ultrathin silicon channel^1,2. For next-generation nanoelectronics, high-mobility two-dimensional (2D) layered semiconductors with an atomic thickness and dangling-bond-free surfaces are expected as channel materials to achieve smaller channel sizes, less interfacial scattering and more efficient gate-field penetration^1,2. However, further progress towards 2D electronics is hindered by factors such as the lack of a high dielectric constant (κ) dielectric with an atomically flat and dangling-bond-free surface^3,4. Here, we report a facile synthesis of a single-crystalline high-κ (κ of roughly 16.5) van der Waals layered dielectric Bi₂SeO₅. The centimetre-scale single crystal of Bi₂SeO₅ can be efficiently exfoliated to an atomically flat nanosheet as large as 250 × 200 μm² and as thin as monolayer. With these Bi₂SeO₅ nanosheets as dielectric and encapsulation layers, 2D materials such as Bi₂O₂Se, MoS₂ and graphene show improved electronic performances. For example, in 2D Bi₂O₂Se, the quantum Hall effect is observed and the carrier mobility reaches 470,000 cm² V^-1 s^-1 at 1.8 K. Our finding expands the realm of dielectric and opens up a new possibility for lowering the gate voltage and power consumption in 2D electronics and integrated circuits.

Non-volatile electric-field control of inversion symmetry

Competition between ground states at phase boundaries can lead to significant changes in properties under stimuli, particularly when these ground states have different crystal symmetries. A key challenge is to stabilize and control the coexistence of symmetry-distinct phases. Using BiFeO₃ layers confined between layers of dielectric TbScO₃ as a model system, we stabilize the mixed-phase coexistence of centrosymmetric and non-centrosymmetric BiFeO₃ phases at room temperature with antipolar, insulating and polar semiconducting behaviour, respectively. Application of orthogonal in-plane electric (polar) fields results in reversible non-volatile interconversion between the two phases, hence removing and introducing centrosymmetry. Counterintuitively, we find that an electric field 'erases' polarization, resulting from the anisotropy in octahedral tilts introduced by the interweaving TbScO₃ layers. Consequently, this interconversion between centrosymmetric and non-centrosymmetric phases generates changes in the non-linear optical response of over three orders of magnitude, resistivity of over five orders of magnitude and control of microscopic polar order. Our work establishes a platform for cross-functional devices that take advantage of changes in optical, electrical and ferroic responses, and demonstrates octahedral tilts as an important order parameter in materials interface design.

Measuring clinical trial set-up complexity: development and content validation of a pharmacy scoring tool to support workload planning

Introduction

Clinical trials are essential for advancing medical knowledge and patient care. Pharmacy plays a vital role in research delivery, safeguarding participants, healthcare professionals and Trusts by ensuring Investigational Medicinal Products (IMPs) are procured, handled, stored, dispensed and used safely. Data have emerged indicating that clinical trial protocols are increasingly more complex for site personnel to execute. Whilst various tools have been developed to support workload planning and costing of clinical trials for clinicians and nursing personnel, the equivalent tool for pharmacy activities is not available.1,2

Aim

This study aims to locally develop and validate a pharmacy scoring tool to assess clinical trial complexity at the set-up stage. Objectives are to develop pharmacy-scoring tool to quantify clinical trials execution complexity with respect to pharmacy activities and determine Content Validity Index (CVI) and Inter-Rater Agreement (IRA) of the scoring tool through an internal vetting process.

Methods

A three-stage process was used to develop and validate the scoring tool. Two researchers contextualised the pharmacy–specific items, organised the content and constructed the tool based on suitable elements for inclusion through a targeted literature search and outputs from an expert panel meeting. Four experts independently rated each items on its relevance, clarity and alignment with clinical trial complexity considerations at the set-up stage using a 4-point Likert scale. Following data analysis, researchers made a judgement on whether to retain, modify, omit or add new items to the tool. Where the desired level of content validity had not been achieved for an item, revisions were made following a group discussion and the tool was re-distributed to the same expert panel for a second round of assessment. Item level-CVI (I-CVI) and tool level-CVI (average-CVI) was calculated for each round. Four experts then utilised the revised tool to retrospectively review 20 random studies to evaluate clinical trial complexity scores independently. IRA among assessors was measured for each individual pharmacy-specific item by dividing the responses into dichotomous ratings (one or two vs. three or four). The study was deemed a service evaluation and approved by the Trust Pharmacy Research and Audit Group therefore ethical submission was waived.

Results

Fourteen pharmacy-specific items were identified for inclusion in the tool with a possible score of 0-3 points per item. The highest possible complexity score when adding up all items is 42 points with a scale of low 0-14, moderate >14-28, and high >28-42. Following two rounds of content validity assessment where clarity revisions were made to four items, 14 out of 14 scored I-CVI of 1 with overall tool level average-CVI score of 1. The IRA shows 100% agreement by item and tool.

Discussion/Conclusion

This clinical trial’s complexity-scoring tool is the first of its kind tailored for pharmacy set-up in the UK. Overall, the results from this study support validity and reliability (content and construct) of this locally developed tool. The formal agreement on the use of this tool with the Trust Research Lead has better facilitated workload and capacity planning as well as ensuing costings for Pharmacy clinical trial activities.

References

1. Department of Health. Attributing the Cost of health and social care Research & Development (AcORD) Published 2012. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/351182/AcoRD_Guidance_for_publication_May_2012.pdf

2. Marta Calvin-Lamas et al. A complexity scale for clinical trials from a pharmacy perspective. European Journal of Hospital Pharmacy 2018;25:251-256

Measuring drug name similarity to prioritise the application of tall-man lettering in a computerised pharmacy dispensing system

Introduction

Medicine name similarity is a contributory factor to medication errors.1 Published lists exists highlighting medicine pairs that are easily confused; locally a Look-Alike-Sound-Alike (LASA) list has expanded over time with no formal system of triage. A multipronged approach is required to address LASA risks. Tall-Man Lettering (TML) is one intervention that uses uppercase lettering for the dissimilarities in look-alike drug names to alert staff to the risk of error.1 For greatest impact, it should be reserved for pairs with the highest risk for patient safety.

Aim

This study aimed to use Levenshtein Distance (LD), Bigram (Bi) and Trigram (Tri) methods to prioritise medicine pairs for TML in the Pharmacy dispensing system. Objectives were to: Produce a comprehensive list of medicines pairs; Establish normalised thresholds from LD, Bi and Tri to prioritise medicine pairs for TML; and, measure drug name similarity using validated software2 applying LD, Bi and Tri to medication pairs as a method of triage for orthographic assessment.

Methods

Approval was obtained by the Trust Pharmacy Research Committee. The need for ethical submission was waived. A LASA list was developed combining medicine name pairs from National Pharmacy Association list3, historical local list and internal incidents where medicine name confusion was cited. Duplicated, branded and non-stock pairs were excluded. A literature search was undertaken to identify published thresholds for accuracy and sensitivity of the methods in the measure of medicine name similarity. LD measures the minimum number of edit operations needed to transform one string into another; Bi and Tri measures the frequency in which two/three similar sequential strings appear within a medicine name respectively. Two assessors independently entered medicine pairs through a validated computer program2 applying LD, Bi and Tri to measure orthographic similarity. Normalised computed similarity scores (between 0-1 where higher values represent increased drug similarity) were collated on Microsoft excel for comparison against thresholds.

Results

Two-hundred and twelve medicine pairs were identified for review. The literature defined Bi and Tri thresholds at ≥0.3 and ≥0.1 respectively; in absence of this for LD, in-house thresholds were assessed then defined at ≥0.6. LD identified 84 medicine pairs; Bi identified 144; and Tri identified 158; none were uniquely found by LD, four by Bi and 18 by Tri. A final look-alike list with 82 medicine pairs meeting all three thresholds was identified for TML.

Discussion/Conclusion

Screening using all three methods led to a 61% reduction in medicines pairs allowing prioritisation of TML as an effective intervention based on look-alike pairs with the highest risk of error. This study focused on identifying orthographic similarity in ‘look-alike’ medicine pairs only. With no single intervention available to prevent LASA errors, future work can explore other interventions. In the absence of literature around normalised LD, the definition of an in-house threshold posed to be another limitation and an area where further exploratory work should be considered. As new LASA incidents arise or the Trust catalogue increases, these methods should be applied to triage their look-alike potential, confirming if TML is an appropriate intervention.

References

1. World Health Organisation. Look-alike, sound-alike medication names. patient safety solutions. 2007 May, Volume 1: Solution 1.

2. Strcmp2. [Internet] Department of Computer Science, University of Toronto: Aditya Bhargava [Date of publication unknown]. Available from: https://www.cs.toronto.edu/~aditya/strcmp2/, Work based on: Grzegorz Kondrak. N-gram similarity and distance. Proceedings of the Twelfth International Conference on String Processing and Information Retrieval. 2005 Nov; pp. 115—126.

3. The National Pharmacy Association Pharmacy Team. Look-alike sound-alike (LASA) items [Internet]. The National Pharmacy Association; 2021. Available from: https://www.npa.co.uk/information-and-guidance/look-alike-sound-alike-lasa-items/

Initial observations on the impact of implementation of a seven-day clinical pharmacy service on dispensary activity and performance

Introduction

The need for seven-day clinical pharmacy services is widely acknowledged, although limited, in the acute sector of the National Health Service.1,2 Timely medicine supply is integral to provision of improved clinical pharmacy services to patients across seven-days, and is essential in effective discharge planning. There is a paucity of evidence for implementation of seven-day clinical pharmacy services, including the impact of service transformation on dispensary activity and performance. This limits planning and development of seven-day pharmacy services.

Aim

To assess the impact of a seven-day clinical pharmacy service on dispensary activity and performance, at the main site of a tertiary-referral teaching hospital.

Methods

A seven-day clinical pharmacy service was implemented in October 2021. Prior to this, pharmacy services were largely dispensary-based with clinical pharmacy services for acute and neurosciences admission and limited ward-based services in other specialities. At implementation, clinical pharmacy technicians and pharmacists (n=16) provided patient-facing pharmaceutical care for 7.5-hours/day across all specialities over the weekend; this included medicines reconciliation, preparation of discharge-medication lists, independent prescribing, counselling and clinical review of prioritised patients. The weekend dispensary staffing, skill-mix and shift patterns were redesigned to facilitate staff release from the dispensary rota. Dispensing activity data were obtained from Ascribe for six months pre- and post-implementation (April 2021-March 2022). Data were categorised as inpatient/discharge and the mean number of items dispensed per month analysed using Microsoft Excel. Discharge turnaround performance was calculated as percentage of discharge prescriptions dispensed within two-hours of dispensary receipt and obtained from the Prescription Tracking System. Verbal staff feedback was sought 4-months post-implementation. The study was deemed a service evaluation by the Pharmacy Research and Audit Group and so ethical approval was not required.

Results

Twelve dispensing staff and one pharmacist were rostered to one of three daily 3.75-hour dispensary shift patterns. Following implementation, mean total inpatient dispensing activity increased from 12799 to 13250 items/month (3.5% increase) and mean weekend activity from 2184 to 2677 items/month (22.6% increase). Mean weekday inpatient activity was stable at 10615 to 10573 items/month. The mean discharge dispensing activity increased from 9065 to 9837 items/month (8.5% increase): mean weekday discharge from 8498 to 8622 items/month (1.5% increase); mean weekend activity from 569 to 1215 items/month (114% increase). Discharge turnaround performance remained stable with 85% discharge prescriptions dispensed within 2-hours, versus 84% pre-implementation. Weekday performance also remained stable - from 84% to 83% and the weekend performance increased from 85% to 92%. Dispensary staff fed-back that weekend shift patterns were effective, activity was manageable and shifts usually ran smoothly and finished on time.

Discussion/Conclusion

Introduction of a seven-day clinical pharmacy service led to an increase in weekend dispensary activity, which was not offset by decrease in weekday activity. Importantly, the dispensary performance was not negatively impacted and weekend discharge performance improved. Increases could be because of weekend medicines reconciliation, pro-active medication ordering and pharmacist-led preparation of discharge-medicine lists. Dispensary activity in Winter 2020 was atypical because of COVID-19, thus it was not feasible to compare data. Further review, including 12 months data would reduce impact of seasonal variations in NHS activity. Limitations include that patient data including length of stay and time to discharge were not within scope.

References

1. Anon. Transformation of seven day clinical pharmacy services in acute hospitals. 2016. http://www.england.nhs.uk/wp-content/uploads/2016/09/7ds-clinical-pharmacy-acute-hosp.pdf. Accessed 29 July 2022.

2. Anon. RPS professional standards for hospital pharmacy services. 2017. http://www.rpharms.com/recognition/setting-professional-standards/hospital-pharmacy-professional-standards. Accessed 29 July 2022.

Prevalence and potential clinical significance of near miss dispensing errors at a large teaching hospital in the United Kingdom (UK)

Introduction

Dispensing is a complex multi-step process where mistakes can arise at any stage leading to a potential to cause patient harm. Published literature identifies near miss dispensing error rates up to 2.7% in UK hospitals.1 Near misses are ‘a dispensing error detected by the checker before it reaches the patient’. Near miss audits are routinely undertaken across two main dispensaries at this teaching hospital where one dispensary (site 1) is automated and the other (site 2) is not.

Aim

To determine the frequency of near miss dispensing errors, by site, and review the potential clinical significance of near misses observed.

Methods

Locally adapted data collection tool based on Royal Pharmaceutical Society near miss error codes2 was developed and piloted. Details on prescription type, drug, dose, strength, route, formulation and near misses were included. Details of all medication orders dispensed were also recorded. Prospective observational audit of near misses identified at the checking bench was undertaken, on three separate days, across three consecutive months. Dean and Barber method3 was used for assessing potential clinical significance of near misses. Four independent assessors: two pharmacists; one nurse and one doctor; reviewed near misses for the likelihood to cause harm. The mean severity score attained across assessors was calculated. Approval was obtained by the Trust Pharmacy Research and Audit Committee. The need for ethical submission was waived.

Results

Overall 3027 items were dispensed; 1539 and 1488 at sites 1 and 2 respectively. There were 177 (5.8%) erroneous dispensed items involving 193 near misses in total (15 items had two near misses and one item had three near misses). Ninety one (5.9%) erroneous dispensed items were captured at site 1 and 86 (5.8%) at site 2 (χ 2, p=0.94). Overall 161 near miss descriptions were assessed for clinical significance: 97 (60.2%) minor, 63 (39.1%) moderate and one (0.6%) severe. Statistically significant difference in severity rating of near misses between prescription type (χ 2(2) = 32.268, p <0.001); mean ranks 80, 57, 125 for discharge, inpatient and outpatient prescriptions respectively. No statistical difference in severity rating of near misses between error type (χ 2(2) = 2.402, p =0.3).

Discussion/Conclusion

Local prevalence of near misses is higher than in published literature.1 However, the majority of errors were considered to have minor clinical impact on patients. Difficult to make direct comparisons between studies due to differences in research methods, definitions, operating systems and hospital settings. There was no statistical difference noted in prevalence between sites despite presence of automation at one and manual dispensing at the other. Two factors may explain this: Firstly, part-pack robotic dispensing, where generation of medication barcodes is a manual process and one subject to human input error itself; although not explored explicitly as part of this study. Secondly, lack of knowledge and complex prescriptions are known to be key contributory factors associated with dispensing errors, but the categories of drugs dispensed at a specialist tertiary dispensary (site 1) were broader and more complex. Further study is needed on the impact of part-pack robotic dispensing on dispensing errors.

References

1. James KL et al. Incidence, type and causes of dispensing errors. A review of literature. Int J Pharm Pract 2009; 17:9-30.

2. Royal Pharmaceutical Society [Internet]. Near Miss Error Log. London: Royal Pharmaceutical Society; 2015. Available from: RPS-NearMissError-LOG.pdf (rpharms.com)

3. Dean BS, Barber ND. A validated, reliable method for scoring the severity of medication errors. Am J Health Syst Pharm. 1999;56:57-62.

Monolayer 1T-NbSe2 as a 2D-correlated magnetic insulator

Monolayer group V transition metal dichalcogenides in their 1T phase have recently emerged as a platform to investigate rich phases of matter, such as spin liquid and ferromagnetism, resulting from strong electron correlations. Newly emerging 1T-NbSe₂ has inspired theoretical investigations predicting collective phenomena such as charge transfer gap and ferromagnetism in two dimensions; however, the experimental evidence is still lacking. Here, by controlling the molecular beam epitaxy growth parameters, we demonstrate the successful growth of high-quality single-phase 1T-NbSe₂. By combining scanning tunneling microscopy/spectroscopy and ab initio calculations, we show that this system is a charge transfer insulator with the upper Hubbard band located above the valence band maximum. To demonstrate the electron correlation resulted magnetic property, we create a vertical 1T/2H NbSe₂ heterostructure, and we find unambiguous evidence of exchange interactions between the localized magnetic moments in 1T phase and the metallic/superconducting phase exemplified by Kondo resonances and Yu-Shiba-Rusinov–like bound states.

Superior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging

The outstanding performance of organic-inorganic metal trihalide solar cells benefits from the exceptional photo-physical properties of both electrons and holes in the material. Here, we directly probe the free-carrier dynamics in Cs-doped FAPbI₃ thin films by spatiotemporal photoconductivity imaging. Using charge transport layers to selectively quench one type of carriers, we show that the two relaxation times on the order of 1 μs and 10 μs correspond to the lifetimes of electrons and holes in FACsPbI₃, respectively. Strikingly, the diffusion mapping indicates that the difference in electron/hole lifetimes is largely compensated by their disparate mobility. Consequently, the long diffusion lengths (3~5 μm) of both carriers are comparable to each other, a feature closely related to the unique charge trapping and de-trapping processes in hybrid trihalide perovskites. Our results unveil the origin of superior diffusion dynamics in this material, crucially important for solar-cell applications.

Flupentixol/melitracen for chronic refractory cough after treatment failure with other neuromodulators

BACKGROUND: Gabapentin and baclofen are recommended for the treatment of chronic refractory cough (CRC). We investigated the efficacy of flupentixol/melitracen in patients unresponsive to these neuromodulators.METHODS: A total of 101 patients with CRC who failed to respond to gabapentin and baclofen were recruited, and treated with flupentixol/melitracen. The prevalence of cough resolution and changes in the Cough Symptom Score (CSS), cough thresholds to capsaicin, Hull Airway Reflux Questionnaire (HARQ), Leicester Cough Questionnaire (LCQ), Generalized Anxiety Disorder-7, Hamilton Anxiety Rating Scale, Patient Health Questionnaire-9, and Hamilton Depression Rating Scale-24 were evaluated after treatment.RESULTS: Ninety-eight patients (97.0%) completed the study. The overall successful cough resolution rate was 62.4% (63/101). Cough resolution was accompanied by an obvious decrease in the CSS and HARQ score and a remarkable increase in cough thresholds to capsaicin challenge and LCQ score, whereas anxiety and depression scores did not change significantly. The prevalence of adverse effects (e.g., insomnia and dizziness) was 21.8%. The prevalence of cough recurrence within 2 weeks after treatment cessation was 17.8%.CONCLUSION: Flupentixol/melitracen may be an efficacious option for CRC unresponsive to other neuromodulators.

Mid-treatment Fluorodeoxyglucose Positron Emission Tomography in Human Papillomavirus-related Oropharyngeal Squamous Cell Carcinoma Treated with Primary Radiotherapy: Nodal Metabolic Response Rate can Predict Treatment Outcomes

AIMS

To evaluate whether biomarkers derived from fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) performed prior to (prePET) and during the third week (interim PET; iPET) of radiotherapy can predict treatment outcomes in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPC).

MATERIALS AND METHODS

This retrospective analysis included 46 patients with newly diagnosed OPC treated with definitive (chemo)radiation and all patients had confirmed positive HPV status (HPV+OPC) based on p16 immunohistochemistry. The maximum standardised uptake value (SUV_max), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary, index node (node with the highest TLG) and total lymph nodes and their median percentage (≥50%) reductions in iPET were analysed, and correlated with 5-year Kaplan-Meier and multivariable analyses (smoking, T4, N2b-3 and AJCC stage IV), including local failure-free survival, regional failure-free survival, locoregional failure-free survival (LRFFS), distant metastatic failure-free survival (DMFFS), disease-free survival (DFS) and overall survival.

RESULTS

There was no association of outcomes with prePET parameters observed on multivariate analysis. A complete metabolic response of primary tumour was seen in 13 patients; the negative predictive value for local failure was 100%. More than a 50% reduction in total nodal MTV provided the best predictor of outcomes, including LRFFS (88% versus 47.1%, P = 0.006, hazard ratio = 0.153) and DFS (78.2% versus 41.2%, P = 0.01, hazard ratio = 0.234). More than a 50% reduction in index node TLG was inversely related to DMFFS: a better nodal response was associated with a higher incidence of distant metastatic failure (66.7% versus 100%, P = 0.009, hazard ratio = 3.0).

CONCLUSION

The reduction (≥50%) of volumetric nodal metabolic burden can potentially identify a subgroup of HPV+OPC patients at low risk of locoregional failure but inversely at higher risk of distant metastatic failure and may have a role in individualised adaptive radiotherapy and systemic therapy.

Phonon renormalization in reconstructed MoS2 moiré superlattices

In moiré crystals formed by stacking van der Waals materials, surprisingly diverse correlated electronic phases and optical properties can be realized by a subtle change in the twist angle. Here, we discover that phonon spectra are also renormalized in MoS₂ twisted bilayers, adding an insight to moiré physics. Over a range of small twist angles, the phonon spectra evolve rapidly owing to ultra-strong coupling between different phonon modes and atomic reconstructions of the moiré pattern. We develop a low-energy continuum model for phonons that overcomes the outstanding challenge of calculating the properties of large moiré supercells and successfully captures the essential experimental observations. Remarkably, simple optical spectroscopy experiments can provide information on strain and lattice distortions in moiré crystals with nanometre-size supercells. The model promotes a comprehensive and unified understanding of the structural, optical and electronic properties of moiré superlattices.

Evidence for a higher-order topological insulator in a three-dimensional material built from van der Waals stacking of bismuth-halide chains

Low-dimensional van der Waals materials have been extensively studied as a platform with which to generate quantum effects. Advancing this research, topological quantum materials with van der Waals structures are currently receiving a great deal of attention. Here, we use the concept of designing topological materials by the van der Waals stacking of quantum spin Hall insulators. Most interestingly, we find that a slight shift of inversion centre in the unit cell caused by a modification of stacking induces a transition from a trivial insulator to a higher-order topological insulator. Based on this, we present angle-resolved photoemission spectroscopy results showing that the real three-dimensional material Bi₄Br₄ is a higher-order topological insulator. Our demonstration that various topological states can be selected by stacking chains differently, combined with the advantages of van der Waals materials, offers a playground for engineering topologically non-trivial edge states towards future spintronics applications.

Nanoscale Conductivity Imaging of Correlated Electronic States in WSe_{2}/WS_{2} Moiré Superlattices

We report the nanoscale conductivity imaging of correlated electronic states in angle-aligned WSe_{2}/WS_{2} heterostructures using microwave impedance microscopy. The noncontact microwave probe allows us to observe the Mott insulating state with one hole per moiré unit cell that persists for temperatures up to 150 K, consistent with other characterization techniques. In addition, we identify for the first time a Mott insulating state at one electron per moiré unit cell. Appreciable inhomogeneity of the correlated states is directly visualized in the heterobilayer region, indicative of local disorders in the moiré superlattice potential or electrostatic doping. Our work provides important insights on 2D moiré systems down to the microscopic level.

Uniform High-k Amorphous Native Oxide Synthesized by Oxygen Plasma for Top-Gated Transistors

The integration of high-k gate dielectrics with two-dimensional (2D) semiconducting channel materials is essential for high-performance and low-power electronics. However, the conformal deposition of a uniform high-k dielectric with sub-1 nm equivalent oxide thickness (EOT) and high interface quality on high-mobility 2D semiconductors is still challenging. Here, we report a facile approach to synthesize a uniform high-k (ε_r ∼ 22) amorphous native oxide Bi₂SeO_x on the high-mobility 2D semiconducting Bi₂O₂Se using O₂ plasma at room temperature. The conformal native oxide can directly serve as gate dielectrics with EOT of ∼0.9 nm, while the original properties of underlying 2D Bi₂O₂Se is preserved. Furthermore, high-resolution area-selective oxidation of Bi₂O₂Se is achieved to fabricate discrete electronic components. This facile integration of a high-mobility 2D semiconductor and its high-k native oxide holds high promise for next-generation nanoelectronics.

miR-18a expression in basal cell carcinoma and regulatory mechanism on autophagy through mTOR pathway

BACKGROUND

Basal cell carcinoma (BCC) is the most common form of skin carcinoma.

AIM

To investigate the function of key micro(mi)RNAs and to explore the potential molecular mechanisms involved in BCC.

METHODS

The microarray dataset GSE34535, which comprises seven BCC samples and seven control samples, was downloaded from the Gene Expression Omnibus database. Differentially expressed miRNAs (DE-miRNAs) were identified. We collected tissue samples from 20 patients with BCC and 20 healthy controls (HCs), to compare the miR-18a expression in their tissue samples. Expression of miR-18a in A431 and HaCaT cells was also assayed. Following this, we upregulated and downregulated miR-18a expression in A431 cells to examine the effects on cell proliferation, migration and apoptosis. To further investigate the relative mechanism, the proteins LC3, Beclin 1, Akt and mammalian target of rapamycin (mTOR) were examined by quantitative real-time PCR and Western blotting. For further verification, we examined the expression of LC3 in the 20 BCC and 20 HC tissue samples.

RESULTS

In total, 19 DE-miRNAs (13 upregulated and 6 downregulated) that were common to the BCC and HC groups were identified. Levels of miR-18a were about three-fold higher in BCC tissues and A431 cells compared with their respective control groups. In vitro, downregulation of miR-18a was shown to inhibit cell proliferation and activate autophagy via the Akt/mTOR signalling pathway, while upregulation of miR-18a promoted proliferation of these cells. LC3 was decreased in BCC compared with HC tissue samples.

CONCLUSIONS

Our data support an oncogenic role of miR-18a through a novel Akt/mTOR/Beclin 1/LC3 axis, and suggest that the antitumour effects of miR-18a inhibitor may make it suitable for BCC therapy.

Unveiling defect-mediated carrier dynamics in monolayer semiconductors by spatiotemporal microwave imaging

The optoelectronic properties of atomically thin transition-metal dichalcogenides are strongly correlated with the presence of defects in the materials, which are not necessarily detrimental for certain applications. For instance, defects can lead to an enhanced photoconduction, a complicated process involving charge generation and recombination in the time domain and carrier transport in the spatial domain. Here, we report the simultaneous spatial and temporal photoconductivity imaging in two types of WS2 monolayers by laser-illuminated microwave impedance microscopy. The diffusion length and carrier lifetime were directly extracted from the spatial profile and temporal relaxation of microwave signals, respectively. Time-resolved experiments indicate that the critical process for photoexcited carriers is the escape of holes from trap states, which prolongs the apparent lifetime of mobile electrons in the conduction band. As a result, counterintuitively, the long-lived photoconductivity signal is higher in chemical-vapor deposited (CVD) samples than exfoliated monolayers due to the presence of traps that inhibits recombination. Our work reveals the intrinsic time and length scales of electrical response to photoexcitation in van der Waals materials, which is essential for their applications in optoelectronic devices.

Unexpected Giant Microwave Conductivity in a Nominally Silent BiFeO3 Domain Wall

Nanoelectronic devices based on ferroelectric domain walls (DWs), such as memories, transistors, and rectifiers, have been demonstrated in recent years. Practical high-speed electronics, on the other hand, usually demand operation frequencies in the gigahertz (GHz) regime, where the effect of dipolar oscillation is important. Herein, an unexpected giant GHz conductivity on the order of 10³ S m^-1 is observed in certain BiFeO₃ DWs, which is about 100 000 times greater than the carrier-induced direct current (dc) conductivity of the same walls. Surprisingly, the nominal configuration of the DWs precludes the alternating current (ac) conduction under an excitation electric field perpendicular to the surface. Theoretical analysis shows that the inclined DWs are stressed asymmetrically near the film surface, whereas the vertical walls in a control sample are not. The resultant imbalanced polarization profile can then couple to the out-of-plane microwave fields and induce power dissipation, which is confirmed by the phase-field modeling. Since the contributions from mobile-carrier conduction and bound-charge oscillation to the ac conductivity are equivalent in a microwave circuit, the research on local structural dynamics may open a new avenue to implement DW nano-devices for radio-frequency applications.

3045Role of osteogenic circulating endothelial progenitor cells in dissemination of large arterial calcification in rheumatoid arthritis

Background

Rheumatoid arthritis is associated with both abnormal bone metabolism and atherogenesis but mechanistic links were missing.

Aim

This study aimed to investigate the role of osteocalcin (OCN)-expressing circulating endothelial progenitor cells (EPC)s in the severity and dissemination of systemic arterial calcifications in rheumatoid arthritis.

Methods

We performed flow cytometry studies in 145 consecutive patients with rheumatoid arthritis to determine osteogenic circulating levels of OCN-positive (OCN+) CD34+KDR+ and OCN+CD34+, versus conventional early EPC CD34+CD133+KDR+. Total calcium load of the thoracic aorta (ascending plus descending) and the carotid arteries were assessed by non-contrast computed tomography (CT) and contrast CT angiography.

Results

Osteogenic EPCs OCN+CD34+KDR+ (P=0.002) and OCN+CD34+ were strikingly associated with the clustered presence of aortic and carotid calcification (P=0.002 and 0.001 respectively, Figure). Multivariable analyses revealed that circulating OCN+CD34+KDR+ (B=14.4 [95% CI 4.0 to 24.8], P=0.007) and OCN+CD34+ (B=9.6 [95% CI 4.9 to 14.3], P<0.001) remained independently associated with increased aortic calcium load. OCN+CD34+ EPC (B=0.8 [95% CI 0.1 to 1.5], P=0.023), but not OCN+CD34+KDR+ EPC (B=1.2 [95% CI −0.2 to 2.6], P=0.09) was further independently associated with carotid calcium load. In comparison, conventional early EPC CD34+CD133+KDR+ had no significant association with aortic or carotid calcium load (P=0.46 and 0.88, respectively).

Conclusions

Circulating level of osteogenic EPC is associated with promulgated aortic and carotid calcification in patients with rheumatoid arthritis, suggesting a potential mechanistic role of the bone-vascular axis in pro-atherogenicity of rheumatic diseases.

Acknowledgement/Funding

General Research Fund, Hong Kong Research Grants Council

A novel phosphoglucomutase-deficient mouse model reveals aberrant glycosylation and early embryonic lethality

Patients with phosphoglucomutase (PGM1) deficiency, a congenital disorder of glycosylation (CDG) suffer from multiple disease phenotypes. Midline cleft defects are present at birth. Overtime, additional clinical phenotypes, which include severe hypoglycemia, hepatopathy, growth retardation, hormonal deficiencies, hemostatic anomalies, frequently lethal, early-onset of dilated cardiomyopathy and myopathy emerge, reflecting the central roles of the enzyme in (glycogen) metabolism and glycosylation. To delineate the pathophysiology of the tissue-specific disease phenotypes, we constructed a constitutive Pgm2 (mouse ortholog of human PGM1)-knockout (KO) mouse model using CRISPR-Cas9 technology. After multiple crosses between heterozygous parents, we were unable to identify homozygous life births in 78 newborn pups (P = 1.59897E-06), suggesting an embryonic lethality phenotype in the homozygotes. Ultrasound studies of the course of pregnancy confirmed Pgm2-deficient pups succumb before E9.5. Oral galactose supplementation (9 mg/mL drinking water) did not rescue the lethality. Biochemical studies of tissues and skin fibroblasts harvested from heterozygous animals confirmed reduced Pgm2 enzyme activity and abundance, but no change in glycogen content. However, glycomics analyses in serum revealed an abnormal glycosylation pattern in the Pgm2^+/- animals, similar to that seen in PGM1-CDG.

Salubrinal enhances eIF2α phosphorylation and improves fertility in a mouse model of Classic Galactosemia

Loss of galactose-1 phosphate uridylyltransferase (GALT) activity in humans results in Classic Galactosemia, and the GalT-deficient (GalT^-/-) mouse mimics the patient condition. GalT^-/- ovaries display elevated endoplasmic reticulum (ER) stress marker, BiP, and downregulated canonical phosphatidylinositol 3-kinase (Pi3k)/protein kinase B (Akt) growth/pro-survival signaling. Numbers of primordial follicles are reduced in the mutants, recapitulating the accelerated ovarian aging seen in human patients. We previously found that oral administration of the compound Salubrinal (an eIF2α phosphatase inhibitor), resulted in reduction of ovarian BiP expression, rescued Pi3k/Akt signaling, and a doubling of primordial follicles in GalT^-/- adults. Here, we further characterized galactosemic stress in GalT^-/- mice versus wild-type (WT) controls, and examined whether Salubrinal treatment improved broader reproductive parameters. We assessed the expression levels of factors of the unfolded protein response (UPR), and found that BiP, phospho-Perk, and phospho-eIF2α were all elevated in GalT^-/- ovaries. However, neither IKK activation (NFκB pathway) nor alternative Xbp1 splicing downstream of ER membrane protein Ire1α activation was induced, suggesting an Xbp1-independent UPR in galactosemic stress. Moreover, Salubrinal treatment significantly increased the number of ovulated eggs in mutant animals after gonadotrophic superovulation. Salubrinal treatment also normalized estrus cycle stage lengths and resulted in significantly larger litter sizes than vehicle-treated mutants. Overall, we show that Salubrinal protects against galactosemia-induced primordial follicle loss in a fashion that includes suppressing the de-phosphorylation of eIF2α, and that intervention in this way significantly improves and extends ovarian function, fertility, and fecundity.

Natural and inducible regulatory B cells are widely distributed in ovine lymphoid tissues

Regulatory B cells that produce IL-10 are now recognized as an important component of the immune system. We previously confirmed that IL-10 secreting CD21⁺ regulatory B cells (B_reg cells) were present in ovine jejunal Peyer's patches (JPP) and this IL-10 production suppressed IL-12 and IFN-γ secretion. It is not known, however, whether ovine B_reg cells are restricted to JPP or are present in other lymphoid tissues. Therefore, CD21⁺ B cells were purified from sheep JPP and from a variety of mucosal and systemic lymphoid tissues using magnetic cell sorting. Purified CD21⁺ B cells were stimulated with a TLR9-agonist, CpG oligodeoxynucleotide (CpG ODN), and the frequency of spontaneous and inducible (i) IL-10-secreting B cells was evaluated by ELISPOT. Spontaneous IL-10 secreting CD21⁺ B cells were present in mucosal (jejunal PP, parabronchial lymph nodes (LN), mesesnteric LN, and palatine tonsils) and systemic (spleen and blood) lymphoid tissues. Mucosal lymphoid tissues (parabronchial and mesenteric LNs and JPP) had the highest frequency of cells spontaneously secreting IL-10 while tonsils had the lowest. The frequency of B cells spontaneously secreting IL-10 was lowest in blood and spleen. There was large inter-animal variation in the frequency of CD21⁺ B cells spontaneously secreting IL-10 and no significant difference was detected following CpG ODN stimulation. When comparing within individual animals there was, however, a consistent increase in the frequency of CD21⁺ cells secreting IL-10 following CpG ODN stimulation versus stimulation with GpC control ODN. The presence of inducible (i)B_reg cells in ovine mucosal tissues supports previous evidence from mice indicating that B cells have the capacity to modulate inflammatory responses. The presence of iB_reg cells in ruminants may also provide a novel therapeutic target for both immunomodulatory drugs and vaccines designed to control antigen-specific mucosal inflammation.

Visualization of Local Conductance in MoS2/WSe2 Heterostructure Transistors

The vertical stacking of van der Waals (vdW) materials introduces a new degree of freedom to the research of two-dimensional (2D) systems. The interlayer coupling strongly influences the band structure of the heterostructures, resulting in novel properties that can be utilized for electronic and optoelectronic applications. Based on microwave microscopy studies, we report quantitative electrical imaging on gated molybdenum disulfide (MoS₂)/tungsten diselenide (WSe₂) heterostructure devices, which exhibit an intriguing antiambipolar effect in their transfer characteristics. Interestingly, in the region with significant source-drain current, electrons in the n-type MoS₂ and holes in the p-type WSe₂ segments are nearly balanced, whereas the heterostructure area is depleted of mobile charges. The spatial evolution of local conductance can be ascribed to the lateral band bending and formation of depletion regions along the line of MoS₂-heterostructure-WSe₂. Our work vividly demonstrates the microscopic origin of novel transport behaviors, which is important for the vibrant field of vdW heterojunction research.

Allogeneic adipose-derived stem cells suppress mTORC1 pathway in a murine model of systemic lupus erythematosus

OBJECTIVE

The aim of our study was to investigate the efficacy of adipose-derived stem cells (ADSC) transplantation in systemic lupus erythematosus (SLE) and to determine the mechanism of ADSC transplantation.

METHODS

B6.MRL/lpr mice were administered ADSC intravenously every week from age 28 to 31 weeks, while the lupus control group and the normal control received phosphate buffered solution (PBS) on the same schedule.

RESULTS

Compared with the lupus control group, the ADSC treatment group had a significant improvement of histologic abnormalities, serologic abnormalities, and immunologic function. Anti-double-stranded DNA antibodies, spleen/weight ratio, deposits of C3/IgG in the kidney, and serum creatinine and blood urea nitrogen levels were significantly decreased with the transplantation of ADSC. A significant decrease of the Th17/CD4⁺ T cell ratio in the spleen, the serum IL-17 concentration, as well as renal IL-17 expression was observed in the ADSC treatment group. Western blot results also showed that ADSC treatment had a lower expression of protein kinase B (Akt), p-Akt, mTOR, p-mTOR, p70S6K, p-p70S6K, and HIF-1α.

CONCLUSION

ADSC treatment can prevent the development of lupus nephritis and significantly ameliorate already-established disease. ADSC treatment reduced Akt, mTOR, p70S6K, HIF-1α, and that this inhibition can avert IL-17-induced inflammation, suggesting that ADSC may be a promising treatment for SLE.

Energy-Resolved Photoconductivity Mapping in a Monolayer-Bilayer WSe2 Lateral Heterostructure

Vertical and lateral heterostructures of van der Waals materials provide tremendous flexibility for band-structure engineering. Because electronic bands are sensitively affected by defects, strain, and interlayer coupling, the edge and heterojunction of these two-dimensional (2D) systems may exhibit novel physical properties, which can be fully revealed only by spatially resolved probes. Here, we report the spatial mapping of photoconductivity in a monolayer-bilayer WSe₂ lateral heterostructure under multiple excitation lasers. As the photon energy increases, the light-induced conductivity detected by microwave impedance microscopy first appears along the heterointerface and bilayer edge, then along the monolayer edge, inside the bilayer area, and finally in the interior of the monolayer region. The sequential emergence of mobile carriers in different sections of the sample is consistent with the theoretical calculation of local energy gaps. Quantitative analysis of the microscopy and transport data also reveals the linear dependence of photoconductivity on the laser intensity and the influence of interlayer coupling on carrier recombination. Combining theoretical modeling, atomic-scale imaging, mesoscale impedance microscopy, and device-level characterization, our work suggests an exciting perspective for controlling the intrinsic band gap variation in 2D heterostructures down to a regime of a few nanometers.

Quantitative measurements of nanoscale permittivity and conductivity using tuning-fork-based microwave impedance microscopy

We report quantitative measurements of nanoscale permittivity and conductivity using tuning-fork (TF) based microwave impedance microscopy (MIM). The system is operated under the driving amplitude modulation mode, which ensures satisfactory feedback stability on samples with rough surfaces. The demodulated MIM signals on a series of bulk dielectrics are in good agreement with results simulated by finite-element analysis. Using the TF-MIM, we have visualized the evolution of nanoscale conductance on back-gated MoS₂ field effect transistors, and the results are consistent with the transport data. Our work suggests that quantitative analysis of mesoscopic electrical properties can be achieved by near-field microwave imaging with small distance modulation.

Tailoring Semiconductor Lateral Multijunctions for Giant Photoconductivity Enhancement

Semiconductor heterostructures have played a critical role as the enabler for new science and technology. The emergence of transition-metal dichalcogenides (TMDs) as atomically thin semiconductors has opened new frontiers in semiconductor heterostructures either by stacking different TMDs to form vertical heterojunctions or by stitching them laterally to form lateral heterojunctions via direct growth. In conventional semiconductor heterostructures, the design of multijunctions is critical to achieve carrier confinement. Analogously, successful synthesis of a monolayer WS₂ /WS_2(1-x) Se_2x /WS₂ multijunction lateral heterostructure via direct growth by chemical vapor deposition is reported. The grown structures are characterized by Raman, photoluminescence, and annular dark-field scanning transmission electron microscopy to determine their lateral compositional profile. More importantly, using microwave impedance microscopy, it is demonstrated that the local photoconductivity in the alloy region can be tailored and enhanced by two orders of magnitude over pure WS₂ . Finite element analysis confirms that this effect is due to the carrier diffusion and confinement into the alloy region. This work exemplifies the technological potential of atomically thin lateral heterostructures in optoelectronic applications.

Out-of-Plane Piezoelectricity and Ferroelectricity in Layered α-In2Se3 Nanoflakes

Piezoelectric and ferroelectric properties in the two-dimensional (2D) limit are highly desired for nanoelectronic, electromechanical, and optoelectronic applications. Here we report the first experimental evidence of out-of-plane piezoelectricity and ferroelectricity in van der Waals layered α-In₂Se₃ nanoflakes. The noncentrosymmetric R3m symmetry of the α-In₂Se₃ samples is confirmed by scanning transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements. Domains with opposite polarizations are visualized by piezo-response force microscopy. Single-point poling experiments suggest that the polarization is potentially switchable for α-In₂Se₃ nanoflakes with thicknesses down to ∼10 nm. The piezotronic effect is demonstrated in two-terminal devices, where the Schottky barrier can be modulated by the strain-induced piezopotential. Our work on polar α-In₂Se₃, one of the model 2D piezoelectrics and ferroelectrics with simple crystal structures, shows its great potential in electronic and photonic applications.