Simple geometric interpretation of signal evolution in phase-sensitive fibre optic parametric amplifier

Visualisation of complex nonlinear equation solutions is a useful analysis tool for various scientific and engineering applications. We have re-examined the geometrical interpretation of the classical nonlinear four-wave mixing equations for the specific scheme of a phase sensitive one-pump fiber optical parametric amplification, which has recently attracted revived interest in the optical communications due to potential low noise properties of such amplifiers. Analysis of the phase portraits of the corresponding dynamical systems provide valuable additional insight into field dynamics and properties of the amplifiers. Simple geometric approach has been proposed to describe evolution of the waves, involved in phase-sensitive fiber optical parametric amplification (PS-FOPA) process, using a Hamiltonian structure of the governing equations. We have demonstrated how the proposed approach can be applied to the optimization problems arising in the design of the specific PS-FOPA scheme. The method considered here is rather general and can be used in various applications

Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

Background: PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods: We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results: We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion: The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04066881

Effectiveness of kangaroo mother care before clinical stabilisation versus standard care among neonates at five hospitals in Uganda (OMWaNA): a parallel-group, individually randomised controlled trial and economic evaluation

BACKGROUND: Preterm birth is the leading cause of death in children younger than 5 years worldwide. WHO recommends kangaroo mother care (KMC); however, its effects on mortality in sub-Saharan Africa and its relative costs remain unclear. We aimed to compare the effectiveness, safety, costs, and cost-effectiveness of KMC initiated before clinical stabilisation versus standard care in neonates weighing up to 2000 g. METHODS: We conducted a parallel-group, individually randomised controlled trial in five hospitals across Uganda. Singleton or twin neonates aged younger than 48 h weighing 700-2000 g without life-threatening clinical instability were eligible for inclusion. We randomly assigned (1:1) neonates to either KMC initiated before stabilisation (intervention group) or standard care (control group) via a computer-generated random allocation sequence with permuted blocks of varying sizes, stratified by birthweight and recruitment site. Parents, caregivers, and health-care workers were unmasked to treatment allocation; however, the independent statistician who conducted the analyses was masked. After randomisation, neonates in the intervention group were placed prone and skin-to-skin on the caregiver's chest, secured with a KMC wrap. Neonates in the control group were cared for in an incubator or radiant heater, as per hospital practice; KMC was not initiated until stability criteria were met. The primary outcome was all-cause neonatal mortality at 7 days, analysed by intention to treat. The economic evaluation assessed incremental costs and cost-effectiveness from a disaggregated societal perspective. This trial is registered with ClinicalTrials.gov, NCT02811432. FINDINGS: Between Oct 9, 2019, and July 31, 2022, 2221 neonates were randomly assigned: 1110 (50·0%) neonates to the intervention group and 1111 (50·0%) neonates to the control group. From randomisation to age 7 days, 81 (7·5%) of 1083 neonates in the intervention group and 83 (7·5%) of 1102 neonates in the control group died (adjusted relative risk [RR] 0·97 [95% CI 0·74-1·28]; p=0·85). From randomisation to 28 days, 119 (11·3%) of 1051 neonates in the intervention group and 134 (12·8%) of 1049 neonates in the control group died (RR 0·88 [0·71-1·09]; p=0·23). Even if policy makers place no value on averting neonatal deaths, the intervention would have 97% probability from the provider perspective and 84% probability from the societal perspective of being more cost-effective than standard care. INTERPRETATION: KMC initiated before stabilisation did not reduce early neonatal mortality; however, it was cost-effective from the societal and provider perspectives compared with standard care. Additional investment in neonatal care is needed for increased impact, particularly in sub-Saharan Africa. FUNDING: Joint Global Health Trials scheme of the Department of Health and Social Care, Foreign, Commonwealth and Development Office, UKRI Medical Research Council, and Wellcome Trust; Eunice Kennedy Shriver National Institute of Child Health and Human Development

Increasing Access to Surgical Services in Sub-Saharan Africa: Priorities for National and International Agencies Recommended by the Bellagio Essential Surgery Group

In this Policy Forum, the Bellagio Essential Surgery Group, which was formed to advocate for increased access to surgery in Africa, recommends four priority areas for national and international agencies to target in order to address the surgical burden of disease in sub-Saharan Africa

Examining oral pre-exposure prophylaxis (PrEP) literacy among participants in an HIV vaccine trial preparedness cohort study

Background PrEP literacy is influenced by many factors including the types of information available and how it is interpreted. The level of PrEP literacy may influence acceptability and uptake. Methods We conducted 25 in-depth interviews in a HIV vaccine trial preparedness cohort study. We explored what participants knew about PrEP, sources of PrEP knowledge and how much they know about PrEP. We used the framework approach to generate themes for analysis guided by the Social Ecological Model and examined levels of PrEP literacy using the individual and interpersonal constructs of the SEM. Results We found that PrEP awareness is strongly influenced by external factors such as social media and how much participants know about HIV treatment and prevention in the local community. However, while participants highlighted the importance of the internet/social media as a source of information about PrEP they talked of low PrEP literacy in their communities. Participants indicated that their own knowledge came as a result of joining the HIV vaccine trial preparedness study. However, some expressed doubts about the effectiveness of the drug and worried about side effects. Participants commented that at the community level PrEP was associated with being sexually active, because it was used to prevent the sexual transmission of HIV. As a result, some participants commented that one could feel judged by the health workers for asking for PrEP at health facilities in the community. Conclusion The information collected in this study provided an understanding of the different layers of influence around individuals that are important to address to improve PrEP acceptability and uptake. Our findings can inform strategies to address the barriers to PrEP uptake, particularly at structural and community levels. Trial registration https://clinicaltrials.gov/ct2/show/NCT0406688

A rare case of a patient with a foreign body in the esophagus for two years which perforated into the mediastinum

A 6-year-old girl was referred to the ENT (Ear nose and throat) unit at Mulago National Referral Hospital with a foreign body in the esophagus diagnosed by routine chest radiograph. The child’s parents recall she had ingested a round object (galvanised iron umbrella cap of a roofing nail) two years prior to this, but they thought that the child had passed it out in stool since she had continued eating and swallowing normally. On arrival at the National referral hospital, the child had two esophagoscopies done but the foreign body was not seen, not until a barium swallow was done was it confirmed that the FB(foreign body) had perforated the esophagus and entered the mediastinum. The cardiothoracic surgeons were consulted, and they removed the foreign body via a thoracotomy. The child recovered well and was discharged from hospital on day 55

A comparison of the use of coaptation U-splintage and a polypropylene brace for humeral shaft fractures

Eighty- eight patients with humeral shaft fractures seen at Mulago hospital, Kampala, were randomly distributed into two groups. In a Group A, 58 patients were treated conservatively using a coaptation U-splint of plaster of Paris while 30 patients in Group B were treated with a humeral brace. There were more males than females (M: F; 1.75:1). Most patients (68%) were aged 18 years or over. Road traffic accidents accounted for 64% of the fractures. Four patients had associated radial nerve damage. There was a statistically significant difference in fracture healing times between closed and open fractures but no statistically significant difference in healing was noted in those patients treated with coaptation U-splints and those with a humeral brace. Full recovery of flexion and extension of the elbow was shorter in patients treated with the humeral brace. Full recovery of flexion and extension of the elbow was shorter in patients treated with humeral brace (group B) than in U- splints ( group A) and the difference was statistically significant (p value <0.001). The functional humeral brace was found to be superior to the coaptation U-splint as regards functional results and is therefore recommended for those patients who can afford its use

Outcome of Emergency Abdominal Surgery at Kigali University Teaching Hospital: A review of 229 cases

Background: Surgical abdominal emergencies constitute an entity of pathologies requiring immediate medical and surgical management in most of the cases. There is little information regarding the clinical spectrum of disease in these patients and the outcome after admissionto hospital. This study was conducted at Kigali University Teaching Hospital (KUTH) and the main objective was to determine the outcome of emergency abdominal surgery at Kigali University Teaching Hospital.Methods: This was a case series study of 229 patients who underwent emergency abdominal surgery at Kigali University Teaching Hospital over a period of 9 months. Variables analysed included the socio-demographic, clinical features, management and outcome of treatment. The multivariate analysis was applied to different factors to analyze their statisticalcorrelation with mortality and morbidity.Results: The patients’ ages ranged from 3 months to 87 years with an average of 28.8 years ±18.2. The male to female sex ratio was 1.7:1.The majority of patients were referred (83.4%). The average time interval between onset of symptoms and admission was 3.6 days. Abdominalpain (100%) and constipation (51.1%) were the commonest complaints and abdominal distension (59%) and tenderness and guarding (45.4%) the most frequent physical findings. Abdominal trauma accounted for 11.8% of the cases. The most common operative findings were peritonitis (41.5%), intestinal obstruction (28.4%) and acute appendicitis (11.8%).Postoperative complications included wound infection (8.7%) and septicaemia (4.8%). The overall mortality was 18%. Variables influencing morbidity and mortality included the transfer (p=0.027), red cell count &lt;4.106 (p = 0.002), haematocrit &lt; 21% (p= 0.023), abnormal leukocytosis (p= 0.008), duration of surgery more than 1 hour (p= 0.034), presence of peritonitis (p = 0.005) and duration of hospitalization &gt;7 days (p = 0.009).Conclusion: Many patients requiring emergency abdominal surgery presented relatively late with an average of 3.6 days time interval between onset of symptoms and admission, serious attention is needed for these patients because the mortality is high