AI-based wavelet and stacked deep learning architecture for detecting coronavirus (COVID-19) from chest X-ray images.

A novel coronavirus (COVID-19), belonging to a family of severe acute respiratory syndrome coronavirus 2 (SARs-CoV-2), was identified in Wuhan city, Hubei, China, in November 2019. The disease had already infected more than 681.529665 million people as of March 13, 2023. Hence, early detection and diagnosis of COVID-19 are essential. For this purpose, radiologists use medical images such as X-ray and computed tomography (CT) images for the diagnosis of COVID-19. It is very difficult for researchers to help radiologists to do automatic diagnoses by using traditional image processing methods. Therefore, a novel artificial intelligence (AI)-based deep learning model to detect COVID-19 from chest X-ray images is proposed. The proposed work uses a wavelet and stacked deep learning architecture (ResNet50, VGG19, Xception, and DarkNet19) named WavStaCovNet-19 to detect COVID-19 from chest X-ray images automatically. The proposed work has been tested on two publicly available datasets and achieved an accuracy of 94.24% and 96.10% on 4 classes and 3 classes, respectively. From the experimental results, we believe that the proposed work can surely be useful in the healthcare domain to detect COVID-19 with less time and cost, and with higher accuracy.

Association Between AMH Levels and Fertility/Reproductive Outcomes Among Women Undergoing IVF: A Retrospective Study.

Background: Anti-mullerian hormone (AMH) is a marker for predicting ovarian response to gonadotropin stimulation. It plays an important role in ovarian primordial follicle recruitment and dominant follicle selection. Therefore, the present study evaluated the AMH levels and their association with fertility/reproductive outcomes among women undergoing IVF. Methods: A retrospective study was conducted on 665 women in GarbhaGudi Institute of Reproductive Health and Research in India from October 2018 to 2019. Subjects were divided into ≥1.1 and ≤1.1 AMH level groups. Data on age, luteinizing hormone; LH (mIU/L), follicle-stimulating hormone values; FSH (mIU/ml), LH value, oocytes retrieved, and oocytes fertilization were collected. AMH category was considered as the primary explanatory variable. Independent sample t-test and chi-square tests were performed. The p<0.05 was considered statistically significant. Results: Couple's age, FSH values (mIU/ml), number of large follicles, matured oocytes, fertilized oocytes, and cleaved embryos were statistically significant (p<0.001) among subjects with ≥1.1 AMH values. Percentage of women with successful embryo transfer was slightly higher among AMH category 1.1 (p=0.09). Fertilization rate (86.67±20.08 vs. 83.64±21.39, p=0.18) and clinical pregnancy rate (43.38% vs. 36.36%, p=0.19) were slightly higher among women with AMH level of ≥1.1 as compared to AMH of <1.1. Live birth rate was slightly higher among women with AMH level of 1.1 (25.85% vs. 22.22%, p=0.45). Also, the number of fertilized oocytes was associated with clinical pregnancy rate (aOR=1.20, 95%CI 1.09-1.33). Conclusion: Women with ≥1.10 serum AMH levels had more number of retrieved oocytes, good oocyte quality, increased embryo transfer, and fertilization rates.

High-resolution dissection of photosystem II electron transport reveals differential response to water deficit and heat stress in isolation and combination in pearl millet [Pennisetum glaucum (L.) R. Br.].

Heat and Water Deficit Stress (WDS) tend to impede and restrict the efficiency of photosynthesis, chlorophyll fluorescence, and maximum photochemical quantum yield in plants based on their characteristic ability to interfere with the electron transport system in photosystem II. Dissection of the electron transport pathway in Photosystem II (PSII) under water deficit and Heat Stress (HS) can be insightful in gaining knowledge on the various attributes of the photosynthetic performance of a plant. We attempt a high-resolution dissection of electron transport in PSII with studies on chlorophyll a fast fluorescence kinetics and non-photochemical quenching (NPQ) as a response to and recovery from these stresses in pearl millet [Pennisetum glaucum (L.) R. Br.] in isolation and combination. In this study, we bring out the mechanisms by which both heat and water stress, in isolation and in combination, affect the photosynthetic electron transport in Photosystem II. Our results indicate that oxygen evolution complex (OEC) damage is the primary effect of heat stress and is not seen with the same intensity in the water-stressed plants. Low exciton absorption flux in heat stress and combined stress was seen due to OEC damage, and this caused an electron transport traffic jam in the donor side of PS II. Both the specific energy flux model and the phenomenological flux model developed from the derived values in our study show that water deficit stress in combination with heat stress has a much stronger effect than the stresses in isolation on the overall electron transport pathway of the PS II in pearl millet plants.

Eco-friendly vaccination: Tackling an unforeseen adverse effect.

The beginning of 2021 was marked by COVID-19 vaccination campaigns worldwide. The pace of production has been accelerated, in order to meet global needs and achieve the desired levels of immunization of the general population against COVID-19 within the year. Several debatable aspects of this endeavor, from logistics to health promotion have been addressed so far. However, the environmental repercussions of plastic syringes used for massive COVID-19 vaccinations are yet to be discussed. This article delves into the impact of the increasing medical waste, associated with massive COVID-19 vaccination on the environment, citing the practices followed and its possible solutions. The increasing production of nonbiodegradable materials is inevitably going to affect the world we live in. .Moreover, this article highlights the importance of developing sustainable methods of vaccination and disposal, providing examples and evidence based recommendations. Along with educating the unaware proportion of the population, there is a need to develop sustainable and recyclable products for a better tomorrow.

Haemorrhagic shock from solid tumours of the adrenal gland: a case of bleeding primary adrenal lymphoma.

Suprarenal or adrenal gland haemorrhage is an uncommon but potentially lethal condition if unrecognised. Adrenal masses rarely present with haemorrhage, but they remain an important differential aetiology for adrenal bleeding. We present a novel case of primary adrenal lymphoma with adrenal haemorrhage in a middle-aged woman who presented with right-sided abdominal pain and class 1 haemorrhagic shock. She was found to have spontaneous unilateral adrenal gland haemorrhage in the absence of any underlying previous pathology. Presenting features, diagnosis and subsequent oncological management are reported.

Coconut shell derived ZnCl2 activated carbon for malachite green dye removal.

The coconut-based agricultural wastes have gained wide attention as an alternative adsorbent for the removal of diverse pollutants from the industrial effluents. This paper presents the zinc chloride activation of adsorbent carbon and the utilization as an adsorbent for the removal of malachite green dye from aqueous solution. The characterisation of activated carbon was performed to get an insight into the adsorption mechanism. The ZnCl2 activated carbon acquired a higher specific surface area (544.66 m2 g-1) and stability (-32.6 mV). The impact of process parameters including contact time (20-220 min) and initial dye concentration (20-80 mg L-1) were evaluated on the effectiveness of activated carbon for dye removal. The results concluded that zinc chloride activated carbon showed a significant dye adsorption (39.683 mg g-1) at an initial concentration of 20 mg L-1 after 3 hours. Based on the correlation coefficient (R2), the Freundlich isotherm model (0.978-0.998) was best fitted for the experimental data followed by the intraparticle diffusion model (0.88-0.929) as the most appropriate model for malachite green dye removal. Additionally, the energy and thermogravimetric analysis portrayed the suitability of the carbon material to be used as an energy alternative to coal.

Targeted editing of tomato carotenoid isomerase reveals the role of 5' UTR region in gene expression regulation.

KEY MESSAGE: A deletion created by CRISPR/Cas9 system in the 5' UTR of the carotenoid isomerase gene in tomato leads to downregulation of the gene resulting in the low conversion of prolycopene to lycopene. CRISPR/Cas9 based genome editing is an effective and useful tool adopted from the bacterial immune response system for altering specific, pre-determined DNA sequences in eukaryotes. Such targeted changes are finding wide application in human health as well as in precision breeding of crop plants for improved traits. Mutations in the coding and regulatory regions can have varying impacts on the function of the gene. In the current study, we demonstrate this on tomato carotenoid isomerase, a key gene in the carotenoid biosynthesis pathway. Mutations were generated in the 5' UTR and exon 1 of the carotenoid isomerase gene using CRISPR/Cas9 expression via Agrobacterium-mediated transformation of tomato variety Periyakulam 1 (PKM1). Molecular and biochemical studies demonstrate that CRISPR-mediated point mutations in the exon sequence lead to complete knockout of protein function whereas deletion in 5' UTR region lowers the expression of the gene leading to changes in plant phenotype.

Role of adjuvant therapy in stage IIIC2 endometrial cancer.

OBJECTIVE: The role of the different types of adjuvant treatments in endometrial cancer with para-aortic node metastases is unclear. The aim of this study was to report oncologic outcomes after adjuvant therapy in patients with stage IIIC2 endometrial cancer. METHODS: This retrospective single-institution study assessed patients with stage IIIC2 endometrial cancer who underwent primary surgery from January 1984 to December 2014. All patients had hysterectomy (±salpingo-oophorectomy) plus lymphadenectomy (para-aortic nodes, ±pelvic nodes). We included all patients with stage III endometrial cancer and documented para-aortic lymph node metastases (International Federation of Obstetrics and Gynecologists stage IIIC2). We excluded patients who did not provide consent, who had synchronous cancer, or who underwent neoadjuvant chemotherapy. Follow-up was restricted to the first 5 years post-operatively. Cox proportional hazards models, with age as the time scale, was used to evaluate associations of risk factors with disease-free survival and overall survival. RESULTS: Among 105 patients with documented adjuvant therapy, external beam radiotherapy was administered to 25 patients (24%), chemotherapy to 24 (23%), and a combination (chemotherapy and external beam radiotherapy) to 56 (53%) patients. Most patients receiving chemotherapy and external beam radiotherapy (80%) had chemotherapy first. The majority of relapses had a distant component (31/46, 67%) and only one patient had an isolated para-aortic recurrence. Non-endometrioid subtypes had poorer disease-free survival (HR 2.57; 95% CI 1.38 to 4.78) and poorer overall survival (HR 2.00; 95% CI 1.09 to 3.65) compared with endometrioid. Among patients with endometrioid histology (n=60), chemotherapy and external beam radiotherapy improved disease-free survival (HR 0.22; 95% CI 0.07 to 0.71) and overall survival (HR 0.28; 95% CI 0.09 to 0.89) compared with chemotherapy or external beam radiotherapy alone. Combination therapy did not improve prognosis for patients with non-endometrioid histology (n=45). CONCLUSIONS: In our cohort of patients with stage IIIC2 endometrioid endometrial cancer, those receiving chemotherapy and external beam radiotherapy had improved survival compared with patients receiving chemotherapy or external beam radiotherapy alone. However, the prognosis of patients with non-endometrioid endometrial cancer remained poor, regardless of the adjuvant therapy administered. Distant recurrences were the most common sites of failure.

A three-dimensional finite element analysis to evaluate stress distribution tooth in tooth implant-supported prosthesis with variations in non-rigid connector design and location.

BACKGROUND: The physiologically mobile natural tooth and rigidly fixed dental implant causes different distribution of stress when connected in prosthesis and nonrigid connector compensates this. Understanding of biomechanical behavior is necessary for an adequate choice and construction of this type of rehabilitation. However, there has been insufficient research focusing on different location and type of the nonrigid connector related with the prognosis of both implant and the tooth. AIM OF THE STUDY: The purpose of this finite element (FE) analysis was to evaluate the stress distribution around bone, implant, and tooth in tooth implant fixed prosthesis under static load with variations in design and location of nonrigid connectors under simulated functional loads. MATERIALS AND METHOD: Three, 3-dimensional FE models connecting tooth and implant were constructed with different location and type of nonrigid connector. Simulated occlusal load was applied on the restorations and stresses developed in the supporting structures were monitored. RESULTS: The highest stresses were found around the implant in model with nonrigid connector placed between the tooth and implant and model with modified nonrigid connector. On the other hand, less stress was noted around the implant where nonrigid connector was placed between the implant and pontic. CONCLUSION: It is advisable to place the nonrigid connector between the implant and the pontic to protect the implant from torque effects in a tooth implant fixed prosthesis.

Dynamically modified C18 silica monolithic column for the rapid determinations of lead, cadmium and mercury ions by reversed-phase high-performance liquid chromatography.

In this article, a new reversed-phase high-performance liquid chromatography (RP-HPLC) method for the rapid, selective and sequential separation of toxic heavy metal ions namely, Pb2+, Hg2+, and Cd2+ is reported. For this RP-HPLC method, a C18 silica monolith column (Chromolith RP-18e, 100 × 4.6 mm) has been surface modified using a laboratory-synthesized amphiphilic organic ligand namely, 1,5-dioctanoyl-1,5-diphenylcarbazide (DODPC), which acts an ion-selective receptor, for the separation of the target analytes. The eluted metal ions were subjected to post-column derivatization reaction with 4-(2-pyridylazo) resorcinol (PAR) prior to their detection using a UV-vis detector (at 520 nm). The post-column reagent (PAR; 4.7 × 10-4 M; pH 9.0; 1.5 mL/min) was mixed with the column eluate through an ingeniously designed T-connector. An ultra-fast separation of Pb2+, Cd2+, and Hg2+ ions with a retention time of 1.67, 1.88 and 3.62 min, respectively was achieved, using 0.0526 mmol of DODPC coated C18 monolithic column along with tartaric acid solution (1.0 × 10-2 M; pH 4.0; 1.0 mL/min), as the isocratic eluent (mobile phase). The chromatographic parameters such as linearity, accuracy, recovery, limits of detection and quantification were validated to achieve superior analytical results. The influence of various analytical parameters such as nature of mobile phase and its concentration, solution pH, flow rate, post-column reagent and its concentration were studied and optimized. The studies revealed a lower detection limits of 0.075, 0.090 and 0.120 µg/L, and a quantification limits of 0.225, 0.270 and 0.450 µg/L, for Pb2+, Cd2+ and Hg2+ ions, respectively. A linear signal response in the concentration range of 0.05-50.0 µg/mL, was observed for the target metal ions, with an average r2 value of 0.9994. The method was selective for the target metal ions, with excellent data reliability and reproducibility that accounts for an average recovery value of 99.76%, with a relative standard deviation of ≤1.83%.

Genotypic variability in physiological, biomass and yield response to drought stress in pigeonpea.

Three pigeonpea (Cajanus cajan L. Millsp.) genotypes- GT-1, AKP-1 and PRG-158 with varying crop duration, growth habit and flowering pattern were evaluated for variability in their response for drought stress. Drought stress was imposed at initiation of flowering and the observations on biomass and seed yield parameters were recorded at harvest. The magnitude of response of individual component to drought stress was found to be genotype specific. Drought stress significantly decreased photosynthetic rate (PN), transpiration rate (Tr) and relative water content (RWC) in all the genotypes, however the magnitude of reduction differed with genotype. With drought stress, the reduction of PN was highest in GT-1 while reduction in Tr was highest in PRG-158. The genotype AKP-1, accumulated significantly higher concentrations of osmotic solutes especially proline under water deficit stress, this facilitated it to maintain higher relative water content (RWC) and lower malondialdehyde (MDA) content as compared to other genotypes. Drought stress also impacted biomass production and their partitioning to vegetative and reproductive components at harvest. There was significant variability between the genotypes for seed yield under drought stress while it was non-significant under well-watered condition. Drought stress enhanced flower drop and decreased flower to pod conversion resulting in reduced pod number and seed number in PRG-158 and GT-1. The genotype AKP-1 recorded superior performance for seed yield under stress environment due to its ability in maintaining pod and seed number as well as improved test weight (100 seed weight). Under drought stress, significant positive association of seed yield with proline, seed number, pod number and test weight clearly indicating their role in drought tolerance.

Evaluation of anxiolytic activity of aqueous extract of Coriandrum sativum Linn. in mice: A preliminary experimental study.

OBJECTIVES: To evaluate the anxiolytic effect of Coriandrum sativum (CS) aqueous extract in mice. To compare the antianxiety activity of CS against standard drug diazepam (3 mg/kg). MATERIALS AND METHODS: After obtaining Institutional Animal Ethics Committee approval, Swiss albino mice (18-25 g) of either sex were randomly divided into five groups of six animals each. Dried powder of CS leaves was boiled with distilled water, cooled, filtered, placed on a hotplate for complete evaporation, finally weighed and stored. The control group, test group, and standard drugs group received saline, CS extract (50, 100, and 200 mg/kg), diazepam (3 mg/kg), respectively, by oral feeding. The antianxiety effect was assessed by elevated plus maze (EPM) in mice. RESULTS: In EPM, it implied that CS 50 mg/kg (Group III), 100 mg/kg (Group IV), and 200 mg/kg (Group V) significantly (P < 0.001) increases the number of entries in open arms compared to control. The time spent in open arms also increased in all the doses of CS extract significantly. CONCLUSION: The current study demonstrates statistically significant dose-dependent antianxiety activity of CS leaves.

Proline over-accumulation alleviates salt stress and protects photosynthetic and antioxidant enzyme activities in transgenic sorghum [Sorghum bicolor (L.) Moench].

Shoot-tip derived callus cultures of Sorghum bicolor were transformed by Agrobacterium tumefaciens as well as by bombardment methods with the mutated pyrroline-5-carboxylate synthetase (P5CSF129A) gene encoding the key enzyme for proline biosynthesis from glutamate. The transgenics were selfed for three generations and T4 plants were examined for 100 mM NaCl stress tolerance in pot conditions. The effect of salt stress on chlorophyll and carotenoid contents, photosynthetic rate, stomatal conductance, internal carbon dioxide concentration, transpiration rates, intrinsic transpiration and water use efficiencies, proline content, MDA levels, and antioxidant enzyme activities were evaluated in 40-day-old transgenic lines and the results were compared with untransformed control plants. The results show that chlorophyll content declines by 65% in untransformed controls compared to 30-38% loss (significant at P < 0.05) in transgenics but not carotenoid levels. Photosynthetic rate (PSII activity) was reduced in untransformed controls almost completely, while it declined by 62-88% in different transgenic lines. Salinity induced ca 100% stomatal closure in untransformed plants, while stomatal conductance was decreased only by 64-81% in transgenics after 4 days. The intercellular CO2 decreased by ca 30% in individual transgenic lines. Malondialdehyde (MDA) content was lower in transgenics compared to untransformed controls. The activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione reductase (GR; EC1.8.1.7) were quantified in leaves exposed to 100 mM NaCl stress and found higher in transgenics. The results suggest that transgenic lines were able to cope better with salt stress than untransformed controls by protecting photosynthetic and antioxidant enzyme activities.

Temperature- and CO2-dependent life table parameters of Spodoptera litura (Noctuidae: Lepidoptera) on sunflower and prediction of pest scenarios.

Predicted increase in temperature and atmospheric CO2 concentration will influence the growth of crop plants and phytophagous insects. The present study, conducted at the Central Research Institute for Dryland Agriculture, Hyderabad, India, aimed at (1) construction of life tables at six constant temperatures viz., 20, 25, 27, 30, 33, and 35 ± 0.5 °C for Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera) reared on sunflower (Helianthus annus L.) grown under ambient and elevated CO2 (eCO2) (550 ppm) concentration in open top chambers and (2) prediction of the pest status in near future (NF) and distant future (DF) climate change scenarios at major sunflower growing locations of India. Significantly lower leaf nitrogen, higher carbon and higher relative proportion of carbon to nitrogen (C:N) were observed in sunflower foliage grown under eCO2 over ambient. Feeding trials conducted on sunflower foliage obtained from two CO2 conditions showed that the developmental time of S. litura (Egg to adult) declined with increase in temperature and was more evident at eCO2. Finite (λ) and intrinsic rates of increase (r(m)), net reproductive rate (Ro), mean generation time, (T) and doubling time (DT) of S. litura increased significantly with temperature up to 27-30 °C and declined with further increase in temperature. Reduction of 'T' was observed from maximum value of 58 d at 20 °C to minimum of 24.9 d at 35 °C. The DT of population was higher (5.88 d) at 20 °C and lower (3.05 d) at 30 °C temperature of eCO2. The data on these life table parameters were plotted against temperature and two nonlinear models were developed separately for each of the CO2 conditions for predicting the pest scenarios. The NF and DF scenarios temperature data of four sunflower growing locations in India is based on PRECIS A1B emission scenario. It was predicted that increased 'rm', 'λ', and 'Ro' and reduced 'T' would occur during NF and DF scenario over present period at all locations. The present results indicate that temperature and CO2 are vital in influencing the population growth of S. litura and pest incidence may possibly be higher in the future.

Drought stress responses in crops.

Among the effects of impending climate change, drought will have a profound impact on crop productivity in the future. Response to drought stress has been studied widely, and the model plant Arabidopsis has guided the studies on crop plants with genome sequence information viz., rice, wheat, maize and sorghum. Since the value of functions of genes, dynamics of pathways and interaction of networks for drought tolerance in plants can only be judged by evidence from field performance, this mini-review provides a research update focussing on the current developments on the response to drought in crop plants. Studies in Arabidopsis provide the basis for interpreting the available information in a systems biology perspective. In particular, the elucidation of the mechanism of drought stress response in crops is considered from evidence-based outputs emerging from recent omic studies in crops.

In silico targeted genome mining and comparative modelling reveals a putative protein similar to an Arabidopsis drought tolerance DNA binding transcription factor in Chromosome 6 of Sorghum bicolor genome.

Arabidopsis Thaliana HARDY (AtHRD) is a gene with an APETELA 2 / Ethylene Responsive Factor (AP2/ERF) domain linked to improved performance under drought in rice. We hypothesized that the sorghum genome could possess a similar gene product and were motivated to conduct a computational genome scale mining for the protein and analyse its structural and functional properties. AtHRD sequence was used as a query to BLAST against the sorghum genome dataset followed by multiple alignment analysis. A homology model of the target was built using a template detected based on the pair-wise comparison of hidden Markov models for alignments. DNA docking with a matrix of homologous interface contacts was done. Functional and structural analysis of the query and target was conducted using various online servers. A High-scoring segment pair from Chromosome 6 of the sorghum genome in the region between 54948120 and 54948668 had 68 amino acid similarities out of the 184 residues and was 1.4% above twilight zone threshold. The homology model showed 86.8% residues in most favoured regions. The target protein which had an AP2/ERF domain when docked with GCC box DNA motif had conserved residues involved in binding; it had a long unstructured region beyond the AP2 domain with several motifs for the recognition of serine/threonine protein kinase group. The protein model showed that it could bind to a GCC box which is present in several drought responsive genes. The presence of possible signalling domains and intrinsic disorder in the target protein suggest that this could play a role in drought tolerance which is an inherent character of sorghum. These results offer a jumpstart for validation experiments which could pave the way for cis/trans genic improvement of a range of crops.

Aesthetic finger prosthesis.

Complete or partial fingers are the most commonly encountered forms of partial hand losses. Though finger amputations are commonly due to traumatic injuries, digit loss may also be attributed to congenital malformations and disease. Irrespective of the etiology, the loss of a finger has a considerable functional and psychological impact on an individual. In order to alleviate these problems, partial or complete finger prosthesis may be fabricated. This clinical report portrays a method to fabricate silicone rubber prosthesis for a patient who has a partial finger loss caused due to trauma.

Investigation of Antidiabetic, Antihyperlipidemic, and In Vivo Antioxidant Properties of Sphaeranthus indicus Linn. in Type 1 Diabetic Rats: An Identification of Possible Biomarkers.

The present investigation was aimed to study the antidiabetic, antihyperlipidemic, and in vivo antioxidant properties of the root of Sphaeranthus indicus Linn. in streptozotocin- (STZ-) induced type 1 diabetic rats. Administration of ethanolic extract of Sphaeranthus indicus root (EESIR) 100 and 200 mg/kg to the STZ-induced diabetic rats showed significant (P < .01) reduction in blood glucose and increase in body weight compared to diabetic control rats. Both the doses of EESIR-treated diabetic rats showed significant (P < .01) alteration in elevated lipid profile levels than diabetic control rats. The EESIR treatment in diabetic rats produced significant increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and decrease in thiobarbituric acid reactive substances (TBARS) levels than diabetic control rats. Administration of EESIR 200 mg/kg produced significant (P < .01) higher antioxidant activity than EESIR 100 mg/kg. The high performance liquid chromatography (HPLC) analysis of EESIR revealed the presence of biomarkers gallic acid and quercetin. In conclusion, EESIR possess antidiabetic, antihyperlipidemic, and in vivo antioxidant activity in type 1 diabetic rats. Its antioxidant and lipid lowering effect will help to prevent diabetic complications, and these actions are possibly due to presence of above biomarkers.

High performance liquid chromatographic studies on lanthanides, uranium and thorium on amide modified reversed phase supports.

The retention behavior of uranium, thorium and lanthanides has been investigated with amide modified reversed phase C(18) supports using alpha-hydroxy isobutyric acid (alpha-HIBA) as the mobile phase. Four structurally different amide moieties namely, 4-hydroxy-N,N-dihexyl butyramide (4HHBA), 4-hydroxy-N,N-di-2-ethylhexylhexanamide (4HEHHA), bis(N,N,N',N'-2-ethylhexyl)malonamide (B2EHM) and N-methyl-tris(dihexylcarbamoyl-3-methoxy)pivolamide (MTDCMPA) have been synthesized and studied. Among the various amide coated columns, the supports modified with 4HHBA, B2EHM and MTDCMPA exhibit an interesting retention for uranium and thorium, which is different from 4HEHHA modified support. The retention time for uranium and thorium increases with increasing amide concentration for 4HHBA, B2EHM and MTDCMPA supports, while the same decreases with increasing 4HEHHA content. However, the separation factor for uranium and thorium is greater on a 4HEHHA support, compared to an unmodified C(18) column, reflecting the amide's preferential complexation of uranium over thorium. Columns modified with 4HHBA, B2EHM and MTDCMPA exhibit relatively higher retentions for lanthanides. However, MTDCMPA modified support shows a different elution profile for lanthanides compared to 4HHBA, and B2EHM modified columns. Individual separations of heavier lanthanides, i.e., from gadolinium to lutetium also have been achieved using 4HHBA and B2EHM modified supports. The influence of modifier content, mobile phase concentration and its pH on the retention of metal ions has also been studied. Based on these investigations, an efficient high performance liquid chromatographic method (HPLC) has been developed for the rapid separation of uranium from thorium as well as for the individual separation of heavier lanthanides.

Extraction chromatographic method for the separation of actinides and lanthanides using EDHBA grafted AXAD-16 polymer.

A new extraction chromatographic method has been developed by grafting chloromethylated polymer support with 4-ethoxy-N,N-dihexylbutanamide (EDHBA), for the selective extraction of U(VI), Th(IV), La(III) and Nd(III) from highly acidic matrices. The developed grafted polymer has been characterized using (13)C-CPMAS NMR spectroscopy, FT-NIR spectroscopy and also by CHN elemental analysis. The water regaining capacity of the grafted polymer is studied by TGA measurements and the active participation of the amide moiety towards metal ion complexation has been confirmed by Far IR spectroscopy. For the quantitative extraction of metal ions to the resin phase, various physio-chemical parameters are optimized by both static and dynamic methods. The developed amide grafted polymeric matrix shows good distribution ratio values even at high acidities, with the maximum metal sorption capacity values being 0.36, 0.69, 0.32 and 0.42mmolg(-1) for U(VI), Th(IV), La(III) and Nd(III), respectively, at 6M HNO(3) medium. The kinetics of metal ion phase equilibration is found to be moderately fast, with t(1/2) values of <6min, for all the analytes of interest. The limits of analyte quantification (LOQ) using the developed method are in the range of 15-30mugL(-1). Moreover, the sequential separation of the sorbed actinides and lanthanides could be achieved by first eluting with 100mL of distilled water (for actinides) followed by elution with 20mL of 0.1M EDTA (for lanthanides). The selectivity behavior and the practical applicability of the developed resin are tested using synthetic low level nuclear reprocessing mixtures and also with monazite sand. The analytical data are within 3.8% relative standard deviation, reflecting the reproducibility and reliability of the developed method.