Combined UV LED and Chlorine for Synergistic Drinking Water Disinfection and Assessment of Disinfection By‐Product Formation

Sequence types diversity of Legionella pneumophila isolates from environmental water sources in Guangzhou and Jiangmen, China

The association between natural drinking water sources and the emergence of zoonotic leptospirosis among grazing beef cattle herds during a human outbreak

Efficient removal of GenX (HFPO-DA) and other perfluorinated ether acids from drinking and recycled waters using anion exchange resins

Application of UV LEDs to inactivate antibiotic resistant bacteria: Kinetics, efficiencies, and reactivations

A large number of natural and artificial water sources are found on the territory of Zhambyl region. This is due to the fact that in the territory located in the mountainous region, the names of rivers, lakes, streams, wells with rich reserves of water resources are often found, and the nature of hydrological objects is clearly indicated. It can be said that the terms defining geographical names that characterize natural water sources have an ecological and geographical basis. Natural water sources have played an important role in the economy and provide extensive geographical information from history. From modern historical and archaeological data it can be seen that the first human settlements were located near water bodies. The article analyzes specific data on the manifestations, formation and features of the names of artificial and natural water sources in the study of microhydrogems of the Zhambyl region. The names of water bodies (hydronyms) are based on hydrographic terms. With the help of the terms contained in the hydronyms, it is possible to determine the type, nature and geographical features of water bodies. Toponymic analysis, geoinformation methods of differentiation and drawing conclusions were used in the study of microhydronyms of Zhambyl region.

Higher optical power and higher UV doses come along with a higher operation temperature of UV LED based light sources. Silver sintered pastes offer a robust lead-free alternative to solder pastes increasing the lifetime of the device and enabling higher heat dissipation. Due to the design of UV LEDs, they have to be connected to a heat spreading submount by flip chip joining. Well established processes are flip chip soldering and thermal compression bonding. However, both methods do not achieve optimal heat dissipation in practice. Solder joining material offers a thermal conductivity in the range of 50-60 W/mK which can be further reduced by voids or uncovered areas. Gold contacts for thermal compression bonding offer excellent thermal conductivity of 320 W/mK, but show a maximum coverage of 50- 70%. Silver sinter paste adapted to the UV LED contact system, is a promising alternative flip chip joining material. In order to evaluate different joining methods, UV LED devices were assembled by thermal compression bonding, diffusion bonding, soldering and sintering and compared according to, thermal resistivity, optical-electrical and mechanical behavior and reliability issues. In addition, different silver sinter pastes were tested and their thermal resistivity was adjusted via processing parameters (pressurization, sintering temperature and time). For pressureless approaches the thermal conductivity and layer thickness are in the range of solder material or below. Using pressure for sintering, several advantages will be introduced. The interconnection thickness can be adjusted to be as thin as possible (below 5 micron), which enhanced the heat dissipation. A thin sintered layer of a few microns shows a lower shrinkage and a better adhesion to the joining partners. The thermal conductivity can be enhanced as well. After sintering, the silver interconnection layer is thermally stable up to 800 °C. These facts speak for sintering pastes as a real alternative for UV LED assembly.

Effect of superfine pulverization of powdered activated carbon on adsorption of carbamazepine in natural source waters

BACKGROUNDThe detection of live Mycobacterium leprae in soil and animals other than humans suggests that the environment plays a role in the transmission of leprosy.OBJECTIVEThe objective of this study was to investigate the presence of viable M. leprae in natural water sources used by the local population in five municipalities in the state of Ceará, northeastern Brazil.METHODSSamples were collected from 30 different sources. Viable bacilli were identified by reverse transcriptase polymerase chain reaction (PCR) of the M. leprae gyrA gene and sequencing of the PCR products. Physicochemical properties of each water source were also assessed.FINDINGSM. leprae gyrA mRNA was found in 23 (76.7%) of the water sources. No association was found between depth of the water and sample positivity, nor was there any association between the type of water used by the population and sample positivity. An association between viable M. leprae and temperature and pH was found. Georeferencing showed a relation between the residences of leprosy cases and water source containing the bacterium.MAIN CONCLUSIONSThe finding of viable M. leprae in natural water sources associated with human contact suggests that the environment plays an important role in maintaining endemic leprosy in the study region.

Narrow riparian woodlands along non-perennial streams have made it possible for vervet monkeys to penetrate the semi-arid karoo ecosystem of South Africa, whilst artificial water points have more recently allowed these populations to colonize much more marginal habitat away from natural water sources. In order to better understand the sequelae of life in these narrow, linear woodlands for historically ‘natural’ populations and to test the prediction that they are ecologically stressed, we determined the size of troops in relation to their reliance on natural and artificial water sources and collected detailed data from two river-centred troops on activity, diet and ranging behaviour over an annual cycle. In comparison to other populations, our data indicate that river-centred troops in the karoo were distinctive primarily both for their large group sizes and, consequently, their large adult cohorts, and in the extent of home range overlap in what is regarded as a territorial species. Whilst large group size carried the corollary of increased day journey length and longer estimated interbirth intervals, there was little other indication of the effects of ecological stress on factors such as body weight and foraging effort. We argue that this was a consequence of the high density of Acacia karroo, which accounted for a third of annual foraging effort in what was a relatively depauperate floristic habitat. We ascribed the large group size and home range overlap to constraints on group fission.Conservation implications: The distribution of group sizes, sampled appropriately across habitats within a conservation area, will be of more relevance to management than average values, which may be nothing more than a statistical artefact, especially when troop sizes are bimodally distributed.

Inactivation of biofilm-bound Pseudomonas aeruginosa bacteria using UVC light emitting diodes (UVC LEDs)

Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

Minimal residual disease (MRD) is an important reason for the failure of autologous hematopoietic stem cell transplantation (auto-HSCT). Reducing MRD in grafts is particularly important to improve the efficacy of auto-HSCT. Previously, we reported that ultraviolet light-emitting diode (UV LED) suppressed the expression of Bcl-2 to induce apoptosis in HL-60 cells. Leukemia can lead to severe hypoxia of the bone marrow. Therefore, this study aimed to investigate the effect of UV LED on leukemia cells under hypoxia. HL-60 cells were irradiated with a UV LED (30 J/m2) and simulated under hypoxia with cobalt chloride. We found that UV LED irradiation or CoCl2 inhibited proliferation, induced apoptosis, decreased the Bcl-2/Bax ratio, and increased the levels of caspase 3, cleaved-caspase 3, and caspase 9 in HL-60 cells. In particular, the combined application of UV and CoCl2 significantly enhanced the apoptosis of HL-60 cells. In conclusion, UV LED in hypoxia exacerbated the inhibition of proliferation and induction of apoptosis and necrosis in HL-60 cells via the regulation of caspase 3/9 and the Bcl-2/Bax ratio-dependent pathway. The application of UV LEDs in hypoxia conditions may be a promising approach to kill residual drug-resistant leukemia cells in autologous grafts.

The subject matter of the paper is related to scientific-and-theoretical basis of power engineering characteristics of heat pump directly depending on the quality of treated water for reliable and uninterrupted operation of heat pump evaporator and compressor. On the basis of experimental data, energy parameters of the heat pump are calculated. The method of the combined technology of the heat pump “water – air” operation is considеred, the efficiency of which is based on the preliminary improvement of the quality of water softened with the use of a membrane ultrafiltration unit. This solution made it possible to reduce the load on the filters and to exclude the use of chemical reagents used in the classical schemes of water heating facilities. In order to improve the operation of the heat pump compressor, a method based on altering the speed of rotation of the shaft by means of electronic microprocessor devices has been proposed. To regulate the compressor performance, a frequency converter with a wide range of alternating current frequency is used. The intervals of alteration of frequency of the alternating current corresponding to energy-efficient values of coefficient of transformation of energy of the heat pump are investigated. The values of the energy conversion coefficient of the heat pump obtained in the course of experiments and determined by calculation are consistent within the experimental errors with the regulation of the compressor performance. The suggested experimental device made it possible to determine the dependence of the main characteristics of the unit of the heat pump unit on the number of revolutions of the compressor and to find out an effective range of its control (50–180 %). The development of advanced technologies for natural water treatment under conditions of increased anthropogenic loads on natural water sources is a priority one among the fundamental and applied research in the field of water treatment.

Section I Processes in Natural Waters.- The Surface Chemistry of Humic Substances in Aquatic Systems.- Microbial Processes Occurring at Surfaces.- Photochemistry of Colloids and Surfaces in Natural Waters and Water Treatment.- Kinetics and Mechanisms of Iron Colloid Aggregation in Estuaries.- The Generation of Suspended Sediment in Rivers and Streams.- Application of the Uranium Decay Series to a Study of Ground Water Colloids.- Section II Water Treatment Processes.- Water Treatment Technology in Australia.- The Role of Surface and Colloid Chemistry in the SIROFLOC Process.- Coagulation and Flocculation - Destabilizing Practices? (With Particular Reference to Metal Ion Coagulants).- Enhanced Biological Removal of Phosphorus from Wastewater.- Some Effects of Dam Destratification upon Manganese Speciation.- Contributors.

BackgroundAn optimal treatment strategy using oxaliplatin and bevacizumab for metastatic colorectal cancer has not been defined. We investigated whether the sequential treatment using fluoropyrimidines with bevacizumab followed by the addition of oxaliplatin at first progression was better than a combination treatment using fluoropyrimidines and oxaliplatin with bevacizumab. MethodsIn the sequential treatment, the escalation from fluoropyrimidines plus bevacizumab to fluoropyrimidines plus oxaliplatin with bevacizumab was recommended in case of progressive disease. Time to failure of strategy was the primary end-point, whereas the secondary end-points were overall survival, progression-free survival, overall response rate and safety. ResultsThree hundred patients with previously untreated metastatic colorectal cancer were randomised to receive either the sequential treatment (n = 151) or the combination treatment (n = 149). The sequential treatment was superior to the combination treatment about time to failure of strategy (15.2 months; 95% CI, 12.5–17.2 months vs. 7.8 months: 95% CI, 6.3–9.5 months; P < 0.001). However, the median overall survival was 27.5 (95% CI, 24.4 to 32.7) months in the sequential treatment and 27.0 (95% CI, 22.8 to 36.0) months in the combination treatment (hazard ratio, 0.92; 95% CI, 0.66 to 1.28; P = 0.61). The overall response rate was 33.1% in the sequential treatment arm and 51.7% in the combination treatment. ConclusionsThe findings support the extension of the sequential treatment starting from fluoropyrimidine plus bevacizumab to selected patients who do not need an objective response to the threatening disease.