Increase In Intensity Of Bands Research Articles

Evaluation of oxidation stability for palm biodiesel with additives using Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and high-performance liquid chromatography

This paper discusses the potential of tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA) and alpha-tocopherol (α-T) in preventing palm biodiesel oxidation over an extended storage period of twelve weeks. A combination of Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) analyses were carried out. The FTIR spectra showed no significant changes to the carbonyl band at 1740 cm−1 across the storage period for fuels with additives, but the control had increased band intensity, which implied that additives prevented the formation of byproducts which have carbonyl groups or cyclic ether rings. From GC-MS analyses, lower transmittance at C18 methyl esters region was evident of methyl oleate, methyl linoleate and methyl linolenate being consumed to the point where their concentrations dropped below those of methyl palmitate in the sample without additives. Furthermore, the analyses indicated that 3-octyl-oxiraneoctanoic acid ME, E−10,13,13-trimethyl-11-tetradecen-1-ol acetate and 17-octadecynoic acid ME were the major oxidation byproducts. Traces of acetal, carboxylic acid, oxirane and alkylnoic acid were also detected. It was shown through HPLC analyses that TBHQ, BHA and α-T were consumed with α-T samples having the highest consumption compared to TBHQ and BHA. Overall, the findings supported the important role of additives in stabilizing the fuel and preventing oxidation during extended storage.

Effects of Casein Hydrolysate Prepared with Savinase on the Quality of Bread Made by Frozen Dough.

The effect of casein savinase hydrolysate (CSH) usage on frozen dough (1%, 1.5% and 2%, g/100 g flour) was investigated in terms of rheological, thermal and structural characteristics of wheat doughs and the textural and color properties of corresponding breads. Rheological measurements showed that CSH addition into dough led to a reduction in G' and G″ values, but a similar trend was not observed in frozen dough samples. The increase in protein band intensity was observed for control dough (CD) after frozen storage (-30 °C, 28 days), while there were no increases in the band intensities of the doughs with CSH. The freezable water content of unfrozen doughs decreased gradually with the addition of CSH, dependent on concentration level. Frozen storage caused a notable reduction in the α-helices structure of the CD sample (p < 0.05) while no significant variation was observed for the doughs containing CSH (p > 0.05). The lowest specific volume reduction and hardness increment were observed for the breads containing 1.5% and 2% CSH. Frozen storage caused a significant reduction in the b* value of bread crust (p < 0.05), while no significant effect was observed for L* and a* value during frozen storage (p > 0.05). Overall, CSH incorporation into frozen dough can be an alternative that could reduce the quality deterioration of frozen bread.

Walnut Flour as an Ingredient for Producing Low-Carbohydrate Bread: Physicochemical, Sensory, and Spectroscopic Characteristics.

Walnut flour (WF) is a nutrient-rich source that can be used as an alternative for individuals on a gluten-free diet. This study aimed to assess the physical, chemical, and sensory changes in low-carbohydrate bread when supplemented with WF. Molecular-level changes were also examined using ATR-FTIR spectra. The bread recipe, containing buckwheat and flaxseed, was enriched with WF at levels ranging from 5% to 20%. The addition of WF resulted in increased loaf volume and decreased baking loss. Enriched bread samples showed higher protein content, while fat and available carbohydrate content decreased. Additionally, WF incorporation led to a decrease in crumb brightness and an increase in redness (from 23.1 to 25.4) and yellowness (from 23.8 to 26.7). WF also increased crumb hardness and chewiness. Moreover, the tested additives primarily influenced the intensity of FTIR spectra, indicating changes in protein, carbohydrate, and fat content, with increased band intensity observed in the protein region. We particularly recommend bread with a WF content of 15%. This type of bread is characterized by high consumer acceptance. Furthermore, compared to bread without the addition of WF, it has a higher content of phenolic compounds, protein, and fat by approximately 40%, 8%, and 4%, respectively. The antioxidant activity of this bread, determined using the ABTS and DPPH methods, is also significantly higher compared to the control bread.

Physicochemical properties of soybean protein isolate-based gel produced through probiotic fermentation

Soy protein isolate (SPI) was used to prepare gels through probiotic fermentation. The effects of fermentation time (0–20 h) on the physicochemical properties of resulting gel were evaluated. The effect of probiotic fermentation on physicochemical properties of gel was found to highly depend on the fermentation time. The probiotic fermentation decreased the pH value below pH 4.75 and this process also induced SPI to form a gel upon 10 h. The formation of gel was indicated by the increase of particle size, viscosity and storage modulus, and appearance of a new peak in molecular weight distribution. The formation of porous and gel-like microstructure, due to the aggregation of SPI molecules, also occurred after 10 h of fermentation. Water holding capacity of SPI-based gel reached the highest value at 15 h fermentation and decreased with further fermentation. The probiotic fermentation caused an increase of band intensity of amide-A in FTIR spectra. It also caused a decrease of surface hydrophobicity and fluorescence intensity in intrinsic tryptophan fluorescence spectra. The subunits of SPI remained intact and were not affected by probiotic fermentation.

Reliable cell preparation protocol for Raman imaging to effectively differentiate normal leukocytes and leukemic blasts

Leukemias are a remarkably diverse group of malignancies originating from abnormal progenitor cells in the bone marrow. Leukemia subtypes are classified according to the cell type that has undergone neoplastic transformation using demanding and time-consuming methods. Alternative is Raman imaging that can be used both for living and fixed cells. However, considering the diversity of leukemic cell types and normal leukocytes, and the availability of different sample preparation protocols, the main objective of this work was to verify them for leukemia and normal blood cell samples for Raman imaging.The effect of glutaraldehyde (GA) fixation in a concentration gradient (0.1 %, 0.5 %, and 2.5 % GA) on the molecular structure of T-cell acute lymphoblastic leukemia (T-ALL) and peripheral blood mononuclear cells (PBMCs) was verified. Changes in the secondary structure of proteins within cells were indicated as the main effect of fixation, as shown by an increase in band intensity at 1041 cm−1, characteristic for in-plane δ(CH) deformation in phenylalanine (Phe).Different sensitivity of mononuclear and leukemic cells to fixation was observed. While the 0.1 % concentration of GA was too low to preserve the cell structure for an extended period of time, a GA concentration of 0.5 % seemed optimal for both normal and malignant cells. Chemical changes in PBMCs samples stored for 11 days were also investigated, which manifested in numerous modifications in the secondary structure of proteins and the content of nucleic acids. The impact of cell preculturing for 72 h after unbanking was verified, and there was no significant effect on the molecular structure of cells fixed with 0.5 % GA. In summary, the developed protocol for the preparation of samples for Raman imaging allows for the effective differentiation of fixed normal leukocytes from malignant T lymphoblasts.

Hydrolytic, thermal and radiation stability of modified urea-formaldehyde composites: Influence of montmorillonite particle size

Urea-formaldehyde (UF) composites with a formaldehyde/urea (FA/U) ratio = 0.8 and different particle sizes of montmorillonite (MMT), namely UF/KSF and UF/K10 were synthesized. The hydrolytic stability of modified UF composites was determined by measuring the content of the liberated formaldehyde of modified UF composites after acid hydrolysis. The synthesized modified UF composites were irradiated (50 kGy) and the effect of γ–irradiation was evaluated on the basis of these thermal behaviors. The thermal behavior was studied by non-isothermal thermo-gravimetric analysis (TG), differential thermo-gravimetry (DTG), and differential thermal analysis (DTA) supported by data from Fourier transform infrared spectroscopy (FTIR). The minimum percentages of free (0.4%) and liberated (1.2%) formaldehyde were obtained in the UF/KSF composite. The modified UF/KSF composite shows better radiation resistance than the modified UF/K10 composite. The shift of temperature values for the selected mass losses (T5%) to higher temperatures indicates an increase in the thermal stability of the UF/K10 composite after γ–irradiation. γ–irradiation causes a decrease in the absorption intensity of bands in the FTIR spectrum of a modified UF/KSF composite and an increase in the absorption intensity of bands in the FTIR spectrum of a modified UF/K10 composite.

Characteristics of silver carp surimi gel under high temperature (≥100 °C): quality changes, water distribution and protein pattern

AbstractThe effects of high‐temperature treatments (100–125 °C) on the properties of silver carp surimi gel were studied. The results showed that the gel strength and water holding capacity (WHC) of surimi gel decreased significantly (P &lt; 0.05), with the increase of heating temperature and the prolongation of heating time, and the higher the temperature, the greater the decrease trend. Hydrophobic interaction and disulphide bonds decreased significantly, while ionic bonds increased significantly (P &lt; 0.05), as well as β‐sheet increased while β‐turn and coil decreased significantly, which confirmed the changes of protein secondary structure caused by high‐temperature treatments. Myosin heavy chain (MHC) and actin bands gradually narrowed, and the production of new bands larger than 250 kDa by SDS‐PAGE showed the aggregation and cross‐linking reaction of proteins. However, the increased band intensity of 50–75 kDa and the increase of trichloroacetic acid (TCA) soluble peptides showed the degradation of proteins. The decrease of PT22 and the increase of PT23 indicated the conversion of immobilised water to free water in the gel matrix. In conclusion, high‐temperature heating caused the changes of protein secondary structure as well as chemical forces and water conversion, resulting in protein denaturation, aggregation, cross‐linking and degradation, forming a loosen and irregular gel network.

Effect of f–d and d–d Interactions on Dielectric and Optical Properties of Pyrochlore Eu2−xFexTi2O7

X‐ray diffraction, Raman spectroscopy, Fourier‐transform infrared (FTIR) spectroscopy, dielectric property, and UV–vis spectroscopy studies of pyrochlore Eu2−xFexTi2O7 have been performed. The X‐ray pattern shows that Eu2−xFexTi2O7 has a pure pyrochlore phase up to x = 0.2. The structural analysis shows a strong distortion of TiO6 octahedral due to the presence of the interstitial anionic vacant site. A significantly increased band intensity of FTIR spectrum with Fe doping suggests the enhanced anionic disorder in the system. The broadening of Raman peaks with increasing x supports the increased disorder in TiO6 octahedral. Dielectric study of Eu2Ti2O7 shows a diffused dielectric transition below 150 K. The dielectric diffusiveness and transition temperature get enhanced with Fe doping due to enhanced anionic distortion. The dielectric constant of Eu2−xFexTi2O7 is also increased on Fe doping. The UV–vis spectrum exhibits a strong absorbance in the UV region and a redshift with Fe doping. The Tauc plot of UV–vis spectrum shows multiple successive valence band edges and the bandgap gets reduced with Fe doping due to the formation of new interbands. Thus, these materials are interesting for people searching for material to be used in tunable electrical and optical devices.

Antibacterial, antioxidative and sensory properties of Ziziphora clinopodioides–Rosmarinus officinalis essential oil nanoencapsulated using sodium alginate in raw lamb burger patties

This study was aimed to encapsulate Ziziphora clinopodioides–Rosmarinus officinalis essential oil (Z-REO) using sodium alginate (NaAlg) and to evaluate its performance on antimicrobial and antioxidative activities and sensory attributes in lamb burger patties during cold storage for 12 days. GC-MS analysis of Z-REO indicated carvacrol (21.5%) and thymol (16.9%) were the major components. SEM images showed the formation of encapsulated particles. The presence of encapsulated Z-REO in NaAlg was proved based on the increase in band intensity of FTIR spectra. By increasing mass ratios of NaAlg:Z-REO from 1:1 to 2:1, and 4:1, encapsulation efficiency was increased. Average zeta-potential values (mV) of the mass ratios 4:1 and 2:1 were −48.67 and −44.83, indicating the stability of encapsulated particles. The average size of particles ranged from 159.14 nm to 256.14 nm. The results showed that the encapsulated nanoparticles could markedly decrease the growth of inoculated Escherichia coli O157:H7 and Staphylococcus aureus and delay the lipid oxidation of lamb patties compared to the control samples and in samples with free Z-REO. Furthermore, nanoparticles efficiently decreased discoloration and off-odor development in the patties. Therefore, NaAlg-Z-REO nanoparticles could efficiently reduce bacterial growth and oxidative or sensory deterioration of lamb patties during storage.

Abstract 11422: Galactosyltransferase 1-Associating Protein Prevents Murine Vascular Runx2 Expression, Osteogenesis and Calcification

Introduction and Hypothesis: The ubiquitin-conjugating enzyme, galactosyltransferase 1-associating protein (GTAP), is an E2 ubiquitin-conjugating enzyme (UBE2q1), involved in stem cell proliferation and differentiation. Increased vascular smooth muscle cell (SMC) calcification characterizes atherosclerotic heart disease. We tested here the hypothesis that GTAP plays a role in regulation of SMC calcification and expression of the osteogenic protein Runx2. Methods and Results: Echocardiography was conducted in sv129 (WT) (n=10) and GTAP-knockout (GTAP -/- ) (n=11) mice, displayed reduced contractility in GTAP -/- vs. WT mice. In histopathology patch myocardial fibrosis, arterial hyperplasia and calcification occurred in GTAP -/- but not WT mice. Significantly increased calcium contents/dry proteins were found in the aortic rings of GTAP -/- vs. WT mice when ex vivo exposed to inorganic phosphate media for 9 days (Fig. 1a, p&lt;0.05). To less extents, heterozygous GTAP -/+ mice also had increased calcium contents. Total proteins were extracted from aortic SMC transduced with cDNA coding for WT GTAP and loss-functional mutant GTAP C351A for Western blot assays. As shown in Fig. 1b, compared with mock treated SMC, WT GTAP overexpressing SMC had increased band intensity of the contractile proteins, α-SM-actin and SM22α, but much lower band intensity of Runx2 protein. SMC with overexpression of the GTAP C351A mutant modestly reduction in Runx2 band density, and had little impact on band intensity of the contractile protein α-SM-actin and SM22α. Conclusions: GTAP exerts protective effects on vascular SMC by inhibiting expression of Runx2 and calcification, while promoting expression of the contractile proteins, α-SM-actin and SM22α.

Atrial Natriuretic Peptide Antibody-Functionalised, PEGylated Multiwalled Carbon Nanotubes for Targeted Ischemic Stroke Intervention.

Stroke is one of the major causes of disability and the second major cause of death around the globe. There is a dire need for an ultrasensitive detection tool and an effective and efficient therapeutic system for both detection and treatment of stroke at its infancy stage. Carbon nanotubes are promising nanomaterials for tackling these challenges. The loading of dexamethasone and decoration of PEGylated multiwalled carbon nanotube with atrial natriuretic peptide (ANP) antibody and fluorescein isothiocyanate for targeting ischemic site in the rat stroke model is presented here. Functionalisation of carbon nanotubes with dexamethasone (DEX), polyethylene glycol (PEG), fluorescein isothiocyanate (FITC), and ANP antibody caused a 63-fold increase in the D band intensity as illustrated by Raman. The characteristic band intensity increase was observed at 1636 nm following functionalisation of carbon nanotubes with polyethylene glycol and dexamethasone as confirmed by Fourier Transform Infrared. These findings have demonstrated the coupling capability of atrial natriuretic peptide antibody to DEX-PEG-CNTs. The baseline plasma atrial natriuretic peptide levels were ranging from 118 to 135.70 pg/mL prior to surgery and from 522.09 to 552.37 following common carotid artery occlusion. A decrease in atrial natriuretic peptide levels to 307.77 was observed when the rats were treated with FITC-DEX-PEG-ANP-CNTs, PEG-CNTs and DEX with a significant drop in the FITC-DEX-PEG-ANP-CNTs treated group. Fluorescence was detected in FITC-DEX-PEG-CNTs and FITC-DEX-PEG-ANP-CNTs treated ischemic stroke rats. The highest fluorescence intensity was reported in plasma (2179) followed by the kidney (1563) and liver (1507). These findings suggest a beneficial role that is played by the FITC-DEX-PEG-ANP-CNTs in the reduction of inflammation in the ischemic stroke induced rats that could induce a successful treatment of ischemic stroke.

Synthesis, LIFDI Mass Spectrometry and Reactivity of Triacyl‐Germenolates

AbstractThe synthesis of stable triacylgermenolates 3 a,b was achieved by using a multiple silyl abstraction methodology. The formation of these new germenolates was confirmed by NMR spectroscopy and UV‐Vis measurements. Moreover, for the triacylgermenolates 2 and 3 a LIFDI mass spectrometry to characterize these new compounds. Germenolates 3 a,b serve as a starting point for a new triaacylgermane 4 a and two octaacyldigermanes 4 c,d. The formation of these acylgermanes was confirmed by NMR spectroscopy, X‐ray crystallography, UV‐Vis measurements and mass spectrometry. The UV‐Vis absorption spectra of 4 c,d show considerably increased band intensities due to the presence of eight chromophores.

The Chemistry of Acylgermanes: Triacylgermenolates Represent Valuable Building Blocks for the Synthesis of a Variety of Germanium-Based Photoinitiators

The formation of a stable triacylgermenolate 2 as a decisive intermediate was achieved by using three pathways. The first two methods involve the reaction of KOtBu or alternatively potassium with tetraacylgermane 1 yielding 2 via one electron transfer. The mechanism involves the formation of radical anions (shown by EPR). This reaction is highly efficient and selective. The third method is a classical salt metathesis reaction toward 2 in nearly quantitative yield. The formation of 2 was confirmed by NMR spectroscopy, UV–vis measurements, and X-ray crystallography. Germenolate 2 serves as a starting point for a wide variety of organo-germanium compounds. We demonstrate the potential of this intermediate by introducing new types of Ge-based photoinitiators 4b–4f. The UV–vis absorption spectra of 4b–4f show considerably increased band intensities due to the presence of eight or more chromophores. Moreover, compounds 4d–4f show absorption tailing up to 525 nm. The performance of these photoinitiators is demonstrated by spectroscopy (time-resolved EPR, laser flash photolysis (LFP), photobleaching (UV–vis)) and photopolymerization experiments (photo-DSC measurements).

Enhancement of Photoluminescence and Raman Scattering in Hybrid Thin-Film Structures of a-C:H with Silver Nanoparticles

The changes occurring in the optical density, photoluminescence (PL), and Raman scattering (RS) spectra of thin-film structures based on a-C:H and granulated silver films after annealing of samples at 200°C are studied. A hypsochromic shift of the main plasmon peak, formation of double resonance spectra, and an increase in band intensities were observed after annealing of samples with a 10-nm gravimetric thickness of the Ag film. It is shown that both the Ag film nanostructure morphology and the a-C:H film electronic structure affect the plasmon enhancement of PL and Raman spectra. A more efficient PL enhancement was observed after annealing of samples based on a-C:H with optical band gap Eg = 0.4 eV. At the same time, the initially higher PL intensity of samples with Eg = 2.7 eV almost did not change. The enhancement of resonance RS had a selective character. It was related to scattering by polycyclic aromatic groups, which are dominant in the structure of the a-C:H film with a narrower optical band gap.

Evaluation of The Genotoxic Effects of Inhalation Anesthetics on the Patients after Single Exposure Using Random Amplification of Polymorphic DNA (RPAD-PCR) Technique

Introduction: DNA is continuously exposed to a variety of biological, chemical and physical agents that may alter its structure and modify its function. Anesthetic gases used in general anesthesia procedures have been claimed to cause genotoxicity. Aim of the work: The present study aimed to evaluate the genotoxic effects of two commonly used anesthetic gases, isoflurane and sevoflurane after single exposure by RAPD PCR method. Methodology: The study was carried out on 50 patients admitted to Sohag University Hospitals for different surgical indications and exposed to inhalation anesthetics for the first time. Results: Obtained results revealed that the exposure to inhalation anesthetics led to DNA changes observed as a difference in the RAPD PCR pattern of the patient before and after exposure to the inhalation anesthetic. Eighty percent of patients exposed to inhalation anesthesia for the first time had a change in the RAPD PCR pattern in the form of band gain, increased band intensity, band loss, or decreased band intensity, however, isoflurane was less mutagenic than sevoflurane . Conclusion: Inhalation anesthetics had genotoxic effect detected by RAPD PCR method. Recommendations: It is recommended to examine patients after a period of exposure to inhalation anesthesia to indicate whether the DNA changes are permanent or temporary. It is important to extend the research using large sample size and diferrent anesthesia protocols.

Raman spectroscopy of intruded coals from the Illinois Basin: Correlation with rank and estimated alteration temperature

Raman spectroscopy was used to evaluate rank for a series of coals collected adjacent to an igneous intrusion. For these intruded coals, Raman parameters for collotelinite and its coked equivalent show complex changes during the transformation from low to very high levels of maturity (with vitrinite reflectance increasing from 0.55% to 5.0%). With increasing coal rank up to anthracite-level reflectance, the Raman spectra show a decrease in both G band full width at half maximum (FWHM) and D band intensity. The D band shape becomes increasingly asymmetric during the bituminization and de-bituminization stages, whereas in the anthracitization stage, the width of the D and G bands continues to decrease while D band intensity increases. In meta-anthracites (as seen in the ancillary Hunan samples), the G band has a low intensity and undergoes an apparent broadening due to the presence of the D2 band that occurs as a shoulder on the G band.Differences in Raman spectral parameters for vitrinite and inertinite macerals suggest differences in molecular structure between the macerals; as such, the heterogeneous nature of coal may affect Raman spectral results significantly if different maceral types are not considered. Within individual samples, Raman spectra indicate a high level of structural homogeneity between and within vitrinite particles, allowing assessment of differences between samples of different ranks.For vitrinite, the Raman spectral parameters G FWHM and DAs/GA (Area(1100-s)/Area(s-1650), s is the saddle point between 1100 cm−1 and 1650 cm−1) are highly correlated (R2 > 0.9) with vitrinite reflectance (Rr) and maximum alteration temperature (Tpeak), and allow establishment of geothermometers over the temperature range of ~70–300 °C that can be used to evaluate temperatures attained in intruded coals.

Anti-diabetic effect of Oyster Mushroom mediates through increased AMP-activated protein kinase (AMPK) and cyclic AMP-response element binding (CREB) protein in Type 2 Diabetic model Rats

AMP-activated protein kinase (AMPK) and c-AMP-response element binding protein (CREB) are found to be important proteins in metabolic system. AMPK has become the focus as a novel therapeutic target for the treatment of metabolic syndromes. Oyster mushroom is traditionally used as remedy of diabetes and hypertension. The present study aims to observe the stimulation of AMPK and CREB in streptozotocin-induced diabetic model rats through Oyster mushroom administration. Long Evan’s rats were used to create type 2 model diabetic rats through intraperitoneal injection of streptozotocin at 90mg/kg body weight of 48hr old pups. Rats were divided into three groups: diabetic control rats, glibenclamide treated diabetic rats (positive control) and mushroom treated diabetic rats (experimental group). Mushroom was administered orally at a dose of 1.25g/kg body weight in semisolid forms. After five weeks rats were sacrificed, serum and tissues were collected for future analysis. Glucose was measured using glucose-oxidase method, lipid profile by enzymaticcolorimetric method. Proteins from different tissues were extracted using RIPA cell lysis buffer, AMPK and CREB were identified using western blot and immuno-precipitation techniques. A significant decreased of fasting glucose was found after 35 days of experiment when it compared with control diabetic rats (M ± SD, mmol/l, Diabetic control group: 8.0±1.1; Mushroom treated diabetic group: 6.4±1.0; p=0.021). Glibenclamide treated diabetic rats have also shown decreased fasting glucose compared to control diabetic rats. In paired ‘t’ test analysis, it has been found that serum fasting glucose level was significantly decreased on 35th day compared the 0 day in both mushroom treated group (p=0.027) and in glibenclamide treated group (p=0.005). Serum TG level was decreased on 35th day compared to 0day in mushroom treated diabetic model rats only (M±SD, mg/dl, 0 day: 84±13; 35th day: 61±6, p=0.002). No significant changes of cholesterol, HDL and LDL were noticed in the experimental groups following treatment with mushroom. Western blot analyses have shown increased band intensity of AMPK and p-CREB in mushroom treated diabetic model rats. Therefore, it can be concluded that Anti-hyperglycemic property of Oyster mushroom could be explained through increased expression of AMPK and activation of CREB.Bangladesh Journal of Medical Science Vol.17(4) 2018 p.661-668

Biochemical studies of comparative haemolymph constituents in fourth instar larvae of Daba trivoltine ecorace of topical tasar silkworm Antheraea mylitta D.

Diapause is endocrine mediated dormancy and the preparatory stages are fourth and fifth instar lan/ae of tasar silkworm, Antheraea mylitta Drury. Different haemolymph biochemical constituents like total protein, free amino acids, trehalose, glycerol and glycogen were estimated in fourth instar lan/ae of Daba trivoltine ecorace of tropical tasar silkworm so as to differentiate between non-diapause destined (NDD- the first and second crops) and diapause destined (DD- third crop) generations and also to relate them as preparatory for undergoing diapause. There was significant difference in the presence of haemolymph glycogen in female larvae (1.9361+0.9605mg/ml) than male larvae (1.0859±0.5393) in TV third crop. No significant different was observed in remaining constituents. The concentration of trehalose was significantly higher in female lan/ae (0.9501 ±0.3784 mg/ml) than male lan/ae (0.3811±0.2420) in TV second crop. A comparison made between the female and male lan/ae of second crop shows the higher level presence of amino acids and proteins in male larvae. Rest of the constituents was higher in female larvae than male in second crop. During third crop, except for total free amino acids all other biochemical constituents were higher in male lan/ae and the difference was observed to be significant in the concentration of glycerol and amino acids A comparison between the non-diapause destined (2 crop) and diapause destined (3^ crop) generations indicated that the diapause destined larvae has significantly higher level of amino acids trehalose (6.5873 + 3.2437 mg/ml in male, 8.1217 ± 3.0710 mg/ml in female) and glycerol (in female). However, a comparison between NDD first crop and third crop indicated that all the haemolymph constituents were significantly higher in diapause destined fourth instar lan/ae, like amino acids protein (11.3999 ± 2.5290mg/ml in male, 11.3264 ± 2.5672mg/ml in female), trehalose glycogen and glycerol. The findings indicate that fourth instar lan/ae of Daba trivoltine of tasar silkworm accumulate energy reserves to skip forthcoming unfavorable conditions in pupal stage. SDS PAGE studies did not indicate any major difference in protein profile but a sharp increase in band intensity of 85kDa, probably a major storage protein and a 43kDa diapause specific band in DD larvae.

Investigation of earth-alkaline (EA = Mg, Ca, Sr) containing methylammonium tin iodide perovskite systems

Methylammonium tin iodide systems containing earth-alkaline ions (CH3NH3Sn1−x (EA) x I3, EA = Ca2+, Sr2+, Mg2+, 0 ≤ x ≤ 0.30) were investigated. The X-ray diffraction patterns detected the formation of tetragonal nearly cubic CH3NH3SnI3 (space group P4mm), SnI2, and not identified phases. The morphological analysis confirmed the presence of secondary phases with formation of irregularly shaped crystallites. The Sn3d and I3d photoemission spectra revealed the typical position and separation of spin–orbit components for Sn2+ in halides. Static thermogravimetric measurements (T = 85 °C) showed a barely measurable weight loss for EA = Mg, a dramatic decrease of the weight loss rate for EA = Ca, and recorded weight losses till t ≈ 1.5 h only for EA = Sr, respectively. The optical spectra displayed absorption edges which increased at increasing the (EA)-content with maximum values for x = 0.050 (λ on-set = 1754 nm, EA = Mg; λ on-set = 1692 nm, EA = Ca; and λ on-set = 1338 nm, EA = Sr, respectively). The Tauc plots revealed a direct semiconducting behavior with band energy gaps depending on the nature and amount of the (EA)-ions. The photoluminescence (PL) spectra showed, for EA = Mg, an increase of the PL-band intensity at increasing the Mg content with a maximum at x = 1.0 and, for EA = Ca, an increase of band intensity at increasing the Ca-content and for EA = Sr, a band intensity maximum at x = 0.025. This was explained by the similar ionic radius between Sn2+ and Sr2+ ions which can be easily exchanged in the SnI6 2− octahedra.

The SERS signature of PbS quantum dot oxidation

Lead chalcogenide quantum dots (QDs) are promising candidates for the use as sunlight absorbers in sensitized solar cells. While conversion efficiencies of QD solar cells have reached potentially commercially interesting values in the order of 10%, the devices are prone to fast oxidative degradation whose mechanism is not understood in detail yet. Furthermore, O2 and/or H2O present during fabrication has been observed to strongly influence device performance. Analytical tools to monitor the chemical state of QDs in situ and on-line, e.g. during fabrication and operation, are sought for. In this work, we demonstrate that surface-enhanced Raman spectroscopy (SERS) provides the chemical selectivity and high sensitivity required to investigate the oxidation behavior of QDs. We investigate the SER signature of PbS QDs that is commonly employed as sensitizer material in solar cells because of their tunable absorption range and simple and cheap fabrication. We observe SERS fingerprints for a set of three model PbS QD samples with different oxidation degrees. Intact PbS QDs exhibit a strong phonon mode around 196cm−1. With increasing PbS oxidation, a relative band intensity increase can be observed in the 250–380cm−1 region. At strong oxidation levels, additional Pb-(sulf)oxide marker bands appear at 614 and 980cm−1. Based on our results, we suggest to employ PbS-oxidation SER spectral markers as monitoring tools during photovoltaic device fabrication.