constant amount
Recently Published Documents


TOTAL DOCUMENTS

140
(FIVE YEARS 19)

H-INDEX

21
(FIVE YEARS 2)

2021 ◽  
Author(s):  
Hee-Woong Kim ◽  
Deug-Chan Lee ◽  
Hae-Ik Rhee

Abstract Alpha-glucosidase (EC.3.2.1.20) is involved in the absorption of monosaccharides in the small intestine of animals. We aimed to find a microorganism capable of proliferating in the intestine and producing α-glucosidase inhibitor. We developed a strain capable of forming spores from dry grass and growing in an anaerobic environment was selected as Bacillus lichenformis. Mixing spores of this strain with a high-fat diet and high-carbohydrate diet, it was confirmed that the weight gain was significantly reduced than the high-calorie diet group without spores. Furthermore it was confirmed that Bacillus lichenformis administered as spores efficiently proliferated in the intestine and consistently produced α-glucosidase inhibitor by securing a constant amount of the strain and α-glucosidase inhibitor in feces after a certain period. This study shows an efficient process in which microorganisms capable of proliferating in the intestine directly produce and supply specific secondary metabolites in the intestine.


2021 ◽  
Vol 26 ◽  
pp. 1-19
Author(s):  
Martín Farach-Colton ◽  
Katia Leal ◽  
Miguel A. Mosteiro ◽  
Christopher Thraves Caro

We consider the Windows Scheduling (WS) problem, which is a restricted version of Unit-Fractions Bin Packing, and it is also called Inventory Replenishment in the context of Supply Chain. In brief, WS problem is to schedule the use of communication channels to clients. Each client c i is characterized by an active cycle and a window w i . During the period of time that any given client c i is active, there must be at least one transmission from c i scheduled in any w i consecutive time slots, but at most one transmission can be carried out in each channel per time slot. The goal is to minimize the number of channels used. We extend previous online models, where decisions are permanent, assuming that clients may be reallocated at some cost. We assume that such cost is a constant amount paid per reallocation. That is, we aim to minimize also the number of reallocations. We present three online reallocation algorithms for Windows Scheduling. We evaluate experimentally multiple variants of these protocols showing that, in practice, all three achieve constant amortized reallocations with close to optimal channel usage. Our simulations also expose interesting tradeoffs between reallocations and channel usage. We introduce a new objective function for WS with reallocations that can be also applied to models where reallocations are not possible. We analyze this metric for one of the algorithms that, to the best of our knowledge, is the first online WS protocol with theoretical guarantees that applies to scenarios where clients may leave and the analysis is against current load rather than peak load. Using previous results, we also observe bounds on channel usage for one of the algorithms.


Author(s):  
Ehsan Najafi ◽  
Amin Mirzaei ◽  
Mahdi Mahdi Rezvanyvardom ◽  
Mahdi Zolfaghar

PV plants are increasing all over the world and they are becoming a distinct part of electric grids. Due to abundance of solar irradiation and almost constant amount of it in certain geographical latitudes, selection of proper capacity of PV plants depends mostly on available places for the site. in this paper, important measures for safe connection of a PV plant in terms of voltage requirements are addressed and several guidelines are introduced for this purpose. In addition, simulation results are included to prove some of the mentioned suggestions. a general algorithm is finally proposed to show the directions for safe connection of PV plants.


2021 ◽  
Vol 21 (No 1) ◽  
Author(s):  
Om Prakash and N. Dwivedi

Cylindrospermum sp. NDOP002 was isolated from agricultural fields of Azamgarh, U.P., India. It was characterized by morphological methods. Total chlorophyll a content was 18.5 µg/ mg dry weight. Organism achieved a stationary phase of growth after 15 days of cultivation. Ammonia excretion was monitored from 6 hrs. of culture to 20 days. The ammonia content of culture increased up to 7 days (Maximum amount of 3.23 µg/ ml) and then decreased. Approximately a constant amount of ammonia was maintained from 9th and onwards days of growth. Maximum glutamine synthetase (GS) activity of 8.33 mM ?glutamyl hydroxamate min-1 mg chl-1 was observed on the 5th day of culture and then decreased. Approximately constant GS activity was observed after 9th and onward days of growth. Algalisation experiment showed an increase in growth parameter of rice plant in algalised set. Length of roots was 6.4-6.9 cm in non algalised and 7.2-7.6 cm in algalised rice plants whereas the length of shoots was 5.7-6.1 cm in non- algalised and 9.5-10.1 cm in algalised rice plants. The amount of ammonia in algalised set was 2.1 µg/ ml on the 10th day of the experiment. Experimental findings clearly suggest Cylindrospermum sp. NDOP002 as suitable inocula for algalisation of rice fields of Azamgarh district, U.P., India.


2021 ◽  
Author(s):  
Hichem Filali ◽  
Nahman Boukheit ◽  
Rafika Bouhroum ◽  
Wassila Chekirou ◽  
Ahcène Karaali

Abstract Samples of pure zinc aluminate (ZnAl2O4) and doped both with lead (Pb2+) at different ratios (0, 0.5, 1, 1.5, 2 and 2.5% mol) and a constant amount of lanthanum (La: 1% mol), were prepared by the citrate sol-gel technique, and then annealed at 900°C for 2h. In order to study the structural, optical and thermal properties; different characterization methods were used, such as: powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), TGA, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The Analyzes by XRD revealed the presence of the cubic single phase ZnAl2O4 for all samples, with a crystallites size between 19 and 25 nm. These results were confirmed using FTIR, Raman spectroscopy and SEM. Also, photocatalytic study for different samples of ZnAl2O4 shows that they can be used like as photocatalyst and good adsorbents for degradation of Hexamethyl crystallized violet dye in aqueous solution.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adeolu A. Adediran ◽  
Abayomi A. Akinwande ◽  
Oluwatosin A. Balogun ◽  
O. S. Olasoju ◽  
Olanrewaju S. Adesina

AbstractBamboo fibers (BF) treated in 1.3 Molar NaOH and particulate coconut shell (PCS) sieved to − 45 µm were incorporated into polyvinyl chloride (PVC) matrix towards improving the properties of PVC composite for ceiling boards and insulating pipes which sags and degrade with time needing improvement in properties. The process was carried out via compression moulding applying 0.2 kPa pressure and carried out at a temperature of 170 °C. Composites developed were grouped according to their composition. Groups A, B, C, and D were infused with 2, 4, 6 and 8 wt% PCS at constant amount, respectively. Each group was intermixed with a varying proportions of BF (0–30 wt% at 5% interval). Tests carried out on the samples produced revealed that the yield strength, modulus of elasticity, flexural strength, modulus of rupture were enhanced with increasing BF proportion from 0 to 30 wt% BF at 2 wt% constant PCS input. Thermal and electrical properties trended downward as the fiber content reduced even as the hardness was enhanced with PCS/BF intermix which was also reflected in the wear loss index. Impact strength was highest on the infix of 4 wt% PCS and 15 wt% BF. Compressive strength was better boasted with increasing fiber and PCS amount but 8 wt% PCS amounted to depreciation in trend. It was generally observed that PCS performed optimally at 2 wt% incorporation while beyond that resulted in lowering of strength. Blending of the two variable inputs; 0–30 wt% BF and 2 wt% PCS presented better enhancement in properties.


2021 ◽  
Author(s):  
Saul Moore

C. elegans is maintained in the laboratory on Nematode Growth Medium (NGM) agar which has been aseptically poured into petri plates. The NGM agar medium can be poured into petri plates easily and aseptically using a peristaltic pump. This pump can be adjusted so that a constant amount of NGM agar is dispensed into each petri plate. A constant amount of agar in the plates reduces the need for refocusing the microscope when you switch from one plate to another. The imaging plates can be 35mm, 60mm or 90mm in diameter depending on the assay design.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245942
Author(s):  
Donald MacGlashan

Background The IgE-mediated activation of mast cells and basophils results in the secretion of many substances, including the release of FceRI-alpha subunit. This released alpha subunit can bind IgE and it may act as a down-regulator of subsequent IgE-dependent reactions. However, previous studies do not observe loss of the mass of FceRI-alpha associated with the cells, at least not for human basophils. This study was designed to understand the basis for the discordant observations. Methods Purified human basophils were stimulated with multiple activating secretagogues and supernatants were examined for histamine and released FceRI-alpha. In addition, cell surface IgE densities (occupied and unoccupied) were measured by flow cytometry and total cellular content of mature and immature FceRI-alpha determined with Western blots. Results Released FceRI-alpha, on average, represented 7% of the total surface FceRI before the reaction. The molecular weight of the soluble FceRI-alpha was approximately 54 kD, larger than immature subunit and somewhat smaller than surface subunit. In addition, 1) release ceased long before internalized FceRI-alpha was processed, 2) release was insensitive to Bafilomycin A, 3) release was independent of the starting density of FceRI and 4) release occurred more effectively with non-IgE-dependent stimuli, FMLP or C5a. Conclusions There appears to be relatively constant amount of nearly mature FceRI-alpha that is susceptible to secretion events induced by any form of stimulation. The amount, on average, represents about 7% of the mature form of FceRI-alpha.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Constantin Bobirică ◽  
Cristina Orbeci ◽  
Liliana Bobirică ◽  
Petru Palade ◽  
Călin Deleanu ◽  
...  

AbstractThe influence of waste glass and red mud addition as alternative source of aluminosilicate precursors on the microstructural, mechanical, and leaching properties of bottom ash-based geopolymer was studied in this work through mineralogical, morphological, and spectroscopic analysis, as well as by conducting compressive strength and leaching tests. The bottom ash-based geopolymer composites were synthesized by adding a constant amount of waste glass (10% by weight) and increasing amounts of red mud (up to 30% by weight). The results derived from FTIR, 29Si and 27Al MAS NMR, and SEM–EDX revealed that adding up to 10% (by weight) red mud to the synthesis mixes leads to an increase in the degree of geopolymerization of the activated mixes. The compressive strength followed the same trend. An increase of more than 10% (by weight) red mud added to the synthesis mixes results in a significant decrease of compressive strength of the geopolymer composites. A low leachability of geopolymer composites in regard with their contaminants was revealed especially for those with good compressive strength.


Sign in / Sign up

Export Citation Format

Share Document