Very low excess noise Al0.75Ga0.25As0.56Sb0.44 avalanche photodiode.

AlxGa1-xAsySb1-y grown lattice-matched to InP has attracted significant research interest as a material for low noise, high sensitivity avalanche photodiodes (APDs) due to its very dissimilar electron and hole ionization coefficients, especially at low electric fields. All work reported to date has been on Al concentrations of x = 0.85 or higher. This work demonstrates that much lower excess noise (F = 2.4) at a very high multiplication of 90 can be obtained in thick Al0.75Ga0.25As0.56Sb0.44 grown on InP substrates. This is the lowest excess noise that has been reported in any III-V APD operating at room temperature. The impact ionization coefficients for both electrons and holes are determined over a wide electric field range (up to 650 kV/cm) from avalanche multiplication measurements undertaken on complementary p-i-n and n-i-p diode structures. While these ionization coefficients can fit the experimental multiplication over three orders of magnitude, the measured excess noise is significantly lower than that expected from the ß/α ratio and the conventional local McIntyre noise theory. These results are of importance not just for the design of APDs but other high field devices, such as transistors using this material.

Anomalous excess noise behavior in thick Al0.85Ga0.15As0.56Sb0.44 avalanche photodiodes.

Al0.85Ga0.15As0.56Sb0.44 has recently attracted significant research interest as a material for 1550 nm low-noise short-wave infrared (SWIR) avalanche photodiodes (APDs) due to the very wide ratio between its electron and hole ionization coefficients. This work reports new experimental excess noise data for thick Al0.85Ga0.15As0.56Sb0.44 PIN and NIP structures, measuring low noise at significantly higher multiplication values than previously reported (F = 2.2 at M = 38). These results disagree with the classical McIntyre excess noise theory, which overestimates the expected noise based on the ionization coefficients reported for this alloy. Even the addition of 'dead space' effects cannot account for these discrepancies. The only way to explain the low excess noise observed is to conclude that the spatial probability distributions for impact ionization of electrons and holes in this material follows a Weibull-Fréchet distribution function even at relatively low electric-fields. Knowledge of the ionization coefficients alone is no longer sufficient to predict the excess noise properties of this material system and consequently the electric-field dependent electron and hole ionization probability distributions are extracted for this alloy.

Psychosocial Predictors of Normative Transgression during the COvID-19 Pandemic in Peruvian Citizens / Predictores psicosociales de transgresión normativa durante la pandemia de COvID-19 en ciudadanos peruanos / Preditores psicossociais de transgressão normativa durante a pandemia de COvID-19 em cidadãos peruanos

This research investigated psychological correlates with norm non-compliance during the National State of Emergency declared in Peru at the time of the COVID-19 pandemic. Specifically, it looks at the relationship between Social Dominance Orientation (SDO), perceptions of legitimacy, strength and efficacy of the normative system, and trust in the institutions. It also looks at individual justifications for norm non-compliance and the frequency of transgression. A correlational research design using questionnaires was developed with a sample of 126 participants. Results show that transgression of government-issued norms during the Peruvian National State of Emergency is linked to the ideological compo- nent of SDO and perceptions of a weak and illegitimate normative system. These results are consistent with previous studies on normative transgression in Latin American countries. Additionally, results suggest that the need for subsistence (i.e., generating resources to sustain the household) is fundamental to comprehensively understanding transgressive behavior in contexts of vulnerability such as a global pandemic. The discussion highlights how a precarious socio-political structure ­ one incapable of meeting the basic needs of large sectors of the population­ emerges as a central cause of normative transgression in times of crisis

Esta investigación indaga los correlatos psicológicos con el incumplimiento de normas durante el Estado de Emergencia Nacional declarado en Perú con ocasión de la pandemia del COVID-19. Específicamente, se exa- mina la relación entre la Orientación a la Dominancia Social (ODS), las percepciones de legitimidad, fortaleza y eficacia del sistema normativo y la confianza en las instituciones. También examina las justificaciones individuales del incumplimiento de las normas, así como la frecuencia de la transgresión. Se desarrolló un diseño de investigación correlacional mediante cuestionarios con una muestra de 126 participantes. Los resultados muestran que la transgresión de las normas emitidas por el Gobierno durante el Estado de Emergencia Nacional peruano, están vinculadas al componente ideológico del ODS y a la percepción de un sistema normativo débil e ilegítimo. Estos resultados son consistentes con estudios previos sobre transgresión normativa en países latinoamericanos. Adicionalmente, los resultados sugieren que la necesidad de subsistencia (es decir, la generación de recursos para el sostenimiento del hogar), es fundamental para comprender de manera integral el comportamiento transgresor en contextos de vulnerabilidad como una pandemia global. La discusión destaca cómo una estructura sociopolítica precaria ­incapaz de satisfacer las necesidades básicas de amplios sectores de la población­ emerge como causa central de la transgresión normativa en tiempos de crisis.

Esta pesquisa investiga as correlações psicológicas com o descumprimento de normas durante o Estado Nacional de Emergência declarado no Peru na época da pandemia da COVID-19. Especificamente, ela analisa a relação entre a orientação de dominância social (ODS), as percepções de legitimidade, força e eficácia do sistema normativo e a confiança nas instituições. Também analisa as justificativas individuais para a não conformidade com a norma, bem como a frequência da transgressão. Um projeto de pesquisa correlacional usando questionários foi desenvolvido com uma amostra de 126 participantes. Os resultados mostram que a transgressão das normas emitidas pelo governo durante o Estado de Emergência Nacional do Peru está ligada ao componente ideológico da ODS e às percepções de um sistema normativo fraco e ilegítimo. Esses resultados são consistentes com estudos anteriores sobre transgressão normativa em países latino-americanos. Além disso, os resultados sugerem que a necessidade de subsistência (ou seja, a geração de recursos para sustentar a família) é fundamental para compreender de forma abrangente o comportamento transgressivo em contextos de vulnerabilidade, como uma pandemia global. A discussão destaca como uma estrutura socio- política precária ­incapaz de atender às necessidades básicas de grandes setores da população­ surge como uma causa central da transgressão normativa em tempos de crise.

Microsurgical Salvage of Neonatal Upper Limb Ischaemia Following Intrauterine Brachial Vessel Constriction.

Neonatal limb ischaemia is a rare disease entity with devastating morbidity, including compartment syndrome, tissue loss, limb loss, reduced limb growth, irreparable neuropathies and Volkmann's syndrome.  We report a case of limb revascularisation and salvage due to intrauterine brachial artery thrombosis. Published literature is limited to case reports and case series, with various treatment modalities discussed. Early recognition, prompt institution of appropriate treatment and monitoring is vital to achieve successful revascularisation and prevention of life-long morbidity. A male baby at (36+6week) gestation was born to a nulliparous mother with gestational diabetes via uncomplicated elective caesarean section. Aetiology was due to dense fibrotic circumferential constriction of the brachial vessels and plexus. Successful revascularization was achieved with a contralateral interposition reversed great saphenous vein graft.  Though extremely rare and the clinical presentation varies with the location and timing after birth, the surgeon should maintain a low threshold for suspicion of in the presence of the characteristic sequelae of ischaemia. Doppler ultrasonography can aid the diagnosis where ambiguous, and therapy should be individualised based on the clinical presentation; this case emphasises the role of surgery in limb salvage.

Complete transection of the sciatic nerve following closed femoral fracture.

Complete transection of the sciatic nerve following femoral fracture is extremely rare. In the setting of closed injury it has only been reported in two other cases. Here we present a teenage motorcyclist who sustained a closed left, mid-femoral fracture following a road traffic collision with complete transection of the sciatic nerve. Despite being a closed injury, the obvious limb deformity of the patient and extreme pain prompted immediate nerve block during the primary survey making formal neurological assessment difficult. This case highlights the possibility of complete major nerve transection in closed injuries, and the importance of careful clinical examination alongside repeat imaging.

Gaining consensus: the challenges of living with a stoma and the impact of stoma leakage.

BACKGROUND: People with a stoma face many unique challenges. Leakage is a significant one but is not sufficiently discussed within the wider area of health and social care. AIMS: This study aimed to articulate and achieve consensus on the problems experienced by people with a stoma, particularly leakage, in the hope of encouraging conversations among patients, clinicians and policymakers on how to solve them. METHODS: Output from a modified Delphi panel, consisting of patient groups, was used to create a set of calls to action, with a particular focus on the issue of leakage. FINDINGS: Leakage has a large impact on daily life and can cause both physical and mental health difficulties. Peer support and specialist care can be offer considerable benefits in dealing with these. CONCLUSIONS: There are significant unmet needs for equitable access to specialist stoma care and peer support, as well as information provision for non-specialist healthcare providers. The calls to action should be implemented.

A review of functional latissimus dorsi transfers for absent elbow flexion and supination.

AIMS: To review patients treated with a functional latissimus dorsi flap for congenital and acquired elbow flexion deficits. METHODS: Retrospective review of functional latissimus dorsi flaps performed in one regional unit. Patient notes were reviewed to determine aetiology, pre-op deficits and function, surgical technique, complications and outcomes. RESULTS: A total of six functional latissimus dorsi transfers were performed on four patients. Two patients had bilateral latissimus dorsi transfers for congenital defects. The remaining two procedures were for traumatic defects. Post-operatively both children had excellent outcomes with full range of active movement allowing them to perform key activities of daily living. SURGICAL TECHNIQUE: Epimysium of latissimus dorsi folded to form a pseudo-tendon, tunnelled subcutaneously and either attached to a remnant of biceps tendon or secured to the radius. Congenital patients achieved better outcomes; pre-operatively, there was no active elbow flexion in all four elbows but 90-100 of passive flexion. COMPLICATIONS: One latissimus dorsi dehiscence which required revision surgery. Two donor-site seromas. CONCLUSIONS: Functional latissimus dorsi transfer has been shown to achieve excellent elbow flexion in patients with congenital absence of biceps and brachialis muscles. Outcomes in older patients with traumatic injuries have been less successful in achieving a full range of active flexion.

The impact of emergency nurse practitioners on referrals to a tertiary hand trauma service: a pilot of referral quality scoring system.

Hand injuries account for 2000 referrals to the Northern Ireland plastic surgery trauma service each year. Emergency nurse practitioners are increasingly utilised to assess and manage minor injuries and independently refer patients to the hand trauma service. This paper uses a newly developed scoring system to assess the impact of varying grades of referring practitioner on the quality and appropriateness of referral.

Telemedicine and trauma referrals--a plastic surgery pilot project.

A pilot study of the use of digital images as an adjunct to telephone referral was undertaken. Hand trauma represented the majority of the twenty patients included in the study, and the system was found to be an effective aid to delivering appropriate management. We have found image analysis to be a useful addition to the telephone referral process already in use in our unit, but it is unlikely to replace the need for real time clinical assessment of the patient.

Outbreak of epidemic methicillin-resistant Staphylococcus aureus in a regional burns unit: management and implications.

Colonization of burn patients with methicillin-resistant Staphylococcus aureus (MRSA) is not uncommon, however an outbreak that necessitates closure of a burns unit is relatively rare. The objective of this study was to present the experience of a regional adult burns unit where an outbreak of epidemic MRSA-15 (EMRSA-15) took place. During the studied period, 176 patients were admitted to the unit, 52 with burns, 48 for elective plastic surgery procedures while the remainder belonged to other specialties. Patients admitted under burns and plastic surgery were investigated together with 46 staff members to control the outbreak. MRSA was isolated in 18 patients out of which 12 had EMRSA-15. Among the staff members, MRSA was isolated in nine of which five had EMRSA-15. The burns unit was closed to all admissions to terminate this outbreak. The MRSA positive staff members were sent on "special leave" and underwent treatment with nasal mupirocin and triclosan body wash. All staff members were able to return to work after one week's treatment. The burns unit underwent re-furbishment and decontamination while it was closed. In conclusion, the study shows that an outbreak of EMRSA was controlled successfully, however, it highlights the implications of such an event for a regional burn service with regard to staff, patients and guidelines for management.

mTHPC-mediated photodynamic therapy for early oral squamous cell carcinoma.

Surgery and radiotherapy are standard treatments for early oral squamous cell carcinoma, both resulting in good tumour control. However, neither of these modalities is without consequent functional or cosmetic impairment, and there are patients in whom both are contraindicated. Furthermore, there is a significant risk of metachronous tumours developing in the oral cavity, and salvage or retreatment with either surgery or radiotherapy poses difficulties. Photodynamic therapy (PDT) offers the potential for improved functional and cosmetic outcomes, while achieving comparable tumour control. We conducted an open-label, multicentre study to assess the efficacy and safety of meta-tetrahydroxyphenylchlorin (mTHPC) in patients with early oral cancer. One hundred twenty-one patients received intravenously administered mTHPC, followed 96 hr later by illumination of the tumour surface with 652 nm laser light. Of these patients, 114 were protocol compliant. A complete tumour response was achieved in 85% of protocol-compliant patients (97 of 114 patients). A complete response was maintained in 85% of responders at 1 year and in 77% at 2 years. One- and 2-year actuarial survival rates were 89% and 75%, respectively. In the opinion of the investigators, tumour clearance was accompanied by excellent cosmetic and functional results, without impact on the patients' performance status. Mild-to-moderate pain at the treatment site, a recognised side effect of PDT in the oral cavity, was reported by 82% of patients but was manageable with appropriate analgesia. Mild-to-moderate skin photosensitivity reactions were reported for 13% of patients. mTHPC offers an effective alternative treatment for early oral squamous cell carcinoma. It is associated with excellent functional and cosmetic results and can be used in conjunction with other standard therapies.

Arterial reconstruction using the basilic vein from the zone of injury in pediatric supracondylar humeral fractures: a clinical and radiological series.

The authors describe the advantages of using the basilic vein as an arterial conduit in the management of children with supracondylar humeral fractures requiring vascular repair. Eight children, aged 3 to 10 years, presented with supracondylar humeral fractures and vascular injury. In all eight children, the arteries were successfully reconstructed with a reversed, interposition basilic vein graft harvested from the ipsilateral arm. The basilic vein was anatomically consistent with few side branches and was an excellent size match for the brachial artery. There were no postoperative thromboses. At a minimum follow-up of 1 year, all children had palpable radial pulses and the vein grafts were patent with no anastomotic or other focal stenoses. This series confirms the safety of using a donor vein from within the zone of injury for arterial reconstruction, after a supracondylar humeral fracture. Benefits include a single surgical wound on the less conspicuous medial side of the arm, reduced operating time, and preservation of donor veins that may be subsequently required for the management of atherosclerotic disease.