193 research outputs found
Power sharing analysis of a new modified multi-input interleaved boost converter based on H-Bridge cells
In this paper, a new modified multi-input boost converter is proposed using H-bridge cells as building blocks and
uncoupled inductors in parallel using interleaved technique as ripple reduction method. The objectives of this paper are to design a high ripple reduction and a high-performance multi-input boost converter. Different operating modes and the switch realization of the new converter are obtained. The modes of operation based on the status of the four switches. The proposed multi-input boost converter is composed of two inputs source that accommodated with some extra semiconductors, inductances and diodes to form the interleaving technique as proposed method. The proposed concept has been investigated through simulation using the MATLAB/Simulink environment. The simulation results confirm the validity of the proposed method, which can be seen as a promising new topology that ensure multi-input converter suitable for renewable energy application
A machine learning approach to explore individual risk factors for tuberculosis treatment non-adherence in Mukono district
Despite the availability and implementation of well-known efficacious interventions for tuberculosis treatment by the Ministry of Health, Uganda (MoH), treatment non-adherence persists. Moreover, identifying a specific tuberculosis patient at risk of treatment non-adherence is still a challenge. Thus, this retrospective study, based on a record review of 838 tuberculosis patients enrolled in six health facilities, presents, and discusses a machine learning approach to explore the individual risk factors predictive of tuberculosis treatment non-adherence in the Mukono district, Uganda. Five classification machine learning algorithms, logistic regression (LR), artificial neural networks (ANN), support vector machines (SVM), random forest (RF), and AdaBoost were trained, and evaluated by computing their accuracy, F1 score, precision, recall, and the area under the receiver operating curve (AUC) through the aid of a confusion matrix. Of the five developed and evaluated algorithms, SVM (91.28%) had the highest accuracy (AdaBoost, 91.05% performed better than SVM when AUC is considered as evaluation parameter). Looking at all five evaluation parameters globally, AdaBoost is quite on par with SVM. Individual risk factors predictive of non-adherence included tuberculosis type, GeneXpert results, sub-country, antiretroviral status, contacts below 5 years, health facility ownership, sputum test results at 2 months, treatment supporter, cotrimoxazole preventive therapy (CPT) dapsone status, risk group, patient age, gender, middle and upper arm circumference, referral, positive sputum test at 5 and 6 months. Therefore, machine learning techniques, specifically classification types, can identify patient factors predictive of treatment non-adherence and accurately differentiate between adherent and non-adherent patients. Thus, tuberculosis program management should consider adopting the classification machine learning techniques evaluated in this study as a screening tool for identifying and targeting suited interventions to these patients
Sorption removal of arsenic (V) by Sn-loaded poly(hydroxamic) acid chelating resin
Sorption conditions of arsenate ions onto Sn-loaded poly (hydroxamic acid) chelating resin (Sn-PHA) have been studied. Sorption isotherms data correlated well to the Langmuir model with maximum capacity of 38.46 mg g-1 at pH 2. Sorption process follows pseudo-second order kinetics. Intraparticle diffusion was found to take part in sorption processes. The free energy (E) was 11.18 kJ mol-1 which shows the sorption is an ion-exchange process. Thermodynamic parameters, ΔH°, ΔS° and ΔG° were also calculated from the experimental data. Standard heat of sorption was found to be endothermic and entropy change value was calculated to be positive. Negative ΔG° value indicates that the sorption process for the arsenic anions onto Sn-PHA is spontaneous
The effect of ultrasound pretreatment on some selected physicochemical properties of black cumin (Nigella Sativa)
Background
In the present study, the effects of ultrasound pretreatment parameters including irradiation time and power on the quantity of the extracted phenolic compounds quantity as well as on some selected physicochemical properties of the extracted oils including oil extraction efficiency, acidity and peroxide values, color, and refractive index of the extracted oil of black cumin seeds with the use of cold press have been studied.
Methods
For each parameter, three different levels (30, 60, and 90 W) for the ultrasound power and (30, 45, and 60 min) and for the ultrasound irradiation time were studied. Each experiment was performed in three replications.
Results
The achieved results revealed that, with enhancements in the applied ultrasound power, the oil extraction efficiency, acidity value, total phenolic content, peroxide value, and color parameters increased significantly (P 0.05).
Conclusions
In summary, it could be mentioned that the application of ultrasound pretreatment in the oil extraction might improve the oil extraction efficiency, the extracted oil’s quality, and the extracted phenolic compounds content.info:eu-repo/semantics/publishedVersio
SORPTION OF Cu(II) BY CHEMICALLY GRAFTED HYDROXAMIC ACID-ZEOLITE (Erapan Cu(II) oleh Zeolit Terubahsuai Dengan Asid Hidroksamik)
Abstract Sorption of Cu(II) by zeolite sorbent chemically modified with hydroxamic acid (HASiZP) is described. The maximum sorption capacity of Cu(II) occurred at pH 5. Sorption capacity of Cu(II) by HASiZP was doubled compared to the original zeolite. Kinetic study shows that Cu(II) sorption followed by second order kinetic model. The sorption of Cu(II) followed Langmuir isotherm model with maximum capacity of 33.32 mg/g at 25°C and increased to 48.12 mg/g at 70°C. Cu(II) sorption by the HASiZP was endothermic and spontaneous processes with positive values of entropy changes. Keywords: Hydroxamic acid-grafted zeolite, Cu(II), sorption. Abstrak Kertas ini membincangkan erapan Cu(II) oleh zeolit terubahsuai oleh asid hidroksamik (HASiZP). Erapan maksimum Cu(II) berlaku pada pH 5. Muatan erapan Cu(II) oleh HASiZP meningkat dua kali ganda berbanding zeolit asal. Kajian kinetik menunjukkan erapan Cu(II) mengikuti model kinetic order kedua. Erapan Cu(II) mematuhi model isotherma Langmuir dengan muatan maksimum 33.32 mg/g pada 25°C dan meningkat kepada 48.12 mg/g pada 70°C. Erapan Cu(II) oleh HASiZP adalah proses endotherma dan spontan dengan perubahan entropi positif. Kata kunci: Zeolit terubahsuai oleh asid hidroksamik, Cu(II), erapan Introduction Heavy metals are toxic substances and must be removed from wastewater prior to their discharge into receiving waters. Among methods available for heavy metal removal, sorption by ion exchange is an attractive one due to its simplicity and safe which requires only mild operating conditions. Using a low cost exchanger such as zeolite, the method can be made cost-effective. Zeolites either synthetic or natural are hydrated aluminosilicate. The structures of zeolites consist of three dimensional frameworks of SiO 4 and AlO 4 tetrahedra. The isomorphous replacement of Si 4+ by Al 3+ produces a negative charge in the lattice. The negative charge is balanced by cations such as Na + and
Synthesis And Comparison Of Liquid Crystal Polymers And Monomers Containing Azobenzene Mesogens
Abstract: The syntheses of novel liquid crystal polymers containing azobenzene moieties were carried out according to convenient route having a acrylate backbone. The azobenzenes are key intermediates of the monomers and the side-chain liquid crystal polymer is the poly [α-{4-[(4-acetylphenyl)diazenyl]phenoxy}alkyloxy]acrylate in which spacer length is varied from 3 to 11 methylene units. The precursors and monomers were characterized by using FT-IR, NMR techniques. The polymers were obtained by conventional free radical polymerization using AIBN as an initiator. The thermal properties of the polymers were studied by using differential scanning calorimetry. The thermal behavior of the polymers are compared with those of the analogous monomers, the α-{4-[(4-acetylphenyl)diazenyl]phenoxy}alkyloxy acrylate and it was found that all polymers exhibited namatic phase near isotropic point and no phase transition observed in the monomers. Abstrak: Polimer hablur cecair kumpulan azobenzena telah disintesis dengan cara yang rengkas dimana akrilat telah digunakan sebagai rangka utama. Azobenzena poli[α-{4-[(4-asetilfenil) diazenil]fenoksi}alkiloksi]akrilat merupakan bahantara utama daripada monomer dan merupakan rantai sisi kepada polimer cecair hablur tersebut dengan panjang kumpulan peruang antara 3 ke 11 unit metilena. Precursor dan monomer telah dicirikan menggunakan teknik FTIR dan NMR. Polimer telah dihasilkan secara pempolimeran radikal bebas konvensional menggunakan bahan pemula AIBN. Sifat terma polimer telah dikaji menggunakan kalorimetri pengimbas pembezaan. Sifat terma polimer telah dibandingkan dengan analog monomer α-{4-[(4-asetilfenil) diazenil]fenoksi}alkiloksi akrilat, dan didapati semua polimer menunjukkan fasa namatik pada titik isotropik tetapi tiada transisi fasa dilihat berlaku pada monomer
Clinical and histopathological study on reproductive lesions caused by Pasteurella multocida type B2 immunogens in buffalo heifers
Haemorrhagic septicaemia (HS) is a globally renowned disease that affects cattle and buffaloes. Its effects on the reproductive system have not been previously studied. The present study evaluated the pathological responses in pre-pubertal female buffaloes infected with immunogens; lipopolysaccharide (LPS) and outer membrane protein (OMP) derived from P. multocida type B:2. Fifteen healthy pre-pubertal female buffaloes were divided into 5 equal groups. Buffaloes in groups 1 and 2 were intravenously and orally inoculated with P. multocida LPS, while those in groups 3 and 4 were sub-cutaneously and orally inoculated with P. multocida OMP. Buffaloes in group 5 were inoculated with sterile phosphate buffered saline (negative control). During the post infection period, all buffaloes were examined for clinical signs throughout 21 days and surviving animals were euthanised for postmortem evaluation. Histopathological evaluation of buffaloes inoculated intravenously with LPS showed a significantly higher occurrence (P<0.05) of necrosis and degeneration in the uterine horn and supramammary glands . Following inoculation with OMP, haemorrhage and congestion was significantly higher (P<0.05) in the ovaries, cervix, vagina, mammary and supra-mammary glands of buffaloes inoculated subcutaneously, while necrosis and degeneration and inflammatory cell infiltration in different organs was also significantly increased in the same group. The findings showed that both P. multocida bacterial LPS and OMP affected the uterine horn, ovaries, cervix, mammary gland and supramammary lymph nodes of buffalo calves inoculated either intravenously or subcutaneously, as compared to those inoculated orally
Age and sex comparison in determining baseline blood and coagulation profiles in semi-extensive Rusa deer (Rusa timorensis)
The objective of the study was to establish the baseline values for blood and coagulation parameters in normaland healthy rusa deer (Rusa timorensis) of different ages and sexes. The sample population consists of 40 rusa deer, divided into four groups of (i) juvenile males (ii) juvenile females (iii) adult males and (iv) adult
females. The findings showed significant (p<0.05) higher values in erythrocyte count, calcium concentration and prothrombin
time in the adult males compared to adult female rusa deer. On the other hand, the total protein concentration was significantly
higher in adult females than adult male deer. No significant differences in blood or coagulation parameters were observed
between sexes in the juvenile deer. Between age group, the adult deer had significantly higher mean cell volume, plasma protein
and globulin concentration than juvenile rusa deer. Thus, it is necessary to take into account the age and sex of the rusa deer
when using blood reference values for the diagnosis of diseases or health assessment
Helicobacter pylori cagA gene variants in Malaysians of different ethnicity
We have defined DNA repeat variability in the 3′-terminus of the cagA gene of Helicobacter pylori strains from Malaysian patients of different ethnicities. We identified different alleles based on the EPIYA repeats. cagA types A-B-D and A-B-B-D are more similar to the sequence of Japanese strains, whereas cagA types A-B-C, A-B-C-C, A-B and A-C displayed similarity to strain 26695 sequences. A significant association was found between cagA genotypes and patients’ ethnicity, with cagA type A-B-D being predominantly isolated from Chinese patients and cagA type A-B-C from Malays and Indians. Our data further corroborate the possibility that variant biological activity of CagA may affect the host specificity and/or pathogenicity of H. pylori
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