003. NU Research Institutes & Centres
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Item Open Access A simple approach to synthesize novel sulfur/graphene oxide/multiwalled carbon nanotube composite cathode for high performance lithium/sulfur batteries(Ionics. Springer-Verlag Berlin Heidelberg 2016, 2016-04-30) Yuan, Guanghui; Zhao, Yan; Jin, Huafeng; Bakenov, ZhumabayA sulfur/graphene oxide/multiwalled carbon nanotube (S/GO/MWNT) composite was synthesized via a simple ultrasonic mixing method followed by heat treatment. By taking advantage of this solution-based self-assembly synthesis route, poisonous and noxious reagents and complicated fabrication processes are rendered unnecessary, thereby simplifying its manufacturing and decreasing the cost of the final product. Transmission and scanning electronic microscopy observations indicated the formation of the threedimensional interconnected S/GO/MWNTcomposite through the environmentally friendly process...Item Open Access Air Pollution in Kazakhstan and Its Health Risk Assessment(Ubiquity Press, 2019-11-08) Saliev, Timur; Kenessary, D; Kenessary, A; Adilgereiuly, Z; Akzholova, N; Erzhanova, A; Dosmukhametov, A; Syzdykov, D; Masoud, Abdul-Razakir pollution in Kazakhstan is caused by many factors and poses serious threats to public health. Ambient air in the cities of Kazakhstan is polluted due to mining and processing of mineral resources, oil and gas production, gasoline and diesel fuel motor vehicles, industrial enterprises.Item Open Access ANALYSIS OF BACTEROIDES FRAGILIS CLINICAL STRAINS ISOLATED IN KAZAKHSTAN(Microbiology Resource Announcements, 2021-02-04) Zholdybayeva, Elena V.; Kozhahmetova, Saniya; Tarlykov, Pavel; Atavliyeva, Sabina; Mukhtarova, Kymbat; Syzdykov, Tleuli; Khasenov, Ruslan; Shevtsov, Alexsandr; Amirgazin, Asylulan; Daniyarov, Asset; Ramankulov, YerlanOur aim was to study the nucleotide sequences of 9 previously undescribed strains of B. fragilis collected from patients with intra-abdominal diseases at city hospitals in Nur-Sultan, Kazakhstan.Item Open Access Assessing reproducibility of matrix factorization methods in independent transcriptomes(OXFORD UNIV PRESS, 2019) Cantini, Laura; Kairov, Ulykbek; de Reynies, Aurelien; Barillot, Emmanuel; Radvanyi, Francois; Zinovyev, AndreiMotivation Matrix factorization (MF) methods are widely used in order to reduce dimensionality of transcriptomic datasets to the action of few hidden factors (metagenes). MF algorithms have never been compared based on the between-datasets reproducibility of their outputs in similar independent datasets. Lack of this knowledge might have a crucial impact when generalizing the predictions made in a study to others. Results We systematically test widely used MF methods on several transcriptomic datasets collected from the same cancer type (14 colorectal, 8 breast and 4 ovarian cancer transcriptomic datasets). Inspired by concepts of evolutionary bioinformatics, we design a novel framework based on Reciprocally Best Hit (RBH) graphs in order to benchmark the MF methods for their ability to produce generalizable components. We show that a particular protocol of application of independent component analysis (ICA), accompanied by a stabilization procedure, leads to a significant increase in the between-datasets reproducibility. Moreover, we show that the signals detected through this method are systematically more interpretable than those of other standard methods. We developed a user-friendly tool for performing the Stabilized ICA-based RBH meta-analysis. We apply this methodology to the study of colorectal cancer (CRC) for which 14 independent transcriptomic datasets can be collected. The resulting RBH graph maps the landscape of interconnected factors associated to biological processes or to technological artifacts. These factors can be used as clinical biomarkers or robust and tumor-type specific transcriptomic signatures of tumoral cells or tumoral microenvironment. Their intensities in different samples shed light on the mechanistic basis of CRC molecular subtyping. Availability and implementation The RBH construction tool is available from http://goo.gl/DzpwYp Supplementary information Supplementary data are available at Bioinformatics online.Item Open Access ASSESSMENT OF BIOCLIMATIC CHANGE IN KAZAKHSTAN, END 20TH-MIDDLE 21ST CENTURIES, ACCORDING TO THE PRECIS PREDICTION(Public Library of Science, 2020-10-02) Lopez Fernandez, Maria Luisa; Zhumabayev, Dauren; Marco Garcia, Ricardo; Baigarin, Kanat; Lopez Fernandez, Maria Soledad; Baisholanov, SakenWe evaluate bioclimatic changes in Kazakhstan from the end of the 20th century until the middle of the 21st century to offer natural resource managers a tool that facilitates their decision-making on measures to adapt agriculture and environmental care to foreseeable climate change. We use climatic data from the “Providing REgional Climates for Impact Studies” (PRECIS) prediction and study them following the Worldwide Bioclimatic Classification System (WBCS) of Rivas-Martínez. For three 25-year intervals (1980–2004, 2010–2034 and 2035–2059), we identify the continentality, macrobioclimates, bioclimates, bioclimatic variants, thermotypes, ombrotypes and isobioclimates of the study area. The results of the work allow us to: locate the territories where bioclimatic conditions will change, quantify the magnitude of the predicted climate changes, and determine the trends of predictable climate change. We present the results in maps, tables and graphs. For the 80-year interval, we identify 3 macroclimates, 3 bioclimatic variants, 10 bioclimates, 11 thermotypes, 10 ombrotypes and 43 isobioclimates. Some of those found bioclimates, thermotypes, ombrotypes and isobioclimates are only located in the E, SE and S mountains, where they occupy very small areas, that decrease in a generalized way as the 20th century progresses. Comparing the three successive periods, the following trends are observed: 36.2% of the territory increases in thermicity; 7.3% of the territory increases in continentality; 9.7% of the territory increases in annual aridity; 9.5% of the territory increases in summer aridity or mediterraneity; and generalized losses occur in the areas of all mountain isobioclimates. The climate change foreseen by the PRECIS model for the middle of the 21st century leads to bioclimatic homogenization, with 20.8% losses in bioclimatic diversity. We indicate on maps the locations of all the predicted bioclimatic changes; these maps may provide decision makers with a scientific basis to take necessary adaptation measures.Item Open Access Atomic Force Microscopy Study of Cross-Sections of Perovskite Layers(EURASIAN CHEMICO-TECHNOLOGICAL JOURNAL, 2019) Migunov, D.; Eidelman, K.; Kozmin, A.; Saranin, D.; Ermanova, I.; Gudkov, D.; Alekseev, A.Improvement of methods for imaging of the volume structure of photoactive layers is one of the important directions towards development of highly efficient solar cells. In particular, volume structure of photoactive layer has critical influence on perovskite solar cell performance and life time. In this study, a perovskite photoactive layer cross-section was prepared by using Focused Ion Beam (FIB) and imaged by Atomic Force Microscopy (AFM) methods. The proposed approach allows using advances of AFM for imaging structure of perovskites in volume. Two different types of perovskite layers was investigated: FAPbBr(3) and MAPbBr(3). The heterogeneous structure inside film, which consist of large crystals penetrating the film as well as small particles with sizes of several tens nanometers, is typical for FAPbBr(3). The ordered nanocrystalline structure with nanocrystals oriented at 45 degree to film surface is observed in MAPbBr(3). An optimized sample preparation route, which includes FIB surface polishing by low energy Ga ions at the angles around 10 degree to surface plane, is described and optimal parameters of surface treatment are discussed. Use of AFM phase contrast method provides high contrast imaging of perovskite structure due to strong dependence of phase shift of oscillating probe on materials properties. The described method of imaging can be used for controllable tuning of perovskite structure by changes of the sample preparation routes....Item Open Access BIOMASS-DERIVED POROUS CARBON FROM AGAR AS AN ANODE MATERIAL FOR LITHIUM-ION BATTERIES(MDPI, 2021-12-22) Issatayev, Nurbolat; Kalimuldina, Gulnur; Nurpeissova, Arailym; Bakenov, ZhumabayNew porous activated carbons with a high surface area as an anode material for lithium-ion batteries (LIBs) were synthesized by a one-step, sustainable, and environmentally friendly method. Four chemical activators—H2SO4, H3PO4, KOH, and ZnCl2—have been investigated as facilitators of the formation of the porous structure of activated carbon (AC) from an agar precursor. The study of the materials by Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM) methods revealed its highly porous meso- and macro-structure. Among the used chemical activators, the AC prepared with the addition of KOH demonstrated the best electrochemical performance upon its reaction with lithium metal. The initial discharge capacity reached 931 mAh g−1 and a reversible capacity of 320 mAh g−1 was maintained over 100 cycles at 0.1 C. High rate cycling tests up to 10 C demonstrated stable cycling performance of the AC from agar.Item Open Access Calculation of Water Wheel Design Parameters for Micro Hydroelectric Power Station(EDP Sciences, 2019-05-29) Kodirov, Dilshod; Tursunov, OThis paper is devoted to the issues such as modelling the design parameters and operating modes and improving the design of micro hydroelectric power plants operating in low-pressure water flow. Taking into consideration above-mentioned issues, it is possible to increase the efficiency of using low-pressure water energy systems. The main dimensions of the water wheel of a micro hydropower plant depend on the water flow velocity v, water volume Q, acting at a fixed point in time on the water wheel blade, and also on the depth of the water level H.Item Metadata only Cardioprotective properties of polyphenol concentrate in Rat model of Doxorubicin-induced Cardiomyopathy(2015-08-01) Shulgau, Z.; Gulyayev, A.; Yermekbayeva, B.; Adilgozhina, G.; Tritek, V.; Nurgozhin, T.; Z., ShulgauPresent study aimed to investigate possible cardioprotective properties of polyphenol concentrates obtained from Cabernet Sauvignon type of Kazakhstani grapes using rat model doxorubicin-induced cardiomyopathy.Item Open Access Characterization of tar generated from the mixture of municipal solid waste and coal pyrolysis at 800 °C(Elsevier, 2020-03-02) Tursunov, O; Suleimenova, B; Kuspangaliyeva, Botagoz; Anthony, E.J.; Sarbassov, YerbolNowadays, comprehensive perception of the tar characteristics generated from municipal solid waste (MSW) and coal to guide pyrolysis or gasification gas yield upgrading and cleaning has attracted massive research attention. In this study, MSW and coal samples were chosen as principal components. The mixture of these products was pyrolyzed in a horizontal tube furnace at 800 °C with a heating rate of 20 °C/min. The tar derived from the pyrolysis of this mixture was further studied. Gas chromatography–mass spectrometry (GC–MS)coupled with a trace GC and a nuclear magnetic resonance (NMR) spectrometer was applied to investigate the tar composition and characterization along with their molecular chemical structures. 1H and 13C NMR spectra indicated that the functional groups of the tar derived from the mixture of MSW and coal were dominant at the resonances of 0.9–1.8 ppm, 1.5–2.6 ppm and 3.8–4.1 ppm for 1H, 10–40 ppm and 60–80 ppm for13C. The results from GC–MS showed that the tar derived from the mixture of MSW and coal contained about 20 major chemical compounds such as benzene, methyl isobutyl, toluene, xylene, phenol, cresol, naphthalene and others.Item Open Access Corn stalk-derived activated carbon with a stacking sheet-like structure as sulfur cathode supporter for lithium/sulfur batteries(Ionics. DOI 10.1007/s11581-015-1528-6, 2015-09-02) Yuan, Guanghui; Yin, Fuxing; Zhao, Yan; Bakenov, Zhumabay; Wang, Gongkai; Zhang, YongguangA novel stacking sheet-like carbon (SSC) has been synthesized by carbonizing the corn stalks and composited with sulfur to prepare a cathode for lithium/sulfur batteries. Scanning electronic microscopy observations showed the formation of irregularly interlaced nanosheet-like structure consisting SSC with uniform sulfur coating on its surface. The SSC nanoflakes in the composite act as nanocurrent collectors, favoring the charge carrier ion transport and electrolyte diffusion. The interlaced SSC nanoflakes irregularly stack together and form a three-dimensional network, which is beneficial for both trapping soluble polysulfide intermediates and rendering the electrical conductivity of the composite electrode...Item Open Access Crystallographic Characterisation of Ultra-Thin, or Amorphous Transparent Conducting Oxides—The Case for Raman Spectroscopy(MDPI, 2020-01-07) Caffrey, David; Zhussupbekova, Ainur; Vijayaraghavan, Rajani K.; Ainabayev, Ardak; Kaisha, Aitkazy; Sugurbekova, Gulnar; Shvets, Igor V.; Fleischer, KarstenThe electronic and optical properties of transparent conducting oxides (TCOs) are closely linked to their crystallographic structure on a macroscopic (grain sizes) and microscopic (bond structure) level. With the increasing drive towards using reduced film thicknesses in devices and growing interest in amorphous TCOs such as n-type InGaZnO4 (IGZO), ZnSnO3 (ZTO), p-type CuxCrO2, or ZnRh2O4, the task of gaining in-depth knowledge on their crystal structure by conventional X-ray diffraction-based measurements are becoming increasingly difficult. We demonstrate the use of a focal shift based background subtraction technique for Raman spectroscopy specifically developed for the case of transparent thin films on amorphous substrates. Using this technique we demonstrate, for a variety of TCOs CuO, a-ZTO, ZnO:Al), how changes in local vibrational moItem Open Access Crystallographic Characterisation of Ultra-Thin, or Amorphous Transparent Conducting Oxides—The Case for Raman Spectroscopy(MDPI, 2020-01-07) Ainabayev, Ardak; Sugurbekova, Gulnar; Caffrey, David; Zhussupbekova, Ainur; Vijayaraghavan, Rajani K.; Kaisha, Aitkazy; Shvets, Igor V.; Fleischer, KarstenThe electronic and optical properties of transparent conducting oxides (TCOs) are closely linked to their crystallographic structure on a macroscopic (grain sizes) and microscopic (bond structure) level. With the increasing drive towards using reduced film thicknesses in devices and growing interest in amorphous TCOs such as n-type InGaZnO 4 (IGZO), ZnSnO 3 (ZTO), p-type Cu x CrO 2 , or ZnRh 2 O 4 , the task of gaining in-depth knowledge on their crystal structure by conventional X-ray diffraction-based measurements are becoming increasingly difficult. We demonstrate the use of a focal shift based background subtraction technique for Raman spectroscopy specifically developed for the case of transparent thin films on amorphous substrates. Using this technique we demonstrate, for a variety of TCOs CuO, a-ZTO, ZnO:Al), how changes in local vibrational modes reflect changes in the composition of the TCO and consequently their electronic properties.Item Metadata only Cytisin Amidophosphate – Promising Role for The Liver Treatment(2015-08-01) Gulyayev, A.; Shulgau, Z.; Yermekbayeva, B.; Sergazy, S.; Nurgozhin, T.; A., GulyayevItem Open Access Diabetes prevalence, awareness and treatment and their correlates in older persons in urban and rural population in the Astana region, Kazakhstan(2016-02-01) Supiyev, Adil; Kossumov, Alibek; Kassenova, Aliya; Nurgozhin, Talgat; Zhumadilov, Zhaxybay; Peasey, Anne; Bobak, Martin; Adil, SupiyevAbstract AimsThe evidence on the prevalence and distribution of diabetes and its determinants in Central Asia is sparse. The aim of the present study was to investigate the prevalence, awareness, treatment, and control of diabetes and factors associated with these characteristics in the population of Astana (capital) city and adjacent rural area in Kazakhstan. MethodsParticipants aged 50-75 years old, residing in Astana city (the capital) and Akmol village were invited to participate in a cross-sectional study. The subjects were randomly selected from polyclinic registers. A total of 953 adults were interviewed (response rate 59%), and their fasting plasma glucose, blood pressure, height and weight were measured. Diabetes was defined as fasting plasma glucose (FPG) ≥7.0mmol/l (126mg/dl) and/or being on diabetes medication. ResultsThe overall prevalence of diabetes was 12.5%, and it was almost twice higher in the urban residents (16.3%) than in the rural population (8.6%). Diabetes prevalence was associated with age, men sex, hypertension, obesity, and Russian ethnicity. Among subjects with diabetes, 72.3% were aware of their condition; 65.6% were on treatment and 27.7% had controlled fasting plasma glucose. The awareness, treatment and control of diabetes were substantially higher in the urban population and among women. ConclusionsThe large differences in all diabetes indices between urban and rural regions, if confirmed in larger studies, may suggest an impact of westernised and urbanised lifestyle as well as access to health care.Item Metadata only Endometrial histology in severely obese bariatric surgery candidates: an exploratory analysis(2015-05-01) Kaiyrlykyzy, Aiym; Freese, Kyle E.; Elishaev, Esther; Bovbjerg, Dana H.; Ramanathan, Ramesh; Hamad, Giselle G.; McCloskey, Carol; Althouse, Andrew D.; Huang, Marilyn; Edwards, Robert P.; Linkov, Faina; Aiym, KaiyrlykyzyAbstract BackgroundEndometrial pathology risk has been linked to obesity; however, little is known of its prevalence in severely obese women not seeking care for endometrial pathology associated symptoms. This pilot study was designed to explore the frequency and risk factors associated with endometrial pathology in cancer-free, severely obese, bariatric surgery candidates using the Pipelle endometrial sampling technique (SureFlex Preferred Curette, Bioteque America, Inc, New Taipei City, Taiwan). MethodsTwenty-nine severely obese bariatric surgery candidates with intact uteruses and no history of endometrial cancer or endometrial ablation were included in this subanalysis from a larger cohort of 47. Endometrial samples were obtained using a Pipelle endometrial suction curette at a single time point before surgery. Logistic regression was used to assess the relationship between body mass index and endometrial pathology when adjusting for age and race. ResultsOf the 29 successful biopsies, 8 (27.6%) were classified as abnormal endometrium: 1 was classified as complex atypical hyperplasia, 1 was classified as hyperplasia without atypia, 4 samples were identified with endometrial polyps, and 2 samples were identified with metaplasia. None presented with cancer. Increasing body mass index was significantly associated with higher risk of abnormal endometrium (OR = 1.19, 95% CI [1.03–1.36], P = .01). ConclusionsThe findings in this sample suggest that obesity may be associated with increased risk of having undiagnosed endometrial pathology. More thorough examination of relationships between levels of obesity and endometrial pathology are needed to better characterize high cancer risk groups who may benefit from introducing new screening measures.Item Metadata only Endometrial histology in severely obese bariatric surgery candidates: an exploratory analysis(2015-05-01) Kaiyrlykyzy, Aiym; Freese, Kyle E.; Elishaev, Esther; Bovbjerg, Dana H.; Ramanathan, Ramesh; Hamad, Giselle G.; McCloskey, Carol; Althouse, Andrew D.; Huang, Marilyn; Edwards, Robert P.; Linkov, Faina; Aiym, KaiyrlykyzyAbstract BackgroundEndometrial pathology risk has been linked to obesity; however, little is known of its prevalence in severely obese women not seeking care for endometrial pathology associated symptoms. This pilot study was designed to explore the frequency and risk factors associated with endometrial pathology in cancer-free, severely obese, bariatric surgery candidates using the Pipelle endometrial sampling technique (SureFlex Preferred Curette, Bioteque America, Inc, New Taipei City, Taiwan). MethodsTwenty-nine severely obese bariatric surgery candidates with intact uteruses and no history of endometrial cancer or endometrial ablation were included in this subanalysis from a larger cohort of 47. Endometrial samples were obtained using a Pipelle endometrial suction curette at a single time point before surgery. Logistic regression was used to assess the relationship between body mass index and endometrial pathology when adjusting for age and race. ResultsOf the 29 successful biopsies, 8 (27.6%) were classified as abnormal endometrium: 1 was classified as complex atypical hyperplasia, 1 was classified as hyperplasia without atypia, 4 samples were identified with endometrial polyps, and 2 samples were identified with metaplasia. None presented with cancer. Increasing body mass index was significantly associated with higher risk of abnormal endometrium (OR = 1.19, 95% CI [1.03–1.36], P = .01). ConclusionsThe findings in this sample suggest that obesity may be associated with increased risk of having undiagnosed endometrial pathology. More thorough examination of relationships between levels of obesity and endometrial pathology are needed to better characterize high cancer risk groups who may benefit from introducing new screening measures.Item Open Access EVALUATING SULFUR-COMPOSITE CATHODE MATERIAL WITH LITHIATED GRAPHITE ANODE IN COIN CELL AND POUCH CELL CONFIGURATION(Frontiers Media, 2020-11-09) Uzakbaiuly, Berik; Mentbayeva, Almagul; Konarov, Aishuak; Kurmanbayeva, Indira; Zhang, Yongguang; Bakenov, ZhumabayHigh-performance sulfur-composite cathode material, sulfur/polyacrylonitrile/ketjen black, was prepared by simple mixing and low-temperature heat treatment route. The cell made of the composite cathode and anode from metallic lithium or lithiated graphite was assembled in coin cell configuration. Half-cells retained about 70% of their initial capacity of 1,270 mAh g−1 after 150 cycles, while full-cells retained about 85% of the initial capacity of 1,500 mAh g−1 for over 150 cycles. Since coin cells do not reflect the true performance of a practical cell, the cathode composite was assembled with lithiated graphite anode in a 45 × 85 × 6 mm3 pouch cell configuration. This cell retained about 81% of its initial capacity for over 100 cycles. At high cycling rates up to 1 C, the pouch cell demonstrated a moderate rate capability and exhibited good recovery and stable performance after high rate cycling. Also, the cell successfully passed safety tests such as overcharge, deep discharge, and mechanical short circuit tests.Item Metadata only Evaluation of health outcomes and cost-effectiveness of 13-valent Pneumococcal Conjugate Vaccination for infants in Kazakhstan(2015-08-01) Bektur, C.R.; Nurgozhin, T.S.; C.R., BekturItem Open Access Exploring 3D microstructural evolution in Li-Sulfur battery electrodes using in-situ X-ray tomography(www.nature.com/scientificreports, 2016-09-17) Yermukhambetova, Assiya; Tan, Chun; Daemi, Sohrab R.; Bakenov, Zhumabay; Darr, Jawwad A.; Brett, Daniel J. L.; Shearing, Paul R.Lithium sulfur (Li-S) batteries offer higher theoretical specific capacity, lower cost and enhanced safety compared to current Li-ion battery technology. However, the multiple reactions and phase changes in the sulfur conversion cathode result in highly complex phenomena that significantly impact cycling life. For the first time to the authors’ knowledge, a multi-scale 3D in-situ tomography approach is used to characterize morphological parameters and track microstructural evolution of the sulfur cathode across multiple charge cycles. Here we show the uneven distribution of the sulfur phase fraction within the electrode thickness as a function of charge cycles, suggesting significant mass transport limitations within thick-film sulfur cathodes. Furthermore, we report a shift towards larger particle sizes and a decrease in volume specific surface area with cycling, suggesting sulfur agglomeration. Finally, we demonstrate the nano-scopic length-scale required for the features of the carbon binder domain to become discernible, confirming the need for future work on in-situ nano-tomography. We anticipate that X-ray tomography will be a powerful tool for optimization of electrode structures for Li-S batteries.
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