Membrane-based hybrid processes for high water recovery and selective inorganic pollutant separation.

The removal of heavy metals (e.g. Pb(II), Cd(II), Cu(II), etc.) and oxyanions (e.g. nitrate, As(III, V), Cr(VI), etc.) is of immense interest for treatment of groundwater and other dilute aqueous systems. However, the presence of non-toxic components, such as hardness (Ca, Mg) and sulfate, can interfere with the separation of toxic species. For example, pressure-driven membrane processes, such as reverse osmosis (RO), have been limited for water treatment due to problems that these extraneous components cause with water recovery and ionic strength (osmotic pressure) of the retentate. In addition, nitrate rejection by RO is considerably lower than NaCl rejection, resulting in permeate concentrations that may be too high for groundwater recharging. Other separation systems that rely solely on sorption of toxic species (e.g. ion exchange resins) may not have sufficient selectivity for efficient use in the presence of competing ions. Hence, implementation of pressure-driven membrane separations and high capacity sorbents in hybrid processes shows much promise for remedying these difficulties. For example, selective separation of nitrate may be achieved by combining nanofiltration (NF) for sulfate removal, followed by RO or ion exchange for nitrate removal (see example 1). When small concentrations of toxic metals are present, the large retentate volumes of RO processes may be reduced by selective removal of toxic species with a high capacity sorbent, thus permitting disposal of a lower volume, non-toxic stream (see example 2). The use of microfiltration membrane-based sorbents containing multiple polymeric functional groups is a novel technique to achieve high metal sorption capacity under convective flow conditions. These sorbents are formed by the attachment of various polyamino acids (MW: 2500-10,000), such as polyaspartic acid (cation sorption), polyarginine (oxyanion sorption), and polycysteine (chelation exchange), directly on the membrane pore surfaces. Since these sorbents have also been found to have high selectivity over non-toxic metals, such as calcium, they are ideal candidates for hybrid processing with RO/NF.

Polycysteine and other polyamino acid functionalized microfiltration membranes for heavy metal capture.

Polycysteine and other polyamino acid functionalized microfiltration membrane sorbents work exceptionally well for the removal and recovery of toxic heavy metals from aqueous streams. These are high capacity sorbents (0.3-3.7 mg/cm2) with excellent accessibility and selectivity for heavy metals, such as Hg(II), Pb(II), and Cd(II) over nontoxic components such as calcium. Polycysteine functionalized membranes work particularly well for metals such as Hg(II) and Cd(II), even in high total dissolved solids containing streams. Parameters such as permeate flow rate,feed metal concentration, and counterion (for Hg(II)) have also been found to influence sorbent behavior. For multicomponent systems, polyglutamic acid functionalized membranes have been found to selectively sorb Pb(II) versus Cd(II). Selective sorption of Cr(III) has also been observed with actual waste streams containing several heavy metals, hardness, and high sodium (2,000 mg/L). The high capacity, site accessibility, and ease of regeneration of these membrane-based sorbents make them ideal for environmental separations when volume reduction or selective recovery is required.

Trisomy 15 mosaic derived from trisomic conceptus: report of a case and a review.

We report on a fetus with 47,XX,+15 chromosome abnormality detected on chorionic villus sampling (CVS). The pregnancy was terminated at 15.5 weeks of gestation and chromosome analysis done on amniocytes and fetal tissues showed a karyotype 46,XX/47,XX,+15. Autopsy showed multiple abnormalities. Short-arm polymorphisms of the three number 15 chromosomes were highly informative in the delineation of parental origin and the stage of meiotic error. Using fluorescent in situ hybridization (FISH) with D15Z1 and a chromosome 15 painting probe, in addition to DA/DAPI and G-banding, we were able to show that the trisomic conceptus was derived through maternal meiosis I error. The trisomic state was then partially corrected by the loss of one of the two maternal 15s resulting in mosaicism without uniparental disomy (UPD). Striking differences in the proportion of trisomic cells in kidneys, blood, intestine, and skin, and lower proportions of trisomic cells in transformed and frozen than in fresh tissues, illustrate the continuing cell selection in this fetus in favour of the normal cell line. Trisomy 15 conceptions are usually aborted spontaneously in the first trimester of pregnancy. The longer survival of this fetus is most probably the result of a chromosome 15 loss from the trisomic zygote. To the best of our knowledge, the presence of this lethal trisomy has been reported in only five live-born infants, and in five fetuses including the present case, it was detected prenatally and the pregnancies were terminated.

Isokinetic trunk testing and employment.

Isokinetic trunk testing is often performed to evaluate ability to perform job tasks. The purpose of this study was to evaluate the effectiveness of isokinetic trunk testing in identifying people with limited functional lifting capability and likely future injury potential. Two hundred thirty work applicants for heavy labor in a steel mill underwent job-related lifting ability and isokinetic trunk evaluation. There was no difference between the isokinetic scores of women who did not meet the job lifting criteria and those who did meet the lifting criteria. There was no difference between the isokinetic scores of workers who experienced occupational low back injury and those workers who did not over almost a 6-year follow-up period. In this study isokinetic trunk evaluation was of no value in employee selection.

The concurrent validity of the survey version of the Clifton Assessment Procedures for the Elderly (CAPE).

The concurrent validity of the survey version of the Clifton Assessment Procedures for the Elderly (CAPE) was assessed by comparing the performance of four groups of elderly women selected to represent different levels of impairment and dependency. It was found to discriminate significantly among patients with severe (n = 100), moderate (n = 40), mild (n = 50) and no (n = 20) dementia; it also significantly distinguished between patients with severe and moderate dementia and patients with physical disability (n = 100) and with signs of 'institutionalization' (n = 25). Patients in the severe, moderate, mild and no dementia groups had all been judged clinically to have been placed appropriately as, respectively, geriatric psychiatry in-patients, geriatric psychiatry day-patients or local authority home residents, or as being able to live independently in the community. However, although the survey version dependency grade is intended for use in allocating patients to health and social services facilities, overall agreement between grades and clinically determined placement was only 63 per cent. Thus while the survey version may be useful in discriminating among groups of elderly people of different levels of impairment for research or screening purposes, its clinical value with individual patients remains uncertain.

Results of a controlled drug trial in membranoproliferative glomerulonephritis.

A prospective randomized drug trial was carried out on 59 patients with confirmed membranoproliferative glomerulonephritis (MPGN). The treatment group (27 patients) received cyclophosphamide, coumadin, and dipyridamole for 18 months, and the control group (32 patients) received no specific therapy. Complications of the renal disease such as hypertension and fluid retention were treated similarly in both groups. Entrance criteria included confirmed renal pathology demonstrating either types I or II MPGN, a corrected creatinine clearance (CCr) of less than 80 ml/min/1.73 m2, and/or proteinuria greater than 2 g/day. Actuarial survival was not different between the treatment and the control groups in either MPGN type and was 85% in type I and 90% in type II at 2 years. The change in renal function, as measured by both the slope of CCr and the plasma creatinine reciprocal (1/Cr) at 6, 12, and 18 months was not significantly different between treatment and control groups in either types I or II when tested by both parametric and nonparametric analysis. The age, sex, and initial level of CCr did not influence the rate of decline. Control and treatment group proteinuria was not different at any time point in either types I or II MPGN. The small numbers of type II MPGN cases do not give sufficient power to allow conclusions regarding this therapy in type II. We can conclude that this treatment is ineffective in altering the natural history of type I MPGN.

Management of severe acute colitis in district hospitals.

Among 10 hospitals of the North East Thames Region, 84 patients were operated on for inflammatory bowel disease in the years 1977-81. There was one death in the 51 patients treated electively. The postoperative mortality was 24% in 33 patients coming to urgent surgery. The factors leading to this continuing high mortality are analysed as a contribution to an improvement in management.

A randomized trial of ascorbic acid in polyposis coli.

The possibility of pharmacological control of large bowel adenomas has been suggested by effectiveness of antioxidants in experimental tumor models and by the results of a limited clinical study using ascorbic acid. Over a two year period we tested this hypothesis in a randomized, double-blind study of 49 patients with polyposis coli. Of 36 patients who were evaluable at completion, 19 had received ascorbic acid, 3 g/day, and 17 had received a placebo. We found a reduction in polyp area in the ascorbic acid-treated group at nine months of follow-up (P less than 0.03) and trends toward reduction in both number and area of rectal polyps during the middle of the trial. A labeling study of rectal epithelium with tritiated thymidine also hinted at a treatment effect. Our data suggest that ascorbic acid temporarily influenced polyp growth or turnover. Although these results have no current therapeutic value, our findings support continued studies of chemoprevention in this and other high risk settings.

The treatment of haemorrhoids by rubber band ligation at St Mark's hospital.

Two hundred and ninety-five patients with symptomatic haemorrhoids were treated by rubber band ligation as out-patients at St Mark's Hospital, London, between April 1972 and December 1975. Follow-up was possible in 260 patients of whom two-thirds were satisfied with the outcome: 69 patients had residual symptoms for which no treatment had been sought. Nineteen patients eventually required a haemorrhoidectomy.