Induced electronic phenomena in crystals of p-GaSe semiconductor promising for optoelectronics

An induced impurity photoconductivity by the electric field, thermally stimulated conductivity and spontaneous pulsations of the dark current were found in the undoped (with a dark resistivity P77≈3•104÷108 Ω-cm at T≈77 K) and erbium doped (NEr=10–5÷10–1 at.%) p-GaSe crystals in the temperature range of T≤240÷250 K at electric field strengths (E) creating a noticeable injection. It was found that the value of the observed impurity photoconductivity (M) monotonically increase at low illumination in undoped crystals with increasing P77 and its spectrum smoothly expands towards longer waves. The value of ∆ii and the width of its spectrum change non-monotonically with increasing NEr in doped crystal and it gets its maximum value at NEr ≈5•10-4 at.%. The intensity of spontaneous pulsations increases with increasing E at the higher electric field strengths. However, the impurity photoconductivity and the peak of thermally stimulated conductivity gradually disappeared. The amplitude and frequency of the observed spontaneous pulsations of the dark current is increased with increasing in the injection ability of the contacts. Moreover, the pulsations of the dark current gradually disappeared with increasing T. It was shown that all these three phenomena are directly caused by the recharge of sticking levels with a depth Er ≈+0.42 eV and a density Nt≈ 1015 cm-3 by injected holes. However, in high-resistance undoped and doped Er ≤10-2 at.% crystals, it is also necessary to consider the presence of random macroscopic defects in the samples to explain their features. A qualitative explanation is proposed based on the obtained results.

Seeing the unseen: A trifoliate (MYB117) mutant allele fortifies folate and carotenoids in tomato fruits

Micronutrient deficiency also termed hidden hunger affects a large segment of the human population, particularly in developing and underdeveloped nations. Tomato the second most consumed vegetable crop in the world after potato can serve as a sustainable source to alleviate micronutrient deficiency. In tomato, the mutations in the R2R3-MYB117 transcription factor elicit trifoliate leaves and initiate axillary meristems; however, its effect on fruit metabolome remains unexplored. The fruits of a new trifoliate (tf) allele (tf-5) were firmer, had higher Brix, folate, and carotenoids. The transcriptome, proteome, and metabolome profiling of tf-5 reflected a broad-spectrum change in homeostasis. The tf-5 allele enhanced the fruit firmness by suppressing cell wall softening-related proteins. The tf-5 fruit displayed a substantial increase in aminome, particularly γ-aminobutyric acid, with a parallel reduction in aminoacyl t-RNA synthases. The increased lipoxygenases proteins and transcripts seemingly elevated jasmonic acid. In addition, increased abscisic acid hydrolases transcripts coupled with reduced precursor supply lowered abscisic acid. The upregulation of carotenoids was mediated by modulation of methylerythreitol and plastoquinone pathways along with an increase in carotenoids isomerization proteins. The upregulation of folate in tf-5 was connoted by the increase in precursor p-aminobenzoic acid and transcripts of several folate biosynthesis pathway genes. The reduction in pterin-6-carboxylate and γ-glutamyl hydrolase activity indicated that the diminished folate degradation also enriched folate levels. Our study delineates that introgression of the tf-5 can be used for the γ-aminobutyric acid, carotenoids, and folate fortification of tomato.

Autoxidation Enhances Anti-Amyloid Potential of Flavone Derivatives

The increasing prevalence of amyloid-related disorders, such as Alzheimer’s or Parkinson’s disease, raises the need for effective anti-amyloid drugs. It has been shown on numerous occasions that flavones, a group of naturally occurring anti-oxidants, can impact the aggregation process of several amyloidogenic proteins and peptides, including amyloid-beta. Due to flavone autoxidation at neutral pH, it is uncertain if the effective inhibitor is the initial molecule or a product of this reaction, as many anti-amyloid assays attempt to mimic physiological conditions. In this work, we examine the aggregation-inhibiting properties of flavones before and after they are oxidized. The oxidation of flavones was monitored by measuring the UV-vis absorbance spectrum change over time. The protein aggregation kinetics were followed by measuring the amyloidophilic dye thioflavin-T (ThT) fluorescence intensity change. Atomic force microscopy was employed to image the aggregates formed with the most prominent inhibitors. We demonstrate that flavones, which undergo autoxidation, have a far greater potency at inhibiting the aggregation of both the disease-related amyloid-beta, as well as a model amyloidogenic protein—insulin. Oxidized 6,2′,3′-trihydroxyflavone was the most potent inhibitor affecting both insulin (7-fold inhibition) and amyloid-beta (2-fold inhibition). We also show that this tendency to autoxidize is related to the positions of the flavone hydroxyl groups.

EFFECT OF VIBRATION STRESS BOTH ON THE SHIFTS OF SOLUBLE PROTEIN FRACTIONS FROM RAT LIVER AND ON THE ARGINASE I ACTIVITY

Vibration pathology is in the second place among diseases connected to the profession. The vibration effect both on the protein fraction shifts and on the activities of I type arginase (Arg) IA and IB from white rat liver has been studied in the conditions of 5-, 10- and 15-day vibration state. In the initial state of vibration some decrease of Arg IA and Arg IB activities was revealed as compared to the control without general protein spectrum change of liver extract. Along with vibration effect, the expression level of Arg IA was increased with duration enhancement, which possibly is due to hyperammonemia, in the result of which ureagenesis is stimulated. Stimulation of easy available adaptation reserves were described due to protein catabolism. Analysis of shifts of general and enzyme protein fractions in the conditions of vibration effect allows to reveal their qualitative and quantitative changes and to make important the organism adaptation reactions that result from anabolic and catabolic process relations. It is possible that the revealed changes in the activity of arginase IA and IB are a biologically expedient mechanism for regulating the activity of hepatic arginase during vibration stress.

The Outdoor Field Test of the 4T III-V on Si Tandem PV Module and Its Energy Yield Modeling

The outdoor field test of the 4-terminal III-V on Si tandem photovoltaic module (specifically, InGaP/GaAs on Si) was investigated and performance model, considering spectrum change affected by fluctuation of atmospheric parameters, was developed and validated. The 4-terminal III-V on Si tandem photovoltaic module had about 40 % advantage in seasonal performance loss compared with standard InGaP/GaAs/InGaAs 2-terminal tandem photovoltaic module. This advantage is expanded in (subarctic zone) < (temperate zone) < (subtropical zone).

A Reversible Spectrophotometric Method Based on a Coupled Microfluidic Chip for Highly Selective Ammonium Detection

A coupled chip aiming at economical and highly selective ammonium detection was fabricated. It consisted of a reaction chip, a gas-diffusion chip, and a detection chip. Zinc tetraphenylporphyrin dyed on the cation-exchange resin microbeads was used as the indicating material to avoid excess consumption for its reversibility. PDMS was selected as the material of the gas-diffusion membrane. A portable spectrometer was applied for spectrum analysis. By analysis of spectrum change, the high selectivity was confirmed because no component had interference on detection effect. Good performance was shown for all the tested concentrations (0.2–50 mg·L−1). The stability and reversibility were also judged by the spectrum data obtained from the indicating process and the recovering process. Finally, real samples containing ammonium were tested and the results were compared to those came from a standard method to confirm the accuracy of our method.

ANALISA PENGARUH GAYA ELEKTROSTATIK PADA SPEKTRUM PENCITRAAN RESONANSI MAGNETIK (MRI) DALAM JARINGAN BIOLOGI

A study of magnetic core resonance imaging modeling of biological tissue has been carried out in analyzing the effect of electrostatic forces with computational approach. This analysis aims to look at the effect of electric and magnetic force on the spectrum of breast cancer tissue. Physical parameters were determined using the modeled wave equation with the application of mathematical wolfram software 9. Computational or modeling results obtained 6 variations of the MRI spectrum showing the peak magnitude of the electric and magnetic spectrum changes by varying the resolution and distance. This is evidenced from the maximum resolution range ie the peak of the electric field spectrum at amplitude 25 a.u is at a concentration of 5 ppm. Resolution of spectrum peak medium is at concentration of 3-4 ppm whereas minimum resolution has 4 peak spectrum that is at concentration 1-2 ppm, 2-3ppm, 3-4ppm and 4ppm. the result of MRI spektrum for distance variation resulted in spectrum change, further reduced the distance then the mri spectrum in magnetic and electric field approaching spin 1.

NUMERICAL INVESTIGATION OF BREAKING IRREGULAR WAVES OVER A SUBMERGED BAR WITH CFD

The study of breaking irregular waves is of great practical interest, because of the waves found in the nature. Regular waves are seldom found in the field. Irregular waves can be viewed as the superposition of a number of regular waves (wave components) with the different frequencies and the amplitudes. The breaking process for irregular waves is more complex as compared to breaking regular waves. The energy transfer between the individual wave components of different frequencies also takes place during the breaking process. Due to this, the spectral characteristics of the incident wave spectrum change during the breaking process. The main purpose of the study is to investigate the hydrodynamics during the interaction of breaking irregular waves with a submerged bar.