24 research outputs found
New Method of Machining Teeth on Unspecialised Machine Tools
In the present work, the authors describe elaborated method of machining teeth with the use of unspecialized machine tools. In the first part of the work the need to develop such a method has been shown and the drawbacks of the known methods have been indicated. Further part of the work describes the process of mathematical modelling the purpose of which was to determine the tool paths during machining. Next, the kinetics of teeth machining with the use of a universal CNC milling centre is presented. Further on, the operation of the algorithm, the user’s interface of the elaborated software and the parameters influencing the machining process have been shown. In the final part of the work, the results of examination of the obtained details have been shown on a gear wheel as an example. The origin of machining errors and their significance has been discussed. In conclusions, summary of obtained results is presented. In last paragraphs, authors discuss machining accuracy of developed method, and application possibilities of described method are emphasised as well. Performed verification proved that developed method is capable of machining gears of quality comparable with these machined with specialised equipment
Exogenous lipoid pneumonia (oil granulomas of the lung)
The authors observed three cases of exogenous lipid pneumonia clinically suspected
of lung carcinoma. Histological examination of material after thoracotomy gave
the possibility of correct diagnosis. The lesions in lungs were characteristic granulomas
around lipid material and with surrounding advanced fibrosis
Iatrogenic injuries to the trachea and main bronchi
INTRODUCTION: Iatrogenic tracheobronchial injuries are rare. AIM: To analyse the mechanism of injury, symptoms and treatment of these patients. MATERIAL AND METHODS: Retrospective analysis of hospital records of all patients treated for main airway injuries between 1990 and 2012 was performed. RESULTS: There were 24 patients, including 21 women and 3 men. Mean time between injury and initiation of treatment was 12 hours (range: 2-48). In 16 patients the injury occurred during tracheal intubation, in 1 during rigid bronchoscopy, in 1 during rigid oesophagoscopy, in 1 during mediastinoscopy and in 5 during open surgery. Mean length of airway tear was 3.8 cm (range: 1.5-8). In 1 patient there was an injury to the cervical trachea and in the remaining 23 in the thoracic part of the airway. The treatment included repair of the membranous part of the trachea performed via right thoracotomy in 10 patients (in 1 patient additionally coverage with a pedicled intercostal muscle flap was used), a self-expanding metallic stent in 1 patient, suture of the right main bronchus and the oesophagus in 1, left upper sleeve lobectomy in 1, right upper lobectomy in 1, implantation of a silicone Y stent in 3, mini-tracheostomy in 1, and conservative treatment in 5 patients. CONCLUSIONS: Intubation is the most frequent cause of iatrogenic main airway injuries. Patients with these life-threatening complications require an individualised approach and treatment in a reference centre
Rotational speed control of multirotor UAV's propulsion unit based on fractional-order PI controller
In this paper the synthesis of a rotational speed
closed-loop control system based on a fractional-order
proportional-integral (FOPI) controller is presented. In particular,
it is proposed the use of the SCoMR-FOPI procedure as the
controller tuning method for an unmanned aerial vehicle’s
propulsion unit. In this framework, both the Hermite-Biehler
and Pontryagin theorems are used to predefine a stability region
for the controller. Several simulations were conducted in order to
try to answer the questions – is the FOPI controller good enough
to be an alternative to more complex FOPID controllers? In what
circumstances can it be advantageous over the ubiquitous PID?
How robust this fractional-order controller is regarding the parametric uncertainty of considered propulsion unit model?info:eu-repo/semantics/publishedVersio
Endosonography-guided fine needle aspiration in the diagnosis of sarcoidosis : a randomized study
There are no widely accepted standards for the diagnosis of sarcoidosis. The aim of this study was to assess the relative diagnostic yield of endobronchial ultrasound
fine-needle aspiration (EBUS‑FNA)
and endoscopic ultrasound fine-needle aspiration (EUS‑FNA),
and to
compare them with standard diagnostic techniques such as endobronchial biopsy (EBB), transbronchial
lung biopsy (TBLB), transbronchial needle aspiration (TBNA), and mediastinoscopy. This was a prospective randomized study including consecutive patients with
clinical diagnosis of stage I or II sarcoidosis. EBB, TBLB, and TBNA were performed at baseline in all
patients. Subsequently, patients were randomized to group A (EBUS‑FNA)
or group B (EUS‑FNA).
Next,
a crossover control test was performed: all patients with negative results in group A underwent EUS‑FNA
and all patients with negative results in group B underwent EBUS‑FNA.
If sarcoidosis was not confirmed,
mediastinoscopy was performed. We enrolled 106 patients, of whom 100 were available for the final analysis. The overall
sensitivity and accuracy of standard endoscopic methods were 64% each. When analyzing each of
the standard endoscopic methods separately, the diagnosis was confirmed with EBB in 12 patients
(12%), with TBLB in 42 patients (42%), and with TBNA in 44 patients (44%). The sensitivity and accuracy
of each endosonographic technique were significantly higher than those of EBB+TBLB+TBNA
(P = 0.0112 vs P = 0.0134). The sensitivity and accuracy of EBUS‑FNA
and EUS‑FNA
are significantly higher than
those of standard endoscopic methods. Moreover, the sensitivity and accuracy of EUS‑FNA
tend to be
higher than those of EBUS‑FNA
PySDM v1 : particle-based cloud modeling package for warm-rain microphysics and aqueous chemistry
PySDM is an open-source Python package for simulating the dynamics of
particles undergoing condensational and collisional growth, interacting with a
fluid flow and subject to chemical composition changes. It is intended to serve
as a building block for process-level as well as computational-fluid-dynamics
simulation systems involving representation of a continuous phase (air) and a
dispersed phase (aerosol), with PySDM being responsible for representation of
the dispersed phase. The PySDM package core is a Pythonic high-performance
implementation of the Super-Droplet Method (SDM) Monte-Carlo algorithm for
representing collisional growth, hence the name. PySDM has two alternative
parallel number-crunching backends available: multi-threaded CPU backend based
on Numba and GPU-resident backend built on top of ThrustRTC. The usage examples
are built on top of four simple atmospheric cloud modelling frameworks: box,
adiabatic parcel, single-column and 2D prescribed flow kinematic models. In
addition, the package ships with tutorial code depicting how PySDM can be used
from Julia and Matlab
Naturalne promieniowanie gamma na poziomie morza wokół kontynentu antarktycznego zarejestrowane na południe od równoleżnika 62°
This study presents the results of dosimetry radiation measurement performed in the Antarctic region at the surface of the sea which was conducted between January and March 2018. Over 2 200 records were collected using a portable Gamma Scout Online radiometer during a 72-day voyage circumnavigating the continent of Antarctica. The mean average of the measured radiation dose rate was 0.091 μSvh-1 and varied from 0.052 to 0.193 μSvh-1. These result are above global average dose rate of radiation at sea level (0.031 μSvh-1) and often higher than those recorded on the Antarctic continent. Yet generally our records fall within well recognized latitudinal trend of radiation being higher toward poles. This is results of troposphere begins at lower altitude in Antarctic in comparison to lower latitudes. The origin of this radiation is natural and results from the presence of higher cosmic rays and secondary radiation induced in the atmosphere. The presence of terrestrial radionuclides in the Antarctic environment has a local, secondary influence on the measured values of radiation. The theoretical calculated annual dose equivalent for humans present in Antarctica could often exceed the limit of 1 mSv as recorded for other Antarctic locations yet our results (0.772 mSv per year) do not confirm that.W pracy przedstawiono wyniki dozymetrycznych pomiarów promieniowania, przeprowadzonych przez załogę jachtu Katharsis II, w trakcie 72-dniowego rejsu wokół Antarktydy. Podczas rejsu trwającego od stycznia do marca 2018 roku, za pomocą przenośnego radiometru Gamma Scout Online rejestrowano dawki promieniowania na poziomie morza w odstępach 10-minutowych. Po wstępnej analizie statystycznej uzyskano dane w postaci 2 200 rekordów, które wykorzystano do wnioskowania o rozkładzie promieniowania w rejonie Antarktyki. Średnia zmierzona moc dawki promieniowania wyniosła 0,091 μSvh-1 i wahała się od 0,052 do 0,193 μSvh-1. Wyniki te są powyżej średniej globalnej mocy dawki promieniowania na poziomie morza (0,031 μSvh-1) i często wyższe niż te zarejestrowane bezpośrednio na Antarktydzie. Jednak, generalnie zarejestrowane przez nas dawki promieniowania mieszczą się w dobrze rozpoznanym równoleżnikowym trendzie, w którym promieniowanie jest wyższe w kierunku biegunów. Związane jest to z cieńszą warstwą troposfery w rejonach biegunowych w porównaniu z niższymi, równikowymi szerokościami geograficznymi. Ogólnie pochodzenie tego promieniowania jest naturalne i związane z silniejszą penetracją troposfery przez promieniowanie kosmiczne oraz obecnością promieniowania wtórnego indukowanego w atmosferze. Obecność radionuklidów naziemnych w środowisku Antarktyki ma lokalny, wtórny wpływ na mierzone wartości promieniowania. Teoretycznie obliczony roczny ekwiwalent dawki dla ludzi, w różnych miejscach Antarktydy, może przekraczać limit 1 mSv, natomiast nasze wyniki (0,772 mSv rocznie) tego nie potwierdzają
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries