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Subhash Chander

Publications and source records attributed to Subhash Chander.

14 recordsLinked to original sources
PubMed2006

Removal and recovery of metal ions from acid mine drainage using lignite--A low cost sorbent.

Acid mine drainage (AMD), has long been a significant environmental problem resulting from the microbial oxidation of iron pyrite in presence of water and air, affording an acidic solution that contains toxic metal ions. The main objective of this study was to remove and recover metal ions from acid mine drainage (AMD) by using lignite, a low cost sorbent. Lignite has been characterized and used for the AMD treatment. Sorption of ferrous, ferric, manganese, zinc and calcium in multi-component aqueous systems was investigated. Studies were performed at different pH to find optimum pH. To simulate industrial conditions for acid mine wastewater treatment, all the studies were performed using single and multi-columns setup in down flow mode. The empty bed contact time (EBCT) model was used for minimizing the sorbent usage. Recovery of the metal ions as well as regeneration of sorbent was achieved successfully using 0.1 M nitric acid without dismantling the columns.

Acids↗
PubMed2006

Single, binary, and multicomponent sorption of iron and manganese on lignite.

Acid mine drainage (AMD) has long been a significant environmental problem resulting from the microbial oxidation of iron pyrite in the presence of water and air, affording an acidic solution that contains toxic metal ions. The main objective of this study was to remove metal ions [Fe(II), Fe(III), Mn(II), Zn(II)] from AMD using lignite, a low-cost adsorbent. The lignite sorbent was utilized for the sorption of ferrous, ferric, manganese, zinc, and calcium ions in aqueous solutions. Studies were performed at different pH to find optimum pH. Equilibrium isotherms were determined to assess the maximum adsorption capacity of lignite for different metal ions. Sorption capacities were compared in single, binary, ternary, and multicomponent systems. The sorption data are correlated with Freundlich and Langmuir isotherms in each system. Both Freundlich and Langmuir isotherms fit the data reasonably well in terms of regression coefficients. Sorption studies were also performed at different temperatures to obtain the thermodynamic parameters of the process. The maximum lignite adsorption capacities at 25 degrees C were 34.22, 25.84, and 11.90 mg/g for Fe(II), Mn(II), and Fe(III), respectively. Adsorption of Fe(2+) (24.70 mg/g at 10 degrees C and 46.46 mg/g at 40 degrees C) increased with increased temperature, while Mn(2+) adsorption (28.11 mg/g at 10 degrees C and 7.70 mg/g at 40 degrees C) decreased with increased temperature.

Journal Article↗
PubMed2006

Improving QTL mapping resolution based on genotypic sampling--a case using a RIL population.

The QTL mapping results were compared with the genotypically selected and random samples of the same size on the base of a RIL population. The results demonstrated that there were no obvious differences in the trait distribution and marker segregation distortion between the genotypically selected and random samples with the same population size. However, a significant increase in QTL detection power, sensitivity, specificity, and QTL resolution in the genotypically selected samples were observed. Moreover, the highly significant effect was detected in small size of genotypically selected samples. In QTL mapping, phenotyping is a more sensitive limiting factor than genotyping so that the selection of samples could be an attractive strategy for increasing genome-wide QTL mapping resolution. The efficient selection of samples should be more helpful for QTL maker assistant selection, fine mapping, and QTL cloning.

Chromosome Mapping↗
PubMed2005

Total skin electron irradiation therapy in mycosis fungoides using high-dose rate mode: a preliminary experience.

INTRODUCTION: Total skin electron irradiation (TSEI) therapy is the treatment of choice for mycosis fungoides. However, conventional TSEI therapy is time consuming as well as patient unfriendly. Therefore we used high-dose rate (HDR) mode TSEI in these patients. High-dose rate mode of TSEI is a technological innovation attached to a Linear Accelerator (Philips, SL-20, Netherlands), which can deliver an electron beam of 30 Gy/min at the iso-center. The iso-center faces the patient, 100 cm away from the target of the linear accelerator. The patient is treated at a distance of 10 feet from the iso-center of the linear accelerator. The dose delivered to the skin was 1.13 Gy/min, making the treatment execution much easier and patient compliance much better. METHODS: Seven male patients between 40 and 64 years in age having mycosis fungoides for 9-18 months were treated by TSEI using high-dose rate mode between 1998 and 2000. The TSEI was performed according to the Stanford technique, delivering a total dose of 36 Gy. Each patient received a dose of 1.2 Gy/field/day. There were six fields, i.e. anterior, posterior, left and right anterior obliques, and left and right posterior obliques in both the upper and lower parts of the body. The eyes and nails were shielded at each session of radiotherapy. The times taken at each session of the therapy and radiation-associated side-effects were determined in each patient. The patients were followed up to 26 months (median 9 months) to look for any relapse. RESULTS: Three patients had early stage disease (IB) whereas four patients had advanced disease (IIB). Six patients out of these had complete remission following TSEI while one patient died as a result of progression of the disease during treatment. The treatment time taken at each treatment session in each individual patient was approximately 15 min. Radiation-associated morbidity was seen in all patients. Cutaneous lesions relapsed in two patients after 4 and 10 months, respectively, while four patients were alive without the disease at the end of 2 years. CONCLUSIONS: Total skin electron irradiation using high-dose rate mode delivery of electrons is an easy, better, compliant and effective therapeutic modality for treatment of mycosis fungoides with an acceptable range of toxicities.

Adult↗
PubMed2005

West Nile virus infection.

OBJECTIVE: Our objective is to present a brief review of the clinical aspects of West Nile virus infection with emphasis on the spectrum of MRI findings. CONCLUSION: West Nile virus infection has become endemic in the United States and radiologists should become aware of the diverse imaging appearances in the central nervous system.

Humans↗
PubMed2004

Retroperitoneal malignant peripheral nerve sheath tumor: evaluation with serial FDG-PET.

Retroperitoneal malignant peripheral nerve sheath tumor (MPNST), a rare type of neurogenic tumor, was diagnosed in a 14-year-old girl with a history of neurofibromatosis type 1 (NF1). Immunochemistry demonstrated spindle cells positive for S-100 protein. The patient had multiple tumor recurrences and she was evaluated with serial F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET). A tumor in the right iliac wing showed increased FDG uptake on PET. FDG-PET played an important role in therapy planning and subsequent follow up. This case emphasizes the important role FDG-PET could play in the staging, restaging, and posttherapy follow up of MPNST.

Adolescent↗
PubMed2002

High 2-deoxy-2-[18F]fluoro-D-glucose accumulation in a case of retroperitoneal fibrosis following resection of carcinoid tumor.

Positron emission tomography (PET) using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) has been shown to be a highly sensitive diagnostic tool to stage, restage, and monitor the progress of various neoplasms. A number of physiological and non-neoplastic conditions, however, also may be associated with focal accumulation of FDG and can cause false-positive results. This work reports a 52-year-old man who had marked FDG accumulation in carcinoid tumor of the distal ileum. The tumor was resected. A follow-up FDG-PET scan one and a half years later revealed intense FDG accumulation in the abdominal periaortic region, suggesting recurrent malignancy. Computerized tomography (CT) of the abdomen showed soft tissue mass surrounding the aorta. Fine-needle aspiration biopsy of the periaortic soft tissue confirmed benign retroperitoneal fibrosis. This case shows that retroperitoneal fibrosis can cause intense FDG accumulation giving false impression of malignancy. In interpretation of whole-body FDG-PET, various physiological and benign causes of FDG accumulation must be considered in order to avoid pitfalls. The authors have reviewed the literature and discussed association of carcinoid tumor and retroperitoneal fibrosis.

Journal Article↗
PubMed2002

Physiologic uterine uptake of FDG during menstruation demonstrated with serial combined positron emission tomography and computed tomography.

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used extensively to stage, restage, and follow neoplastic disease. However, focal accumulation of FDG may cause false-positive results in certain physiologic conditions. In this report, a unique PET and computed tomography (CT) combination scan helped define physiologic accumulation of FDG in the uterus during menstruation in a 40-year-old woman with a history of rectal melanoma and possible recurrent disease. An initial PET study, performed during menstruation, was followed immediately by a PET-CT scan, which showed marked accumulation of FDG in the posterior pelvis, localized to a retroverted uterus. An FDG PET-CT scan repeated 2 weeks later confirmed resolution of this "lesion." Thus, combined PET-CT correctly differentiated physiologic FDG uptake in a retroverted uterus from recurrent rectal melanoma. This case shows that physiologic FDG accumulation in the uterus should be considered when focal FDG accumulation is observed in the pelvis in women of reproductive age.

Adult↗