Granular Surface Research Articles

Extraction, characterization of xylan from Azadirachta indica (neem) sawdust and production of antiproliferative xylooligosaccharides

Xylan extracted from neem sawdust gave 22.5%, (w/w) yield. The extracted xylan was composed of xylose and glucuronic acid at a molar ratio of 8:1 and with a molecular mass, ~66 kDa. FTIR and NMR analyses indicated a backbone of xylan substituted with 4-O-methyl glucuronic acid at the O-2 position. FESEM analysis showed a highly porous and granular surface structure of xylan. A thermogravimetric study of xylan showed thermal denaturation at 271 °C. The hydrolysis of xylan by recombinant endo-β-1,4-xylanase produced a mixture of xylooligosaccharides ranging from degree of polymerization 2–7. Xylooligosaccharides inhibited cell growth of human colorectal cancer (HT-29) cells but did not affect the mouse fibroblast cells confirming its biocompatibility. Western blotting, DNA laddering and flow cytometric analysis displayed inhibition of HT-29 cells by xylooligosaccharides. FLICA staining and mitochondrial membrane potential analyses confirmed the activation of the intrinsic pathway of apoptosis. The study amply indicated that the xylooligosaccharides produced from neem xylan could be potentially used as an antiproliferative agent.

Impact of aerobic availability of readily biodegradable COD on morphological stability of aerobic granular sludge

Operational disturbances in aerobic granular sludge (AGS) systems can result in aerobic availability of readily biodegradable COD (rbCOD). Different from activated sludge, morphological consequences on the short and long term are not well described in literature. This study investigated the effect of incomplete anaerobic uptake of acetate on the morphological and process stability of AGS using a lab-scale reactor. A fraction of the total acetate load was dosed aerobically, which was increased stepwise while monitoring granular morphology. A good granular morphology and an SVI of 40 ml/g were obtained during initial enrichment and maintained for ≤20% aerobic acetate load dosed at 4 mg COD/g VSS/h. Biological phosphorus removal efficiency was initially unaffected, but the aerobic acetate dosage rate did decrease the aerobic phosphate uptake rate. This led to loss of phosphorus removal for >20% aerobic acetate load dosed at 8 mg COD/g VSS/h over the course of 12 days. Subsequently, significant outgrowth formed on the granular surfaces and developed over time into finger-like structures. Under these high aerobic acetate loads the SVI increased to 80 ml/g and resulted in significant biomass washout due to deteriorating settling properties of the sludge. The sludge settleability and biological phosphorus removal recovered 10 days after aerobic feeding of acetate was stopped. Aerobic presence of rbCOD can be tolerated if mostly anaerobic acetate uptake is maintained, thereby ensuring stable granular morphology and good settleability. The high enrichment of phosphate accumulating organisms in the granular sludge through bottom-feeding and selective wasting of flocs makes aerobic granular sludge resilient to morphological deterioration in aerobic presence of rbCOD.

MICROINVASIVE ORAL SQUAMOUS CELL CARCINOMA ARISING DURING LEUKOPLAKIA FOLLOW-UP: CASE REPORT

This study aims to report a case of recurrence of leukoplakias that due to absence of follow-up evolved to microinvasive squamous cell carcinoma (SCC). A 31-year-old female patient denied smoking and alcoholism and used dental prostheses. She was referred for lesion evaluation in a painless, leukoplastic, granular surface, measuring 3 cm, on the right lateral border of the tongue. Histopathological biopsy of hyperkeratosis and acanthosis compatible with a diagnosis of leukoplakia was performed. After 1 year, a new lesion appeared, and an excisional biopsy was made. The lesion was a lichenoid reaction, with a 3-month follow-up. Remained 6 years without follow-up. Upon return, he clinically presented lesion in the same location, painful, white, and verrucous. An excisional biopsy was performed and the diagnosis was microinvasive SCC. Adequate follow-up of potentially malignant disorders is essential for the early diagnosis of possible malignancies, thus, improving the patient’s prognosis and survival.

Effect of Cd precursor on structure and optical properties of spin coated Zn0:9Cd0:1O films for optoelectronics applications

Abstract The development of transparent conducting oxide materials has gained an increased interest in the scientific community for developing efficient low cost optoelectronic devices. The effect of Cd precursor on structural and optical properties of sol-gel synthesized Zn0:9Cd0:1O nanostructured films has been studied by using XRD, AFM, optical absorption and emission spectroscopic techniques. X-ray diffraction confirms the hexagonal wurtzite crystal structure of the deposited films and the relative intensity of diffraction peaks has been observed with different cadmium salts. The granular surface morphology of the synthesized films has been observed from AFM measurements. The optical transmission, band gap and luminescence intensity was found to change for different cadmium salts. These results are very important for developing new materials for optoelectronic applications.

Outlining cell interaction and inflammatory cytokines on UV-photofunctionalized mixed-phase TiO2 thin film.

Photofunctionalization mediated by ultraviolet (UV) light seems to be a promising approach to improve the physico-chemical characteristics and the biological response of titanium (Ti) dental implants. Seeing that photofunctionalization is able to remove carbon from the surface, besides to promote reactions on the titanium dioxide (TiO2) layer, coating the Ti with a stable TiO2 film could potentialize the UV effect. Thus, here we determined the impact of UV-photofunctionalized mixed-phase (anatase and rutile) TiO2 films on the physico-chemical properties of Ti substrate and cell biology. Mixed-phase TiO2 films were grown by radiofrequency magnetron sputtering on commercially pure titanium (cpTi) discs, and samples were divided as follow: cpTi (negative control), TiO2 (positive control), cpTi UV, TiO2 UV (experimental). Photofunctionalization was performed using UVA (360nm - 40W) and UVC (250nm - 40W) lamps for 48h. Surfaces were analyzed in terms of morphology, topography, chemical composition, crystalline phase, wettability and surface free energy. Pre-osteoblastic cells (MC3T3E1) were used to assess cell morphology and adhesion, metabolism, mineralization potential and cytokine secretion (IFN-γ, TNF-α, IL-4, IL-6 and IL-17). TiO2-coated surfaces exhibited granular surface morphology and greater roughness. Photofunctionalization increased wettability (p<0.05) and surface free energy (p<0.001) on both surface conditions. TiO2-treated groups featured normal cell morphology and spreading, and greater cellular metabolic activity at 2 and 4days (p<0.05), whereas UV-photofunctionalized surfaces enhanced cell metabolism, cell adhered area, and calcium deposition (day 14) (p<0.05). In general, assessed proteins were found slightly affected by either UV or TiO2 treatments. Altogether, our findings suggest that UV-photofunctionalized TiO2 surface has the potential to improve pre-osteoblastic cell differentiation and the ability of cells to form mineral nodules by modifying Ti physico-chemical properties towards a more stable context. UV-modified surfaces modulate the secretion of key inflammatory markers.

Defects induced resistive switching behavior in Ca doped YMnO3–based non–volatile memory devices through electronic excitations

Defect induced structural, microstructural, resistive switching (RS) characteristics and related responsible charge conduction mechanisms of Y0·95Ca0·05MnO3 (YCMO) manganite films, grown on single crystalline (100) Nb:SrTiO3 (SNTO) substrates (0.2 wt% Nb doped at Ti–site in SrTiO3), are reported in this communication. Films were irradiated by 100 MeV O+7swift heavy ions (SHI) with different ion fluence. Structural studies were performed using X–ray diffraction (XRD) and XRD φ–scan measurements for all pristine and irradiated films. Atomic force microscopy (AFM) measurement was performed to understand the granular morphology and surface modifications in YCMO films due to SHI irradiation. Observed RS behavior has been ascribed to the trapping–detrapping processes, modifications in the depletion region, movement of oxygen vacancies and tunneling process across the interface barriers between YCMO and SNTO. Various models and mechanisms have been employed to understand the observed charge transport across the interfaces. All the films show endurance and retention behaviors that suggest the reproducibility, dynamic stability and reliability of presently studied films as non–volatile memory devices.

Network of Interconnected Mesoporous Iron Oxide Nanoparticles for Electrochemical Supercapacitor Application

AbstractElectrochemically synthesized iron oxide thin films are deposited on stainless steel (1.5 × 5 cm) by using 0.1 M aqueous ferric chloride as a precursor solution. X‐ray diffraction spectra of the prepared samples show orthorhombic crystal structure with polycrystalline in nature of iron oxide (Fe2O3) and field emission scanning electron microscopy micrographs show compact granular and mesoporous surface morphology. Prepared electrodes show mixed capacitive behavior, the highest specific capacitance of Fe2O3 (annealed at 300 °C for 1 h) is 408.45 F g–1 at 2 mV s–1 scan rate in 1 M Na2SO4. Charge–discharge behavior exhibits specific energy 8.41 W h kg–1, specific power 7.465 kW kg–1 and columbic efficiency 91% of the Fe2O3 electrode. Impedance spectroscopy carried from 1 mHz to 1 MHz frequency range reveals the capacitive behavior of the electrode and gives internal resistance of 2.35 ohm.

Colon mucosal neoplasia referred for endoscopic mucosal resection: Recurrence of adenomas and prediction of submucosal invasion

BACKGROUNDEndoscopic mucosal resection (EMR) is an effective and minimally invasive alternative to surgery for large polyps and laterally spreading lesions. Gross morphology and surface characteristics may help predict submucosal invasion of the lesion (SMIL) during endoscopic evaluation. This is one of the largest single-center studies reporting endoscopic mucosal resection for larger (≥ 20 mm) colorectal lesions in the United States.AIMTo determine the recurrence rate of adenomas and endoscopic features that may predict submucosal invasion of colonic mucosal neoplasia.METHODSThis is a retrospective cohort study of all the patients referred for endoscopic mucosal resection for lesions ≥ 20 mm, spanning a period from January 2013 to February 2017. The main outcome measure was identifying features that may predict submucosal invasion of mucosal lesions and predict recurrence of adenomas on follow-up surveillance colonoscopy performed at 4-6 mo.RESULTSA total of 480 patients with 500 lesions were included in the study. The median age was 68 (Inter quantile range: 14) with 52% males. The most common lesion location was ascending colon (161; 32%). Paris classification 0-IIa (Flat elevation of mucosa - 316; 63.2%); Kudo Pit Pattern IIIs (192; 38%) and Granular surface morphology (260; 52%) were most prevalent. Submucosal invasion was present in 23 (4.6%) out of 500 lesions. The independent risk factors for SMIL were Kudo Pit Pattern IIIL + IV and V (Odds ratio: 4.5; P value < 0.004) and Paris classification 0-IIc (Odds ratio: 18.2; P value < 0.01). Out of 500, 354 post-endoscopic mucosal resection scars were examined at surveillance colonoscopy. Recurrence was noted in 21.8% (77 cases).CONCLUSIONThere was overall low prevalence of SMIL in our study. Kudo pit pattern (IIIL + IV and V) and Paris classification 0-IIc were the only factors identified as an independent risk factor for submucosal invasion. The independent risk factor for recurrence was adenoma size (> 40 mm). Almost all recurrences (98.8%) were treated endoscopically.

Epidermal Verrucal Lesion with Velvety-Like Granular Surface at Female External Genitalia and Medial Aspect of the Thigh Compatible with Previous History of Longstanding Psoriasis : A Case Report

Psoriasiform dermatoses are a wide spectrum of inflammatory diseases, with several major forms represented by different clinical entities. Psoriasis is the prototype of psoriasiform dermatoses. Other conditions include pustular psoriasis, Reiter’s syndrome, pityriasis rubra pilaris, lichen simplex chronicus and large-plaques parapsoriasis. These lesions represent a diagnostic challenge, both on clinical and histopathological basis. This could be attributed to overlapping clinical and histopathological features. All of them share the hyperactivity of keratinocytes leading to extensive hyperkeratosis, orthokeratosis, congestion and perivascular lymphocytic infiltration.&#x0D; We presented a 25 years old female patient. She complained of epidermal verrucal lesion at the external genitalia and medial aspect of the thigh and pubic region. The surface of the skin was rough with variable velvety like granular surface from one area to another. The cut section showed marked thickening of the epidermis with upper dermal congested vessels. This lesion was compatible with the previous history of long-standing psoriasis. A wide local excision was performed with closure of the wide area with minimal scar. The specimen was sent for histopathological examination and it revealed a picture of psoriasiform dermatitis.

Pre-treatment of granular rice starch to enhance branching enzyme catalysis

Effects of different pre-treatments of granular rice starch using ethanol (ET) and maltogenic α-amylase (MA), separately or combined sequentially ET→MA, were performed to enable efficient subsequent modification with branching enzyme (BE). The pre-treated samples were characterized with respect to morphology, molecular structure, physicochemical properties and the rate of digestion to amylolytic enzymes. MA produced pores and also eroded the granular surface whereas ET caused coapted granules, noticeable swelling but no pores. Crystallinity and enthalpy of gelatinization dramatically decreased with ET and ET→MA. Subsequent BE catalysis increased the specific surface area, crystallinity, α-1,6-glucosidic linkage ratio and enthalpy. BE catalyzed branching resulted in more intact granules, less swelling capacity, solubility and granular separation as compared to their control. These effects were related to reduced amylolytic susceptibility. Pre-treatment prior to BE catalysis offers an efficient alternative way to modify granular starch with different structure and properties depending on the pre-treatment protocol.

Intraoral Herniation of a Sinonasal Polyp: An Underreported Complication of Maxillary Extraction?

The aim of the present study was to increase awareness of an underreported surgical complication by presenting the relevant findings of cases of herniated oroantral sinonasal polyp (OASNP) identified from our biopsy service and from previously reported cases. The present study was a retrospective descriptive case series with a review of the reported data. Cases of OASNP were identified from our biopsy service, and the clinical, radiographic, surgical, and demographic information was retrieved. Previously reported cases of OASNP were also reviewed. We identified 14 cases of OASNP in our biopsy service and an additional 10 reported cases. Overall, OASNP was more prevalent in males (71%). The age range was 19 to 85years (overall mean, 46.6years; median, 43.5years). OASNP typically presented as a red polypoid mass that was frequently pedunculated with a smooth or granular surface. The lesions were located on the maxillary alveolus in the molar region. The most commonly implicated tooth was a maxillary first molar (74%). In some cases, the OASNP had been mistaken for a tumor or pyogenic granuloma. Almost all were at least 1cm in the greatest dimension, with 43% measuring at least 2cm in size, and 1 lesion reaching 5cm in diameter. The reported period for development of the lesion ranged from 2days to 5years, with 60% developing within 2months of the extraction. All lesions had undergone surgical excision. Antibiotic use and surgical closure of the oroantral communication had been described for some of the cases. The results from our study suggest that herniation of a sinonasal polyp through an oroantral defect could be an underreported complication of maxillary exodontia. Additional research would help to enhance our knowledge and understanding of this interesting condition.

Surface Morphology Studies on Laser Irradiated Target and Bi(Pb)SrCaCuO Thin Films

In this study, pulsed laser deposition technique was used to deposit bismuth plumbum strontium calcium copper oxide {Bi (Pb)SrCaCu0} thin films on MgO single crystal substrate. Solid state procedure which is inexpensive technique used in the production process of the Bi (Pb)SrCaCu0 superconductor bulk sample. In this work, Handy YAG Lasers (model: HYL 101 E) has been used. It is a high power class 4 solid state (ND: YAG) Q-switched pulsed laser and 532 nm (visible green: second harmonic) has been used to ablate the films. The substrate used in this work was single crystal MgO with the (100) orientation. Scanning Electron Microscopy (SEM) was used to observe the microstructure of fracture surface and cross section of thin film materials. Variable Pressure Scanning Electron Microscope (LEO-VPSEM) was used to study the correlation between the microstructure features. SEM studies have shown that the surface morphology of the bulk sample comprises platelets of average size ≈10μm with uniform and homogenous microstructure. The typical morphology of the as deposited films showed a continuous phase, granular structure, which spherical particles up to 5μm in diameter. The most prominent types of particulates BPSCCO films on MgO substrate are droplets with smooth surface, bigger droplets with granular surface, spherically-shaped features confined by randomly oriented facets, submicron rod-like features, Cu-enriched needles, platelets, irregularly-shaped Cu-rich outgrowths, strongly Cu-enriched tabular outgrowths, big target fragments, island growth structure, cubic and rectangular cubic structures. SEM analysis also showed that the deposition time have a pronounced influence on the particle size. The target morphology, which develops under laser-irradiation, depends on the laser fluence and the technique, by which the laser beam is moved relatively to the target during ablation. Laser-irradiated surfaces normally become altered both physically and chemically and morphological changes take the form of periodic structures such as ripples and ridges.

First Report of Castor Dark Leaf Spot Caused by Phyllosticta capitalensis in Zhanjiang, China

Castor (Ricinus communis L.) is an important oil crop. Leaf spots on castor with disease incidence of about 22.5% have been observed on about 2,000 plants in a field located in Zhanjiang (21.17N, 110.18E), China, since 2016. Initial leaf symptoms were round spots with gray centers, surrounded by yellow halos. Ultimately, the spots then gradually spread and merged. Six samples of symptomatic leaves were collected from six diseased plants, and they were surface disinfested before isolation. Potato dextrose agar (PDA) was used to culture pathogens. Successively, pure cultures were obtained by transferring hyphal tips to new PDA plates. A total of 15 isolates were obtained from the affected leaves. Two single-spore isolates (RiL-1 and RiL-2) were obtained and confirmed to be identical based on morphological characteristics. Therefore, the representative isolate RiL-1 was selected for further study on the morphological and molecular characteristics. The colony of isolate RiL-1 was about 4 cm in diameter on a PDA plate in 5 days, dark green with a granular surface, and irregular white (later turning black) edge. Conidia were single-celled, oval, narrow at the end with a single apical appendage, and 8.9 to 12.6 × 4.0 to 7.5 µm (n = 40). Morphological characteristics of isolate RiL-1 were consistent with the description of Phyllosticta capitalensis (Wikee et al. 2013). The internal transcribed spacer (ITS) region, translation elongation factor 1-α (tef1-α), and actin (ACT) were amplified using primers ITS1/ITS4, EF1-728F/EF1-986R (Druzhinina et al. 2005), and ACT-512F/ACT-783R (Wikee et al. 2013), respectively. Sequences were deposited in GenBank with accession numbers MN548089 for ITS, MN565576 for tef1-α, and MN565573 for ACT. BLASTn analysis demonstrated that these sequences were 99 to 100% similar to the corresponding ITS (MF170677), tef1-α (KU716086), and ACT (KY855659) sequences of P. capitalensis. Also, by the neighbor-joining method, a phylogenetic tree showed that isolate RiL-1 (MN548089) clustered together with P. capitalensis (MF800912) from China. From the combination of the morphological and molecular characteristics, isolate RiL-1 was determined to be P. capitalensis. A pathogenicity test was performed in a greenhouse with 80% relative humidity at 25 to 30°C. Sterilized cotton balls were immersed in spore suspension (1 × 10⁶ spores/ml) or sterile water for 1 min. Sixteen healthy plants were divided into two groups (wounded group and unwounded group). Spore-containing cotton balls covered the inoculated sites on four plants in the wounded group and four in the unwounded group, with the same procedure for the water-only cotton balls, and kept for 48 h before removing the cotton. After 15 days, disease symptoms were observed on both wounded and unwounded leaves, whereas control plants (both wounded and unwounded) remained healthy. Morphological characteristics and the ITS sequences of the fungal isolates reisolated from the diseased leaves were identical to those of RiL-1. P. capitalensis has caused leaf spot on various host plants around the world (Wikee et al. 2013), including on tea plant in China (Cheng et al. 2019) and oil palm in Malaysia (Nasehi et al. 2020), but it has not been reported on castor. Thus, this is the first report of P. capitalensis causing leaf spot on castor. This study will provide an important reference for the control of the disease. The epidemiology of P. capitalensis on castor should be investigated in further research.

Suppressing transition metal dissolution and deposition in lithium-ion batteries using oxide solid electrolyte coated polymer separator**Project supported by the National Key R&D Program of China (Grant No. 2016YFB0100100) and the National Natural Science Foundation of China (Grant Nos. 51822211, U1932220, U1964205, and U19A2018).

The dissolution of transition metal (TM) cations from oxide cathodes and the subsequent migration and deposition on the anode lead to the deconstruction of cathode materials and uncontrollable growth of solid electrode interphase (SEI). The above issues have been considered as main causes for the performance degradation of lithium-ion batteries (LIBs). In this work, we reported that the solid oxide electrolyte Li1.5Al0.5Ti1.5(PO4)3 (LATP) coating on polyethylene (PE) polymer separator can largely block the TM dissolution and deposition in LIBs. Scanning electron microscopy (SEM), second ion mass spectroscopy (SIMS), and Raman spectroscopy characterizations reveal that the granular surface of the LATP coating layer is converted to a dense morphology due to the reduction of LATP at discharge process. The as-formed dense surface layer can effectively hinder the TM deposition on the anode electrode and inhibit the TM dissolution from the cathode electrode. As a result, both the LiCoO2/SiO-graphite and LiMn2O4/SiO-graphite cells using LATP coated PE separator show substantially enhanced cycle performances compared with those cells with Al2O3 coated PE separator.

Asymmetries in Snowfall, Emissivity, and Albedo of Mars' Seasonal Polar Caps: Mars Climate Sounder Observations

AbstractThe stability of the residual carbon dioxide cap near the south pole of Mars is currently not well understood. The cap's survival depends on its radiation budget, controlled by the visible albedo and infrared emissivity. We investigated the role of CO2 snowfall in altering the albedo and emissivity, leading to the observed asymmetry in the net CO2 accumulation at the two poles. Uncontaminated snowfall increases albedo, and lowers emissivity, due to scattering by optically thick clouds and granular surface deposits. Data from the Mars Climate Sounder (MCS) show that fall and winter snowfall is correlated with higher springtime albedo at both poles. For the seasonal CO2 deposits in each polar region &gt;60° latitude, we find mean albedo values of 0.39 in the north and 0.51 in the south, and winter 32‐μm emissivity values of 0.84 in the north and 0.87 in the south. Using a radiative transfer model and the MCS data, we find that the north polar deposits have ∼10× higher dust content than those in the south, explaining the ∼31% lower albedo of the north seasonal cap during spring. Our model shows that greater amounts of snowfall can explain the ∼4% lower emissivity of the north polar seasonal cap. These findings demonstrate that winter snowfall and dust transport affect the composition of Mars' seasonal ice caps and polar energy balance. Snowfall and dust loading are therefore important in modeling the CO2 cycle on Mars, as well as the planet's long‐term climate variations.

Characterization of the flowability dynamics of granular material flowing down a narrow channel

The flowability of granular material is commonly determined from shear cell tests, but in the real world, the granular flow is quite different in many cases. For this paper, the flowabilities in a narrow channel of five different granular materials were investigated. The flow parameters of the granular flows were determined to classify the flowabilities. Granular flow surface velocities and flow heights and thicknesses were measured, and it was found that the mean shear rates in the linear portions of the velocity profiles increase with both flow rates and inclination. A universal parameter, the ratio of the sine of the inclination to the shear rate in the linear part of the velocity profile, is proposed as a constant. This constant is independent of particle properties. In addition, a flowability parameter, the ratio of the mean shear rate to the cosine of the inclination, is proposed to characterize the friction between the particles in the flowing granular material.

In Russian

The aim of this work is to study the influence of the chemical nature of grafted β-cyclodextrins side functional groups on chemically modified silica gels sorption affinity for cadmium, lead, and copper cations as the most typical water pollutants. Two organo-inorganic sorbents that differ only in the chemical nature of side functional groups of grafted β-cyclodextrin molecules wide edge were synthesized by chemical immobilization of mono-(6-O-(toluenesulfonyl))-β-cyclodextrins on the granular mesoporous silica gel surface. The obtained functionalized silica gels were characterized by IR and UV spectroscopy, chemical, elemental and derivatographic analysis, pH-metry, low-temperature nitrogen adsorption-desorption as well as sorption measurements. The results of studying the sorption of cadmium, lead, and copper cations from nitrate buffer solutions with pH = 2.0 were analyzed using the Lagergren kinetic model for pseudo-first and pseudo-second order processes, and the equilibrium sorption results were analyzed using the Langmuir and Freindlich models for homogeneous and heterogeneous surfaces. It has been found that only β-cyclodextrin-containing surface centers of chemically modified silica gels participate in the sorption of metal cations. The simultaneous formation of inclusion complexes of grafted β-cyclodextrin molecules with nitrate anions of the solution and mixed complexes of metal cations with side functional groups of the wide edge of immobilized cyclic oligosaccharides occurs during the interaction of synthesized silica gels with buffer solutions of cadmium, lead and copper nitrates. The sorption affinity of β-cyclodextrin-containing silica gel with secondary alcohol groups in the structure increases in the order Cd 2+ < Pb 2+ < Cu 2+ . The cation sorption sequence is opposite – Cu 2+ < Pb 2+ < Cd 2+ – for β-cyclodextrin-containing silica gel with side thiosemicarbazidoethyl groups. The change in the sorption specificity of functionalized silica gels to metal cations is interpreted from the standpoint of the theory of “soft” and “hard” acids and bases. The formation of “β-cyclodextrin ‒ nitrate-anion” inclusion complexes with a composition of 1:1 on the surface of chemically modified silica gels promotes metal cations sorption. The results obtained make it possible to predict the sorption specificity of β-cyclodextrin-containing silica materials and its directed change using various functional derivatives of β-cyclodextrin.

Spinel MnFe2O4 nanoparticles (MFO-NPs) for CO2 cyclic decomposition prepared from ferromanganese ores

Ferromanganese ores with high contents of Mn and Fe are abundant worldwide. In this study, spinel-type MnFe2O4 nanoparticles (MFO-NPs) were first synthesized via a novel solid-state reaction process followed by ball-milling, magnetic separation, and nano-grinding. The synthetic MFO-NPs presented a stable spinel structure, fine granularity, and large specific surface; these characteristics highlight their potential in the preparation of thermochemical catalysts. We additionally conducted H2 reduction (HR) and CO2 decomposition reaction (CDR) cyclic tests to investigate the catalytic performance of MFO-NPs. The MFO-NPs showed excellent recyclability and thermal stability during CO2 decomposition; moreover, oxygen-defect MFO-NPs were able to completely decompose CO2 into carbon quantum dots. The mechanism of CO2 decomposition on the MFO-NPs’ surfaces was analysed in detail by XRD, SEM, TEM, TG, Raman, XPS.

Comparative studies of CdS thin films by chemical bath deposition techniques as a buffer layer for solar cell applications

Cadmium sulfide (CdS) buffer layer that decouples the absorber layer and window layer in thin-film solar cells was synthesized by two different chemical bath deposition (CBD) techniques with varying deposition parameters. X-ray diffraction (XRD) revealed that the CdS thin film crystallizes in a stable hexagonal wurtzite structure having a preferential orientation along (002) reflection plane with a crystallite size varying from 20 to 40 nm. First longitudinal optical phonon mode was identified at Raman shift of 305 cm−1. Uniform, granular, continuous, and smooth surface with an average grain sizes (< 100 nm) as well as small roughness (< 9 nm) was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The symmetric composition of cadmium and sulfur along with larger grains (20 nm) was observed at higher deposition temperatures and times. The optical band gap of CdS samples obtained from process one was in the range of 2.3–2.35 eV, while the band gap by the second CBD process lay in between 2.49 and 2.65 eV, showing the most stable compound of CdS. The presence of a green emission band in photoluminescence spectra (PL) demonstrated that the CdS material has better crystallinity with minimum defect density. Hall effect studies revealed the n-type conductivity of CdS thin films with a carrier concentration values in the order of 1016 cm−3. Furthermore, CdS thin films fabricated by CBD process exposed better quality that might be more suitable material as a buffer layer for thin-film solar cells.

Effect of dual modification with annealing, heat moisture treatment and cross-linking on the physico-chemical, rheological and in vitro digestibility of underutilised kithul (Caryota urens) starch

Kithul starch was subjected to annealing, heat moisture treatment, cross-linking, annealing after cross-linking and heat moisture treatment after cross-linking and its physico-chemical, functional properties and in vitro digestibility was studied. Moisture and amylose content significantly (p ≤ 0.05) reduced after modifications. Phosphorus content of kithul starch increased after cross-linking. X-ray diffraction pattern (type A) did not change and crystalline properties increased after modifications. HLS (cross-linked heat moisture treated kithul starch) showed highest relative crystallinity among the modified starches. Swelling index, solubility and light transmittance decreased after modifications. Single and dual modifications caused severe damages such as fissures and holes on the granular surface. Peak viscosity of ANS (annealed kithul starch), CLS (cross-linked kithul starch) and ALS (cross-linked annealed kithul starch) increased and HMS (heat moisture treated kithul starch) and HLS (cross-linked heat moisture treated kithul starch) decreased as compared with NS (native kithul starch). Modified kithul starches showed lower break down viscosity and higher set back and final viscosity. Rheological analysis showed higher hardness of modified starch gel (higher storage and loss modulus) as compared with NS gel. In vitro digestibility decreased after modifications and HLS showed higher resistant starch (RS). Gelatinization temperature varied after modifications. Enthalpy of gelatinization significantly increased after single and dual modifications.