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T J Mason

Publications and source records attributed to T J Mason.

At least 37 records · Page 2Linked to original sources
PubMed2000

Double-structured ultrasonic high frequency reactor using an optimised slant bottom.

The present work has been carried out in order to design a new type of ultrasonic reactor consisting of a double-structured tank. The inner working compartment is built with a slant bottom to allow a better ultrasonic transmission. This paper reports the effect of the inclination angle on acoustic efficiency for several different plates, e.g. two plates made of glass (2 mm and 3 mm thickness) and one made of PVC (3 mm thickness). The acoustic efficiency was determined as the ratio of the signal measured by a hydrophone in the presence of the plate to that signal in the absence of the plate. Having optimised the system, the ultrasonic powers in the inner and the outer compartments of the slant bottom reactor were determined by hydrogen peroxide dosimetry.

Journal Article↗
PubMed2000

Large scale sonochemical processing: aspiration and actuality.

It has been recognised for many years that power ultrasound has great potential in a wide variety of processes in the chemical and allied industries. Some of these processes have been known for many years and continue to flourish as major commercial applications, e.g. plastic welding and cleaning. Others, like ultrasonic drilling, while showing great potential have not been widely exploited to date. The potential for the industrial use of power ultrasound is enormous, and yet industry seems somewhat reluctant to adopt it. In this article the existing uses of power ultrasound in processing are reviewed and the potentials are explored.

Journal Article↗
PubMed2000

Dye effluent decolourisation using ultrasonically assisted electro-oxidation.

Solutions of the acidic dye, Sandolan Yellow, were subjected to sonolysis, electrolysis and sonoelectrolysis. Decolourisation did not take place using ultrasound alone but was achieved using an electro-oxidation process. The rate of electro-chemical decolourisation in the absence of ultrasound was dependent on the type of electrode used, electrolyte concentration, reaction temperature and the current density. Electro-oxidation of Sandolan Yellow using platinum electrodes was enhanced using ultrasound when carried out in a semi-sealed cell, which minimised the effects of ultrasonic degassing.

Journal Article↗
PubMed1997

An investigation into the ultrasonic treatment of polluted solids.

Granular pieces of brick impregnated with copper oxide were used as a model for contaminated soil. Washing this model substrate by passing water across the substrate on an ultrasonically shaken tray irradiation afforded a 40% reduction in copper content. This was compared with only a 6% reduction when the sample was treated under otherwise identical conditions but using a tray shaken conventionally. The majority of the copper was removed as a result of the removal of surface materials which were more heavily contaminated with the copper oxide.

Copper↗
PubMed1997

The development and evaluation of ultrasound in the biocidal treatment of water.

The effect of ultrasound upon the destruction of micro-organisms has been studied and reported here. The results obtained from the work carried out has shown that ultrasound can be used effectively for water disinfection and has several advantages. When used in conjunction with chlorine it significantly reduces the number of bacteria present in water samples. Ultrasound also reduces the amount of chlorine required for disinfection. Increasing the power of ultrasound leads to greater efficiency in the destruction of bacterial cells. High frequency ultrasound is more beneficial than low frequency in the disinfection of water.

Chlorine↗
PubMed1997

Comparison of conventional and ultrasonically assisted extractions of pharmaceutically active compounds from Salvia officinalis.

Conventional as well as ultrasonically assisted extractions of biologically active compounds from Salvia officinalis using 65% ethanol have been studied. Cineole, Thujone and Borneol were used as standards for the GLC-MS evaluation of the extracts. The effect of temperature, stirring and mode of sonication (ultrasonic bath or horn system) have been studied. The results indicate that ultrasonically assisted extraction with mechanical stirring at room temperature in a period of 12 h produces a substantial improvement over conventional methodology.

Bicyclic Monoterpenes↗
PubMed1997

Effect of ultrasound on the immunogenic corn cob xylan.

Changes in the structural, molecular and functional properties of the immunogenic corn cob xylan evoked by ultrasonication in water, 1% NaOH and 5% NaOH were investigated. The reduction of the high molar mass (MM) fraction was more intense than that of the medium MM fraction, depending on the sonic power, sonication time, and alkali concentration. The chain degradation was more effective in the alkaline media. The UV-absorbing component, accompanying the xylan polymers in the whole MM range, showed an accumulation in the high MM region as well as shiftening to higher sizes, particularly in 5% NaOH. The sugar composition and primary structure of the xylan was almost retained under all irradiation conditions studied. Although the biological activity of the xylan was affected by the ultrasound, no significant decrease of the biological response was found at short irradiation time and low sonic power.

Carbohydrate Sequence↗
PubMed1995

Elective surgery for asymptomatic, unruptured, intracranial aneurysms: a cost-effectiveness analysis.

Cost-effectiveness analysis uses both economic and clinical outcomes data to evaluate treatment options. In this era of economic constraints on health care, treatments that are not cost-effective will increasingly be denied public and private insurance reimbursement. The authors used mathematical modeling techniques to assess the cost-effectiveness of elective surgery for the treatment of asymptomatic, unruptured, intracranial aneurysms. Input values for the Markov model used in this study were determined from both the literature and clinical judgment. Direct medical costs for hospitalization and physician fees were derived from Medicare cost reports and resource-based relative-value units, expressed in 1992 U.S. dollars. Costs and benefits were discounted at an annual rate of 5%. Using baseline model assumptions for a 50-year-old patient, elective aneurysm surgery provides an average of 0.88 additional quality-adjusted life years (QALYs) compared with nonsurgical treatment. However, prompt elective surgery ($23,300) costs more than expectant management ($2100), in which only patients whose aneurysms rupture incur treatment costs. Combining the outcomes and cost data, the incremental cost-effectiveness of elective aneurysm surgery is $24,200 per QALY, which is comparable to other accepted medical or surgical interventions, such as total knee arthroplasty ($15,200/QALY) or antihypertensive therapy in a 50-year-old patient ($29,800/QALY). Prompt elective surgery for asymptomatic, unruptured, intracranial aneurysms is recommended as a cost-effective use of medical resources provided: 1) surgical morbidity and mortality remain at reported levels; 2) the patient has a life expectancy of at least 13 additional years; and 3) the patient experiences a decrease in quality of life from knowingly living with an unruptured aneurysm.

Adult↗
PubMed1992

Evidence for immune selection of hepatitis C virus (HCV) putative envelope glycoprotein variants: potential role in chronic HCV infections.

E2/nonstructural protein 1, the putative envelope glycoprotein (gp72) of HCV, possesses an N-terminal hypervariable (E2 HV) domain from amino acids 384 to 414 of unknown significance. The high degree of amino acid sequence variation in the E2 HV domain appears to be comparable to that observed in the human immunodeficiency virus type 1 gp120 V3 domain. This observation and the observation that the HCV E2 HV domain lacks conserved secondary structure imply that, like the V3 loop of human immunodeficiency virus 1 gp120, the N-terminal E2 region may encode protective epitopes that are subject to immune selection. Antibody-epitope binding studies revealed five isolate-specific linear epitopes located in the E2 HV region. These results suggest that the E2 HV domain is a target for the human immune response and that, in addition to the three major groups of HCV, defined by nucleotide and amino acid sequence identity among HCV isolates, E2 HV-specific subgroups also exist. Analysis of the partial or complete E2 sequences of two individuals indicated that E2 HV variants can either coexist simultaneously in a single individual or that a particular variant may predominate during different episodes of disease. In the latter situation, we found one individual who developed antibodies to a subregion of the E2 HV domain (amino acids 396-407) specific to a variant that was predominant during one major episode of hepatitis but who lacked detectable antibodies to the corresponding region of a second variant that was predominant during a later episode of disease. The data suggest that the variability in the E2 HV domain may result from immune selection. The findings of this report could impact vaccine strategies and drug therapy programs designed to control and eliminate HCV.

Amino Acid Sequence↗
PubMed1992

New opportunities for screening and early detection of bladder cancer.

In the United States, over 51,000 new cases of urinary bladder tumors are diagnosed annually. Approximately 75-85% of all newly diagnosed cases are superficial transitional cell carcinomas (TCCs). Incidence is highest (80% of the cases) in the 50-79 year age group. Recent studies have reported that 21-25% of risk for bladder cancer among United States white males is due to occupational exposure. The DuPont Chambers Works in Deepwater, New Jersey, was a major producer of two chemicals now known to be human bladder carcinogens (beta-naphthylamine and benzidine) as well as two suspected human bladder carcinogens [ortho-toluidine and 4,4'-methylene- bis,2-chloroaniline (MOCA)]. Between 1954 and 1982, DuPont screened 1723 exposed employees annually at the Chambers Works using the Papanicolaou test for urinary cytology and microscopic urinalysis. A review of the prior screening program found that employees who developed bladder cancer during this time period were approximately twice as likely to have had hematuria than those comparably exposed who did not develop bladder cancer. Building on this finding, a three-year screening study evaluated a home self-test for microscopic hematuria to aid early detection of treatable urologic conditions among exposed workers at this chemical plant. Every six months, subjects tested their urine at home for 14 consecutive days, for the presence of blood. A high degree of adherence to our protocol (over 92% completed and returned the self-testing record) as well as high compliance with repeat screening (85% returned for screening in subsequent quarters) demonstrated good acceptance and performance of the recommended schedule of self-testing. Through the first 7 periods of screening, two new cases and one recurrence of TCC of the bladder were detected.

Humans↗
PubMed1991

Systematic fractionation of serum antibodies using multiple antigen homologous peptides as affinity ligands.

The fractionation of polyclonal antibodies on multiple peptide ligands is described. The method is an application of a procedure for the synthesis of large numbers of peptides on individual polyethylene pins (Geysen et al., 1987). In this application, each pin-bound peptide is used as an affinity support. Antibodies bound to the peptides are then eluted, using buffers of either high or low pH. Each eluted antibody is then tested for specific binding to peptides or proteins, using ELISA procedures. A rabbit antiserum raised to gonococcal pilin was fractionated on a complete set of octapeptides homologous with the sequence of the pilin protein. Antibodies eluted from some of the peptides bound to pilin in solution. In a second example three hyperimmune sera raised to three different potyviruses were fractionated on their respective homologous peptide sequences. Testing the eluted antibodies on the three virus coat proteins revealed peptides which bound cross-reacting antibodies. Thus the method can be used to confirm direct peptide binding evidence for sequential epitopes. These peptides can then be used in affinity chromatography to increase the specificity of polyclonal sera. This can be achieved either by elution of the specific antibody from the peptide or by removal of cross-reacting antibodies from the whole serum by absorption on peptide.

Amino Acid Sequence↗
PubMed1991

Subtype-specificity of antipeptide antibodies raised against unique sequences of human interferons-alpha.

A strategy for the production of human interferon-alpha (IFN-alpha) subtype-specific antibodies, based on immunizing rabbits with short unique synthetic peptides coupled to protein carriers, has been validated. These peptides correspond to amino acid residues 99-111 of IFN-alpha 1, 50-57 and 103-116 of IFN-alpha 2, and 37-50 of IFN-alpha 4. The antipeptide antibodies [anti-IFN alpha 1(99-111), anti-IFN alpha 2(50-57C), anti-IFN alpha 2(103-116) and anti-IFN alpha 4(C37-50)] were tested by ELISA and Western blotting for their reactivity with immunoaffinity-purified recombinant human IFN-alpha 1, -alpha 2b and -alpha 4a. The anti-IFN alpha 1(99-111) and anti-IFN alpha 2(50-57C) reacted with their corresponding IFN-alpha and did not crossreact with the other IFN subtypes. The anti-IFN alpha 2(103-116) reacted with IFN-alpha 2b and also crossreacted slightly with the other subtypes. The anti-IFN alpha 4(C37-50) reacted well with IFN-alpha 4a, crossreacted with significantly lower affinity with IFN-alpha 1 and did not bind IFN-alpha 2b. Residues 104-107 and 108-111 are the major components of the epitopes recognized by anti-IFN alpha 1(99-111) and anti-IFN alpha 2(103-116), respectively, as determined by ELISA against overlapping octapeptides.

Amino Acid Sequence↗
PubMed1991

Lung cancer risk associated with cancer in relatives.

Family history data from an incident case-control study of lung cancer conducted in the Texas Gulf Coast region between 1976 and 1980 were analyzed to evaluate the contribution of cancer in first-degree relatives to lung cancer risk. Odds ratios (OR) increased slightly as the number of relatives with any cancer increased (reaching 1.5 with 4 or more relatives with cancer). Risks were higher for tobacco-related cancers (OR = 1.5 for 2 or more relatives with these tumors) and greatest for first-degree relatives with lung cancer (OR = 2.8 for lung cancer in 2 or more relatives). For cases of squamous cell carcinoma and adenocarcinoma of the lung, risks with 3 or more relatives with any cancer were increased 2-fold (OR = 1.8 and 1.9 respectively), and a significantly elevated risk was found for having a first-degree relative with lung cancer for each histologic type (ORs from 1.7-2.1). Having a spouse with lung cancer increased lung cancer risk (OR = 2.5), and cases with lung cancer reported in a first-degree relative were diagnosed at an earlier age, as were case siblings with lung cancer.

Adenocarcinoma↗
PubMed1990

Case-control study of residential radon and lung cancer among New Jersey women.

To evaluate the association of indoor radon exposure with lung cancer risk, yearlong alpha track detector measurements of radon were conducted in dwellings which had been occupied for at least 10 years by 433 New Jersey female lung cancer cases and 402 controls who were subjects in a larger population-based study. Adjusted odds ratios were 1.1 (90% confidence interval, 0.79-1.7), 1.3 (90% confidence interval, 0.62-2.9), and 4.2 (90% confidence interval, 0.99-17.5) for exposures of 1.0-1.9, 2.0-3.9, and 4.0-11.3 pCi/liter, respectively, relative to exposures of less than 1.0 pCi/liter, showing a significant trend (1-sided P = 0.04) with increasing radon concentration. The trend was strongest among light smokers (less than 15 cigarettes/day, 1-sided P = 0.01). The trend for lung cancer risk with estimated cumulative radon exposure was slightly weaker (1-sided P = 0.09). The increase in relative risk for each unit of cumulative exposure, 3.4% (90% confidence interval 0.0-8.0%) per working level month, was consistent with the range of 0.5-4.0% per working level month generally reported for underground miner studies, supporting the extrapolation of the occupational data to the residential setting. However, the possibility of selection biases, the small number of high exposures, and other uncertainties necessitate caution in interpretation of these data.

Adult↗
PubMed1990

Bladder cancer screening at the Dupont Chambers Works: a new initiative.

Persons occupationally exposed to known or suspected human bladder carcinogens are being recruited for a 3-year case-control study of the efficacy of and adherence to a home self-testing protocol for microscopic hematuria as a method for early detection of treatable urologic conditions, including bladder cancer. All employees of the DuPont Chambers Works who are currently in the tumor surveillance program (those known to have been exposed to beta-naphthylamine, benzidine, and 4,4'-methylenebis(2-chloroaniline] will be asked to participate. Age-matched controls will be recruited from the community. Recent advances in identifying clinical signs of underlying bladder disease among the asymptomatic have been implemented in our screening design. Quarterly urinalyses will include the traditional microscopic examination of the urine to detect red blood cells. Participants will test their urine for microhematuria using the Ames HemastixR for 14 consecutive days every other quarter. On alternating quarters, cytologies will be performed. Persons who test positive (hematuria and/or abnormal cytology) will be referred for a complete urologic workup.

Chemical Industry↗
PubMed1990

Epitope mapping of the Mycobacterium bovis secretory protein MPB70 using overlapping peptide analysis.

The gene encoding the major Mycobacterium bovis secreted protein MPB70 was cloned and isolated from a DNA library in lambda EMBL 3, and the restriction map of the area of chromosome containing the gene ascertained. After sub-cloning, the complete DNA sequence and predicted amino acid sequence were determined, and from this information a series of overlapping octapeptides encoding all possible linear epitopes of eight or less amino acids were synthesized. These peptides were probed with monoclonal antibodies specific for M. bovis and with sera from M. bovis-infected cattle. Epitopes defined by this technique were then examined using a substitution analysis that allowed the significance of each amino acid in the putative epitope to be quantified, and the exact specificity of the antibody response for the epitope determined.

Amino Acid Sequence↗