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2021 ◽  
Author(s):  
Uchechukwu Madukaku Chukwuocha ◽  
Joshua Chisom Ogboeze ◽  
Ayoola Oluwaseun Bosede ◽  
Lilian Anulike Oduenyi ◽  
Amarachukwu Blessing Chukwujekwu ◽  
...  

Abstract Background The use of facemask for the control of the spread of COVID-19 virus among the population has been recommended by the health authorities. This observational study was carried out to assess the use of facemask in Southeastern Nigeria. Methods Using a two-stage sampling technique, a total of 3100 participants were observed from both rural and urban settings. Frequency distribution tables were used to categories and describe the observed variables, Chi-square (X2) test was used to check for the association between categorical variables. Results Among the observed participants, 46.4% made use of facemask. The most common facemask used was cloth mask (28.6%). About 16.0% of the participants correctly used their facemasks. The highest usage was observed in the urban location (49.2%). A statistically significant association was found between facemask usage and study location (p < 0.001), also between the appropriateness of usage and age category (p < 0.001). Conclusions The observed rate of mask usage may not be able to protect the population against the spread of COVID-19, therefore adequate sensitization on the need for proper use of face masks by the public should be prioritized.


2021 ◽  
Author(s):  
Mi Wang ◽  
Xiangfeng Chen ◽  
Umar Khan ◽  
Wim Bogaerts

Abstract We propose a novel filter circuit that incorporates a double ring resonator with a balanced Mach-Zehnder interferometer (MZI).The circuit has a response equivalent to a conventional ring loaded MZI filter, but with added flexibility in terms of configurability. The second-order filter can also be cascaded to realize higher-order filters. The circuit incorporates a two-stage input and output coupler to further reduce the effect of dispersion. A combination of local and global optimization strategies to program the filter, using tailored objective functions, have been tested in simulation and experiments. To our best knowledge, this is the first time a global optimization strategy is directly used in ARMA filter synthesis and simulation without any additional requirement. We further extend the optimization strategy into experiments and demonstrated its use in practical case for programmable filter circuits.


Author(s):  
A. V. Syrkina ◽  
I. E. Pashkova ◽  
A. R. Monakhov ◽  
O. V. Silina ◽  
E. V. Chekletsova ◽  
...  

Background. In young children, the most common liver disease leading to transplantation is biliary atresia. Liver transplantation has fundamentally improved the survival rate of children with biliary atresia. Studies on developmental outcomes in children are mostly limited to small samples; there are no such studies in the Russian Federation.Objective: to determine the cognitive outcomes in children undergoing one-stage or two-stage surgical treatment of biliary atresia.Materials and Methods. 83 children were divided into groups: 36 children underwent transplantation without previous surgical interventions (group 1), 47 children underwent the Kasai palliative portoenterostomy (group 2). Inclusion criteria: 24 months of age or younger at the moment of transplantation, no medical history of neurological pathology. All children were examined before transplantation and at 1, 3, 6 and 12 months after liver transplantation. Psychomotor development was assessed using the Griffiths Psychomotor Development Scale for children under 24 months (translated by E.S. Keshishian), the Griffiths Intellectual Development Scale for children aged 2 to 8 years, and the Modified Checklist for Autism in Toddlers, Revised, for children 16-30 months old.Results. All children had developmental delays at the time of transplantation. Up to 50% of the children had signs of cachexia, with a shoulder circumference of less than 3 percentile. Only two children showed obvious hepatic encephalopathy in the form of depressed consciousness. After liver transplantation, 94% of group 1 children recovered their preoperative psychomotor development levels, and only 68% in group 2 made these gains. At 3 and 6 months after transplantation, about 80% of group 1 children showed normal psychomotor development, whereas in group 2, only 61% did. By 12 months after liver transplantation, the difference between the groups was more evident: 83.3% of group 1 children and only 53.2% of group 2 children were developing according to age. The difference between the groups was statistically significant (p < 0.05).Conclusion. Children who received one-stage treatment of biliary atresia and underwent liver transplantation have better neuropsychological development within a year after surgery than children with two-stage surgical treatment.


2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Sarah N. Ur ◽  
Kevin D. Corbett

The specialized two-stage meiotic cell division program halves a cell's chromosome complement in preparation for sexual reproduction. This reduction in ploidy requires that in meiotic prophase, each pair of homologous chromosomes (homologs) identify one another and form physical links through DNA recombination. Here, we review recent advances in understanding the complex morphological changes that chromosomes undergo during meiotic prophase to promote homolog identification and crossing over. We focus on the structural maintenance of chromosomes (SMC) family cohesin complexes and the meiotic chromosome axis, which together organize chromosomes and promote recombination. We then discuss the architecture and dynamics of the conserved synaptonemal complex (SC), which assembles between homologs and mediates local and global feedback to ensure high fidelity in meiotic recombination. Finally, we discuss exciting new advances, including mechanisms for boosting recombination on particular chromosomes or chromosomal domains and the implications of a new liquid crystal model for SC assembly and structure. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 18 (3) ◽  
pp. 6-18
Author(s):  
M. V. Mikhaylovskiy ◽  
V. L. Lukinov

Objective. To perform multivariate comparison of two surgical strategies in the treatment of patients with severe Scheuermann’s disease.Material and Methods. The search of sources (in Scopus and Web of Science databases) revealed  56 publications containing the required information. The literature data were analyzed in four directions: the results of one- and two-stage interventions are compared in terms of the magnitude of achieved correction and its preservation, the complication rate, the surgery duration and the volume of intraoperative blood loss, and the quality of life of patients in the postoperative period.Results. The magnitude of the achieved correction of kyphotic deformity and postoperative loss of correction in patients after one- and two-stage operations are almost identical. Implant-associated complications are more often observed after one-stage operations, and purulent, neurological and other complications – after two-stage operations. Surgery duration and intraoperative blood loss volume are greater in two-stage operations. The quality of life assessed by various questionnaires is significantly improved, regardless of the type of surgery.Conclusion. Two-stage surgical correction of Scheuermann’s kyphosis has no noticeable advantages over one-stage surgery, however, new studies with long (more than 15–18 years) postoperative follow-up are needed.


2021 ◽  
Vol 13 (18) ◽  
pp. 3689
Author(s):  
Yingjun Li ◽  
Wenpeng Zhang ◽  
Biao Tian ◽  
Wenhao Lin ◽  
Yongxiang Liu

RCS reconstruction is an important way to reduce the measurement time in anechoic chambers and expand the radar original data, which can solve the problems of data scarcity and a high measurement cost. The greedy pursuit, convex relaxation, and sparse Bayesian learning-based sparse recovery methods can be used for parameter estimation. However, these sparse recovery methods either have problems in solving accuracy or selecting auxiliary parameters, or need to determine the probability distribution of noise in advance. To solve these problems, a non-parametric Sparse Iterative Covariance Estimation (SPICE) algorithm with global convergence property based on the sparse Geometrical Theory of Diffraction (GTD) model (GTD–SPICE) is employed for the first time for RCS reconstruction. Furthermore, an improved coarse-to-fine two-stage SPICE method (DE–GTD–SPICE) based on the Damped Exponential (DE) model and the GTD model (DE–GTD) is proposed to reduce the computational cost. Experimental results show that both the GTD–SPICE method and the DE–GTD–SPICE method are reliable and effective for RCS reconstruction. Specifically, the DE–GTD–SPICE method has a shorter computational time.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anna Dębicka ◽  
Karolina Olejniczak ◽  
Joanna Skąpska

PurposeAs a new concept for humane entrepreneurship (HumEnt) evolves, many new research questions arise. At the exploratory stage, the authors found it relevant to examine and discuss the perception of the fundamental assumptions of the HumEnt concept and activities undertaken in this area by business practice.Design/methodology/approachTo thoroughly understand the studied phenomenon, a combination of quantitative and qualitative methods was used. An exploratory survey was obtained from 126 purposefully selected enterprises in Poland; then, a single case study was analysed.FindingsThe conducted analysis showed differences between the activities of enterprises and the perception of the HumEnt concept among employees that are especially noticeable at different levels of the management hierarchy.Research limitations/implicationsThe multifaceted nature of the results obtained is limited by the inability to infer international differences, to capture trends over time and to generalise to the total population of enterprises.Practical implicationsAlthough the surveyed companies recognise the importance of the HumEnt concept, it is not tantamount to its execution. The research results may be valuable, especially for smaller enterprises, where the business practice may require support in applying the HumEnt approach.Originality/valueThe research explored both the actual state confirmed by the actions taken and the perception of the importance of individual elements of HumEnt. A knowing–doing gap has been demonstrated between these planes. Moreover, thanks to a two-stage study, practices were selected that can be successfully implemented also in small and medium-sized enterprises.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Katrin Osmanski-Zenk ◽  
Annett Klinder ◽  
Christina Rimke ◽  
Dieter C. Wirtz ◽  
Christoph H. Lohmann ◽  
...  

Abstract Background There are different procedures for both, the diagnosis and the therapy of a periprosthetic joint infection (PJI), however, national or international guidelines for a standardised treatment regime are still lacking. The present paper evaluates the use of the predominant treatment protocols for PJI in certified total joint replacement centres (EPZ) in Germany based on an EndoCert questionnaire. Materials and methods The questionnaire was developed in cooperation with the EndoCert Certification Commission to survey the treatment protocols for septic revision arthroplasties in EPZ. Questions targeted the various treatment options including prosthesis preserving procedures (DAIR - Debridement, antibiotics, irrigation, and retention of the prosthesis), one-stage revision, two-stage revision, removal of the endoprosthesis and diagnostic sampling prior to re-implantation. All certified EPZ participated (n = 504) and the results from the current survey in 2020 were compared to data from a previous analysis in 2015. Results The number of centres that performed DAIR up to a maximum of 4 weeks and more than 10 weeks after index surgery decreased since 2015, while the number of centres that provided a one-stage revision as a treatment option increased (hip: + 6.3%; knee: + 6.6%). The majority of the centres (73.2%) indicated a 4–8 week period as the preferred interval between prosthesis removal and re-implantation in two-stage revision in hip as well as knee revisions. Centres with a higher number of revision surgeries (> 200 revisions/year), opted even more often for the 4–8 week period (92.3%). In two-stage revision the use of metal-based spacers with/without reinforcement with antibiotic-containing cement as an interim placeholder was significantly reduced in 2020 compared to 2015. There was also a clear preference for cemented anchoring in two-stage revision arthroplasty in the knee in 2020, whereas the majority of hip replacements was cementless. Additionally, in 2020 the number of samples for microbiological testing during the removal of the infected endoprosthesis increased and 72% of the centres took five or more samples. Overall, the number of EPZ with a standardised protocol for the procedure expanded from 2015 to 2020. Conclusion While there was a trend towards standardised therapeutic algorithms for PJI with more uniform choices among the centres in 2020 compared to 2015, the treatment often remains an individual decision. However, since a consistent treatment regime is of vital importance with an expected rise of total numbers of revision arthroplasties, uniform definitions with regard to comparability and standardisation are necessary for the further development of the EndoCert system.


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