Sanitary sewage disinfection with ultraviolet radiation and ultrasound.

Currently, the world is facing a horrible situation due to SARS-CoV-2. Though its RNA was found in wastewater, there are still no studies on RNA contamination detected in sewage. Hence, a possible treatment of sewage is suggested in this work. The disinfection stage is extremely important in the treatment of effluents, minimizing the impacts on the receiving body of water and promoting public health. In this context, the sequential use of ultrasound and ultraviolet radiation, on a bench scale, was investigated as a way to improve the disinfection of anaerobically treated effluents. Two types of treated effluents were tested, by septic tank and anaerobic filter, for which, two ultrasound frequencies, 25 and 40 kHz, and four doses of UV, 3.6; 9.0; 18 and 36 mJ cm-2 were applied. Physicochemical and microbiological parameters were observed for individual and sequential assays. The better quality of the anaerobic filter effluent influenced the performance of both processes, decreasing the concentration of organic load and turbidity, even though a concentration of total coliforms and Escherichia coli occurred in the lowest quality effluent (septic tank). The application of ultrasound has a positive effect on the inactivation of total coliforms and E. coli up to 1.0 log and provides better conditions for ultraviolet radiation to be sequentially applied. The UV radiation applied for the septic tank and the anaerobic filter inactivates 2.5 log for total coliforms and 3.5 log for E. coli, respectively. It is suggested that the disinfection methods applied in this work to inactivate gram-negative bacteria (E. coli) can also be applied to secondary treatment effluents, as well as being better tested for viruses, protozoa, and helminths. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-021-03764-7.

A critical overview of household slow sand filters for water treatment.

Household, or point-of-use (POU), water treatments are effective alternatives to provide safe drinking water in locations isolated from a water treatment and distribution network. The household slow sand filter (HSSF) is amongst the most effective and promising POU alternatives available today. Since the development of the patented biosand filter in the early 1990s, the HSSF has undergone a number of modifications and adaptations to improve its performance, making it easier to operate and increase users' acceptability. Consequently, several HSSF models are currently available, including those with alternative designs and constant operation, in addition to the patented ones. In this scenario, the present paper aims to provide a comprehensive overview from the earliest to the most recent publications on the HSSF design, operational parameters, removal mechanisms, efficiency, and field experiences. Based on a critical discussion, this paper will contribute to expanding the knowledge of HSSF in the peer-reviewed literature.

Drinking water treatment by multistage filtration on a household scale: Efficiency and challenges.

Universalising actions aimed at water supply in rural communities and indigenous populations must focus on simple and low-cost technologies adapted to the local context. In this setting, this research studied the dynamic gravel filter (DGF) as a pre-treatment to household slow-sand filters (HSSFs), which is the first description of a household multistage filtration scale to treat drinking water. DGFs (with and without a non-woven blanket on top of the gravel layer) followed by HSSFs were tested. DGFs operated with a filtration rate of 3.21 m3 m-2.d-1 and HSSFs with 1.52 m3 m-2.d-1. Influent water contained kaolinite, humic acid and suspension of coliforms and protozoa. Physical-chemical parameters were evaluated, as well as Escherichia coli, Giardia spp. cysts and Cryptosporidium spp. oocyst reductions. Removal was low (up to 6.6%) concerning true colour, total organic carbon and absorbance (λ = 254 nm). Nevertheless, HMSFs showed turbidity decrease above 60%, E. coli reduction up to 1.78 log, Giardia cysts and Cryptosporidium oocysts reductions up to 3.15 log and 2.24 log, respectively. The non-woven blanket was shown as an important physical barrier to remove solids, E. coli and protozoa.

Fluorescent membrane markers elucidate the association of Borrelia burgdorferi with tick cell lines.

This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.

Fluorescent membrane markers elucidate the association of Borrelia burgdorferi with tick cell lines

This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.

Water loss at normal enamel histological points during air drying at room temperature.

This in vitro study aimed to quantify water loss at histological points in ground sections of normal enamel during air drying at room temperature (25°C) and relative humidity of 50%. From each of 10 ground sections of erupted permanent human normal enamel, three histological points (n = 30) located at 100, 300 and 500 µm from enamel surface and along a transversal following prisms paths were characterized regarding the mineral, organic and water volumes. Water loss during air drying was from 0 to 48 h. Drying occurred with both falling and constant-drying rates, and drying stabilization times (Teq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples (n = 5; 15 points), Teq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10⁻8 cm² s⁻¹. Our data provide evidence of air drying resulting in air replacing enamel's loosely bound water in prisms sheaths following a unidirectional water diffusion rate of 3.47 × 10⁻8 cm² s⁻¹ (from the original enamel surface inward), not necessarily resulting in water evaporating directly into air, with important implications for transport processes and optical and mechanical properties.

Natural enamel caries in polarized light microscopy: differences in histopathological features derived from a qualitative versus a quantitative approach to interpret enamel birefringence.

Lesion area measurement of enamel caries using polarized light microscopy (PLM) is currently performed in a large number of studies, but measurements are based mainly on a mislead qualitative interpretation of enamel birefringence in a single immersion medium. Here, five natural enamel caries lesions are analysed by microradiography and in PLM, and the differences in their histopathological features derived from a qualitative versus a quantitative interpretation of enamel birefringence are described. Enamel birefringence in different immersion media (air, water and quinoline) is interpreted by both qualitative and quantitative approaches, the former leading to an underestimation of the depth of enamel caries mainly when the criterion of validating sound enamel as a negatively birefringent area in immersion in water is used (a current common practice in dental research). Procedures to avoid the shortcomings of a qualitative interpretation of enamel birefringence are presented and discussed.

Postural bipedance in paraplegics under neuromuscular electrical stimulation: is it possible to improve it based on sagittal spinal alignment?

STUDY DESIGN: Experimental trial based on the analytical study of radiographic standards of the sagittal spinal alignment in paraplegics in upright position under surface neuromuscular electrical stimulation (NMES). OBJECTIVES: To evaluate changes in radiographic standards of the sagittal spinal alignment of paraplegics under three different models of NMES used to optimize the global bipedal posture. SETTING: The University Hospital Ambulatory (UNICAMP), Campinas, SP, Brazil. METHODS: Ten paraplegic patients were selected. Each patient underwent three different models of NMES. The influence that each NMES model exerted over the sagittal balance of the spine was evaluated by lateral panoramic X-rays. Wilcoxon's test was used to compare the modifications observed in each NMES model in the group studied. RESULTS: Using the femoral quadriceps muscles' NMES as the starting point, the inclusion of the gluteus maximus' NMES generated an increase of the lumbar lordosis and a decrease of the spinal tilt angle. These alterations resulted in partial improvement of the anterior sagittal imbalance. NMES of the paralyzed paravertebral lumbar muscles resulted in a more expressive increase on the lumbar lordosis, with no significant change on the spinal tilt. On the latter model, however, an improvement of 20% was observed in the global sagittal imbalance due to a posterior translation of the spine as pointed out by the decrease in the C7-HA horizontal distance. CONCLUSIONS: The proposed NMES models were able to partially amend the anterior sagittal imbalance of the paraplegic patients in bipedal posture.

Removing textile mill effluent recalcitrant COD and toxicity using the H2O2/UV system.

The potential of the H2O2/UV process for improving quality of an industrial textile effluent before biological treatment was evaluated in the laboratory using a multivariate experimental design to determine the effects of pH, H2O2 dose and reaction time on colour, COD and toxicity removal efficiencies. Increasing reaction time (from 10 to 120 min) and H2O2 dose (from 0 to 5 mmol L(-1)) significantly improved removal efficiencies, while increasing pH (from 4 to 10) had a negative effect on colour and toxicity removals. Laboratory H2O2/UV treatment of the mill effluent under optimum conditions (pH 7, 5 mmol L(-1) H2O2, 120 min) resulted in decreases in colour (70%), COD (21%) and toxicity (67%), without lowering BOD. H2O2 was consumed within the first 30-60 min, while the effluent average oxidation state stabilized after 60 min. Decreasing reaction time to 60 min resulted in similar colour (63%) and COD (20%) removals but lower toxicity removal (44%). Spectrophotometric monitoring of the optimized reaction indicated partial destruction of residual aromatic azo dyes. H2O2 and residual peroxide and average oxidation state of the effluent Effluent biodegradability (BOD/COD) increased by 28% after the H2O2/UV treatment. Improvements observed in effluent quality are expected to enhance combined AOP-biological treatment efficiency of the mill effluent.

Advanced oxidation of bleached eucalypt kraft pulp mill effluent.

In this study a poorly biodegradable (BOD/COD = 0.3) industrial alkaline ECF bleaching filtrate was treated using different advanced oxidation processes to evaluate their use in combined chemical-biological treatment aimed at increasing recalcitrant COD removal and improving final effluent quality. Oxidative treatments included ozonation combined with hydrogen peroxide (2, 5, 10, 20 mmol L(-1) O3/0.7, 2, 5, 10 mmol L(-1) H2O2) and photocatalysis with hydrogen peroxide (UV/2, 4 and 8 mmolL(-1) H2O2) and with TiO2 (UV/TiO2/0.7 and 4 mmol L(-1) H2O2). The O3/H2O2 process increased effluent biodegradability by up to 68% as a result of increasing BOD and decreasing COD. Increasing the O3 dose had a greater effect on biodegradability improvement and lignin and colour removal efficiencies than increasing the H2O2 dose. A combined oxidant dose of 5 mmol L(-1) O3 and 2 mmol L(-1) H2O2 resulted in 75% lignin removal, 40% colour removal and 6% carbohydrate loss without mineralizing the organic carbon. The photocatalytic processes led to a decrease in effluent biodegradability through combined decrease in BOD and increase in COD and did not result in efficient lignin or colour removal. Photocatalytic oxidation was apparently inhibited by the high chloride and COD levels in the alkaline filtrate, and may be more efficient in recalcitrant COD removal if performed after biological.

Avaliação nutricional em crianças com infecçoes por enteroparasitas / Nutritional evaluation of children with enteroparasitosis

PURPOSE: To evaluate the nutritious state in children of low social-economic class in order to look over a possible corelationship among this status and the infections caused by enteroparasites. METHODS: 103 children were submitted to a nutritions evolution and to accomplish a exam of serial samples. The method employed searched protozoan cystos, helmints eggs and larvae and it counted helmint eggs when presented through 4 different methods of diagnosis. RESULTS: The results obtained show that the poor environmental and social-economic conditions helped create a high infectious frequency caused by enteroparasites, mainly by Trichuris trichiura and Ascaris lumbricoides, among the helminthes, and Endolimax nana and Giardia lamblia, among the protozoans. light malnutrition without protein deficit was found in 93.55% and moderate malnutrition in 6.45% of the children malnutrition (30.7%). CONCLUSION: Then, it is possible to suggest that children besides bearing many parasitosis were not weth their nutritional state deeply compromised.

Lateral femoral cutaneous neuralgia: an anatomical insight.

A detailed anatomic study was carried out on the lateral femoral cutaneous nerve to better understand the etiology and treatment of lateral femoral cutaneous neuralgia. As it passed from the pelvis into the thigh, the lateral femoral cutaneous nerve ran through an "aponeuroticofascial tunnel," beginning at the iliopubic tract and ending at the inguinal ligament; as it passed through the tunnel, an enlargement in its side-to-side diameter was observed, suggesting that the fascial structures proximal to the inguinal ligament may be implicated in the genesis of lateral femoral cutaneous neuralgia. The finding of pseudoneuromas at this location, distant from the inguinal ligament, supports this hypothesis. The anterior superior iliac spine is located approximately 0.7 cm from the lateral femoral cutaneous nerve and serves as the bony landmark for nerve localization. Within the first 3 cm of leaving the pelvis, the lateral femoral cutaneous nerve was observed deep to the fascia lata; therefore, surgical dissection within the subcutaneous fascia may be conducted with relative impunity near the anterior superior iliac spine just inferior to the inguinal ligament. In 36% of cases there was no posterior branch of the nerve, which is correlated to lateral femoral cutaneous neuralgia symptoms often being limited to the anterior branch region. An accessory nerve was found in 30% of cases.