Operation of passive membrane systems for drinking water treatment.

The widespread adoption of submerged hollow fibre ultrafiltration (UF) for drinking water treatment is currently hindered by the complexity and cost of these membrane systems, especially in small/remote communities. Most of the complexity is associated with auxiliary fouling control measures, which include backwashing, air sparging and chemical cleaning. Recent studies have demonstrated that sustained operation without fouling control measures is possible, but little is known regarding the conditions under which extended operation can be sustained with minimal to no fouling control measures. The present study investigated the contribution of different auxiliary fouling control measures to the permeability that can be sustained, with the intent of minimizing the mechanical and operational complexity of submerged hollow fiber UF membrane systems while maximizing their throughput capacity. Sustained conditions could be achieved without backwashing, air sparging or chemical cleaning (i.e. passive operation), indicating that these fouling control measures can be eliminated, substantially simplifying the mechanical and operational complexity of submerged hollow fiber UF systems. The adoption of hydrostatic pressure (i.e. gravity) to provide the driving force for permeation further reduced the system complexity. Approximately 50% of the organic material in the raw water was removed during treatment. The sustained passive operation and effective removal of organic material was likely due to the microbial community that established itself on the membrane surface. The permeability that could be sustained was however only approximately 20% of that which can be maintained with fouling control measures. Retaining a small amount of air sparging (i.e. a few minutes daily) and incorporating a daily 1-h relaxation (i.e. permeate flux interruption) period prior to sparging more than doubled the permeability that could be sustained. Neither the approach used to interrupt the permeate flux nor that developed to draw air into the system for sparging using gravity add substantial mechanical or operational complexity to the system. The high throughput capacity that can be sustained by eliminating all but a couple of simple fouling control measures make passive membrane systems ideally suited to provide high quality water especially where access to financial resources, technical expertise and/or electrical power is limited.

Sperm DNA fragmentation in couples with unexplained recurrent spontaneous abortions.

The aim of the present study was to evaluate the degree of sperm DNA fragmentation in couples with idiopathic recurrent spontaneous abortion (RSA) and in those with no history of infertility or abortion. In this cohort study, 30 couples with RSA and 30 fertile couples as control group completed the demographic data questionnaires, and their semen samples were analysed according to World Health Organization (WHO) standards (September 2009-March 2010) for evaluation of sperm DNA fragmentation, using sperm chromatin dispersion (SCD) technique. The percentage of morphologically normal sperm was significantly lower in RSA patients compared with control group (51.50 ± 11.60 versus 58.00 ± 9.05, P = 0.019), but not in other parameters. Additionally, the level of abnormal DNA fragmentation in the RSA group was significantly higher than in the control group (43.3% versus 16.7%, P = 0.024). Our results indicated a negative correlation between the number of sperm with progressive motility and DNA fragmentation (r = -0.613; P < 0.001). The sperm from men with a history of RSA had a higher incidence of DNA fragmentation and poor motility than those of the control group, indicating a possible relationship between idiopathic RSA and DNA fragmentation.

Relationship between Low Birth Weight Neonate and Maternal Serum Zinc Concentration.

BACKGROUND: Zinc deficiency can lead to clinically relevant disturbances in tissue functions and particularly important for birth weight of neonates. The aim of this study was to determine the relationship between serum zinc in pregnant women and the incidence of low birth weight (<2500 g) in their newborns. METHODS: This case-control study was done on women who delivered low birth weight infants (Cases), and normal birth weight infants (Controls). Blood samples got in all women within 5 minutes of delivery, and assessed the concentration of zinc using electrothermal atomic absorption spectrometry. Serum concentration of zinc was compared. RESULTS: One hundred and seventeen mothers were enrolled, of them, 65 cases were low birth weight infants (1845±472 g) and 52 were controls (3166± 435 g). Mothers in the case and control groups did not differ in age, body mass index, and socioeconomic or demographic factors. Maternal zinc concentration differed between cases and controls; 753.34±15 µg/l vs. 654.76±12 µg/l respectively. Maternal zinc differed between premature and full term deliveries. CONCLUSION: Maternal zinc concentration was shown to affect birth weight and prematurity.

Characterizing hypervascular and hypovascular metastases and normal bone marrow of the spine using dynamic contrast-enhanced MR imaging.

BACKGROUND AND PURPOSE: The role of DCE-MR imaging in the study of bone marrow perfusion is only partially developed, though potential applications for routine use in the clinical setting are beginning to be described. We hypothesize that DCE-MR imaging can be used to discriminate between hypervascular and hypovascular metastases based on measured perfusion variables. MATERIALS AND METHODS: We conducted a retrospective study of 26 patients using conventional MR imaging and DCE-MR imaging. Patients were assigned to a hypervascular or hypovascular group based on tumor pathology. ROIs were drawn around normal-appearing bone marrow (internal controls) and enhancing tumor areas. Average wash-in enhancement slope, average peak enhancement signal percentage change, and average peak enhancement signal percentage change in areas of highest wash-in enhancement slope were calculated. Indices were compared among control, hypervascular, and hypovascular groups. Conventional imaging was assessed by calculating pre- to postgadolinium signal percentage changes in hypervascular and hypovascular lesions. RESULTS: Hypervascular and hypovascular tumors differed significantly with regard to wash-in enhancement slope (P < .01; hypervascular 95% CI, 22.5-26.5 AU/s; hypovascular 95% CI, 14.1-20.9 AU/s) and peak enhancement signal percentage change in areas of highest wash-in enhancement slope (P < .01; hypervascular 95% CI, 174.1-323.3%; hypovascular 95% CI, 39.5-150.5%). Peak enhancement signal percentage change over all voxels was not significant (P = .62). Areas of normal-appearing marrow showed no appreciable contrast enhancement. Conventional contrast-enhanced MR imaging was unable to differentiate between hypervascular and hypovascular tumors (P = .58). CONCLUSIONS: Our data demonstrate that, unlike conventional MR imaging sequences, DCE-MR imaging may be a more accurate technique in discriminating hypervascular from hypovascular spinal metastases.

Pain tracker diagnostic instrument: effect on patients' satisfaction with their interactions with the primary care physician.

In a randomized trial, the pain tracker instrument was evaluated as a diagnostic screening tool and for its effect on patients' satisfaction with their interactions with the primary care physician. The instrument form was filled in by the physician after asking the study patients about symptoms. Control (n = 53) and study patients (n = 49) were interviewed and the instrument's effect was analysed from responses to 15 statements. The pain tracker group were significantly more satisfied with the physician relationship than were controls (mean satisfaction score 85 +/- 8 versus 61 +/- 9). A direct linear correlation was found between patients' assessment of the visit and overall satisfaction (r = 0.86). The pain tracker can be an important component in history taking and a useful diagnostic screening tool in pain presentations.

Pain tracker diagnostic instrument: effect on patients' satisfaction with their interactions with the primary care physician

In a r and omized trial, the pain tracker instrument was evaluated as a diagnostic screening tool and for its effect on patients' satisfaction with their interactions with the primary care physician. The instrument form was filled in by the physician after asking the study patients about symptoms. Control [n = 53] and study patients [n = 49] were interviewed and the instrument's effect was analysed from responses to 15 statements. The pain tracker group were significantly more satisfied with the physician relationship than were controls [mean satisfaction score 85 +/- 8 versus 61 +/- 9]. A direct linear correlation was found between patients' assessment of the visit and overall satisfaction [r = 0.86]. The pain tracker can be an important component in history taking and a useful diagnostic screening tool in pain presentations