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1.
Adv Neurobiol ; 36: 849-875, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38468067

RESUMO

Imagine a world in which damaged parts of the body - an arm, an eye, and ultimately a region of the brain - can be replaced by artificial implants capable of restoring or even enhancing human performance. The associated improvements in the quality of human life would revolutionize the medical world and produce sweeping changes across society. In this chapter, we discuss several approaches to the fabrication of fractal electronics designed to interface with neural networks. We consider two fundamental functions - stimulating electrical signals in the neural networks and sensing the location of the signals as they pass through the network. Using experiments and simulations, we discuss the favorable electrical performances that arise from adopting fractal rather than traditional Euclidean architectures. We also demonstrate how the fractal architecture induces favorable physical interactions with the cells they interact with, including the ability to direct the growth of neurons and glia to specific regions of the neural-electronic interface.


Assuntos
Encéfalo , Fractais , Humanos , Encéfalo/fisiologia , Redes Neurais de Computação , Eletrônica , Neurônios
2.
Adv Neurobiol ; 36: 877-906, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38468068

RESUMO

In parallel to medical applications, exploring how neurons interact with the artificial interface of implants in the human body can be used to learn about their fundamental behavior. For both fundamental and applied research, it is important to determine the conditions that encourage neurons to maintain their natural behavior during these interactions. Whereas previous biocompatibility studies have focused on the material properties of the neuron-implant interface, here we discuss the concept of fractal resonance - the possibility that favorable connectivity properties might emerge by matching the fractal geometry of the implant surface to that of the neurons.To investigate fractal resonance, we first determine the degree to which neurons are fractal and the impact of this fractality on their functionality. By analyzing three-dimensional images of rat hippocampal neurons, we find that the way their dendrites fork and weave through space is important for generating their fractal-like behavior. By modeling variations in neuron connectivity along with the associated energetic and material costs, we highlight how the neurons' fractal dimension optimizes these constraints. To simulate neuron interactions with implant interfaces, we distort the neuron models away from their natural form by modifying the dendrites' fork and weaving patterns. We find that small deviations can induce large changes in fractal dimension, causing the balance between connectivity and cost to deteriorate rapidly. We propose that implant surfaces should be patterned to match the fractal dimension of the neurons, allowing them to maintain their natural functionality as they interact with the implant.


Assuntos
Fractais , Neurônios , Humanos , Ratos , Animais , Próteses e Implantes , Hipocampo
3.
Forensic Sci Int Synerg ; 8: 100463, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38496345

RESUMO

Outreach initiatives involves mentoring students, university collaboration, and program creation to diversify roles between academia and forensic practitioners. Mixer exercises foster student-forensic scientist interaction. Emphasis is placed on improving understanding of forensic science, particularly in regions like Southern Africa, where media portrayals often distort perceptions. The outreach initiative aims to correct these misconceptions, promote evidence-based forensic education, and address research shortages through collaboration between forensic laboratories and universities. A permanent committee within the Southern Africa Regional Forensic Science Forum is proposed to facilitate cooperation and coordination. By fostering collaboration and encouraging participation in conferences and research publication, the initiative aims to meet the region's forensic scientist needs.

4.
Anaesthesia ; 2024 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-38369586

RESUMO

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest. An activity survey estimated UK paediatric anaesthesia annual caseload as 390,000 cases, 14% of the UK total. Paediatric peri-operative cardiac arrests accounted for 104 (12%) reports giving an incidence of 3 in 10,000 anaesthetics (95%CI 2.2-3.3 per 10,000). The incidence of peri-operative cardiac arrest was highest in neonates (27, 26%), infants (36, 35%) and children with congenital heart disease (44, 42%) and most reports were from tertiary centres (88, 85%). Frequent precipitants of cardiac arrest in non-cardiac surgery included: severe hypoxaemia (20, 22%); bradycardia (10, 11%); and major haemorrhage (9, 8%). Cardiac tamponade and isolated severe hypotension featured prominently as causes of cardiac arrest in children undergoing cardiac surgery or cardiological procedures. Themes identified at review included: inappropriate choices and doses of anaesthetic drugs for intravenous induction; bradycardias associated with high concentrations of volatile anaesthetic agent or airway manipulation; use of atropine in the place of adrenaline; and inadequate monitoring. Overall quality of care was judged by the panel to be good in 64 (62%) cases, which compares favourably with adults (371, 52%). The study provides insight into paediatric anaesthetic practice, complications and peri-operative cardiac arrest.

5.
Anaesthesia ; 79(1): 43-53, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37944508

RESUMO

Complications and critical incidents arising during anaesthesia due to patient, surgical or anaesthetic factors, may cause harm themselves or progress to more severe events, including cardiac arrest or death. As part of the 7th National Audit Project of the Royal College of Anaesthetists, we studied a prospective national cohort of unselected patients. Anaesthetists recorded anonymous details of all cases undertaken over 4 days at their site through an online survey. Of 416 hospital sites invited to participate, 352 (85%) completed the survey. Among 24,172 cases, 1922 discrete potentially serious complications were reported during 1337 (6%) cases. Obstetric cases had a high reported major haemorrhage rate and were excluded from further analysis. Of 20,996 non-obstetric cases, 1705 complications were reported during 1150 (5%) cases. Circulatory events accounted for most complications (616, 36%), followed by airway (418, 25%), metabolic (264, 15%), breathing (259, 15%), and neurological (41, 2%) events. A single complication was reported in 851 (4%) cases, two complications in 166 (1%) cases and three or more complications in 133 (1%) cases. In non-obstetric elective surgery, all complications were 'uncommon' (10-100 per 10,000 cases). Emergency (urgent and immediate priority) surgery accounted for 3454 (16%) of non-obstetric cases but 714 (42%) of complications with severe hypotension, major haemorrhage, severe arrhythmias, septic shock, significant acidosis and electrolyte disturbances all being 'common' (100-1000 per 10,000 cases). Based on univariate analysis, complications were associated with: younger age; higher ASA physical status; male sex; increased frailty; urgency and extent of surgery; day of the week; and time of day. These data represent the rates of potentially serious complications during routine anaesthesia care and may be valuable for risk assessment and patient consent.


Assuntos
Anestesia , Anestésicos , Feminino , Gravidez , Humanos , Masculino , Incidência , Estudos Prospectivos , Anestesia/efeitos adversos , Hemorragia , Reino Unido/epidemiologia
6.
Anaesthesia ; 79(1): 31-42, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37972480

RESUMO

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. We report the results of the 12-month registry phase, from 16 June 2021 to 15 June 2022, focusing on management and outcomes. Among 881 cases of peri-operative cardiac arrest, the initial rhythm was non-shockable in 723 (82%) cases, most commonly pulseless electrical activity. There were 665 (75%) patients who survived the initial event and 384 (52%) who survived to hospital discharge. A favourable functional outcome (based on modified Rankin Scale score) was reported for 249 (88%) survivors. Outcomes varied according to arrest rhythm. The highest rates of survival were seen for bradycardic cardiac arrests with 111 (86%) patients surviving the initial event and 77 (60%) patients surviving the hospital episode. The lowest survival rates were seen for patients with pulseless electrical activity, with 312 (68%) surviving the initial episode and 156 (34%) surviving to hospital discharge. Survival to hospital discharge was worse in patients at the extremes of age with 76 (40%) patients aged > 75 y and 9 (45%) neonates surviving. Hospital survival was also associated with surgical priority, with 175 (88%) elective patients and 176 (37%) non-elective patients surviving to discharge. Outcomes varied with the cause of cardiac arrest, with lower initial survival rates for pulmonary embolism (5, 31%) and bone cement implantation syndrome (9, 45%), and hospital survival of < 25% for pulmonary embolism (0), septic shock (13, 24%) and significant hyperkalaemia (1, 20%). Overall care was rated good in 464 (53%) cases, and 18 (2%) cases had overall care rated as poor. Poor care elements were present in a further 245 (28%) cases. Care before cardiac arrest was the phase most frequently rated as poor (92, 11%) with elements of poor care identified in another 186 (21%) cases. These results describe the management and outcomes of peri-operative cardiac arrest in UK practice for the first time.


Assuntos
Reanimação Cardiopulmonar , Parada Cardíaca , Embolia Pulmonar , Recém-Nascido , Humanos , Reanimação Cardiopulmonar/métodos , Parada Cardíaca/epidemiologia , Parada Cardíaca/terapia , Sistema de Registros , Anestesistas
7.
Anaesthesia ; 79(1): 18-30, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37972476

RESUMO

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. Here we report the results of the 12-month registry, from 16 June 2021 to 15 June 2022, focusing on epidemiology and clinical features. We reviewed 881 cases of peri-operative cardiac arrest, giving an incidence of 3 in 10,000 anaesthetics (95%CI 3.0-3.5 per 10,000). Incidence varied with patient and surgical factors. Compared with denominator survey activity, patients with cardiac arrest: included more males (56% vs. 42%); were older (median (IQR) age 60.5 (40.5-80.5) vs. 50.5 (30.5-70.5) y), although the age distribution was bimodal, with infants and patients aged > 66 y overrepresented; and were notably more comorbid (73% ASA physical status 3-5 vs. 27% ASA physical status 1-2). The surgical case-mix included more weekend (14% vs. 11%), out-of-hours (19% vs. 10%), non-elective (65% vs. 30%) and major/complex cases (60% vs. 28%). Cardiac arrest was most prevalent in orthopaedic trauma (12%), lower gastrointestinal surgery (10%), cardiac surgery (9%), vascular surgery (8%) and interventional cardiology (6%). Specialities with the highest proportion of cases relative to denominator activity were: cardiac surgery (9% vs. 1%); cardiology (8% vs. 1%); and vascular surgery (8% vs. 2%). The most common causes of cardiac arrest were: major haemorrhage (17%); bradyarrhythmia (9%); and cardiac ischaemia (7%). Patient factors were judged a key cause of cardiac arrest in 82% of cases, anaesthesia in 40% and surgery in 35%.


Assuntos
Parada Cardíaca , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Anestesia , Anestésicos , Anestesistas , Parada Cardíaca/epidemiologia , Parada Cardíaca/etiologia , Lactente
8.
Anaesthesia ; 78(12): 1453-1464, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37920919

RESUMO

The Royal College of Anaesthetists' 7th National Audit Project baseline survey assessed knowledge, attitudes, practices and experiences of peri-operative cardiac arrests among UK anaesthetists and Anaesthesia Associates. We received 10,746 responses, representing a 71% response rate. In-date training in adult and paediatric advanced life support was reported by 9646 (90%) and 7125 (66%) anaesthetists, respectively. There were 8994 (84%) respondents who were confident in leading a peri-operative cardiac arrest, with males more confident than females, but only 5985 (56%) were confident in leading a debrief and 7340 (68%) communicating with next of kin. In the previous two years, 4806 (46%) respondents had managed at least one peri-operative cardiac arrest, of which 321 (7%) and 189 (4%) of these events involved a child or an obstetric patient, respectively. Respondents estimated the most common causes of peri-operative cardiac arrest to be hypovolaemia, hypoxaemia and cardiac ischaemia, with haemorrhage coming fifth. However, the most common reported causes for the most recently attended peri-operative cardiac arrest were haemorrhage; (927, 20%); anaphylaxis (474, 10%); and cardiac ischaemia (397, 9%). Operating lists or shifts were paused or stopped after 1330 (39%) cardiac arrests and 1693 (38%) respondents attended a debrief, with 'hot' debriefs most common. Informal wellbeing support was relatively common (2458, 56%) and formal support was uncommon (472, 11%). An impact on future care delivery was reported by 196 (4%) anaesthetists, most commonly a negative psychological impact. Management of a peri-operative cardiac arrest during their career was reported by 8654 (85%) respondents. The overall impact on professional life was more often judged positive (2630, 30%) than negative (1961, 23%), but impact on personal life was more often negative.


Assuntos
Parada Cardíaca , Adulto , Masculino , Feminino , Humanos , Criança , Inquéritos e Questionários , Anestesistas , Hemorragia , Isquemia
9.
Anaesthesia ; 78(12): 1442-1452, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37920932

RESUMO

We report the results of the Royal College of Anaesthetists' 7th National Audit Project organisational baseline survey sent to every NHS anaesthetic department in the UK to assess preparedness for treating peri-operative cardiac arrest. We received 199 responses from 277 UK anaesthetic departments, representing a 72% response rate. Adult and paediatric anaesthetic care was provided by 188 (95%) and 165 (84%) hospitals, respectively. There was no paediatric intensive care unit on-site in 144 (87%) hospitals caring for children, meaning transfer of critically ill children is required. Remote site anaesthesia is provided in 182 (92%) departments. There was a departmental resuscitation lead in 113 (58%) departments, wellbeing lead in 106 (54%) and departmental staff wellbeing policy in 81 (42%). A defibrillator was present in every operating theatre suite and in all paediatric anaesthesia locations in 193 (99%) and 149 (97%) departments, respectively. Advanced airway equipment was not available in: every theatre suite in 13 (7%) departments; all remote locations in 103 (57%) departments; and all paediatric anaesthesia locations in 23 (15%) departments. Anaesthetic rooms were the default location for induction of anaesthesia in adults and children in 148 (79%) and 121 (79%) departments, respectively. Annual updates in chest compressions and in defibrillation were available in 149 (76%) and 130 (67%) departments, respectively. Following a peri-operative cardiac arrest, debriefing and peer support programmes were available in 154 (79%) and 57 (29%) departments, respectively. While it is likely many UK hospitals are very well prepared to treat anaesthetic emergencies including cardiac arrest, the survey suggests this is not universal.


Assuntos
Anestésicos , Parada Cardíaca , Adulto , Criança , Humanos , Inquéritos e Questionários , Hospitais , Reino Unido
10.
Anaesthesia ; 78(6): 701-711, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36857758

RESUMO

Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3-4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4-69.1) to 52.8 (32.1-69.2) years. The median (IQR) BMI increased from 24.9 (21.5-29.5) to 26.7 (22.3-31.7) kg.m-2 . The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.


Assuntos
Anestésicos , COVID-19 , Humanos , Pré-Escolar , Carga de Trabalho , Pandemias , COVID-19/epidemiologia , Anestesia Geral/métodos , Reino Unido/epidemiologia
11.
Anaesthesia ; 77(12): 1376-1385, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36111390

RESUMO

Cardiac arrest in the peri-operative period is rare but associated with significant morbidity and mortality. Current reporting systems do not capture many such events, so there is an incomplete understanding of incidence and outcomes. As peri-operative cardiac arrest is rare, many hospitals may only see a small number of cases over long periods, and anaesthetists may not be involved in such cases for years. Therefore, a large-scale prospective cohort is needed to gain a deep understanding of events leading up to cardiac arrest, management of the arrest itself and patient outcomes. Consequently, the Royal College of Anaesthetists chose peri-operative cardiac arrest as the 7th National Audit Project topic. The study was open to all UK hospitals offering anaesthetic services and had a three-part design. First, baseline surveys of all anaesthetic departments and anaesthetists in the UK, examining respondents' prior peri-operative cardiac arrest experience, resuscitation training and local departmental preparedness. Second, an activity survey to record anonymised details of all anaesthetic activity in each site over 4 days, enabling national estimates of annual anaesthetic activity, complexity and complication rates. Third, a case registry of all instances of peri-operative cardiac arrest in the UK, reported confidentially and anonymously, over 1 year starting 16 June 2021, followed by expert review using a structured process to minimise bias. The definition of peri-operative cardiac arrest was the delivery of five or more chest compressions and/or defibrillation in a patient having a procedure under the care of an anaesthetist. The peri-operative period began with the World Health Organization 'sign-in' checklist or first hands-on contact with the patient and ended either 24 h after the patient handover (e.g. to the recovery room or intensive care unit) or at discharge if this occured earlier than 24 h. These components described the epidemiology of peri-operative cardiac arrest in the UK and provide a basis for developing guidelines and interventional studies.


Assuntos
Anestésicos , Parada Cardíaca , Humanos , Estudos Prospectivos , Parada Cardíaca/epidemiologia , Parada Cardíaca/etiologia , Parada Cardíaca/terapia , Anestesiologistas , Estudos de Coortes
12.
Cytopathology ; 29(2): 133-142, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29350424

RESUMO

INTRODUCTION: Primary HPV screening will be implemented into the English Cervical Screening Programme by 2019. Its impact upon women referred to colposcopy, with negative cytology but persistently positive high-risk HPV (hrHPV), remains unreported from UK Sentinel sites. HPV primary screening was introduced in Sheffield, UK in April 2013; this paper reports its impact on the service. METHODS: A retrospective cohort study was performed from June 2014 to July 2016 at the Jessop Wing Colposcopy Unit, Sheffield. UK. Data were obtained from the pathology and colposcopy databases and cross-referenced with case-notes and pathology results for women referred with persistently positive hrHPV, cytology negative samples. Patient demographics, hrHPV genotype, biopsy rates, histological diagnoses, management, and outcomes were collected and baseline statistics performed. RESULTS: During the study 1076 women were seen. Most frequent hrHPV genotypes were: hrHPV other, 41%; and HPV16, 33%. The majority (72%) were found to have normal colposcopy; 28% had an abnormal colposcopic assessment (11% low-grade; 11% high-grade; 6% inadequate). The majority were discharged (83%) and only 5% underwent LLETZ. No cancers were detected. High-grade cervical intraepithelial neoplasia (CIN) was found in 7%; overall risk of CIN2 was 1/29; 1/30 for CIN3. Presence of HPV16 was associated with a significantly higher risk of high-grade CIN; 1/9. CONCLUSION: This is the first study to report results for women referred to colposcopy with cytology negative, persistently positive hrHPV. Disease prevalence is low, although women with HPV16 have a significantly higher likelihood of high-grade disease compared to other HPV subtypes.


Assuntos
Genótipo , Papillomaviridae/genética , Infecções por Papillomavirus , Displasia do Colo do Útero , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/genética , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/virologia , Prevalência , Estudos Retrospectivos , Displasia do Colo do Útero/epidemiologia , Displasia do Colo do Útero/genética , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/virologia
13.
Eur J Neurol ; 24(12): 1457-1463, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28800199

RESUMO

BACKGROUND AND PURPOSE: To date, no pathophysiological model has sufficiently accounted for all the findings encountered in patients with idiopathic intracranial hypertension (IIH). Intracranial elastance is an index of volume-buffering capacity known to play a role in certain disorders of cerebrospinal fluid (CSF) dynamics, which has not been previously investigated in relation to IIH patients. METHODS: This was a single-center retrospective cohort study from 1 July 2011 to 1 July 2016. Values for opening pressure (PO ), closing pressure (PC ) and volume (V) of CSF removed were collected, as well as demographic and clinical covariates. Intracranial elastance (E) and pressure-volume index (PVI) were calculated according to established equations: E = (PO -PC )/V and PVI = V/log10 (PO /PC ), respectively. Those with an alternative central nervous system pathology, including meningitis, encephalitis and normal pressure hydrocephalus were excluded. Eligible patients were subdivided into two groups based on final diagnosis: a control group and an IIH group. RESULTS: In our cohort (n = 49), a significant association of both E (P < 0.0001) and PVI (P = 0.005) with a diagnosis of IIH was observed. Median E was 0.45 [interquartile range (IQR) 0.29-0.63] in the control group and 1 (IQR 0.59-1.29) in the IIH group, and median PVI was 98.07 (IQR 59.92-135.86) in the control group and 64.1 (IQR 42.4-91.7) in the IIH group. Neither E nor PVI were significantly associated with age, gender or body mass index. PVI was independent of opening pressure. CONCLUSIONS: As calculated by clinically accessible indices, our study provides evidence that intracranial elastance is increased in IIH, reflecting a novel insight into disease pathogenesis.


Assuntos
Pseudotumor Cerebral/fisiopatologia , Adulto , Elasticidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pseudotumor Cerebral/líquido cefalorraquidiano , Estudos Retrospectivos , Adulto Jovem
14.
PLoS One ; 12(2): e0171289, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28196082

RESUMO

Rorschach inkblots have had a striking impact on the worlds of art and science because of the remarkable variety of associations with recognizable and namable objects they induce. Originally adopted as a projective psychological tool to probe mental health, psychologists and artists have more recently interpreted the variety of induced images simply as a signature of the observers' creativity. Here we analyze the relationship between the spatial scaling parameters of the inkblot patterns and the number of induced associations, and suggest that the perceived images are induced by the fractal characteristics of the blot edges. We discuss how this relationship explains the frequent observation of images in natural scenery.


Assuntos
Fractais , Processamento de Imagem Assistida por Computador , Teste de Rorschach
15.
J Synchrotron Radiat ; 23(2): 385-94, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26917124

RESUMO

JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications at free-electron lasers and synchrotron light sources. The JUNGFRAU 0.4 prototype presented here is specifically geared towards low-noise performance and hence soft X-ray detection. The design, geometry and readout architecture of JUNGFRAU 0.4 correspond to those of other JUNGFRAU pixel detectors, which are charge-integrating detectors with 75 µm × 75 µm pixels. Main characteristics of JUNGFRAU 0.4 are its fixed gain and r.m.s. noise of as low as 27 e(-) electronic noise charge (<100 eV) with no active cooling. The 48 × 48 pixels JUNGFRAU 0.4 prototype can be combined with a charge-sharing suppression mask directly placed on the sensor, which keeps photons from hitting the charge-sharing regions of the pixels. The mask consists of a 150 µm tungsten sheet, in which 28 µm-diameter holes are laser-drilled. The mask is aligned with the pixels. The noise and gain characterization, and single-photon detection as low as 1.2 keV are shown. The performance of JUNGFRAU 0.4 without the mask and also in the charge-sharing suppression configuration (with the mask, with a `software mask' or a `cluster finding' algorithm) is tested, compared and evaluated, in particular with respect to the removal of the charge-sharing contribution in the spectra, the detection efficiency and the photon rate capability. Energy-dispersive and imaging experiments with fluorescence X-ray irradiation from an X-ray tube and a synchrotron light source are successfully demonstrated with an r.m.s. energy resolution of 20% (no mask) and 14% (with the mask) at 1.2 keV and of 5% at 13.3 keV. The performance evaluation of the JUNGFRAU 0.4 prototype suggests that this detection system could be the starting point for a future detector development effort for either applications in the soft X-ray energy regime or for an energy-dispersive detection system.

16.
Cytopathology ; 27(3): 210-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26415635

RESUMO

OBJECTIVE: This study looks at the importance of large loop excision of the transformation zone (LLETZ) excision margins and residual cervical intraepithelial neoplasia (CIN) in women undertaking high-risk human papillomavirus (hrHPV) test of cure (TOC). METHODS: A retrospective cohort study with interval analysis performed June 2007 and June 2012 on all women undertaking treatment for CIN and subsequent hrHPV TOC 6 months post LLETZ. RESULTS: Final analysis group comprised 2093 women treated by LLETZ (1396 completely excised; 697 incompletely excised). 298 out of 1794 women (13%) were hrHPV positive at TOC. Thirty-six women who failed TOC and attended colposcopy had residual CIN. No statistically significant difference existed between the completely and incompletely excised groups with regards to the detection of residual CIN at 6 months post-treatment. There was no correlation of margins of excision with hrHPV status at TOC. The overall cure rate at TOC was 98%. CONCLUSIONS: TOC pathways recommend subsequent follow-up in primary care. This study identified no safety issues with TOC pathways. We can no longer assess histological failure rates at 12 months; we, therefore, recommend that this measure of treatment failure be redefined for post TOC women. It seems time to question the benefits of routine excision margins reporting, in the absence of invasion, for treated CIN. Future reporting needs to be reconsidered by the Royal College of Pathologists.


Assuntos
Colo do Útero/patologia , Margens de Excisão , Infecções por Papillomavirus/diagnóstico , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Adulto , Idoso , Colo do Útero/cirurgia , Colposcopia , Citodiagnóstico , Feminino , Humanos , Pessoa de Meia-Idade , Teste de Papanicolaou , Papillomaviridae , Gravidez , Estudos Retrospectivos , Resultado do Tratamento , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/cirurgia , Adulto Jovem , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/cirurgia
17.
Cytopathology ; 26(6): 381-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25412857

RESUMO

OBJECTIVE: When the Sheffield screening laboratory changed the high-risk human papillomavirus (hrHPV) platforms from hybrid capture 2(®) (HC2; Digene Ltd) and to cobas 4800(®) (Roche) an unexpected and substantial increase in the number of cytology-negative/hrHPV-positive test-of-cure (ToC) samples after large loop excision of the transformation zone (LLETZ) was noted. We explore the potential reasons for these increased rates and discuss the implications this may have on the English NHS cervical screening programme (CSP). METHODS: A retrospective cohort study with interval analysis between June 2007 and June 2012. RESULTS: ToC was performed on 1530 women with HC2 and 396 with cobas 4800: 95.1% and 92.4% of women had negative cytology at ToC in the HC2 and cobas4800 testing period, respectively. Of these 13.9% and 27.8% tested positive for hrHPV in the HC2 and cobas 4800 group, respectively (P = <0.0001). No clinically significant increase in the number of cases of cervical intraepithelial neolpasia (CIN) was detected by the cobas4800 test in spite of doubling the number of cytology-negative/hrHPV-positive ToC samples. CONCLUSIONS: As far as we are aware, this is the first study reporting potential differences between different HPV platforms currently available in the English programme. The immediate impact of this increase in rates of hrHPV detection with cobas4800 is an increased number of colposcopy referrals to our service. The NHSCSP needs to assess whether this increase is acceptable and, if not, whether specific HPV platforms more suited to screening in a ToC scenario should be recommended.


Assuntos
Colo do Útero/patologia , DNA Viral/isolamento & purificação , Eletrocirurgia , Hibridização de Ácido Nucleico , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/patologia , Displasia do Colo do Útero/patologia , Neoplasias do Colo do Útero/patologia , Adolescente , Adulto , Idoso , Colo do Útero/cirurgia , Estudos de Coortes , Colposcopia , Detecção Precoce de Câncer , Inglaterra , Reações Falso-Negativas , Feminino , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Infecções por Papillomavirus/diagnóstico , Estudos Retrospectivos , Sensibilidade e Especificidade , Neoplasias do Colo do Útero/diagnóstico , Adulto Jovem , Displasia do Colo do Útero/diagnóstico
19.
Rev Sci Instrum ; 86(12): 123110, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26724009

RESUMO

JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10(4) photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 µm(2) pixels and is bump-bonded to a 320 µm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm(2). Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.


Assuntos
Artefatos , Eletrônica/instrumentação , Fotometria/instrumentação , Fótons , Radiometria/instrumentação , Semicondutores , Desenho de Equipamento , Falha de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Razão Sinal-Ruído , Eletricidade Estática
20.
HIV Med ; 15(4): 233-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24025074

RESUMO

OBJECTIVES: The aim of the study was to describe the relationship between preterm delivery (PTD; < 37 weeks of gestation) and antiretroviral therapy in a single-centre cohort of pregnant women with HIV infection. METHODS: A retrospective analysis of data for 331 women who received care in a dedicated HIV antenatal clinic between 1996 and 2010 was carried out. Data on first CD4 cell count and viral load (HIV-1 RNA copies/mL) recorded in pregnancy, class and timing of antiretroviral therapy, gestational age at delivery, and risk factors for and causes of PTD were available from a clinical database. RESULTS: Overall, 13.0% of deliveries were preterm, of which 53% were severe preterm (< 34 weeks of gestation). The lowest rate of PTD was observed in women treated with zidovudine monotherapy (6.2%). Higher rates of PTD were observed in women starting combination antiretroviral therapy (cART) in pregnancy compared with women conceiving while on cART [odds ratio (OR) 2.52; 95% confidence interval (CI) 1.22-5.20; P = 0.011]. Of the women who were eligible for zidovudine monotherapy on the basis of CD4 counts and HIV viral load but who were treated with short-term cART to prevent HIV mother-to-child transmission, 28.6% delivered preterm. Women on short-term cART remained at the highest risk of PTD compared with zidovudine monotherapy in multivariate analysis (OR 5.00; 95% CI 1.49-16.79; P = 0.015). CONCLUSIONS: The causes of PTD are multiple and poorly understood. The timing of initiation and type of antiretroviral therapy administered during pregnancy appear to contribute to PTD risk. Understanding this association should improve the safety of antiretroviral therapy in pregnancy without increasing the risk of transmission.


Assuntos
Fármacos Anti-HIV/efeitos adversos , Infecções por HIV/tratamento farmacológico , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Complicações Infecciosas na Gravidez/tratamento farmacológico , Nascimento Prematuro/induzido quimicamente , Zidovudina/efeitos adversos , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Contagem de Linfócito CD4 , Feminino , Infecções por HIV/transmissão , Humanos , Gravidez , Nascimento Prematuro/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Carga Viral
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