375 research outputs found
Modern scientific and practical approaches to the production of substrates from semiconductor compounds А3В5. Review
Modern electronic and optical engineering uses А3В5 single-crystal semiconductor materials (GaAs, GaSb, InAs, InSb, and InP) as substrates for epitaxial growth. These materials are obtained in the form of massive single-crystal ingots. Therefore, technologies for processing of these A3B5 wafers are developed to produce the substrates for epitaxial growth. The miniaturization of modern systems and devices demands the high quality of the substrates surface. One of the main criteria is a low surface roughness (Ra) (of about 0.5 nm). To meet this requirement, it is necessary to elaborate the existing methods of surface treatment.
The review analyses the current approaches to the treatment of the surface of semiconductor wafers of А3В5 single-crystal materials. It considers the specifics of wafers machining followed by their polishing. The article also presents an analysis of the polishing methods. It reveals that at the moment the chemical-mechanical polishing of А3В5 wafers is the most commonly used method. The review presents the main parameters of this process and systematizes the existing theoretical approaches. The analysis determined the key tendencies in the development of chemical-mechanical polishing of semiconductor А3В5 wafers aimed at increasing the quality of wafers. The article also analyses the latest studies regarding the methods of chemical polishing as an alternative to chemical-mechanical polishing. The next section focuses on surface
passivation methods used upon obtaining wafers with a low roughness. Passivation is performed to reduce the reactivity of the surface and stabilize surface states of wafers.
A classification of passivation methods is suggested based on the obtained chemical composition of the surface, when the passivation layers are created using oxidation, sulfidizing, or nitriding. Another classification is based on the method of creating passivating coatings and includes wet chemical methods and physico-chemical method
Oxidation of olefins with H<sub>2</sub>O<sub>2</sub> catalyzed by gallium(III) nitrate and aluminum(III) nitrate in solution
Soluble gallium and aluminum nitrates (simple salts of non-transition metals) are good catalysts for the epoxidation of olefins (cyclooctene, dec-1-ene) including terpenes (carvone, limonene) with hydrogen peroxide in ethyl acetate or tetrahydrofurane (THF). Typically, the gallium salt is more efficient in comparison with the aluminum derivative. Products are formed in yields up to 93%, turnover numbers (TONs) attained 40. Addition of trifluoroacetic acid or pyrazine-2-carboxylic acid (PCA) accelerates the reaction and improves the yield. In striking contrast, added 2,2′-bipyridine or phenanthroline dramatically inhibit the oxidation
Disorders in the System of Mineral and Bone Metabolism Regulators—FGF-23, Klotho and Sclerostin—in Chronic Kidney Disease: Clinical Significance and Possibilities for Correction
The chapter discusses the current understanding of the system of mineral and bone metabolism regulators—FGF-23, Klotho and sclerostin—disturbances in chronic kidney disease (CKD). In the chapter we presented the date, including our own results, which allow to suggest the change in the ratio of FGF-23-Klotho-sclerostin in CKD as an early biomarker not only for the chronic kidney damage but also for high cardiovascular (CV) risk. Results of studies show that disorders in FGF-23-Klotho-sclerostin ratio correlate with the frequency and severity of hypertension, vascular calcification, cardiac remodelling, anaemia, malnutrition, inflammation and strong aggravate CV risk in CKD. It was found independent from blood pressure (BP) action of increased serum FGF-23 on the myocardium as well as the correlation of serum high-sensitive troponin I with increased serum FGF-23 and low Klotho levels in CKD patients. At the same time, it was shown that renoprotective therapy, including renin-angiotensin blockers, low-protein diet with amino/keto acid supplementation and phosphate binders, erythropoiesis stimulators, vitamin D metabolites used to get the target levels of BP, serum phosphorus, haemoglobin, parathyroid hormone and nutritional status disorders correction can reduce the risk of CV events, as the major cause of death in CKD patients
High Catalytic Activity of Heterometallic (Fe6Na7 and Fe6Na6) Cage Silsesquioxanes in Oxidations with Peroxides
International audienceTwo types of heterometallic (Fe(III),Na) silsesquioxanes—[Ph5Si5O10]2[Ph10Si10O21]Fe6(O2‒)2Na7(H3O+)(MeOH)2(MeCN)4.5.1.25(MeCN), I, and [Ph5Si5O10]2[Ph4Si4O8]2Fe6Na6(O2‒)3(MeCN)8.5(H2O)8.44, II—were obtained and characterized. X-ray studies established distinctive structures of both products, with pair of Fe(III)-O-based triangles surrounded by siloxanolate ligands, giving fascinating cage architectures. Complex II proved to be catalytically active in the formation of amides from alcohols and amines, and thus becoming a rare example of metallasilsesquioxanes performing homogeneous catalysis. Benzene, cyclohexane, and other alkanes, as well as alcohols, can be oxidized in acetonitrile solution to phenol—the corresponding alkyl hydroperoxides and ketones, respectively—by hydrogen peroxide in air in the presence of catalytic amounts of complex II and trifluoroacetic acid. Thus, the cyclohexane oxidation at 20 °C gave oxygenates in very high yield of alkanes (48% based on alkane). The kinetic behaviour of the system indicates that the mechanism includes the formation of hydroxyl radicals generated from hydrogen peroxide in its interaction with di-iron species. The latter are formed via monomerization of starting hexairon complex with further dimerization of the monomer
Nutritional Status Disorders in Chronic Kidney Disease: Practical Aspects (Systematic Review)
Despite the significant achievements in the management of chronic kidney disease (CKD) patients, the mortality rate of these patients still remains high. Nutritional status disorders (NSD) are considered now as one of the prognostic risk factors not only for dialysis but also for predialysis CKD stages. Since the publication of KDIGO 2012 guidelines for CKD patient’s management, there has been some significant advancement in our understanding of main NSD mechanisms in CKD, including different nosological group patients (first, in diabetic and systemic diseases patients). At the same time, there is still an urgent need for randomized trials for better-informed decisions and future optimization of CKD patients’ care. This chapter provides the current data on all aspects of NSD in CKD: etiology, diagnosis, prevention, and treatment approaches, as well as on risk factors of NSD at predialysis stages and in chronic hemodialysis patients. Considerable attention was devoted to the diagnosis and differential diagnosis of NSD in CKD patients. It was determined that the overall strategy for dietary treatment contributed to improving the life quality of patients and slowing down of CKD progression. The review is written based on the published results of clinical studies performed on the position of evidence-based medicine
Синтез та оптимізація нечітких регуляторів у системах керування піролізними реакторами
Козлов, О. В. Синтез та оптимізація нечітких регуляторів у системах керування піролізними реакторами = Synthesis and optimization of fuzzy controllers in the control systems of pyrolysis reactors / О. В. Козлов, Г. В. Кондратенко, Ю. П. Кондратенко // Зб. наук. пр. НУК. – Миколаїв : НУК, 2017. – № 4 (471). – С. 25–36.Анотація. Запропоновано комплексну методику синтезу та оптимізації нечітких регуляторів (НР) типу Мамдані для систем автоматичного керування (САК) температурними режимами реакторів спеціалізованих піролізних комплексів (СПК). Для дослідження ефективності розробленої методики проведено проектування НР для САК температурою реактора експериментального СПК. Доведено, що застосування створених на основі представленої методики НР в САК температурними режимами піролізних реакторів СПК дозволяє забезпечувати достатньо високі показники якості керування за їхньої відносно нескладної програмно-апаратної реалізації.Abstract. The article presents a development of the complex methodology of synthesis and optimization of Mamdani fuzzy controllers (FC) for automatic control systems (ACS) for temperature modes of the reactors of specialized pyrolysis complexes (SPC). The proposed complex methodology allows performing preliminary synthesis of the structure and parameters of the Mamdani FCs for the ACSs regulating the temperature modes of the SPC reactors on the basis of expert evaluations, as well as further sequential procedures for optimizing the parameters and rule-base structure of the given FCs with mathematical programming methods. To study the effectiveness of the developed methodology, this paper considers the design of the FC for the ACS of the temperature of the experimental SPC reactor. Application of the FCs developed on the basis of the given methodology in the ACSs under study allows providing sufficient level of control indicators when using relatively simple hardware and software.Аннотация. Предложена комплексная методика синтеза и оптимизации нечетких регуляторов (НР) типа Мамдани для систем автоматического управления (САУ) температурными режимами реакторов специализированных пиролизных комплексов (СПК). Для исследования эффективности разработанной методики проведено проектирование НР для САУ температурой реактора экспериментального СПК. Доказано, что применение созданных на основе данной методики НР в САУ температурными режимами пиролизных реакторов СПК позволяет обеспечивать достаточно высокие показатели качества управления при относительно несложной их программно-аппаратной реализации
Anemia in Chronic Kidney Disease and After Kidney Allotransplantation (Systematic Review)
Anemia in chronic kidney disease (CKD) has been recognized as a separate independent risk factor of cardiovascular (CV) events. The aim of the review is to provide a literature summary concerning early diagnosis and treatment of anemia in CKD that may be useful for clinicians and contribute to decrease CV mortality. Literature searches were made in such major databases as: PubMed, Medline, Embase, Cochrane Library, CINAHL, Wiley Online Library, Scopus, Web of Science, e-library, and website of WHO. This search encompassed original articles, systematic reviews, and meta-analyses relevant to CKD and anemia over recent 15 years. A total of 54 references from 562 reviewed articles were selected as they met to the search criteria (anemia and CKD, including diabetes mellitus, systemic diseases and post-transplant anemia). The publications included 27 randomized controlled trials, 20 experimental studies representing new data on the links of CKD anemia and cardiovascular risk markers (cytokines, Klotho, fibroblast growth factor (FGF-23), hyperglycemia, hypoalbuminemia and some others), 4 systematic reviews and 3 clinical practice guidelines. The main attention was devoted to the analysis of the studies provided an early diagnosis of anemia, an ability to minimize the factors contributing to its severity that have allowed to improve CV and total outcomes and to reduce costs of hospital treatment of CKD patients with anemia
Multiple Myeloma Treatment in Real-world Clinical Practice : Results of a Prospective, Multinational, Noninterventional Study
Funding Information: The authors would like to thank all patients and their families and all the EMMOS investigators for their valuable contributions to the study. The authors would like to acknowledge Robert Olie for his significant contribution to the EMMOS study. Writing support during the development of our report was provided by Laura Mulcahy and Catherine Crookes of FireKite, an Ashfield company, a part of UDG Healthcare plc, which was funded by Millennium Pharmaceuticals, Inc, and Janssen Global Services, LLC. The EMMOS study was supported by research funding from Janssen Pharmaceutical NV and Millennium Pharmaceuticals, Inc. Funding Information: The authors would like to thank all patients and their families and all the EMMOS investigators for their valuable contributions to the study. The authors would like to acknowledge Robert Olie for his significant contribution to the EMMOS study. Writing support during the development of our report was provided by Laura Mulcahy and Catherine Crookes of FireKite, an Ashfield company, a part of UDG Healthcare plc, which was funded by Millennium Pharmaceuticals, Inc, and Janssen Global Services, LLC. The EMMOS study was supported by research funding from Janssen Pharmaceutical NV and Millennium Pharmaceuticals, Inc. Funding Information: M.M. has received personal fees from Janssen, Celgene, Amgen, Bristol-Myers Squibb, Sanofi, Novartis, and Takeda and grants from Janssen and Sanofi during the conduct of the study. E.T. has received grants from Janssen and personal fees from Janssen and Takeda during the conduct of the study, and grants from Amgen, Celgene/Genesis, personal fees from Amgen, Celgene/Genesis, Bristol-Myers Squibb, Novartis, and Glaxo-Smith Kline outside the submitted work. M.V.M. has received personal fees from Janssen, Celgene, Amgen, and Takeda outside the submitted work. M.C. reports honoraria from Janssen, outside the submitted work. M. B. reports grants from Janssen Cilag during the conduct of the study. M.D. has received honoraria for participation on advisory boards for Janssen, Celgene, Takeda, Amgen, and Novartis. H.S. has received honoraria from Janssen-Cilag, Celgene, Amgen, Bristol-Myers Squibb, Novartis, and Takeda outside the submitted work. V.P. reports personal fees from Janssen during the conduct of the study and grants, personal fees, and nonfinancial support from Amgen, grants and personal fees from Sanofi, and personal fees from Takeda outside the submitted work. W.W. has received personal fees and grants from Amgen, Celgene, Novartis, Roche, Takeda, Gilead, and Janssen and nonfinancial support from Roche outside the submitted work. J.S. reports grants and nonfinancial support from Janssen Pharmaceutical during the conduct of the study. V.L. reports funding from Janssen Global Services LLC during the conduct of the study and study support from Janssen-Cilag and Pharmion outside the submitted work. A.P. reports employment and shareholding of Janssen (Johnson & Johnson) during the conduct of the study. C.C. reports employment at Janssen-Cilag during the conduct of the study. C.F. reports employment at Janssen Research and Development during the conduct of the study. F.T.B. reports employment at Janssen-Cilag during the conduct of the study. The remaining authors have stated that they have no conflicts of interest. Publisher Copyright: © 2018 The AuthorsMultiple myeloma (MM) remains an incurable disease, with little information available on its management in real-world clinical practice. The results of the present prospective, noninterventional observational study revealed great diversity in the treatment regimens used to treat MM. Our results also provide data to inform health economic, pharmacoepidemiologic, and outcomes research, providing a framework for the design of protocols to improve the outcomes of patients with MM. Background: The present prospective, multinational, noninterventional study aimed to document and describe real-world treatment regimens and disease progression in multiple myeloma (MM) patients. Patients and Methods: Adult patients initiating any new MM therapy from October 2010 to October 2012 were eligible. A multistage patient/site recruitment model was applied to minimize the selection bias; enrollment was stratified by country, region, and practice type. The patient medical and disease features, treatment history, and remission status were recorded at baseline, and prospective data on treatment, efficacy, and safety were collected electronically every 3 months. Results: A total of 2358 patients were enrolled. Of these patients, 775 and 1583 did and did not undergo stem cell transplantation (SCT) at any time during treatment, respectively. Of the patients in the SCT and non-SCT groups, 49%, 21%, 14%, and 15% and 57%, 20%, 12% and 10% were enrolled at treatment line 1, 2, 3, and ≥ 4, respectively. In the SCT and non-SCT groups, 45% and 54% of the patients had received bortezomib-based therapy without thalidomide/lenalidomide, 12% and 18% had received thalidomide/lenalidomide-based therapy without bortezomib, and 30% and 4% had received bortezomib plus thalidomide/lenalidomide-based therapy as frontline treatment, respectively. The corresponding proportions of SCT and non-SCT patients in lines 2, 3, and ≥ 4 were 45% and 37%, 30% and 37%, and 12% and 3%, 33% and 27%, 35% and 32%, and 8% and 2%, and 27% and 27%, 27% and 23%, and 6% and 4%, respectively. In the SCT and non-SCT patients, the overall response rate was 86% to 97% and 64% to 85% in line 1, 74% to 78% and 59% to 68% in line 2, 55% to 83% and 48% to 60% in line 3, and 49% to 65% and 36% and 45% in line 4, respectively, for regimens that included bortezomib and/or thalidomide/lenalidomide. Conclusion: The results of our prospective study have revealed great diversity in the treatment regimens used to manage MM in real-life practice. This diversity was linked to factors such as novel agent accessibility and evolving treatment recommendations. Our results provide insight into associated clinical benefits.publishersversionPeer reviewe
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