Exploring Muscle Synergies for Performance Enhancement and Learning in Myoelectric Control Maps.

This work proposes two myoelectric control maps based on a DoF-wise synergy algorithm, inspired by human motor control studies. One map, called intuitive, matches control outputs with body movement directions. The second one, named non-intuitive, takes advantage of different synergies contribution to each DoF, without specific correlation to body movement directions. The effectiveness and learning process for the two maps is evaluated through performance metrics in ten able-bodied individuals. The analysis was conducted using a 2-DoFs center-reach-out task and a survey. Results showed equivalent performance and perception for both mappings. However, learning is only visible in subjects that performed better in non-intuitive mapping, that required some familiarization to then exploit its features. Most of the myoelectric control designs use intuitive mappings. Nevertheless, non-intuitive mapping could provide more design flexibility, which can be especially interesting for patients with motor disabilities.

Building on Capacity Established through US Centers for Disease Control and Prevention Global Health Programs to Respond to COVID-19, Cameroon.

The COVID-19 pandemic has highlighted the need for resilient health systems with the capacity to effectively detect and respond to disease outbreaks and ensure continuity of health service delivery. The pandemic has disproportionately affected resource-limited settings with inadequate health capacity, resulting in disruptions in health service delivery and worsened outcomes for key health indicators. As part of the US government's goal of ensuring health security, the US Centers for Disease Control and Prevention has used its scientific and technical expertise to build health capacity and address health threats globally. We describe how capacity developed through global health programs of the US Centers for Disease Control and Prevention in Cameroon was leveraged to respond to coronavirus disease and maintain health service delivery. The health system strengthening efforts in Cameroon can be applied in similar settings to ensure preparedness for future global public health threats and improve health outcomes.

Comparison of carbetocin and oxytocin infusions in reducing the requirement for additional uterotonics or procedures in women at increased risk of postpartum haemorrhage after Caesarean section.

INTRODUCTION: Postpartum haemorrhage is a major cause of maternal mortality and morbidity, commonly due to uterine atony. Prophylactic oxytocin use during Caesarean section is recommended; patients with a high risk of postpartum haemorrhage may require additional uterotonics or procedures. Carbetocin is a long-acting analogue of oxytocin which has shown beneficial results, compared with oxytocin. This study compared the requirement for additional uterotonics or procedures between at-risk women who underwent carbetocin infusion and those who underwent oxytocin infusion. METHODS: This retrospective cohort study included women at increased risk of postpartum haemorrhage after Caesarean section for various indications in a public hospital. Women who received carbetocin infusion and women who received oxytocin infusion were compared, stratified by Caesarean section timing (elective or emergency). The primary outcome was the requirement for additional uterotonic agents or procedures. Secondary outcomes included total blood loss, operating time, rate of postpartum haemorrhage, need for blood transfusion, and need for hysterectomy. RESULTS: Of 1236 women included in the study, 752 received oxytocin first and 484 received carbetocin first. The two groups had comparable blood loss, operating time, rate of postpartum haemorrhage, requirement for additional uterotonics or procedures, need for blood transfusion, and need for hysterectomy. There was a reduction in the requirement for additional uterotonics or procedures, and in the rate of postpartum haemorrhage for women with major placenta praevia or with multiple pregnancies, following receipt of carbetocin first. CONCLUSION: Compared with oxytocin, carbetocin can reduce the requirement for additional uterotonics or procedures in selected high-risk patient groups.

Hong Kong Society of Clinical Blood Management recommendations for implementation of patient blood management.

Patient blood management (PBM) is a patient-centred, multidisciplinary approach to optimise red cell mass, minimise blood loss, and manage tolerance to anaemia in an effort to improve patient outcomes. Well-implemented PBM improves patient outcomes and reduces demand for blood products. The multidisciplinary approach of PBM can often allow patients to avoid blood transfusions, which are associated with less favourable clinical outcomes. In Hong Kong, there has been increasing demand for blood in the ageing population, and there are simultaneous blood safety and donor issues that are adversely affecting the blood supply. To address these challenges, the Hong Kong Society of Clinical Blood Management recommends implementation of a PBM programme in Hong Kong, including strategies such as optimising red blood cell mass, improving anaemia management, minimising blood loss, and rationalising the use of blood and blood products.

Genetic alterations in primary melanoma in Taiwan.

BACKGROUND: Acral melanoma (AM) is the most common histopathological subtype of malignant melanoma in Asians. However, differences in the mutational profiles underlying AM and nonacral cutaneous melanoma (NAM) in Asians are not well understood. OBJECTIVES: To augment the understanding of the prevalence, patterns and associations of various mutations between different subtypes of melanoma. METHODS: We performed comprehensive genomic profiling of 409 cancer-associated genes, using next-generation sequencing, in 66 primary melanomas comprised of 45 AMs and 21 NAMs. RESULTS: Most of the AMs (n = 27/45; 60%), but only five of 21 (24%) NAMs, were triple wild-type (triple-WT) tumours. Compared with AMs, NAMs exhibited a significantly higher frequency of BRAF mutations. The frequencies of NRAS/KRAS mutations, cell-cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and gains of receptor tyrosine kinase genes were significantly higher in AMs. Ulceration was found at significantly higher rates in the AMs and NAMs with cell-cycle aberrations and gains of receptor tyrosine kinase genes. Notably, cell-cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma-specific survival in the 66 patients with melanoma and especially in the 45 patients with AM. Multivariate analysis showed that lymph node metastasis and cell-cycle aberrations were independent prognostic factors of melanoma-specific survival. CONCLUSIONS: This study strengthens our understanding of the patterns and clinical associations of oncogenic mutations in AMs and NAMs in Asians. What's already known about this topic? Mutation frequencies of driver genes vary between melanoma subtypes. Acral melanoma is the most common subtype of melanoma in Asians. KIT mutations and copy number variations occur more frequently in the acral subtype of melanoma than in the nonacral subtype What does this study add? NRAS/KRAS mutations, cell-cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and amplifications of receptor tyrosine kinase genes were significantly enriched in acral melanoma and could be potential targets for treatment. Melanomas with cell-cycle aberrations and gains in receptor tyrosine kinase genes were significantly more likely to contain ulceration. What is the translational message? Cell-cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma-specific survival. These observations should be explored further for future drug development.

The Value of Contrast-Enhanced CT in the Detection of Residual Disease After Neo-Adjuvant Chemotherapy in Ovarian Cancer.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic performance of contrast-enhanced computed tomography (CT) in predicting residual disease following neo-adjuvant chemotherapy (NACT) in stage III/IV ovarian cancer. MATERIALS AND METHODS: This was a retrospective observational cohort study including consecutive patients with primary stage III/IV ovarian cancer who received NACT before interval debulking surgery. CT findings before interval debulking surgerywere correlated with histological/surgical findings. Diagnostic characteristics were calculated on patient-based and lesion-based analyses. False negative results on peritoneal carcinomatosis detection were correlated with lesion size and site. RESULTS: On patient-based analysis, CT (n = 58) had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 92.16%, 57.14%, 94.00%, 50.00%, and 87.93%. On lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 63.01%, 73.47%, 82.51%, 50.00%, and 66.51%. False negative results were associated with lesion size (p < 0.001). The diagnostic performance of CT on the detection of peritoneal carcinomatosis was low at the subdiaphragmatic spaces, bowel serosa and mesentery (p < 0.001). CONCLUSION: CT had low negative predictive value in determining residual disease following NACT on both patient-based and lesion-based analyses, especially for non-measurable lesions and at the subdiaphragmatic spaces, bowel serosa and mesentery.

Lumbar model generator: a tool for the automated generation of a parametric scalable model of the lumbar spine.

Low back pain is a major cause of disability and requires the development of new devices to treat pathologies and improve prognosis following surgery. Understanding the effects of new devices on the biomechanics of the spine is crucial in the development of new effective and functional devices. The aim of this study was to develop a preliminary parametric, scalable and anatomically accurate finite-element model of the lumbar spine allowing for the evaluation of the performance of spinal devices. The principal anatomical surfaces of the lumbar spine were first identified, and then accurately fitted from a previous model supplied by S14 Implants (Bordeaux, France). Finally, the reconstructed model was defined according to 17 parameters which are used to scale the model according to patient dimensions. The developed model, available as a toolbox named the lumbar model generator, enables generating a population of models using subject-specific dimensions obtained from data scans or averaged dimensions evaluated from the correlation analysis. This toolbox allows patient-specific assessment, taking into account individual morphological variation. The models have applications in the design process of new devices, evaluating the biomechanics of the spine and helping clinicians when deciding on treatment strategies.

Comparing Modified Huddart-Bodenham Scoring System and GOSLON Yardstick to Assess Dental Arch Relationships in Unilateral Cleft Lip and Palate Patients.

OBJECTIVE: To test the reliability of the modified Huddart-Bodenham (MHB) numerical scoring system and its agreement with the GOSLON Yardstick categorization for assessing the dental arch relationships in unilateral cleft lip and palate (UCLP) cases. DESIGN: A retrospective study. SETTING: Faculty of Dentistry, The University of Hong Kong. PATIENTS: Forty-one nonsyndromic UCLP consecutive patients attending the Joint Cleft Lip/Palate Clinic at Faculty of Dentistry in the University of Hong Kong were selected. INTERVENTIONS: Study models at 8 to 10 years old (T1) and 10 to 12 years old (T2) were obtained from each patient. MAIN OUTCOME MEASURES: Models were rated with the MHB scoring system and GOSLON Yardstick index. The intra- and interexaminer reliabilities as well as correlation of both scoring systems were evaluated. Furthermore, to investigate the outcome measurements consistency, the MHB scoring system and GOSLON Yardstick were independently used to compare the dental arch relationships from T1 to T2, with the samples split into intervention and nonintervention groups. RESULTS: The MHB scoring system presented good intra- and interexaminer agreement, which were comparable to those of the GOSLON Yardstick. The correlation between the MHB scoring system and GOSLON Yardstick scores was good. Both scoring systems showed similar results when assessing the change in the dental arch relationships from T1 to T2. CONCLUSIONS: The MHB scoring system can be used as an alternative method to the commonly used GOSLON Yardstick for assessing dental deformities in UCLP patients. Both scoring systems showed similar results in assessing the improvement in dental arch relationships.

A wind tunnel study of effects of twisted wind flows on the pedestrian-level wind field in an urban environment.

The influence of twisted wind flows on the pedestrian-level wind (PLW) field of an urban area was evaluated by testing a typical urban site (Tsuen Wan, Hong Kong) in a boundary layer wind tunnel. Four twisted wind profiles with different magnitudes and directions of yaw angles were employed to investigate variations in wind speed with the properties of the twisted wind flows at the pedestrian level. An additional conventional wind profile with similar wind speeds and turbulence intensities to the twisted winds but with zero yaw angles was simulated for comparisons. The mean wind speeds at 77 locations including the perimeter, roadsides, and groups of high-rise buildings were analysed for the conventional and the four twisted wind flows. The comparisons show a tendency of twisted winds to generate higher wind speeds at the pedestrian level than the conventional wind profile. The wind speeds of the twisted winds have a strong dependence on the magnitude and direction of the yaw angles, particularly at locations where the densities of buildings in the neighbourhood are low and hence local wind circulations are significantly modified by the twisted winds.

New inflow boundary conditions for modeling twisted wind profiles in CFD simulation for evaluating the pedestrian-level wind field near an isolated building.

The hilly topography of Hong Kong influences oncoming winds and gradually changes their wind directions along the profiles' height. The vertical variation in wind directions, or the twist effect, significantly influences the Pedestrian Level Wind (PLW) field in urban areas of Hong Kong, thus it is a topic demanding systematic investigations. In this study, a new set of inflow boundary conditions are proposed to model twisted wind flows in Computational Fluid Dynamic (CFD) simulations. The new inflow boundary condition derived based on the horizontal homogeneous assumption, specifies a vertical profile of lateral wind speeds at the inlet boundary to sustain the twist effect in the empty computational domain. The proposed boundary conditions are used to simulate the PLW fields near three isolated buildings with different Height-to-Width ratio using two CFD codes; OpenFOAM, and FLUENT. The results reveal that OpenFOAM is more reliable in simulating PLW fields in twisted wind flows using the new set of boundary conditions. The three-dimensional flow field provided by the OpenFOAM simulation shows sparse streamlines downstream the buildings, indicating lack of organized eddies in the building far wake, which negatively affects the dispersion of air pollutants in twisted winds.

Integrating twisted wind profiles to Air Ventilation Assessment (AVA): The current status.

Twisted wind flows generated by the complex terrain of Hong Kong induce two types of complication to Air Ventilation Assessment (AVA), first, imposing a false boundary condition on the wind tunnel tests done for AVA and, second, creating an ambiguity in determining the approaching wind direction in calculating the probability of occurrence of winds. The latter issue is partially solved using correction methods in post-analysis of AVA but the accuracy of these methods is not yet accessed. This study employs two twisted wind profiles to test an urban area in a boundary layer wind tunnel to investigate the influence of twisted wind flows on the outcomes of AVA and to estimate the accuracy of three common correction methods: No-Shift, Threshold, and Proportional methods. The results reveal significant differences in wind speeds at the pedestrian level for twisted and conventional wind flows at locations with low building densities. The discrepancies in wind speeds are minimum at the locations where the density of buildings is high. The indicators calculated by the No-Shift method frequently deviate from those of the twisted wind flows, while the Threshold and Proportional methods routinely over-predict the indicators of AVA.

Well-differentiated papillary mesothelioma of tunica vaginalis testis of unknown malignant potential: Sonographic appearance.

Paratesticular mesothelioma is a rare differential diagnosis in the presence of scrotal hydrocele. A 17-year-old boy presented with a 3-year history of progressive hydrocele. Sonography revealed a large left paratesticular mass within the hydrocele. Serum tumor markers were negative. Left hydrocelectomy was performed and pathological analysis of the epididymal mass revealed a well-differentiated papillary mesothelioma. We discuss the sonographic and pathological findings of this rare neoplasm.

Elevated angiopoietin 2 in aqueous of patients with neovascular age related macular degeneration correlates with disease severity at presentation.

Angiopoietin 2 (ANG2) is a proangiogenic cytokine which may have an implication in neovascular age related macular degeneration (nAMD). In 24 eyes of 24 subjects presenting with treatment naïve nAMD and 26 eyes of 26 control patients, aqueous humor samples were collected at the time of intervention (intravitreal injection of anti-vascular endothelial growth factor or cataract extraction). Best corrected visual acuity (BCVA) with and central macular thickness (CMT) using optical coherence tomography (OCT) were measured before each injection in the nAMD group. Aqueous cytokine levels were determined by immunoassay using a multiplex array (Quansys Biosciences, Logan, UT). Levels of ANG2 in the aqueous were significantly higher in nAMD patients than those of the control group (p < 0.0001), so were hepatocyte growth factor (HGF), interleukin-8 (IL-8) and tissue inhibitor of metalloproteinase 1 (TIMP 1), all with p < 0.001. ANG2 correlated with worse BCVA (r = 0.44, p-value = 0.027) and greater CMT (r = 0.66, p-value < 0.0001) on optical coherence tomography (OCT). ANG2 is upregulated in patients with nAMD and correlates with severity of disease at presentation.

Evaluation of pedestrian wind comfort near 'lift-up' buildings with different aspect ratios and central core modifications.

Owing to the void space at lower heights, lift-up buildings have high building permeability at ground level and subsequently improve the air circulation in congested urban areas. Despite this advantage, the lift-up design has been sparsely adopted for buildings in urban areas partly because of the lack of understanding of the combined effects of building dimensions and lift-up design on the surrounding pedestrian level wind (PLW) field. Therefore, this study aims to investigate the influence of lift-up buildings with different aspect ratios (height/width) on the surrounding PLW field and pedestrian wind comfort level. Five lift-up buildings with aspect ratios 4:1 to 0.5:1 were tested in a boundary layer wind tunnel and results were compared with those of five buildings with similar dimensions but without lift-up design. The results reveal a strong dependence of the maximum wind speed in lift-up areas with building height, which results subsequently a small area of acceptable wind conditions near tall and slender lift-up buildings. Lift-up designs adopted for short and wide buildings produce larger areas of pedestrian wind comfort. The central cores modified with corner modifications are effective in increasing the pedestrian wind comfort in the lift-up area of tall and slender buildings.

Adopting 'lift-up' building design to improve the surrounding pedestrian-level wind environment.

Modern megacities are teeming with closely-spaced tall buildings, which limit air circulation at the pedestrian level. The resultant lack of air circulation creates poorly ventilated areas with accumulated air pollutants and thermal discomfort in the summer. To improve air circulation at the pedestrian level, buildings may be designed to have a 'lift-up' shape, in which the main structure is supported by a central core, columns or shear walls. However, a lack of knowledge on the influence of the 'lift-up' design on the surrounding wind environment limits the use of 'lift-up' buildings. This study aims to investigate the influence of 'lift-up' buildings and their dimensions on the pedestrian-level wind environments using wind tunnel tests. A parametric study was undertaken by using 9 'lift-up' building models with different core heights and widths. The results were compared with the surrounding wind environment of a control building with similar dimensions. The results reveal that the 'lift-up' core height is the most influential parameter and governs the area and magnitude of high and low wind speed zones around such buildings. Based on wind tunnel test results and a selected comfort criterion, appropriate core dimensions could be selected to have acceptable wind conditions near lift-up buildings.

Angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in a Chinese paediatric population.

OBJECTIVE: To identify specific angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in Chinese paediatric patients. DESIGN: Retrospective cross-sectional observational study. SETTING: Four locoregional tertiary neurosurgical centres in Hong Kong: Queen Elizabeth Hospital, Tuen Mun Hospital, Kwong Wah Hospital, and Pamela Youde Nethersole Eastern Hospital. PATIENTS: Patients aged 18 years or younger who underwent pretreatment digital subtraction angiography for brain arteriovenous malformation between 1 January 2005 and 31 July 2013 were included. Patients were divided into haemorrhagic and non-haemorrhagic groups based on the initial presentation. Pretreatment digital subtraction angiographies were independently reviewed by two experienced neuroradiologists. MAIN OUTCOME MEASURES: The following parameters were evaluated for their association with haemorrhagic presentation by univariate and multivariate analyses: nidus location, nidus size, nidus morphology (diffuse or compact); origin and number of arterial feeders; venous drainage; number of draining veins; presence of aneurysms, venous varices, and venous stenosis. RESULTS: A total of 67 children and adolescents (28 male, 39 female) with a mean age of 12 years were included. Of them, 52 (78%) presented with haemorrhage. Arteriovenous malformation size (P=0.004) and morphology (P=0.05) were found to be associated with haemorrhagic presentation by univariate analysis. Small arteriovenous malformation nidus size and diffuse nidal morphology were identified as independent risk factors for haemorrhage by multivariate analysis. CONCLUSION: Smaller arteriovenous malformation size and diffuse nidal morphology are angiographic factors independently associated with haemorrhagic presentation. Bleeding risk is important in determining the therapeutic approach (aggressive vs conservative) and timeframe, particularly in paediatric patients.

The role of laparoscopy in staging of different gynaecological cancers.

Apart from cervical and vaginal cancers that are staged by clinical examination, most gynaecological cancers are staged surgically. Not only can pelvic and para-aortic lymphadenectomy offer accurate staging information that helps determine patients' prognosis and hence their treatment plan, but it may also provide a therapeutic effect under certain circumstances. In the past, such a procedure required a big laparotomy incision. With the advent of laparoscopic lighting and instrument, laparoscopic lymphadenectomy became popular since the late 1980s. Dargent et al. published the first report on laparoscopic staging in cervical cancers, and many studies then followed. To date, there are numerous case series and trials evaluating the efficacy and safety of laparoscopic surgery in managing gynaecological cancers. In general, compared with laparotomy, laparoscopic lymphadenectomy has less intraoperative blood loss and post-operative pain, fewer wound complications, shorter length of hospital stay and more speedy recovery. However, this is at the expense of longer operative time. The incidence of port-site metastasis is extremely low, although it may be higher in advanced ovarian cancer. Preliminary data showed that there was no significant effect on recurrence and survival, but long-term data are lacking. In this article, the roles of laparoscopy in staging of uterine, cervical and ovarian cancers, the three most common gynaecological cancers, will be reviewed. Novel technologies such as robot-assisted surgery, single-port surgery and sentinel node biopsy will also be discussed.