Band Positions Research Articles

Bi2Ti2O7/PbCdS2/PbS solar cells with NiS@rGO Electrocatalyst: A strategy for enhancing light absorption and polysulfide reduction

The pyrochlore structure of bismuth titanate (Bi2Ti2O7) has been used as a photo-anode to fabricate PbCdS2 sensitized solar cells. The ternary PbCdS2 alloy has been coated with the thin Bi2Ti2O7 (BTO) films by optimizing the successive ionic layer adsorption and reaction (SILAR) cycles. The structure and chemical composition have been identified through X-ray diffraction and X-ray photoelectron spectral analysis. The nanorods-like morphology has been observed from the morphological analysis. J-V results demonstrate that the BTO/3PbCdS2 with NiS counter electrode (CE) cell has a better power conversion efficiency (PCE) of 1.03 % with a JSC of 4.56 mA cm−2, VOC of 49 mV, and FF of 0.39, which is superior to other BTO/PbCdS2 combinations and pristine CdS and PbS. Furthermore, the PCE is increased by sandwiching the NiS-rGO CE with the BTO/3PbCdS2/Sn2-/S2- and attaining a maximum JSC of 5.65 mA cm−2, VOC of 539 mV, FF of 0.56, and PCE of 2 %. The obtained FF and are 43 % and 94 % higher than the BTO/3PbCdS2/Sn2-/S2-/NiS cell, respectively. The improvement is owing to increased light absorption, perhaps due to a favorable band position, lower carrier recombination, and the effective polysulfide reduction of NiS-rGO. The results suggest that optimized SILAR cycles are not the only approach to attaining a superior PCE; implanting an effective electrocatalyst is also a viable option.

A mechanistic study on enhanced solar photocatalytic activity of SnWO4/BiMoO6 nanocomposites for degradation of tetracycline

Step-scheme band configuration is considered to be an excellent option for photocatalytic applications including degradation of organic pollutants. This phenomenon has been demonstrated here via sunlight mediated photocatalytic degradation of trace concentrations of antibiotics in water by SnWO4/BiMoO6 nanocomposites. The structural, morphological, textural, compositional and optical properties of the hydrothermally synthesized SnWO4/BiMoO6 nanocomposites are critical towards enhanced photocatalytic degradation kinetics of tetracycline, used here for mimicking antibiotic residue in water. The optimized batch of 0.10SnWO4/Bi2MoO6 photocatalyst exhibited step-type band position and accounted for 95 % sunlight mediated photocatalytic degradation of tetracycline solution at a rate constant of 0.031 min−1. The degradation rate is six times higher than that of pristine Bi2MoO6 and fifteen times higher than that of SnWO4 nanoparticles. The mechanism involved in the photocatalytic degradation of tetracycline hydrocloride has been addressed in the light of (a) enhanced absorption of sunlight by 0.10SnWO4/Bi2MoO6; (b) favourable type-II-like band position of Bi2MoO6 and SnWO4 leading to heterojunction formation, (c) electrochemical studies showing charge carrier mobility and photocurrent measurements showing inhibition of charge carrier recombination, and (d) in situ generation of hydroxyl radicals.

Efficient photo-assisted degradation of wastewater dyes using CdS nanoparticles confined in porous G-C3N4/SiO2 composites

Porous g-C3N4/SiO2 (CNS) nanocomposite was prepared using nanosized colloidal SiO2 by a sol/gel/condensation technique from thiourea and tetraethyl-orthosilicate (TEOS). The fabricated sample was confined with different amounts of CdS nanoparticles (NPs) through precipitation route. various characterization techniques were used to determine the structural, morphological, optical, and textural properties of the investigated photocatalysts. The band gap energies and the potential positions of the valence band (VB) and conduction band (CB) levels in the nanocomposite were determined. We have also explored the different degradation behaviors of the studied photocatalysts toward Rhodamine B (Rh.B) and Remazol Brilliant blue R (Re.B) under solar light irradiation. Amongst all the utilized photocatalysts, 8CNS demonstrated the best photocatalytic performance with degradation rate constants of 0.069 min−1 and 0.022 min−1 for Rh.B and Re.B, respectively. These values are found to be higher than the corresponding rates obtained at g-C3N4 and CdS. The higher degradation efficiency and photostability of CdS/CNS nanocomposites can be attributed to the presence of SiO2 and the synergetic effect of CdS which led to improving both their surface area and charge separation efficiency. Our investigated photocatalyst were found to retain their degradation efficiency after multiple usages demonstrating their sustainability. Based on the potential positions of the reactive species and trapping studies, the photocatalytic degradation mechanism has thus been proposed using superoxide radicals (.O2–) and photoinduced holes (h+) as the main reactive species participate in the degradation process. Our findings should pave novel routes for the elimination of the environmentally toxic dyes using affordable photocatalysts.

Electronic and nanoscale structures of metal oxyhalide intergrowth photocatalysts

Multimetal oxyhalide intergrowths show promise for photocatalytic water splitting. However, the relationships between intergrowth stoichiometry and their electronic and nanoscale structures are yet to be identified. This study investigates Bi4TaO8Cl–Bi2GdO4Cl intergrowths and demonstrates that stoichiometry controls the tilting of [TaO6] octahedra, influencing the bandgap of the photocatalyst and its valence and conduction band positions. To determine how the [TaO6] octahedral tilting in the intergrowths manifests as a function of intergrowth stoichiometry, we investigated changes in crystal symmetry by analyzing features arising at the higher order Laue zone (HOLZ) of convergent-beam electron diffraction patterns. Higher Ta content intergrowths displayed a more intense outer HOLZ ring compared to lower Ta content intergrowths, indicating transformation from P21cn (orthorhombic) to P4/mmm (tetragonal). This finding suggests that more distortion occurs along the ⟨001⟩ directions of the crystal than the ⟨100⟩ and ⟨010⟩ directions. This variation directly impacts the electronic structure, affecting both conduction and valence band energy levels. By combining ultraviolet photoelectron spectroscopy, UV-visible diffuse reflectance spectroscopy, and electron energy loss spectroscopy, the absolute band positions of the intergrowths were determined. Agreement between the bandgaps obtained via ensemble and nanoscale measurements indicates nanoscale homogeneity of the electronic structure. Overall, the integrated approach establishes that the bandgap energy increases with increasing Ta content, which is correlated with the crystal symmetry and [TaO6] octahedral tilting. Broadly, the modular nature of intergrowths provides building block layers to tune octahedral tilting within perovskite layers for manipulation of optoelectronic properties.

Enhanced photocatalytic hydrogen evolution over coal-based carbon quantum dots modified CoMoO4/g-C3N4

In pursuit of exploring functional applications of coal, this study ultrasound-assisted hydrogen peroxide was used to transform cheap coal into environmentally friendly and high-value coal-based carbon quantum dots (CQDs). These CQDs are then harnessed to synergistically assist the photocatalytic water splitting for hydrogen evolution, in collaboration with CoMoO4 (CM) and g-C3N4 (CN). The results indicated that the novel composite photocatalyst, CMCN-11/8%SCQDs, exhibited high hydrogen evolution activity, reaching a maximum hydrogen production rate of 4916.63 μmol g−1 h−1 at pH 9. At a wavelength of 420 nm, the apparent quantum efficiency (AQE) was 1.78%. The conduction and valence band positions of CM were determined to be −1.03 eV and 1.65 eV, respectively, while those of CN were −0.83 eV and 1.72 eV, suggesting the formation of an S-type heterojunction between CM and CN. The significant role of SCQDs in enhancing the photocatalytic hydrogen evolution was extensively investigated, demonstrating that the synergistic effect between SCQDs, CM, and CN could enhance the hydrogen evolution activity. SCQDs exhibited excellent electron transfer capabilities, serving as bridges for electron transport, functioning both as electron acceptors and donors, effectively impeding the rapid recombination of electron-hole pairs and enhancing their separation efficiency. This study provides crucial insights into the utilization of coal-based CQDs for photocatalytic water splitting, offering an economically viable and sustainable option for the functional application of coal and opening new avenues for the rational design of efficient and cost-effective photocatalysts.

Spectroscopic properties of close-to-perfect-monolayer quasi-free-standing epitaxial graphene on 6H[sbnd]SiC(0001)

In this report, we present transfer-free p-type hydrogen-intercalated quasi-free-standing epitaxial Chemical Vapor Deposition graphene on 15-mm × 15-mm semi-insulating vanadium-compensated on-axis 6HSiC(0001), characterized in that its room-temperature direct-current Hall-effect-derived hole mobility μp= 5019 cm2/Vs, and its statistical number of layers (N), as indicated by the relative intensity of the SiC-related Raman-active longitudinal optical A1 mode at 964 cm−1, equals N= 1.05. The distribution of the ellipsometric angle Ψ measured at an angle of incidence of 50° and λ= 490 nm points out to N= 0.97. The close-to-unity value of N implies that the material under study is a close-to-perfect quasi-free-standing monolayer, which is further confirmed by High-Resolution Transmission Electron Microscopy. Therefore, its spectroscopic properties, which include the SiH peak at 2131 cm−1, the histograms of Ψ and Δ, and the Raman G and 2D band positions, widths, and the 2D-to-G band intensity ratios, constitute a valuable reference for this class of materials.

Electronic and vibrational spectroscopies of aromatic clusters with He in a supersonic jet: The case of neutral and cationic phenol-Hen (n = 1 and 2).

Van der Waals clusters composed of He and aromatic molecules provide fundamental information about intermolecular interactions in weakly bound systems. In this study, phenol-helium clusters (PhOH-Hen with n ≤ 2) are characterized for the first time by UV and IR spectroscopies. The S1 ← S0 origin and ionization energy both show small but additive shifts, suggesting π-bound structures of these clusters, a conclusion supported by rotational contour analyses of the S1 origin bands. The OH stretching vibrations of the PhOH moiety in the clusters match with those of bare PhOH in both the S0 and D0 states, illustrating the negligible perturbation of the He atoms on the molecular vibration. Matrix shifts induced by He attachment are discussed based on the observed band positions with the help of complementary quantum chemical calculations. For comparison, the UV and ionization spectra of PhOH-Ne are reported as well.

Standardization of Cu2O nanocubes synthesis: Role of precipitation process parameters on physico-chemical and photo-electrocatalytic properties

A facile, reproducible, and scalable wet precipitation method was optimized to synthetise Cu2O nanocubes with tuneable morphology and photocatalytic properties. The synthesis process was standardized by controlling the flow rate of addition of the reducing agent. This allowed to control the Cu2O crystallites size, which decreased from 60 nm to 30 nm by increasing the L-ascorbic acid flow rate, while maintaining a high yield (ranging from 87% to 97%) and reproducibility, as confirmed by X-Ray diffraction, scanning electron microscopy, and X-Ray photoelectron spectroscopy analyses. Moreover, the role of the synthesis conditions on the Cu2O nanocubes specific surface area and electrochemical surface area (ECSA) were investigated and correlated to their photo-electrocatalytic activity for the reduction of water and CO2 under ambient conditions, on electrodes made by air brushing. Decreasing of the Cu2O crystallites size enhanced the photo-electrocatalytic activity most probably due to a superior surface area, ECSA and an optimum valence and conduction band positions, which improves the charge transfer properties of the photocatalyst. The here proposed methodology and outcomes are very promising for the scale-up of the precipitation synthesis, not only of Cu2O but also of other nanostructured metal oxides to be exploited as photo-catalysts for environmental and energy applications.

Synthesis of quercetin-iron (Fe) complex and its in silico and in vitro confirmation towards antibacterial activity.

Aim: In this study quercetin-iron complex (QFC) was synthesized and the structural characterizations such as x-ray diffraction, field emission-scanning electron microscopy, energy-dispersive x-ray and Brunner-Emmitt-Teller adsorption-desorption isotherm analysis revealed the crystallinity state, surface morphology and nature of the adsorbing surface with surface area value. Methodology: Functional characterizations such as UV-visible spectrometric and Fourier transform infrared analysis collectively indicated the chemical changes that appeared after complex formation in terms of characteristic change in the spectrum and band position, respectively. Results: The in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus has shown a dose-dependent decrease in colony count and achieved significant removal at 15 mg/ml concentration of QFC. Conclusion: The molecular docking study supports the therapeutic application of QFC.

Visible light sensitized graphitic carbon nitride based semiconducting materials for photoelectrochemical water splitting

Semiconductor based photoelectrochemical water splitting technology directly harvests solar energy into fuels with environment friendly byproducts. The semiconducting material implemented in this technology should be highly photoactive, chemically stable, nontoxic, inexpensive and environmentally benevolent. Even though, various semiconducting materials have been implemented for this purpose, graphitic carbon nitride (GCN) has emerged as an efficient electrode material for water splitting through photoelectrochemical (PEC) route to generate sustainable hydrogen energy owing to its appropriate band position for water reduction reaction, low cost, visible light response, good chemical stability and non-toxicity. However, the practical application of GCN is hindered for PEC water splitting because of numerous challenges, such as its poor electrical conduction ability and high recombination rate. In this paper, we address the fundamental principles for PEC splitting of water with respect to GCN. The broad spectrum of modification strategies for the improvement of GCN based photoelectrodes including heteroelement doping, heterojunction construction, defect engineering and morphology control are also explored. These modification strategies made GCN an efficient material for photoelectrochemical water splitting. The maximum photocurrent density was reported as 320µA cm−2. Conclusively, the crucial challenges and probable solutions for forthcoming advancement in PEC water splitting by GCN based photoelectrodes are highlighted.

First principles insight on enhanced photocatalytic performance of sulfur-doped bismuth oxide iodate

Bismuth oxide iodate photocatalyst is mostly limited in photocatalytic applications due to its large band gap. Doping by metal and nonmetal ions is one of the simplest and most effective ways to solve the problem. The effect mechanism of nonmetallic sulfur atoms doping on the BiOIO3 semiconductor was studied via the first principles of density functional theory (DFT). A series of doping sites were determined, and the differences in energy band structure, density of states, and light absorption spectra of BiOIO3crystals after sulfur doping were carefully investigated. The doping of any oxygen site may cause the crystal conduction band position to move down, reduce the energy band gap, and the energy required for electron transition is easier to meet, which enhances the photocatalytic activity of the semiconductor. Iodine site doping gives a more reasonable crystal formation energy than substituting oxygen site doping. Moreover, the crystal with iodine doping will introduce obvious impurity states around the Fermi level, and the impurity level can act as a bridge for the electron transition. This work is also helpful in understanding the improvement of photocatalytic performance through crystal doping modification.

Enhancing Pollutant Mineralization through Organic-Inorganic Defect-Transit Dual S-scheme with a Robust Internal Electric Field.

Achieving superior photomineralization of pollutants relies on a rational design of a dual S-scheme with a robust internal electric field (IEF). In this study, to tackle the low mineralization rate in type-II In2 O3 /In2 S3 (IO/IS) systems, an organic-inorganic dual S-scheme In2 O3 /PDI/In2 S3 (IO/PDI/IS) nanostructured photocatalyst is synthesized via a method combining solvent-induced self-assembly and electrostatic forces. Due to the unique energy band position and strong IEF, the photoinduced defect-transit dual S-scheme IO/PDI/IS facilitates the degradation of lignin and antibiotics. Notably, a promising mineralization rate of 80.9% for sodium lignosulfonate (SL) is achieved. The charge transport pathway of IO/PDI/IS are further validated through the analysis of in situ X-ray photoelectron spectroscopy (in situ XPS), density functional theory calculations, and radical trapping experiments. In-depth, two possible pathways for the photocatalytic degradation of lignin are proposed based on the intermediates monitored by liquid chromatography-mass spectrometry (LC-MS). This study presents a new strategy for the design of organic-inorganic dual S-scheme photocatalysts with a robust IEF for pollutant degradation.

Forging Fenton-like system to functionalize electron/hole enrichment regions for ATZ photocatalytic degradation

Independent functional regions for electrons and holes enrichment are usually driven by the construction of multiple heterostructures, which is difficult to achieve fine-controlling, resulting in the limited photocatalytic activity. TiO2-based photocatalysts with suitable forbidden band widths are promising for wide application prospects, where the construction of Schottky heterojunctions is the trick to achieve directional migration of electrons and holes. Here, a regionalized surface modification method of H–TiO2 with oxygen vacancy (Ov) and defects for efficient carrier separation was reported, in which interspersed Ag nanoparticles and SiO2 layers serve as electron/hole enrichment regions, respectively. Meanwhile, SiO2 can be served as adsorption sites for photocatalytic oxidation of small-molecule pollutants, while Ag nanoparticles with H+ adsorption capacity and reasonable guide band position can be used as an engine of Fenton-like reactions to cyclically generate the active substance H2O2 to participate in the reduction reaction. The degradation efficiency of Ag–SiO2–H–TiO2 (ASHT) can be increased by 159% for pesticide atrazine (ATZ). The superoxide radicals generated by electrons and oxygen in ASHT also generate H2O2, which promotes the centralized generation of hydroxyl radicals to improve photocatalytic performance. The structural design strategy of ASHT provides a new concept for the process of ring-opening reactions of benzene-containing contaminants in water and conversion to small molecules which will eventually be rapidly mineralized.

Structural, spectroscopic, magnetic, and magneto-transport behavior of Ruddlesden-Popper Ca4Mn3-xWxO10 (x = 0, 0.05, 0.1) compounds

This report comprehensively investigates the crystal structure, magnetism, and transport properties of tungsten (W6+) substituted polycrystalline Ca4Mn3-xWxO10 (x = 0, 0.05, 0.1) compounds. The compounds were synthesized using the solid-state method and found to exhibit a single-phase orthorhombic structure confirmed by the Rietveld refinement. The substitution of (W6+) induces a change in the Mn octahedron and enhances the unit cell volume. The morphology indicates the crystalline nature of all the samples. The FTIR spectroscopic study revealed the position of the IR bands, which is highly sensitive to the oxidation state of Mn-ions. The shift to higher wavenumbers indicates reduced oxidation from Mn4+ to Mn3+ species. The appearance of the Mn4+ oxidation state in (x = 0) and the emergence of Mn3+ on W6+ substitution for (x = 0.05, 0.1) compounds are explored. The electrical resistivity plots revealed that compounds are semiconducting. The magnitude of resistivity decreases with W6+ substitution. The reported compounds exhibit a significant negative magneto-resistance towards lower temperatures. The compounds also demonstrate short-range ferromagnetic (FM) behavior attributed to the charge compensation effect's double exchange interaction (DE) connecting Mn4+ and Mn3+. The negative value of thermoelectric power (S) suggests the presence of charge carriers such as electrons, and the value ofSfirst increased and then decreased in doped samples. The conduction in the studied compound is attributed to small polaron hopping.

Oxidized Graphitic-C3N4 with an Extended π-System for Enhanced Photoelectrochemical Property and Behavior

In this work, an oxidized g-C3N4 film was successfully synthesized using a two-step acid treatment and electrophoretic deposition method. The delocalized π-system of the oxidized g-C3N4 film was extended via an annealing treatment. We investigated the influence of hydrogen bonding reversibility and the oxidation treatment of g-C3N4 on the photoelectrochemical property and photocathodic protection for 304 stainless steel (304 SS). The resulting oxidized g-C3N4 photoelectrode with an extended π-system presents a remarkably enhanced photogenerated electron transfer capability from the photoelectrode to 304 SS (photoinduced OCP negative shift of −0.55 VAgCl) compared with oxidized g-C3N4 and protonated g-C3N4. The oxidation of g-C3N4 facilitates the formation of a porous structure and the introduction of abundant oxygen functional groups, which could promote the effective separation and transport of photogenerated electron–hole pairs. The hydrogen bonding reversibility contributes to the extension of the delocalized π-conjugation system, which could enhance light absorption efficiency. Meanwhile, the annealing treatment is beneficial for prolonging the lifetime of photoelectrons, which could reduce the recombination rate of charge carriers. In addition, to understand how the oxidation treatment and annealing treatment affect the charge transfer behavior, the electronic band structure was investigated, and we found that the oxidized g-C3N4 film with an extended π-system possesses a more negative conduction band position, which could reduce the energy barrier of the photogenerated electron transfer.

Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Vacuum ultraviolet and thermal activation spectroscopies were used to study the nature of intrinsic emission and the mechanisms of the formation of electron and hole trapping centres in irradiated Li2SO4 powders and crystals. The obtained results along with excitation spectra showed that recombination emission at 3.8–4.2 eV and 4.5–5.5 eV occurs when an electron passes from the second and third sub-bands of the valence band formed from the 2p state of oxygen to the conduction band. It has been determined that Li2SO4 electron and hole trapping centres are created when electrons are trapped in the SO42– anionic sites. The holes are localised in the form of SO4 – radicals. The spectral position and intensity of individual emission bands are dependent on the crystallographic arrangement of localised holes.

Impact of CVD chemistry on band alignment at the MoS2/SiO2 interface

Reliable knowledge of energy alignment of electronic bands at interfaces of few layered Molybdenum Disulfide (MoS2) is crucial for designing MoS2 based electronic devices. In this work, we have applied internal photoemission spectroscopy (IPE) to characterize this band alignment. MoS2 films grown on SiO2(50 nm)/Siusing two different methods have been analyzed by IPE to determine the energy position of the semiconductor valence band (VB) relative to the reference level of the insulator conduction band (CB). We found that changing the MoS2 growth method from Vapor Phase Reaction (VPR) of MoO3 and sulfur, to Solid Precursor Film (SPF) of sulfurized AHM-NaOH spin coated MoS2 film, results in significant (≈600 meV) enhancement in the electron barrier. Such effects are ascribed to the interaction of hydroxy groups from NaOH and AHM promoters with the SiO2 surface leading to interface dipole modification.

Empirical Raman calibration of trioctahedral ferromagnesium chlorite minerals

AbstractChlorite is a common hydrated‐aluminous phyllosilicate mineral group that forms in most geological environments (e.g., hydrothermal, igneous, sedimentary, and metamorphic). The chemical composition of chlorite depends on several factors including temperature, pressure, fluid, and bulk rock composition. Raman spectroscopy is proposed as a quick and cost‐effective alternative to scanning electron microscopy and electron probe micro‐analysis, which involve complex sample preparation. In this paper, we demonstrate that Raman spectroscopy is a viable technique to determine the chemical composition of chlorite. Our results show that chlorite's Raman spectra changes quantitatively as a function of its chemical composition. Iron (Fe) and magnesium (Mg) content (APFU) is linearly correlated with the peak positions of three bands: Band 1 (99–104 cm−1), Band 8 (546–553 cm−1), and Band D (3,570–3,580 cm−1). In contrast, silicon (Si) and tetrahedral aluminum (AlIV) are correlated with a single band's position, Band 9b (663–679 cm−1). We derived 18 empirical rules from these correlations, aiding geoscientists in accurately identifying and determining chlorite composition using Raman spectroscopy. Moreover, this technique holds potential for determining chlorite's chemical composition during planetary exploration, leveraging existing Raman spectrometers deployed on Mars and for future space missions.

Application of Organic Petrology and Raman Spectroscopy in Thermal Maturity Determination of the Karoo Basin (RSA) Shale Samples

An assessment performed using raman spectroscopy has found space in the black shales of the Cisuralian-age rocks of the Karoo Basin in South Africa, particularly those from the Guadalupian Ripon, Cisuralian Whitehill and Prince Albert Formations. It is used in conjunction with geochemical screening techniques such as organic petrology and programmed pyrolysis. In turn, the combination of these techniques is used for the assessment of the thermal maturity of the sedimentary organic matter from the perspective of hydrocarbon generation, retention, and expulsion. To provide further understanding of the black shales in the Cisuralian-age rocks of the Karoo Basin in South Africa, this study focuses on the characterization of samples from the KWV−01 borehole drilled in the southeastern Karoo Basin. In addition, the USA Devonian/Carboniferous Berea Sandstone project samples were included for comparison, and were used as a quality assurance measure. Organic petrology was utilized to assess the organic quality and thermal maturity of the black shales. The results obtained showed that the Karoo Basin shales are overmature, containing an abundance of solid bitumen, and this often characterizes a shale reservoir with moveable hydrocarbons (shale gas). The programmed pyrolysis analysis conducted on the black shales of the Karoo Basin yielded artifact results, as they were determined from a very low and poorly defined S2 peak. This indicated the shales to be overmature and categorized them to be of poor hydrocarbon generation potential. Raman spectroscopy was used to gain insights about the molecular structure of the black shales and to assess if this technique could be used as a complimentary tool to determine the thermal maturity of the shale samples. Raman parameters such as G–D1 Band separation, G and D1 band full width at half maximum (Gfwhm and D1fwhm) and G band position were successfully correlated with vitrinite reflectance (RoV), demonstrating a good potential for Raman spectroscopy to predict the thermal maturity of the shales. Overall, the study provides valuable information and knowledge concerning black shale sample characterization (particularly the thermal maturity and molecular structural characterization) in the Karoo Basin, South Africa.

FTIR spectroscopic investigations of protein conformation provide clues of radioadaptation in the kidney of low-dose irradiated rats

Proteins comprise almost half of the weight of plasma membrane and are responsible for preforming various membrane functions. Functionality of the protein is sensitive to its structure. Therefore, modification of the protein conformation can abrogate its function. We demonstrate the induction of radioadaptation in the kidney of low-dose irradiated rats in the form of diminishing the alterations of the protein secondary structure. The FTIR amide I absorption band fitting using Lorentz function was used to identify the various components of the protein secondary structure. FTIR data show changes in amide I band position, amide I/amide II area ratio, FWHM of amide I band, the shifts in the β-structure bands at 1611, 1623, 1634 cm−1 and the decrease in the β/α ratio. 2Gy x-irradiation lead to an increase in the β-structure at the expense of the α-helix. The effect of 2Gy x-irradiation was diminished when preceded with 100 mGy x-rays 24 h earlier. The data provide clue of induction of radioadaptation in the kidneys of whole-body irradiated rats following receiving a low priming dose 24 h prior to a challenging dose.