Investigation of the electro-coagulation treatment process for the removal of total suspended solids and turbidity from municipal wastewater

In this work, raw municipal wastewater was electro-coagulated for the removal of total suspended solids (TSS), turbidity, and particulate BOD using stainless steel electrodes. The removal efficiency of TSS and turbidity is shown to depend on the amount of iron generated from the anode of the reactive electrode used in this study, when applying the lower currents of 0.05 A and 0.1A. For such lower currents, the results suggested that the removal is consistent with charge neutralization coagulation mechanism. When applying higher currents of 0.2 A, 0.4 A, and 0.8 A, the results suggested that the dominant removal mechanism is sweep-floc coagulation as the generated soluble ferrous ions are converted to insoluble ferric ions due to oxidation with chlorine generated during the electrochemical process at the higher currents. The highest TSS removal efficiency of 95.4% occurred at a current of 0.8A and contact time of 5 min. The effect of electro-coagulation on the removal of particulate BOD was shown to depend on the TSS removal efficiency.     

Comparison of Cryptosporidium parvum viability and infectivity assays following ozone treatment of oocysts

Several in vitro surrogates have been developed as convenient, user-friendly alternatives to mouse infectivity assays for determining the viability of Cryptosporidium parvum oocysts. Such viability assays have been used increasingly to determine oocyst inactivation following treatment with chemical, physical, or environmental stresses. Defining the relationship between in vitro viability assays and oocyst infectivity in susceptible hosts is critical for determining the significance of existing oocyst inactivation data for these in vitro assays and their suitability in future studies. In this study, four viability assays were compared with mouse infectivity assays, using neonatal CD-1 mice. Studies were conducted in the United States and United Kingdom using fresh (<1 month) or environmentally aged (3 months at 4 degrees C) oocysts, which were partially inactivated by ozonation before viability and/or infectivity analyses. High levels of variability were noted within and between the viability and infectivity assays in the U.S. and United Kingdom studies despite rigorous control over oocyst conditions and disinfection experiments. Based on the viability analysis of oocyst subsamples from each ozonation experiment, SYTO-59 assays demonstrated minimal change in oocyst viability, whereas 4',6'-diamidino-2-phenylindole-propidium iodide assays, in vitro excystation, and SYTO-9 assays showed a marginal reduction in oocyst viability. In contrast, the neonatal mouse infectivity assay demonstrated significantly higher levels of oocyst inactivation in the U.S. and United Kingdom experiments. These comparisons illustrate that four in vitro viability assays cannot be used to reliably predict oocyst inactivation following treatment with low levels of ozone. Neonatal mouse infectivity assays should continue to be regarded as a "gold standard" until suitable alternative viability surrogates are identified for disinfection studies.     

Contribution of GJB2 Mutations to Hearing Loss in the Hazara Division of Pakistan

Mutations of GJB2, which encodes connexin 26, are the most common cause of hereditary hearing loss in many human populations. This study was initiated to determine the prevalence of GJB2 mutations in individuals with hearing loss from the Hazara Division in Pakistan. We recruited 70 participants with nonsyndromic deafness segregating as an apparently recessive trait and directly sequenced the GJB2 coding region from their DNA. The homozygous mutations c.71 G→A (p.W24X), c.104 T→G (p.I35S), and c.35delG (p.G12VfsX1) were identified as the cause of hearing loss in three participants (4.28%); in populations from other areas of Pakistan, frequencies of 6–7% have been observed. The mutations c.104 T→G and c.35delG were identified in Pakistan for the first time. These results confirm the low prevalence of GJB2 mutations in Hazara and suggest that mutations in other genes may play a significant role in the etiology of deafness in this population.     

Blind trials evaluating in vitro infectivity of Cryptosporidium oocysts using cell culture immunofluorescence

An optimized cell culture immunofluorescence (IFA) procedure, using the HCT-8 cell line, was evaluated in blind trials to determine the sensitivity and reproducibility of measuring the infectivity of flow-cytometry-prepared inocula of Cryptosporidium parvum oocysts. In separate trials, suspensions consisting of between 0% and 100% viable oocysts were prepared at the US Environmental Protection Agency, shipped to the American Water Laboratory, and analyzed blindly by cell culture IFA. Data indicated the control (100% live) oocyst suspensions yielded statistically similar results to cell culture dose-response curve data developed previously at the American Water Laboratory. For test samples containing oocyst suspensions of unknown infectivity, cell culture IFA analyses indicated a high degree of correlation (r2 = 0.89; n = 26) with the values expected by the US Environmental Protection Agency. Cell culture infectivity correlates well with neonatal mouse infectivity assays, and these blind validation trials provide credibility for the cell culture IFA procedure as a cost-effective and expedient alternative to mouse infectivity assays for determining in vitro infectivity of C. parvum oocysts.     

Role of nitrogen and magnesium for growth,yield and nutritional quality of radish

Nitrogen (N) affects all levels of plant function from metabolism to resource allocation, growth, and development and Magnesium (Mg) is a macronutrient that is necessary to both plant growth and health. Radish (Raphanus sativus L.) occupies an important position in the production and consumption of vegetables globally, but there are still many problems and challenges in its nutrient management. A pot trial was conducted to investigate the effects of nitrogen and magnesium fertilizers on radish during the year 2018–2019. Nitrogen and magnesium was applied at three rates (0, 0.200, and 0.300 g N kg⁻¹ soil) and (0, 0.050, and 0.100 g Mg kg⁻¹ soil) respectively. The experiment was laid out in a completely randomized design (CRD) and each treatment was replicated three times. Growth, yield and quality indicators of radish (plant height, root length, shoot length, plant weight, total soluble sugar, ascorbic acid, total soluble protein, crude fiber, etc.) were studied. The results indicated that different rates of nitrogen and magnesium fertilizer not only influence the growth dynamics and yields but also enhances radish quality. The results revealed that the growth, yield and nutrient contents of radish were increased at a range of 0.00 g N. kg⁻¹ soil to 0.300 g N. kg⁻¹ soil and 0.00 g Mg. kg⁻¹ soil to 0.050 g Mg. kg⁻¹ soil and then decreased gradually at a level of 0.100 g Mg. kg⁻¹ soil. In contrast, the crude fiber contents in radish decreased significantly with increasing nitrogen and magnesium level but increased significantly at Mg₂ level (0.050 g Mg. kg⁻¹ soil). The current study produced helpful results for increasing radish quality, decreasing production costs, and diminishing underground water contamination.     

Structural and biochemical alterations in Giardia lamblia cysts exposed to ozone

Because of its efficacy in inactivating waterborne protozoan cysts and oocysts, ozone is frequently used for disinfection of drinking water. The effect of ozone on cysts of Giardia lamblia was investigated in gerbils (Meriones unguiculatus), using an infectivity assay by scanning electron microscopy, immunoblotting, and flow cytometry. Cysts recovered from experimentally infected gerbils were exposed to an initial ozone concentration of 1.5 mg/L for 0, 30, 60, and 120 sec.This treatment resulted in a dose-dependent reduction in cysts concentration, loss of infectivity in gerbils, and profound structural modifications to the cyst wall. Exposure for 60 sec or longer resulted in extensive protein degradation and in the disappearance of a cyst wall and a trophozoite antigen.     

Inter-Specific Differences in Cotton for Nutrient Partitioning from Subtending Leaves to Reproductive Parts at Various Developmental Stages: Consequences for Fruit Growth and Yield

A field study was carried out to unravel the inter-specific differences in cotton for the partitioning of N, P, K, S, Ca, Mg, Na and Cl from the subtending leaves to the reproductive parts of Gossypium hirsutum, G. barbadense and G. arboreum at various developmental stages. Results revealed significant differences among the species for the various parameters studied. Overall there was a greater fresh and dry matter yield of various reproductive parts and subtending leaves of G. hirsutum and G. barbadense than G. arboreum, although the leaf photosynthetic rate was similar. Age-dependent increase in leaf area/leaf mass ratio indicated a greater partitioning of earlier acquired assimilates to the growth of reproductive parts. Results indicated greater partitioning of N, P, S and Ca during later reproductive growth (from boll production to its opening) in G. hirsutum and G. barbadense but during earlier reproductive growth in G. arboreum (from bud up to flower formation) as was evident by decreased subtending leaf/reproductive parts ratio. It is concluded that better N, P, S and Ca partitioning ability of G. hirsutum and G. barbadense at the onset of boll development played a major role in the better yield and good quality fiber characteristics. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antibacterial effects of Tungsten nanoparticles on the Escherichia coli strains isolated from catheterized urinary tract infection (UTI) cases and Staphylococcus aureus

A significant proportion of all incidents of nosocomial infections in acute-care hospitals is due to contaminated catheters. Alternative strategies e.g. antibiotics as well as surface modifications have been devised in an attempt to reduce the incidence of catheter-associated urinary tract infections (CAUTI), but most have proven unsuccessful. Therefore, the race to identify such substances which can combat pathogenic bacteria is ongoing in order to improve the quality of health care. Novel technologies such as the potential use of antiseptic or antimicrobial coatings on catheters hold promise for reducing these infections in the fight against antimicrobial resistance. In this study, the bactericidal activity of newly synthesized tungsten-nanoparticles was tested on clinical multiple drug resistant Escherichia coli isolates from UTI patients with indwelling catheters and Staphylococcus aureus reference strain. The results suggest that the particles tested in this study certainly mediate the inhibition of bacterial growth. We believe that the fabrication of W-NPs on catheters could possibly prevent them from being contaminated by pathogens and hence provide continuous protection of the site. This study is the first of its type testing the antibacterial effects of W-NPs on clinical bacterial isolate from catheterized human UTI case.     

Inheritance of inter-simple-sequence-repeat polymorphisms and linkage with a fusarium wilt resistance gene in chickpea

 The inheritance of an inter-simple-sequence-repeat (ISSR) polymorphism was studied in a cross of cultivated chickpea (Cicer arietinum L.) and a closely related wild species (C. reticulatum Lad.) using primers that anneal to a simple repeat of various lengths, sequences and non-repetitive motifs. Dinucleotides were the majority of those tested, and provided all of the useful banding patterns. The ISSR loci showed virtually complete agreement with expected Mendelian ratios. Twenty two primers were used for analysis and yielded a total of 31 segregating loci. Primers based on (GA)_n repeats were the most abundant while primers with a (TG)_n repeat gave the largest number of polymorphic loci. Nucleotides at the 5′ and 3′ end of the primers played an important role in detecting polymorphism. All the markers showed dominance. We found an ISSR marker linked to the gene for resistance to fusarium wilt race 4. The marker concerned, UBC-855₅₀₀, was found to be linked in repulsion with the fusarium wilt resistance gene at a distance of 5.2 cM. It co-segregated with CS-27₇₀₀, a RAPD marker previously shown to be linked to the gene for resistance to fusarium wilt race 1, and was mapped to linkage group 6 of the Cicer genome. This indicated that genes for resistance to fusarium wilt races 1 and 4 are closely linked. The marker UBC-855₅₀₀ is located 0.6 cM from CS-27₇₀₀ and is present on the same side of the wilt resistance gene. To our knowledge this is the first report of the utility of an ISSR marker in gene tagging. These markers may provide valuable information for the development of sequence-tagged microsatellite sites (STMS) at a desired locus. Received: 10 August 1997 / Accepted: 6 October 1997     

Genetic analysis of heterogeneous DNA circles formed after prophage Mu induction.

Induction of a Mu prophage in Escherichia coli Hfr strains lyosgenic for Mu cts62 leads to the generation of F' episomes. Each episome thus formed carries at least one copy of the Mu genome. These results suggest that integration of Mu is mandatory for the formation of the heterogeneous circles during the lytic cycle. The circles may be precursors for phage maturation.