bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Propagation and NaCl Tolerance of the Multipurpose Medicinal Halophyte Limoniastrum monopetalum
Authors: Martini Aikaterini N. , Papafotiou Maria
Published: February 2020

Limoniastrum monopetalum is an evergreen perennial shrub native to Mediterranean coastal sands and salt marshes. It has adapted to a variety of environmental stresses and is used in traditional medicine and as an ornamental plant. In the present study, an efficient micropropagation protocol for this species was developed to facilitate the production of selected genotypes and promote its wider use. Research has focused on the effects of various cytokinin types [benzyladenine (BA), zeatin, 6-furfurylaminopurine (kinetin) or 6-γ-γ-dimethylallilopurine (2iP)] and concentrations (0.0–4.0 mg·L−1) and various NaCl concentrations (0.0–20 g·L−1) during all stages of in vitro culture. For in vitro establishment, Murashige and Skoog (MS) medium supplemented with 0.5 mg·L−1 BA and 0.0 or 5.0 g·L−1 NaCl was most appropriate (100% explant response, 3–4 shoots per explant, 2 cm shoot length). The best results for shoot multiplication (100% response, 9 shoots per explant, 0.8–1.0 cm shoot length) were obtained with low (0.5 mg·L−1) BA or relatively high (2.0 mg·L−1) kinetin concentrations in the medium; however, 0.5 mg·L−1 kinetin should be preferred in the case of production of multiple rooted microshoots during one stage. The addition of NaCl at relatively low concentrations (2.5 or 5.0 g·L−1) in a medium supplemented with 0.5 mg·L−1 BA doubled shoot multiplication but did not improve shoot elongation (100% explant response, 16 shoots per explant, 0.8 cm shoot length). For in vitro rooting, half-strength MS medium supplemented with 1.0 mg·L−1 IBA was most appropriate (97% rooting, 9.4 roots per microshoot, 1.2 cm root length). Regarding the effects of NaCl on in vitro rooting, microshoots were relatively tolerant to NaCl concentrations up to 10.0 g·L−1. The effects of NaCl depend on the micropropagation stage; they are synergistic during shoot multiplication and tolerant during rooting. However, explants responded satisfactorily in its absence, indicating that NaCl was not necessary as a medium component. Ex vitro acclimatization and establishment of plantlets was 100% successful in a mixture of peat:perlite 1:1 or 2:1 (v/v).
Cloning and Characterization of a Tryptophan–Aspartic Acid Repeat Gene Associated with the Regulation of Anthocyanin Biosynthesis in Oriental Hybrid Lily
Authors: Dou Xiaoying , Bai Jinrong , Wang Huan , Kong Ying , Lang Lixin , Bao Fang , Shang Hongzhong
Published: February 2020

Anthocyanins are major pigments responsible for the color of lily (Lilium sp.) flowers. Anthocyanin synthesis is part of the flavonoid metabolic pathway. Numerous transcription factors, including R2R3-MYBs, basic helix-loop-helix (bHLH), and tryptophan–aspartic acid repeat (also known as WD40 or WD repeat) proteins, known to regulate flavonoid biosynthesis have been identified in various plant species. However, there is limited information available on WD repeat proteins in lilies. In this study, we identified a WD repeat gene in the Oriental hybrid lily ‘Sorbonne’ (Lilium hybrid WD repeat, LhWDR). LhWDR contains no introns, and has a 1100–base pair open reading frame, encoding a putative protein of 370 amino acids. LhWDR was found to be localized in the cytoplasm of transgenic Arabidopsis thaliana root cells. Expression patterns of LhWDR in different organs and at different periods of lily tepal growth revealed that the expression levels of this gene are closely associated with anthocyanin accumulation. A yeast two-hybrid assay demonstrated that full-length LhWDR interacts with the 420 N-terminal amino acids of Lilium hybrid bHLH2. Interestingly, overexpression of LhWDR in A. thaliana led to an upregulation of the dihydroflavonol 4-reductase gene, which is an important structural gene downstream of the anthocyanin pathway. These results indicate that the WD repeat protein LhWDR might interact with a bHLH transcription factor to regulate anthocyanin biosynthesis.
Reaction between Cu-bearing minerals and hydrothermal fluids at 800 °C and 200 MPa: Constraints from synthetic fluid inclusions
Authors: Qi Dongmei , Behrens Harald , Botcharnikov Roman , Derrey Insa , Holtz Francois , Zhang Chao , Li Xiaoyan , Horn Ingo
Published: February 2020

Transport and deposition of copper in the Earth's crust are mainly controlled by the solubility of Cu-bearing phases and the speciation of Cu in magmatic-hydrothermal fluids. To improve our understanding of copper mobilization by hydrothermal fluids, we conducted an experimental study on the interaction between Cu-bearing phases (metallic copper, Cu2O, CuCl) and aqueous chloride solutions (H2O ± NaCl ± HCl; with Cl concentrations of 0 to 4.3 mol kg-1). The experiments were run in rapid heat/rapid quench cold-seal pressure vessels at 800 °C, 200 MPa, and logfO2 ~ NNO+2.3. Either Cu or Au capsules were used as containers. The reaction products were sampled in situ by the entrapment of synthetic fluid inclusions in quartz. Fluid composition was subsequently determined by analyzing individual fluid inclusions using a freezing cell and laser ablation inductively coupled plasma-mass spectrometry. Our results show that large isolated and isometric inclusions, free of late-stage modifications, can be preserved after the experiment even when using a high cooling rate of 25 K s-1.

The obtained results demonstrate that: (1) reaction between native Cu, NaCl solution, and quartz (± silica gel) leads to the coexistence of fluid inclusions and Na-bearing silicate melt inclusions. Micrometer-to submicrometer-sized cuprite (Cu2O) crystals have been observed in both types of the inclusions, and they are formed most probably due to the dissociation of CuOH. (2) When Cu0 reacts with HCl and CuCl solutions, or Cu+ reacts with NaCl solution, nantokite (CuCl) formed due to oversaturation has been found in fluid inclusion. Copper concentration in the fluid shows a strong positive dependence on the initial chlorine content, with Cu/Cl molal ratios varying from 1:9 to 1:1 in case 1 and case 2, respectively. When Cl is fixed to 1.5 m, initial fluid acidity has a major control on the Cu content, i.e., 0.17 ± 0.09 and 1.29 ± 0.57 m Cu were measured in fluids of case 1 and case 2, respectively. Cu solubility in pure water and in 1.5 m NaCl solutions are 0.004 ± 0.002 and 0.16 ± 0.07 m, respectively. The main responsible Cu-bearing complexes are CuOH(H2O)x in water, NaCuCl2 in NaCl solutions and HCuCl2 in alkali-free solutions. These results provide quantitative constraints on the mobility of Cu in hydrothermal solutions and confirm that Cl is a very important ligand responsible for Cu transport. The first observation that silicate melt can be generated in the fluid-dominated and native-copper-bearing system implies that transitional thermosilicate liquids can coexist with metal-rich fluids and may enhance Cu mobility in magmatic-hydrothermal systems. This may have important implications for the formation of Cu deposits in the systems with low S activities.
Experimental determination of the solubility constant of kurnakovite, MgB3O3(OH)5·5H2O
Authors: Xiong Yongliang
Published: February 2020

In this study, I present experimental results on the equilibrium between boracite [Mg3B7O13C1(cr)] and kurnakovite [chemical formula, Mg2B6O11·15H2O(cr); structural formula, MgB3O3(OH)5·5H2O(cr)] at 22.5 ± 0.5 °C from a long-term experiment up to 1629 days, approaching equilibrium from the direction of supersaturation, Mg3B7O13C1(cr) + H+ + 2B(OH)4− + 18H2O(1) ⇌ 3MgB3O3(OH)5·5H2O(cr) + C1−.

Based on solubility measurements, the 10-based logarithm of the equilibrium constant for the above reaction at 25 °C is determined to be 12.83 ± 0.08 (2σ).

Based on the equilibrium constant for dissolution of boracite, Mg3B7O13C1(cr) + 15H2O(1) = 3Mg2+ + 7B(OH)4− + C1− + 2H+ at 25 °C measured previously (Xiong et al. 2018) and that for the reaction between boracite and kurnakovite determined here, the equilibrium constant for dissolution of kurnakovite, MgB3O3(OH)5·5H2O(cr) = Mg2+ + 3B(OH)4− + H+ + H2O(1) is derived as −14.11 ± 0.40 (2σ).

Using the equilibrium constant for dissolution of kurnakovite obtained in this study and the experimental enthalpy of formation for kurnakovite from the literature, a set of thermodynamic properties for kurnakovite at 25 °C and 1 bar is recommended as follows: ΔHf0 = −4813.24 ± 4.92 kJ/mol, ΔGf0 = −4232.0 ± 2.3 kJ/mol, and S0 = 414.3 ± 0.9 J/(mol·K). Among them, the Gibbs energy of formation is based on the equilibrium constant for kurnakovite determined in this study; the enthalpy of formation is from the literature (Li et al. 1997), and the standard entropy is calculated internally with the Gibbs-Helmholtz equation in this work. The thermodynamic properties of kurnakovite estimated using the group contribution method for borate minerals based on the sums of contributions from the cations, borate polyanions, and structural water to the thermodynamic properties from the literature (Li et al. 2000) are consistent, within their uncertainties, with the values listed above.

Since kurnakovite usually forms in salt lakes rich in sulfate, studying the interactions of borate with sulfate is important to modeling kurnakovite in salt lakes. For this purpose, I have re-calibrated our previous model (Xiong et al. 2013) describing the interactions of borate with sulfate based on the new solubility data for borax in Na2SO4 solutions presented here.
Orthovanadate wakefieldite-(Ce) in symplectites replacing vanadium-bearing omphacite in the ultra-oxidized manganese deposit of Praborna (Aosta Valley, Western Italian Alps)
Authors: Tumiati Simone , Merlini Marco , Godard Gaston , Hanfland Michael , Fumagalli Patrizia
Published: February 2020

Because of their unique structure and properties, rare-earth (REE) orthovanadates have been extensively employed for decades in advanced ceramics, in particular in the laser industry in replacement of Nd:YAG. A Ca-bearing REE orthovanadate with the empirical formula (Ce0.279Ca0.271Y0.267Gd0.057Nd0.055Dy0.032Sm0.027La0.020Th0.027Sr0.002)(V0.9085+Cr0.0673+Fe0.0173+As0.0055+)O4⋅nH2O has been found in metacherts from Praborna (Italian Alps) as micrometer-sized euhedral crystals in clinopyroxene + plagioclase symplectites replacing eclogite-facies vanadium-bearing omphacite (Aegirine55–48Jadeite42–33Diopside10–8 with V2O3 ≤ 1.39 wt%). We applied the synchrotron radiation, single crystal, micro-diffraction technique, recently optimized at ID09A beamline (ESRF, France), to determine the crystal structure of this mineral. It is tetragonal and isostructural with zircon, with a = 7.2233(12) Å, c = 6.3949(18) Å, V = 333.66(13) Å3, Z = 4, space group I41/amd, and it has been therefore identified as Ca- and Y-bearing wakefieldite-(Ce) (ideally CeV5+O4). Cell parameters are in agreement with those of synthetic Ce0.7Ca0.3VO4. Raman spectra of the studied wakefieldite-(Ce) are comparable with natural and synthetic wakefieldite-(Ce) spectra and revealed the presence of OH groups and/or water of hydration, which is also suggested by the low totals in microprobe analyses. Mass balance indicates that wakefieldite-(Ce) is a by-product of the omphacite breakdown; omphacite and Mn-rich epidote, a minor reactant, provided vanadium and REE, respectively. Petrological observations and thermodynamic modeling suggest that the mineral, coexisting with hematite, Mn-rich epidote, and braunite, formed during retrogression to greenschistfacies conditions at ultra-oxidized conditions (DFMQ ≥ +16 log units), which are often observed in Mn-oxide ores. Wakefieldite is an effective scavenger of REE in oxidized geological environments at P-T conditions that range from sedimentary to medium-grade metamorphic settings, even where the REE bulk concentration is negligible. Its rarity reflects both the overall low abundance of vanadium and the need for ultra-oxidized conditions that are rarely achieved in metamorphic rocks, where REE phosphates (i.e., monazite, xenotime) are commonly found instead.
Acanthamoeba spp. in river water samples from the Black Sea region, Turkey
Authors: Koyun İlknur , Kolören Zeynep , Karaman Ülkü , Tsiami Amalia , Karanis Panagiotis
Published: February 2020

The present study aims to investigate the occurrence of free living amoeba (FLA) in water resources (rivers and tap water) in Samsun in the Black Sea. The presence of Acanthamoeba spp. was confirmed in 98 of 192 water samples collected from 32 sites of Samsun province (Samsun centre, Terme, Carsamba, Tekkekoy, Bafra) by PCR. Acanthamoeba spp. were found in 15/36 river samples from Samsun, in 58/90 from Terme, in 12/30 from Carsamba, in 7/18 from Tekkekoy and in 6/18 from Bafra. No Acanthamoeba species were detected in tap water samples. The highest rate in river waters contaminated with Acanthamoeba species was in Terme followed by Samsun centre (41.7%), Carsamba (40%), Tekkekoy (38.9%) and Bafra districts (33.3%), respectively. The result of the subsequent sequence analysis showed Haplotype I (A. triangularis) in 5%, Haplotype II (A. polyphaga) in 29.6%, Haplotype III (Acanthamoeba spp.) in 62% and Haplotype IV (A. lenticulata) in 3%. The most common genotype was Acanthamoeba T4 (Acanthamoeba spp., A. polyphaga, A. triangularis) and T5 genotype was also found in 3%. The T4 genotype is the most common genotype associated with Acanthamoeba keratitis (AK) worldwide; therefore, humans and animals living in the area are at risk after contact with such waters.
Characterization of slowly-biodegradable organic compounds and hydrolysis kinetics in tropical wastewater for biological nitrogen removal
Authors: How Seow Wah , Sin Jia Huey , Wong Sharon Ying Ying , Lim Pek Boon , Mohd Aris Alijah , Ngoh Gek Cheng , Shoji Tadashi , Curtis Thomas P. , Chua Adeline Seak May
Published: February 2020

Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 °C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3–40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15–60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 °C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.
Adsorption characteristics and mechanism of norfloxacin in water by γ-Fe2O3@BC
Authors: Wang Jinpeng , Zhang Ming , Zhou Runjuan , Li Jiyuan , Zhao Wei , Zhou Jinghong
Published: February 2020

Using waste pomelo peel as raw material, pomelo peel-based biochar (BC) was prepared by pyrolysis at 400 °C, and the pomelo peel-based biochar was prepared by loading γ-Fe2O3 onto the surface of the pomelo peel-based biochar by unlimited oxygen chemical precipitation. The results showed that the pomelo peel biochar loaded with γ-Fe2O3 had higher specific surface area and larger pore volume. The load of γ-Fe2O3 gives γ-Fe2O3@BC excellent magnetic separation ability, and its magnetic saturation intensity is as high as 30.60 emu/g. BC and γ-Fe2O3@BC were applied to remove norfloxacin (NOR) from a water body. It was found that the adsorption of NOR by both of them followed the pseudo-second-order kinetic model. The adsorption isotherm mainly conforms to the Sips model, and the adsorption process of NOR is a spontaneous endothermic reaction. The pH and ionic strength have a great influence on the adsorption of NOR by BC and γ-Fe2O3@BC, and they play a role mainly by influencing the morphology of NOR in water. The adsorption mechanism showed that cation exchange and hydrogen bonding were the main forces for BC to adsorb NOR. Moreover, the γ-Fe2O3 particles enhanced the hydrophobicity of the pomelo peel-based biochar, making the hydrophobicity become the main force for the adsorption of NOR by the γ-Fe2O3@BC. The adsorption–desorption experiment showed that after four cycles of recycling, the adsorption capacity of γ-Fe2O3@BC for NOR was still up to 61.43% of the initial adsorption capacity, and it had a good recycling property.
A method for reclaiming nutrients from aquacultural waste for use in soilless growth systems
Authors: Ezziddine Maha , Liltved Helge , Homme Jan Morten
Published: February 2020

The aim of this work was to develop a method that allows the recovery of nutrients from aquaculture sludge, not only to alleviate the disposal problem, but also to address the future scarcity of non-renewable fertilizers. This method includes two steps: Nutrient mobilization using aerobic digestion followed by solids precipitation using chitosan as the flocculant. The aerobic digestion experiments were conducted in aerated batch reactors, while a jar test apparatus was used to assess the capacity of chitosan to remove total suspended solids (TSS) and turbidity. During aerobic digestion, the concentration of soluble N (sum of NH4-N, NO2-N, NO3-N) increased from 181 mg/L at the start to 890 mg/L after three weeks, and to 903 mg/L after four weeks and solids removal by chitosan flocculation. The corresponding concentrations for soluble P were 8.2 mg/L at start, 110 mg/L after three weeks of aerobic digestion, and 160 mg/L after four weeks of aerobic digestion and chitosan flocculation. Other macronutrients (K, Ca, Mg, S) and micronutrients (Fe, Mn, Zn, B, Cu, Mo) were mobilized to concentrations close to or higher than levels recommended for hydroponic growth of vegetables. Chitosan flocculation and precipitation using a dose of 15 mg/L resulted in a reduction of the turbidity by 96% from 156 to 6.5 FNU. After chitosan precipitation, 80% of the sludge could be reclaimed as a nutrient-rich clear phase, low in TSS and turbidity.
Kinetic study on nitrification of ammonium nitrogen-enriched synthetic wastewater using activated sludge
Authors: Bhattacharya Roumi , Mazumder Debabrata
Published: February 2020

Nitrification of ammonium nitrogen (NH4+-N)-bearing synthetic wastewater was performed in a batch-activated sludge reactor by varying the initial ammonium nitrogen concentration up to 400 mg/L at a pH of 8.1 ± 0.2 and temperature of 36 ± 2 °C for developing the process kinetics using acclimatised biomass. Maximum ammonium nitrogen removal efficiency of 98.3% was achieved with initial ammonium nitrogen and mixed liquor suspended solids concentration of 235 mg/L and 2,180 mg/L, respectively, at 48 h batch period. Based on the experimental results, kinetic constants for ammonia nitrogen removal following Monod's approach were obtained as maximum substrate removal rate coefficient = 0.057 per day, yield coefficient = 0.336 mg volatile suspended solids/mg ammonium nitrogen, half velocity constant = 12.95 mg NH4+-N/L and endogenous decay constant = 0.02 per day. Nitrification is a consecutive reaction with ammonium oxidation as the first step followed by nitrite oxidation. The overall rate of nitrite and nitrate formation was observed to be 1.44 per day and 0.34 per day, respectively.
To the theory analysis of tightness of tank of pressure testing
Authors: Shagapov Vladislav Sh. , Khusainov Ismagilyan G. , Galiakbarova Emiliya V. , Khakimova Zulfya R.
Published: February 2020

This article studies the process of relaxation of the pressure in a tank with the damaged area of the wall after pressure-testing. The authors use different methods for the diagnosis of the technical condition of objects of petroleum products storage. Pressure testing is one of nondestructive methods. The rate of pressure decrease is characteristic of the system tightness.
This article studies the cases of ground and underground location of the tank. Pressure testing involves excess pressure inside of a tank and observing its decrease. Over time, one can assess the integrity of the system. This has required creating mathematical models to account the filtration of the liquid depending on the location of the tank. The results include the analytical solution of the task and the formulas for describing the dependence of the relaxation time of pressure in the tank from the liquid and soil parameters, geometry of the tank, and the damaged portion of the wall. The two- and three-dimensional cases of liquids filtration for the case of underground location of the tank were considered. The results of some numerical calculations of the dependence of reduction time and the time of half-life pressure from the area of the damaged portion of the wall were shown. The obtained solutions allow assessing the extent of the damaged area by the pressure testing with known values of tank, liquid, and soil.
Using neural networks for predicting the dynamics of water cut of horizontal wells
Authors: Kislitsyn Anatolii A. , Kuznetsov Sergey V. , Podnebesnykh Aleksandr A. , Granovsky Andrey M.
Published: February 2020

This article presents the problem of determining the conditions of intensive flooding of horizontal wells for complicated geological structure strata, such as the Pokur formation at the Vostochno-Messoyakhskoye oil field. It corresponds to alluvial continental planes or to coastal-sea conditions of sedimentary rocks accumulation. The principal peculiarity of the geological structure of these strata is the high lateral heterogeneity, which is connected with riverbed migration by sedimentary rocks accumulation. Using the neural network method, the authors have developed an algorithm that allows explaining the different dynamics of displacement characteristics for the wells with identical geological and technological indicators. Having analyzed the dynamics and causes of water cut of 125 wells at East-Messoyahskoe oil field, the authors show that the geo-statistical methods do not apply to the task of describing continental accumulation objects with compound construction. However, the results of seismic data interpretation provide the basic volume of information about the inter-well space. The authors have developed an algorithm for complete regression analysis for the adaptation of the hydrodynamic model, which includes the method for constructing a cube of sandiness based on neural network modeling. It follows the basic factors, those exert influence on dynamics of water cut. They include distance at well’s tube to water-oil contact, and presence of impenetrable or semi penetrable interlayer between tube and water-oil contact. The neural network algorithm (Genetic Inversion) allowed performing the test calculations on one of group wells most operated. The suggested approaches in the construction of the reservoir distribution in the inter-well space allow achieving better integral convergence of the dynamics of water cut at the first iterations of the full-scale hydrodynamic model.
The heat exchange intensification under incomplete hydrophobization oil reservoirs
Authors: Salikhov Rustam Sh. , Mazitov Ruslan F. , Pacharukov Yuriy V.
Published: February 2020

High-viscosity oil recovery often requires thermal methods of enhanced oil recovery combining surface acting agent (SAA) injection. Thermal treatment allows increasing hydrocarbon movability. Efficiency raisings’ limiting factor of this method includes injecting agent’s thermal loss (water and steam) as well as SAA molecules thermal destruction. This article assesses nanoparticles adding in SAA water solution’s influence. The authors consider a theoretic capability of increasing heat exchange’s inetnsity between oil reservoir and injected agents by means of adding nanoparticles as well as increase of the SAA thermostability’s capability under high temperatures influence. The results of the laboratory experiments on SAA’s adsorbed layer structure on the surface of solid state show the structure’s dependence on SAA concentration in the solution. According to the developed mathematic model, a periodic adsorbed field will lead to the increase of heat transfer coefficient by means of the Nusselt number increment. This will allow increasing efficiency of thermal methods EOR application.
Perforated One Anastomosis Gastric Bypass, How We Managed and Review of Literature
Authors: Al-Masari Hayder , Nofal Heba , Ainawi Reham , Mahdy Tarek , Rashed Marwan
Published: February 2020

:

Marginal ulcer formation remains a common complication of the one anastomosis gastric bypass procedure, the ulcer can further perforate and present as peritonitis and although this is uncommon, it is considered one of the life threatening sequela associated with this surgery, we report here 2 different cases of perforated marginal ulcers that presented months after the procedure with acute abdomen, and discuss the surgical management using the laparoscopic approach to repair the perforation.
Willingness of Medical Students to Practice in Their Country of Origin after Studies: A Nigerian Perspective
Authors: CHIME Onyinye Hope , ORJI Chinonyelu Jennie , NDIBUAGU Edmund Onyemaechi , ARINZE-ONYIA SussanUzoamaka , ANEKE Tonna Jideofor , NWOKE Ijeoma Ngozi , MADU AnselemChekwube
Published: February 2020

Background:

Availability of skilled manpower at service locations is an important indicator of the strength of the healthcare system and is critical for effective healthcare service delivery in developing countries. Emigration of doctors reported in Africa over the years has tremendously increased in recent times. The health sector in this low-income region has registered a great setback in their health indices following a severe shortage of manpower.

Objective:

This study was undertaken to assess the willingness of medical students to practice in Nigeria after the completion of their medical education.

Methods:

This was a cross-sectional study performed among medical students in Enugu State University Teaching Hospital, Parklane, Enugu, Nigeria. A pretested self-administered questionnaire was used for data collection. Information was analyzed using Statistical Package for Social Sciences version 22 software. Descriptive statistics were used to summarize and present data. Degree of bivariate associations were measured using the Pearson Chi-Square test at a significance level of p<0.05.

Results:

The mean age of the respondents were 23.9 ± 3.4 years. Majority were males (58.0%) and a greater proportion of the respondents (83.5%) did not desire to practice in Nigeria after their studies with the USA (29.3%) and Canada (17.8%) being the most preferred countries of migration. Advancement in technology and better remuneration were the most compelling factors for emigration.

Conclusion:

To ensure adequacy and efficiency in the health sector as recommended by the World Health Organization, governments of low-income countries should put measures in place to make medical practice in their countries more attractive to young doctors. Such measures include improved remuneration for services rendered and incorporation of more modern technology into health care delivery system.
Synergistic Effect of Tazobactam on Amikacin MIC in Acinetobacter baumannii Isolated from Burn Patients in Tehran, Iran
Authors: Azimi Leila , Tahbaz Sahel V. , Alaghehbandan Reza , Alinejad Farank , Lari Abdolaziz R.
Published: February 2020

Background:

Burn is still an important global public health challenge. Wound colonization of antibiotic resistant bacteria such as Acinetobacter baumannii can lead to high morbidity and mortality in burn patients. The aim of this study was to evaluate the inhibitory effect of tazobactam on efflux pump, which can cause aminoglycoside resistant in A. baumannii isolated from burn patients.

Methods:

In this study, 47 aminoglycoside resistant A. baumannii spp. were obtained from burn patients, admitted to the Shahid Motahari Burns Hospital in Tehran, Iran, during June-August 2018. The inhibitory effect of tazobactam against adeB such as efflux pump was evaluated by Minimum Inhibitory Concentration (MIC) determination of amikacin alone and in combination with tazobactam. Fractional Inhibitory Concentration index (FIC) was used to determine the efficacy of tazobactam/ amikacin combination. Further, semi-quantitative Real- Time PCR was performed to quantify the expression rates of the adeB gene before and after addition of tazobactam/amikacin.

Results:

The MIC values were significantly reduced when a combined amikacin and tazobactam was utilized. The most common interaction observed was synergistic (78.2%), followed by additive effects (21.8%), as per FIC results. The adeB mRNA expression levels were found to be downregulated in 60.7% of isolates treated with tazobactam.

Conclusions:

Tazobactam can have impact on resistance to aminoglycoside by inhibiting efflux pump. Thus, the combination of tazobactam with amikacin can be used as an alternative treatment approach in multidrug resistant A. baumannii infections.
Biomarkers for Early Detection of Colitis-associated Colorectal Cancer - Current Concepts, Future Trends
Authors: Mackiewicz Tomasz , Sowa Aleksander , Fichna Jakub
Published: February 2020

Colitis-associated colorectal cancer (CAC) remains a critical complication of ulcerative colitis (UC) with mortality of approximately 15%, which makes early CAC diagnosis crucial. The current standard of surveillance, with repetitive colonoscopies and histological testing of biopsied mucosa samples is burdensome and expensive, and therefore less invasive methods and reliable biomarkers are needed. Significant progress has been made thanks to continuous extensive research in this field, however no clinically relevant biomarker has been established so far. This review of the current literature presents the genetic and molecular differences between CAC and sporadic colorectal cancer and covers progress made in the early detection of CAC carcinogenesis. It focuses on biomarkers under development, which can be easily tested in samples of body fluids or breath and, once made clinically available, will help to differentiate between progressors (UC patients who will develop dysplasia) from non-progressors and enable early intervention to decrease the risk of cancer development.
NLRP3 Promotes Colorectal Cancer Cell Proliferation and Metastasis via Regulating Epithelial Mesenchymal Transformation
Authors: Shao Xinyu , Lei Zhiyi , Zhou Chunli
Published: February 2020

Background:

Nucleotide-binding domain Leucine-rich Repeat Protein 3 (NLRP3) plays a regulatory
role in the immune and inflammatory responses, and has been implicated in Colorectal Cancer (CRC) progression
and metastasis. However, the underlying molecular mechanisms have not been fully elucidated.

Methods:

In this study, we analyzed the expression levels of NLRP3 in human CRC tissues, and performed
functional assays in CRC cell lines and a subcutaneous tumor model to elucidate its role in the development and
progression of CRC.

Results:

In this study, we found that NLRP3 was significantly upregulated in human CRC tissues and was associated
with tumor size and invasion, lymph node metastasis, venous invasion, neural invasion and TNM staging.
Furthermore, knockdown of NLRP3 in CRC cells inhibited their migration and growth in vitro and in vivo, and
reversed Epithelial-Mesenchymal Transition (EMT) in vitro.

Conclusion:

Our findings indicate that NLRP3 likely regulates CRC metastasis by activating the EMT program,
and is a potential therapeutic target.
A Hypothesis for the Relationship between Depression and Cancer: Role of Ca2+/cAMP Signalling
Authors: Bergantin Leandro B.
Published: February 2020

Limitations on the pharmacotherapy and a high prevalence worldwide are critical issues related to
depression and cancer. It has been discussed that a dysregulation of intracellular Ca2+ homeostasis is involved in
the pathogenesis of both these diseases. In addition, depression raises the risk of cancer incidence. Consistent
data support the concept that depression is an independent risk issue for cancer. However, the cellular mechanisms
involved in this link between depression and cancer remain uncertain. Considering our previous reports
about Ca2+ and cAMP signalling pathways (Ca2+/cAMP signalling), I herein discussed the putative contribution
of Ca2+/cAMP signalling in this link between depression and cancer. Moreover, it is important to take depression
into account during the process of prevention and treatment of cancer.
Prevalence of Nonalcoholic Fatty Liver Disease in Familial Mediterranean Fever
Authors: Tasliyurt Turker , Gokce Erkan , Sahin Safak , Aslan Asiye Baris , Demir Ayse Kevser , Uzun Suheyla , Kutluturk Faruk
Published: February 2020

Introduction:

Nonalcoholic fatty liver disease (NAFLD) is closely associated with metabolic
syndrome (MetS), insulin resistance (IR) and chronic inflammation. Although familial Mediterranean
fever (FMF) patients have no symptoms in the periods between attacks, their subclinical inflammation
continues. The aim of the present study was to determine the NAFLD frequency in FMF
patients and to evaluate their MetS, IR and lipid profiles.

Methods:

The study included 54 FMF patients and 54 control subjects. The clinical and demographic
characteristics of the subjects were recorded, and the patients’ Pras disease severity score was calculated.
IR was determined using the homeostasis model assessment (HOMA) index. MetS was
diagnosed using the revised National Cholesterol Education Program Adult Treatment Panel III criteria
(NCEP ATP III). Hepatic ultrasonography was used to diagnose NAFLD.

Results:

NAFLD was observed in 15 FMF patients (27.8%) and 14 controls (25.9%). The difference
between the groups was not significant (p=0.828). Similarly, no significant difference was found between
the two groups for MetS frequency and HOMA index levels. Fasting plasma glucose was significantly
higher in FMF patients, whereas differences between the two groups were not significant for
lipid levels and other parameters. When FMF patients with and without NAFLD were compared, no
significant difference was found in Pras disease severity score, duration of the disease and daily colchicine
dose.

Conclusion:

The present study showed that NAFLD frequency was not increased in FMF patients, and
that patients’ MetS frequency, IR and lipid profiles were not different from control subjects.
Telfairia occidentalis Potentiates the Antiplasmodial Activity of Artemisinins and Amodiaquine Combination Therapy
Authors: Ebong Aniekan S. , Eseyin Olorunfemi A. , Etim Emmanuel I. , Okokon Jude E. , Anah Victor U. , Attih Emmanuel E. , Charles Goodnews E.
Published: February 2020

Background:

Drug-phytochemical interactions sometimes result in various unpredictable outcomes.

Objective:

The aim of this study was to evaluate the in vivo antiplasmodial activity of the aqueous leaf extract
of Telfairia occidentalis and its potentiation of the activity of Amodiaquine (AQ) and dihydroartemisinin
(DHA) on mice infected with Plasmodium berghei.

Methods:

Phytochemical screening of the extract was carried out using standard procedures. The extract
prepared in 250 and 500 mg/kg/body weight together with amodiaquine and dihydroartemisinin were administered
as a single dose and in combination to albino mice by oral gavage, adopting the standard procedures
of prophylactic, suppressive and curative antiplasmodial assay models.

Results:

Phytochemical screening of the extract confirms the abundance of alkaloids, saponins and tannins.
The analysis reveals a significant (p < 0.05) competitive reduction of parasitaemia by the conventional
drugs and the extract in a dose-dependent order. The aqueous extract of T. occidentalis at 250 and 500
mg/kg gave a percentage parasitaemia reduction of 83.90 % and 85.00%, respectively when compared
with the negative control. The concurrent administration of the extract and the drugs produced a synergistic
effect in a dose-dependent order. When AQ plus DHA waer administered concurrently with 250 mg/kg
and 500 mg/kg of extract, the percentage reduction in parasitaemia increased to 99.50 % and 99.59%, respectively.

Conclusion:

This shows that the aqueous extract of T. occidentalis possesses significant (p < 0.05) antiplasmodial
activity which is comparable to AQ and DHA. It also enhances the efficacy of the standard
drugs which indicates an advantage in the treatment of uncomplicated falciparum malaria.
Study of Pulsation Pressures in the Stages of an Electric Submersible Pump at Shut-Off Under Various Speeds of Operation
Authors: Dhanasekaran Arumugam , Kumaraswamy Sivasailam
Published: February 2020

Background:

Electric Submersible Pumps (ESPs) are widely used in agricultural fields,
petroleum, and various other industries. These pumps are mostly driven at a constant speed since an A.C.
motor is normally used as the drive. However, ESPs can also be operated at various speeds by employing
a Variable Frequency Drive (VFD). Several patents have been published in ESP. Normally these pumps
are started with the discharge valve at its closed position in order to control the starting current. When the
ESP runs at its shut-off position, it will develop a higher head and an increase in fluctuating pressure. In
order to evaluate the effects of pressure fluctuation, its characteristics must be investigated.

Objective:

Experimentally investigate the characteristics of pressure pulsation which are generated at
each stage of a multistage ESP during shut-off condition at various speeds.

Methods:

An ESP with five stages was selected for conducting experiments. A VFD was used for operating
the ESP at five speed settings from 80 to 120 % of its rated speed. Piezoresistive transducer was
placed at the delivery side of the pump to acquire the signals of unsteady pressure. The pump was operated
at closed valve condition at each speed, and unsteady pressure signals due to pressure pulsation
were captured.

Results:

Obtained results have indicated the presence of fundamental frequency pertaining to vane
passing frequency and harmonics of higher frequencies.

Conclusion:

Study of pressure fluctuations at shut-off will help to analyze the failures of ESP due to
vibration which occur when the pump runs at closed valve position for a prolonged length of time and
stability of these pumps at lower flow rates.
Effects of Vitamin C and E Against Oxidative Stress: Is Antioxidant Supplementation Efficient?
Authors: Merzouk Amel Saidi , Loukidi Bouchra , Bettioui Réda , Merzouk Hafida
Published: February 2020

Objective:

Numerous epidemiological studies show an increased prevalence of
metabolic diseases related to oxidation stress causing cell damage. Antioxidant supplementation is
therefore useful to protect against the oxidative stress mediated disease development and has
become an increasingly popular practice. In this review, a selection of clinical and in vitro studies
on vitamin C and E supplementation and the evaluation of their beneficial or negative effects have
been analyzed.

Results:

Clinical studies and supplementation trials show a correlation between antioxidants and
metabolic improvement in different diseases such as cancer, cardiovascular disease, diabetes,
obesity. Vitamin C (ascorbic acid) and E (α-tocopherol) appear to be among the most commonly
used antioxidants. However, taking antioxidant supplements in high doses can be harmful. In some
studies, little supportive evidence has been provided on substantial protection against chronic
diseases by antioxidants. In addition, previous studies have revealed negative effects of antioxidant
supplements such as pro-oxidant activities in particular conditions including their dosage and the
body oxidant/ antioxidant status.

Conclusion:

Antioxidant supplements should be used with caution.
Turning Apparent Waste into New Value: Up-Cycling Strategies Exemplified by Brewer’s Spent Grains (BSG)
Authors: Salman Wagd , Ney Yannick , Nasim Muhammad Jawad , Bohn Torsten , Jacob Claus
Published: February 2020

Background:

The production, distribution, consumption, and removal of food produces
a wide range of organic by-products and, eventually, waste. This kind of waste not only places a
considerable burden on the environment and food economy, it also represents an opportunity to
harvest additional value, often within an unexpected context and with little connection to the
original food item it originates from.

Objectives:

Brewer’s spent grain (BSG) is such a waste material produced in considerable
quantities as a by-product of the beer industry. Although traditionally discarded or fed to animals,
it is rich in a wide range of interesting biomolecules and can be converted into a wide spectrum of
valuable products.

Results:

Traditional and more innovative applications of BSG illustrate the concept of up-cycling
in the food industry. With the relevant scientific and engineering base in place, BSG can be turned
into a range of valuable products such as Brewer’s vinegar, creams, high-fibre bread, grain burgers,
bioplastics, and pellets.

Conclusion:

In the medium term, rather than composting BSG for biogas or feeding it to animals,
it may be seen as a valuable raw material to inspire various small- and medium-sized local
industries and bedrock of an entire industry.
Подвижность ионных носителей заряда в пьезоэлектрических кристаллах Li-=SUB=-2-=/SUB=-B-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=-
Authors: Сорокин Н.И. , Писаревский Ю.В. , Гребенев В.В. , Ломонов В.А.
Published: February 2020

The impedance measurements of Li2B4O7 single crystal with Ag electrodes in the frequency range
1-3*107 Hz at room temperature have been made. The Li2B4O7 crystal (sp. gr. I41cd, Z = 8) was oriented along crystallographic axis c. Contributions from the bulk crystal and crystal / electrode boundaries in the impedance hodograph of the Ag | Li2B4O7 | Ag system were selected. The structural mechanism of lithium-ion transport in Li2B4O7 has been discussed. Based on electrophysical and structural data, the conductivity σdc = 2.3 × 10–9 S / cm, carrier mobility (vacancies VLi) μmob = 6 × 10−10 cm2 / sV and their concentration nmob = 2.4 × 1019 cm – 3 (0.14% of the amount of lithium in the crystal lattice) have been determined.
Особенности импульсного перемагничивания высококоэрцитивного материала на основе наночастиц ε-Fe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-
Authors: Попков С.И. , Красиков А.А. , Семенов С.В. , Дубровский А.А. , Якушкин С.С. , Кириллов В.Л. , Мартьянов О.Н. , Балаев Д.А.
Published: February 2020

The magnetic structure of the polymorphic modification of iron oxide ε-Fe2O3 is collinear ferrimagnetic in the range from room temperature to ~ 150 K. Further, with decreasing a temperature in ε-Fe2O3, a magnetic transition occurs, accompanied by a significant decrease in the coercive force HC, and in the low temperature range ε-Fe2O3 is characterized by a complex incommensurate magnetic structure. In this work, we experimentally investigated the processes of dynamic magnetization reversal of ε-Fe2O3 nanoparticles of an average size of 8 nm in the temperature range of 80–300 K, comprising various types of magnetic structure of this iron oxide. A bulk material was studied - xerogel SiO2 with ε Fe2O3 nanoparticles embedded in pores. To measure the magnetic hysteresis loops under dynamic magnetization reversal, a pulsed magnetic field technique of Hmax up to 130 kOe was used, using the method of discharging a capacitor bank through a solenoid. The coercive force of HC during dynamic magnetization reversal noticeably exceeds HC for quasi-static conditions. This is caused by processes of superparamagnetic relaxation of the magnetic moments of particles during pulsed magnetization reversal. In the range from room temperature to ~ 150 K, the rate of change of the external field dH / dt is the main parameter determining the behavior of the coercive force under the conditions of dynamic magnetization reversal. This behavior is expected for a system of single-domain ferro- and ferrimagnetic particles. Under external conditions (at a temperature of 80 K), when the magnetic structure of ε Fe2O3 is incommensurate, the coercive force during pulsed magnetization reversal already depends on the parameter dH / dt, and is largely determined by the maximum applied field Hmax. Such a behavior, atypical for systems of ferrimagnetic particles, is already caused by dynamic spin processes inside ε-Fe2O3 particles during fast magnetization reversal.
Проявление квантоворазмерных эффектов в нанокристаллах и аморфных нанокластерах германия в плeнках GeSixOy
Authors: Гамбарян М.П. , Кривякин Г.К. , Черкова С.Г. , Stoffel M. , Rinnert H. , Vergnat M. , Володин В.А.
Published: February 2020

The non-stoichiometric germanosilicate films of two types GeOx[SiO](1-x) and GeOx [SiO2](1-x) were obtained by high-vacuum evaporation of GeO2 and either SiO or SiO2 powders and sputtering on a cold Si (001) substrate. The as-deposited and annealed (550 and 650 oC, 1 hour) samples were studied by IR spectrocopy, electron microscopy, Raman spectroscopy and photoluminescence (PL). From an analysis of Raman spectra, it was found that the as-deposited GeO[SiO2] film did not contain germanium clusters, and the as-deposited GeO[SiO] film contained amorphous germanium clusters; according to electron microscopy, it’s size was ~3 nm. According to IR spectroscopy, the films contained Si-O, Ge-O, and Si-O-Ge bonds. After annealing at 550 °C, amorphous germanium clusters were detected in both films, and after annealing at 650 °C, germanium nanocrystals were observed. A wide PL band with a maximum of 1050 nm was found in the as-deposited films at low temperatures. PL is probably due to defects, presumably oxygen vacancies and excess germanium atoms. Annealing causes a transformation of both film structure and PL spectra. In films containing germanium nanoclusters, PL is observed with a maximum of 1500–1600 nm. In this case, the PL signal from defects decreased. The temperature dependence of the intensity of the PL peaks was studied; it decreased with increasing temperature but remained at temperatures up to 200 K. The contribution to the PL from germanium nanocrystals formed during annealing is discussed.
Исследование модификации структуры и эрозии поверхности вольфрама и молибдена при плазменном облучении
Authors: Рахадилов Б.К. , Миниязов А.Ж. , Скаков М.К. , Сагдолдина Ж.Б. , Туленбергенов Т.Р. , Сапатаев Е.Е.
Published: February 2020

The article presents the results of a study of the structure modification and erosion of tungsten and molybdenum surfaces under plasma irradiation. It was revealed that during irradiation of the samples, a change in the surface is observed as a growth of the relief as a result of non-uniform etching of the surface. Metallographic analysis showed that when irradiating samples of tungsten with T=1000 °C and 1500 °C, the degree of relief development is low compared with a sample of tungsten irradiated at T=700 °C. It was determined that the greatest increase in roughness in samples irradiated at T=1500 °C, which is associated with the formation of small cracks in the surface layer. It is determined that appreciable erosion of the samples of tungsten and molybdenum by irradiation with plasma streams that simulated the stationary regime of the plasma occurs only at relatively high temperatures of the target. It is found that the size of cracks increases with increasing ion energy from 1.5 keV up to 2 keV. It was found that as a result of irradiating tungsten with a stationary plasma, etching pits in the size from 100 nm to 500 nm are formed in the grain body, and when irradiated with an accelerating potential of 1.6 keV, a large number of small pores ranging in size from 0.2 μm to 1.0 μm are formed as a result of surface etching.