Maize Husk Ash as a Renewable Source for the Production of Value Added Silica Gel and Its Application

Nowadays, silica gels have developed a lot of interest due to their extraordinary properties and their existing and potential applications in science and technology. Silica gel has a lot of applications such as a desiccant, as a preservation tool to control humidity, as an adsorbent, as a catalyst and as a catalyst support. Silica gel is a rigid three-dimensional network of colloidal silica, and is classified as: aquagel, xerogel and aero-gel.  Extraction of amorphous silica from Maize Husk Ash (MHA) was carried out in this study. Silica xerogel was produced by dissolving MHA with alkali solution to form sodium silicate solution and lowering the pH to7 by adding hydrochloric acid to form silica aquagel followed by drying to form silica xerogel. The silica xerogel was characterized using SEM, XRD and FTIR techniques. Silica and mineral contents of MHA and xerogel were determined by EDS, X-ray diffraction patterns revealed amorphous nature of extracted silica. Fourier transform infrared (FTIR) data indicates the presence of siloxane and silanol groups. Silica yield from MHA was 56.32% while moisture content was 2.89% and also the SEM presented appropriated morphological characteristics of the best silica. MHA proved to be a potential low cost raw material for the production of silica gel. Keywords: Maize husk ash, amorphous silica, xerogel, surface properties DOI: 10.7176/CMR/13-3-01 Publication date:October 31st 2021

Synthesis and Characterization of Silica from Ragi Husk Ash (Finger Millet) by a Sol-gel Method

Silica aerogel, a mesoporous material, was prepared from ragi husk ash by sol–gel method and dried under atmospheric pressure. In this method, ragi  husk ash, which is rich in silica, was extracted with sodium hydroxide solution to produce a sodium silicate solution. This solution was neutralized with acid to form a silica aerogel. The aged gel was washed carefully by de ionized water and ethanol and finally dried under atmospheric air. A temperature of 7000C was found to be optimum ashing temperature with maximum amorphous silica content. From a morphological analysis obtained by SEM and diffraction patterns (XRD), a longitudinal fibrous and amorphous structure was observed for Ragi Husk. FTIR characterization indicated the presence of silanol and siloxane groups. Thermo gravimetric was used to characterize burning behaviour and also to determine the activation energies. This economic technology, as applied to waste material, also provides many benefits to the local agro-industry. Keywords: Ragi husk Ash, Sol- gel method, Amorphous silica, Aeroge

Clinical and Computerized Tomographic Evaluation of Lateral Ridge Augmentation using Corticocancellous Block Autograft Harvested from the Symphysis Region: A 6 Month Study

BACKGROUND: The present study was to evaluate the clinical and spiral computer tomographic outcome of Misch & Judy Division B Ridge defects following reconstructive surgery with the use of corticocancellous block autograft harvested from the symphysis region and were followed for 6 months interval. MATERIALS & METHOD: Nine patients selected from the Outpatient Department of Periodontics, Ragas Dental College & Hospital, Chennai, were included in this clinical trial for horizontal ridge augmentation using corticocancellous block autograft obtained from the symphysis region. These patients exhibited with Misch & Judy Division B ridge defect, with missing single tooth in the maxillary and mandibular region. All these patients were assessed clinically and with spiral Computer Tomography at baseline and 6 months. The clinical parameters assessed were mean width of keratinized gingiva, mean changes in the horizontal ridge dimension using spiral computer tomography and mean changes in the vertical bone height at the edentulous site using radiographs were done at baseline and 6 months. Statistical analysis was done using paired T test. RESULTS: At the end of 6 month period there was no significant difference in the mean width of keratinized gingiva at the augmented sites. Spiral Computer Tomographic analysis at the augmented sites exhibited an average increase of 1.6 mm at the crest level, 2.9mm at 2mm level from the crest and 2.8mm at 4mm from the crest level 6 months post operatively. In terms of radiographs at the vertical bone changes at the augmented sites most of the sites exhibited loss of crestal bone at 6 months with a change of 2.5mm. CONCLUSION: The present clinical study clearly demonstrates the use of corticocancellous autogenous block graft in horizontal ridge augmentation of Misch & Judy Division B ridge defects as a predictable treatment modality

Preparation and Characterization of Silica Material from Rice Husk Ash – An Economically Viable Method

Rice husk is a form of agricultural biomass that provides an abundant silicon source. Rice husks are widely burnt in agricultural fields in India because it is difficult to find other uses for them. Farmers burn rice hulls usually under incomplete combustion conditions to avoid accidental fires. The objective of this study was to develop a new method of amorphous silica was prepared from rice husk ash by sol - gel method. Initially received from Rice husk ash was calcined at 4000C, 5000C, 6000C and 7000C for 5 hrs to remove the volatiles in the sample and determine the amorphous structure of SiO2. Next, the thermally treated RHA was mixed with alkali solution to produce sodium silicate solution and precipitated silica was produced by the neutralization of sodium silicate solution. Rice Husks soaked in nitric acid produced the maximum amount of the sodium silicate solution and precipitated silica. Sodium oxide (Na2O) content and silica (SiO2) content in the sodium silicate solution were also determined. Extracted precipitated silica particles were characterized by Fourier transform infrared (FTIR), X-Ray diffraction and Optical microscopy techniques. The chemical composition of silica was confirmed by FTIR and SEM with EDX.. Highly pure amorphous silica was derived from rice husk ash was confirmed by XRD pattern. The morphology of the obtained materials was analyzed by SEM. At optimized conditions, a nano sized highly pure silica was produced with a high reactivity and 99.9% amorphous in form. This economic technology as applied to waste material also provides many benefits to the local agro industry. Thus this paper may be providing a low cost and simple method to prepare functional materials. Keywords: Rice husk ash, Silica gel, Minerals, Amorphous material, Agricultural bio-wast

Chemical profiling of fern Cheilosoria mysurensis (Wall. ex Hook.) Ching & Shing and its biological activity

Cheilosoria mysurensis (Wall. ex Hook.) Ching & Shing, a medicinal fern traditionally used to treat burns, throat pain and bone fracture. There is no any scientific report regarding anticancer studies of this species. The aim of the study was to find out the chemical components through GC/MS analysis with their antioxidant and cytotoxic activity. GC-MS analysis shows primary ingredients viz, Cis-9, 10-epoxyoctadecan-1-ol and Oxiraneundecanoic acid, 3-pentyl-, methyl ester, trans were present. High free-radical scavenging activity has been discovered in 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and showed the IC50 value of 52.13±0.33. Furthermore, C. mysurensis also showed good cytotoxic effects against DLA and EAC cell lines with values of 72.9% and 79.5% at 200 µg/ml dose respectively. Overall findings suggested that the identified chemical compounds proved to be rich in antioxidant property. Further, this fern can be a good resource for pharma industry to produce novel anti-cancer drugs

Mitigation of noise-induced bias of PET radiomic features

INTRODUCTION: One major challenge in PET radiomics is its sensitivity to noise. Low signal-to-noise ratio (SNR) affects not only the precision but also the accuracy of quantitative metrics extracted from the images resulting in noise-induced bias. This phantom study aims to identify the radiomic features that are robust to noise in terms of precision and accuracy and to explore some methods that might help to correct noise-induced bias. METHODS: A phantom containing three 18F-FDG filled 3D printed inserts, reflecting heterogeneous tracer uptake and realistic tumor shapes, was used in the study. The three different phantom inserts were filled and scanned with three different tumor-to-background ratios, simulating a total of nine different tumors. From the 40-minute list-mode data, ten frames each for 5 s, 10 s, 30 s, and 120 s frame duration were reconstructed to generate images with different noise levels. Under these noise conditions, the precision and accuracy of the radiomic features were analyzed using intraclass correlation coefficient (ICC) and similarity distance metric (SDM) respectively. Based on the ICC and SDM values, the radiomic features were categorized into four groups: poor, moderate, good, and excellent precision and accuracy. A "difference image" created by subtracting two statistically equivalent replicate images was used to develop a model to correct the noise-induced bias. Several regression methods (e.g., linear, exponential, sigmoid, and power-law) were tested. The best fitting model was chosen based on Akaike information criteria. RESULTS: Several radiomic features derived from low SNR images have high repeatability, with 68% of radiomic features having ICC ≥ 0.9 for images with a frame duration of 5 s. However, most features show a systematic bias that correlates with the increase in noise level. Out of 143 features with noise-induced bias, the SDM values were improved based on a regression model (53 features to excellent and 67 to good) indicating that the noise-induced bias of these features can be, at least partially, corrected. CONCLUSION: To have a predictive value, radiomic features should reflect tumor characteristics and be minimally affected by noise. The present study has shown that it is possible to correct for noise-induced bias, at least in a subset of the features, using a regression model based on the local image noise estimates

Cystatin C and lactoferrin concentrations in biological fluids as possible prognostic factors in eye tumor development

Objectives. To investigate the possible role of cystatin C in eye biological fluids locally and in serum and lactoferrin revealing anti-tumor activity in eye tumor development. Background. The increased number of eye tumors was registered recently not only in the countries with high insolation, but also in the northern countries including Russia (11 cases per million of population). Search for new biological markers is important for diagnosis and prognosis in eye tumors. Cystatin C, an endogenous inhibitor of cysteine proteases, plays an important protective role in several tumors. Lactoferrin was shown to express anti-tumor and antiviral activities. It was hypothesized that cystatin C and lactoferrin could serve as possible biomarkers in the diagnosis of malignant and benign eye tumors. Study design. A total of 54 patients with choroidal melanoma and benign eye tumors were examined (part of them undergoing surgical treatment). Serum, tear fluid and intraocular fluid samples obtained from the anterior chamber of eyes in patients with choroidal melanoma were studied. Methods. Cystatin C concentration in serum and eye biological fluids was measured by commercial ELISA kits for human (BioVendor, Czechia); lactoferrin concentration – by Lactoferrin-strip D 4106 ELISA test systems (Vector-BEST, Novosibirsk Region, Russia). Results. Cystatin C concentration in serum of healthy persons was significantly higher as compared to tear and intraocular fluids. In patients with choroidal melanoma, increased cystatin C concentration was similar in tear fluid of both the eyes. Lactoferrin level in tear fluid of healthy persons was significantly higher than its serum level. Significantly increased lactoferrin concentration in tear fluid was noted in patients with benign and malignant eye tumors. Conclusion. Increased level of cystatin C in tear fluid seems to be a possible diagnostic factor in the eye tumors studied. However, it does not allow us to differentiate between malignant and benign eye tumors. Similar changes were noted for lactoferrin in tear fluid

Noise sensitivity of 89Zr-Immuno-PET radiomics based on count-reduced clinical images

PURPOSE: Low photon count in (89)Zr-Immuno-PET results in images with a low signal-to-noise ratio (SNR). Since PET radiomics are sensitive to noise, this study focuses on the impact of noise on radiomic features from (89)Zr-Immuno-PET clinical images. We hypothesise that (89)Zr-Immuno-PET derived radiomic features have: (1) noise-induced variability affecting their precision and (2) noise-induced bias affecting their accuracy. This study aims to identify those features that are not or only minimally affected by noise in terms of precision and accuracy. METHODS: Count-split (89)Zr-Immuno-PET patient scans from previous studies with three different (89)Zr-labelled monoclonal antibodies were used to extract radiomic features at 50% (S50p) and 25% (S25p) of their original counts. Tumour lesions were manually delineated on the original full-count (89)Zr-Immuno-PET scans. Noise-induced variability and bias were assessed using intraclass correlation coefficient (ICC) and similarity distance metric (SDM), respectively. Based on the ICC and SDM values, the radiomic features were categorised as having poor [0, 0.5), moderate [0.5, 0.75), good [0.75, 0.9), or excellent [0.9, 1] precision and accuracy. The number of features classified into these categories was compared between the S50p and S25p images using Fisher’s exact test. All p values < 0.01 were considered statistically significant. RESULTS: For S50p, a total of 92% and 90% features were classified as having good or excellent ICC and SDM respectively, while for S25p, these decreased to 81% and 31%. In total, 148 features (31%) showed robustness to noise with good or moderate ICC and SDM in both S50p and S25p. The number of features classified into the four ICC and SDM categories between S50p and S25p was significantly different statistically. CONCLUSION: Several radiomic features derived from low SNR (89)Zr-Immuno-PET images exhibit noise-induced variability and/or bias. However, 196 features (43%) that show minimal noise-induced variability and bias in S50p images have been identified. These features are less affected by noise and are, therefore, suitable candidates to be further studied as prognostic and predictive quantitative biomarkers in (89)Zr-Immuno-PET studies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40658-022-00444-4