Polycarbonate Membrane Filters Research Articles

Prevalence and Intensity of Urinary Schistosoma Haematobium Eggs Among the School Aged Children in Kona Ward, Ardo Kola Lga, Taraba State, Nigeria

The study was conducted to examine the prevalence and intensity of urinary Schistosomiasis haematobium in two Kona ward settlement of Ardo kola local government, area of Taraba State, Nigeria. The study employed urine filtration technique using polycarbonate membrane filters to detect Schistosoma haematobium eggs in urine. Standard culture techniques to isolate urinary tract pathogens with their susceptibility patterns were carried out. Questionnaires were administered to collect information on socio-demographic data on the children. A total of 1153 urine samples were collected and analysed for the eggs of Schistosoma haematobium, Out of 675 children infected with urinary schistosomiasis, the highest occurrence of bacteriuria (61.3%) was recorded in the heavy intensity (>50 eggs/10ml urine) while low intensity (1 – 50 eggs/10ml urine) recorded the lowest occurrence of bacteriuria (59.2%). Chi square analysis showed significant association between intensity and bacteriuria (χ2 = 309.5, p = 0.000). Spearman’s correlation coefficient for bacteriuria also showed significant relationship between urinary schistosomiasis and bacteriuria (r = 0.518, p<0.001). The percentage occurrence of E. coli in heavy ova intensity (>50 eggs/10ml urine) is slightly higher (56.9%) than in light intensity (55.0%). Occurrence of Klebsiella spp in heavy intensity is slightly above (24.9%) that of light intensity (24.4%). P aeroginosa and Proteus spp occur more in light intensity (24.9%) and (28.9%) respectively than in heavy intensity (14.2%) and (14.6%) respectively. Occurrence of S. aureus is significantly higher in heavy intensity (4.2%) than in light intensity (1.7%). In subjects negative for urinary schistosomiasis, occurrence of bacteria isolates follows similar pattern with Klebsiella spp occurring more (3.3%) than the other isolates. These findings indicate that the areas is endemic to urinary schistosomiasis and therefore prompt intervention in the study areas is needed. Keywords: prevalence, intensity, Schistosoma haematobium, school aged children, kona ward, Ardo kola, Taraba State, Nigeria

Occurrence and Isolation of Urinary Tract Bacteria Associated with Urinary Schistosomiasis Among the School Aged Children in Sorbai and Murbai Area of Kona Ward, Ardo Kola Lga, Taraba State, Nigeria

This study was carried out to determine the occurrence and isolation of urinary Schistosomiasis and co-infection with bacteria among the school aged children in two Kona settlements. Schistosomiasis is a parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma and is common among the rural community dwellers that have occupation or recreation activities that link them with infected water bodies. The disease wreak a lot of havoc in the victims which range from anaemia, increase risk of liver fibrosis and bladder cancer, enlarged liver, difficult and painful urination, infertility etc. Nigeria has been reported to be the most endemic country in the world for schistosomiasis with about 29 million infected cases. However, people with urinary schistosomiasis are vulnerable to secondary infections caused by bacteria as a result of the break down in the mucosa barrier occasioned by the wear and tear of the spiny eggs of the schistosomes. The study employed urine filtration technique using polycarbonate membrane filters to detect Schistosoma haematobium eggs in urine. Standard culture techniques to isolate urinary tract pathogens with their susceptibility patterns were carried out. Questionnaires were administered to collect information on socio-demographic data on the children. Of the 1153 urine samples examined, 675 (58.4%) were infected with Schistosoma haematobium, out of whom 405 (60.0%) were positive for bacteriuria. Bacteriuria differed significantly between the two settlements (χ2 =25.55, p=0.000) and sexes (χ 2 =29.55, p=0.000) with females recording high occurrence (84.6%) than males (39.2%). Similarly, significant association in prevalence was observed in the different age groups (χ 2 =92.97, p=0.000) with the 1-5years old being the highest, while the 11-15years the lowest. Spearman correlation coefficient showed significant association between urinary Schistosomiasis and bacteriuria (r=0.518, p˂0.01). The different bacterial pathogen isolated in urine samples include: Escherichia coli (33.9%), Klebsiella spp (15.5%), Proteus sp (14.5%) Pseudomonas aeruginosa (12.8%) Staphylococcus aureus (2.0%). This study revealed a high occurrence of schistosomiasis and significant bacteriuria in the study areas which suggests that bacterial presence may be a potent complication in the management of urinary schistosomiasis. Keywords: Schistosomiasis, isolation, bacteria, school aged children, antibiotic urinary tract, sorbai, murbai, kona, ardo kola, Taraba state, Nigeria

Element Composition of Fractionated Water-Extractable Soil Colloidal Particles Separated by Track-Etched Membranes

Membrane fractionation with track-etched membranes was used to size-profile the microelement composition of water-extractable soil colloids (WESCs). The aim of the study is the element composition of narrow WESC fractions of typical chernozems in the range of 0.01–10 µm. Micro-/ultrafiltration through a cascade of track-etched polycarbonate membrane filters with pore sizes of 5, 2, 1, 0.8, 0.4, 0.2, 0.1, 0.05, 0.03, and 0.01 µm at room temperature was used. ICP–AES using direct spraying of obtained fractions without decomposition was used; Al, Ba, Cd, Cr, Cu, Fe, Mn, Si, Sr, Ti, Zn, Ca, K, Mg, Na, P, and S were found. Narrow WESC fractions differ significantly. For macro- and microelements, maximum amounts of Si, Al, Fe, and Ti and their maximum percentages are observed in fractions with sizes above 1 µm, while Ca, Mg, Mn, Cu, Zn, K, and S are accumulated more in fractions with sizes below 1 µm. The developed approach provides preparative isolation of a detailed set of narrow WESC fractions in the micrometer–nanometer range. This provides element soil profiles that reveal distinct differences and the individual character of each fraction as well as trends in changes in the mineral matrix and microelement composition with fraction size.

39 Investigation of Workplace Silica Exposures Using Novel Samplers and Methods

Abstract Scientists from the Health and Safety Executive visited a range of workplaces where there was the potential for exposure to silica. The aim of the visits was to determine potential worker exposures to dust and respirable crystalline silica by static air monitoring and exhaled breath condensate (EBC). To evaluate potential airborne exposures low-cost particle monitors were deployed alongside more established scientific equipment. On site airborne dust concentrations were measured at different locations using two photometers, an optical particle counter (OPC) and a respirable cyclone. The size distribution was measured in real-time using a low-cost OPC and by offline analysis of a polycarbonate membrane filter housed inside an inhalable sampler using a Coulter Counter III. Pre and post shift samples of EBC were taken from 29 workers, with samples analysed by single particle inductively coupled plasma tandem mass spectrometry to measure Si-containing particles. The real-time air monitoring data showed sustained increased concentrations or peaks corresponding to specific areas or activities, therefore indicating the tasks and/or locations most likely to contribute to worker exposure. The low-cost instruments were also effective in highlighting site locations and tasks most likely to contribute to worker exposure. An approach combining multiple sampling techniques provided a good characterisation of airborne, silica containing dusts. The EBC results consistently showed increased numbers of silicon containing particles post-shift compared with pre-shift.

106 Investigation of Workplace Silica Exposures Using Novel Samplers and Methods

Abstract Scientists from the Health and Safety Executive visited a manufacturing workplace where coatings are prepared by loading powders, frit and water into various sized mills. The aim of the visit was to determine potential worker exposures to dust and respirable crystalline silica by static air monitoring and exhaled breath condensate. Low-cost particle monitors were deployed alongside more established scientific equipment. Airborne dust concentrations were measured at three site locations using two photometers, an optical particle counter (OPC) and a respirable cyclone. The size distribution was measured in real-time using a low-cost OPC and by offline analysis of a polycarbonate membrane filter housed inside an inhalable sampler. Pre and post shift samples of exhaled breath condensate were collected from 6 workers, with samples analysed by single particle inductively coupled plasma mass spectrometry to measure the number and size of silicon containing particles present. The real-time air monitoring data at all three locations showed peaks in airborne concentrations corresponding to the loading activities and indicating the tasks most likely to contribute to worker exposure. The average concentration of respirable dust measured closest to the process was 0.13 mg.m-3 for the 8-hour shift. The low-cost monitors provided good information about the changes in concentration over time relating to worker activities.

Investigation of the occurrence of binder material on airborne respirable mineral wool fibers

ABSTRACT Mineral wool fibers can be released to the air during production and handling of a mineral wool product where a small fraction of fibers will stay airborne and can potentially be inhaled. The aerodynamic fiber diameter determines how far an airborne fiber can pass through the human airway. Respirable fibers with an aerodynamic diameter < 3 µm can reach the deep part of the lungs (i.e., the alveolar region). Binder material (i.e., organic binder and mineral oil) is used in the production of mineral wool products. However, at the current stage it is unknown if airborne fibers can contain binder material. We explored binder presence on airborne respirable fiber fractions being released and collected during installation of two mineral wool products (a stone wool product and a glass wool product). Fiber collection was done by pumping a controlled air volume (2, 13, 22, and 32 l/min) through polycarbonate membrane filters during installation of the mineral wool products. Morphological and chemical composition of the fibers were studied using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDXS) analysis. The study demonstrates that binder material is found on the surface of the respirable mineral wool fiber mainly as circular or elongated droplets. Our findings suggest that respirable fibers explored in previous epidemiological studies, which have been used for proving lack of hazardous effects of mineral wool on humans, may have also contained binder materials on the fibers.

Engineered Nanovesicles from Fibroblasts Modulate Dermal Papillae Cells In Vitro and Promote Human Hair Follicle Growth Ex Vivo.

Alopecia is a common medical condition affecting both sexes. Dermal papilla (DP) cells are the primary source of hair regeneration in alopecia patients. Therapeutic applications of extracellular vesicles (EVs) are restricted by low yields, high costs, and their time-consuming collection process. Thus, engineered nanovesicles (eNVs) have emerged as suitable therapeutic biomaterials in translational medicine. We isolated eNVs by the serial extrusion of fibroblasts (FBs) using polycarbonate membrane filters and serial and ultracentrifugation. We studied the internalization, proliferation, and migration of human DP cells in the presence and absence of FB-eNVs. The therapeutic potential of FB-eNVs was studied on ex vivo organ cultures of human hair follicles (HFs) from three human participants. FB-eNVs (2.5, 5, 7.5, and 10 µg/mL) significantly enhanced DP cell proliferation, with the maximum effect observed at 7.5 µg/mL. FB-eNVs (5 and 10 µg/mL) significantly enhanced the migration of DP cells at 36 h. Western blotting results suggested that FB-eNVs contain vascular endothelial growth factor (VEGF)-a. FB-eNV treatment increased the levels of PCNA, pAKT, pERK, and VEGF-receptor-2 (VEGFR2) in DP cells. Moreover, FB-eNVs increased the human HF shaft size in a short duration ex vivo. Altogether, FB-eNVs are promising therapeutic candidates for alopecia.

Health risk assessment of particulate matter 2.5 in an academic metallurgy workshop.

Exposure to indoor PM2.5 is associated with allergies, eye and skin irritation, lung cancer, and cardiopulmonary diseases. To control indoor PM2.5 and protect the health of occupants, exposure and health studies are necessary. In this study, exposure to PM2.5 released in an academic metallurgy workshop was assessed and a health risk assessment was conducted for male and female students and technicians. Polycarbonate membrane filters and an active pump operating at a flow rate of 2.5L/min were used to collect PM2.5 from Monday to Friday for 3months (August-October 2020) from 08:00-16:00. PM2.5 mass concentrations were obtained gravimetrically, and the Multiple-Path Particle Dosimetry model was used to predict the deposition, retention, and clearance of PM2.5 in the respiratory tract system. The risk of developing carcinogenic and non-carcinogenic effects among students and technicians was determined. The average PM2.5 mass concentration for August was 32.6μg/m3 32.8μg/m3 for September, and 32.2μg/m3 for October. The head region accounted for the highest deposition fraction (49.02%), followed by the pulmonary (35.75%) and tracheobronchial regions (15.26%). Approximately 0.55 mg of PM2.5 was still retained in the alveolar region 7 days after exposure. The HQ for male and female students was <1 while that of male and female technicians was >1, suggesting that technicians are at risk of developing non-carcinogenic health effects compared with students. The results showed a risk of developing carcinogenic health effects among male and female technicians (>1 × 10-5 ); however, there was no excess cancer risk for students (<1 × 10-6 ). This study highlights the importance of exposure and health studies in academic micro-environments such as metallurgy workshops which are often less researched, and exposure is underestimated. The results also indicated the need to implement control measures to protect the health of the occupants and ensure that the workshop rules are adhered to.

Application of iron flocculation to concentrate white spot syndrome virus in seawater

The iron flocculation method, which comprises the Fe-virus flocculate formation-filtration-resuspension steps, is extensively used to concentrate and precipitate viruses distributed in water. To apply this method to concentrate white spot syndrome virus (WSSV) in seawater, viral genomic and infective recovery yields were compared between polyethylene sulfone (PES) and polycarbonate (PC) membrane filters and two types of resuspension buffers (oxalate and ascorbate). Viral genome quantitation was determined above a 95 % limit of detection (11.48 viral DNA copies/μL) using quantitative real-time PCR. From WSSV-spiked seawater (100–106 viral DNA copies/mL), the viral genomic recovery yields of the PES-Oxalate, PC-Oxalate, PES-Ascorbate, and PC-Ascorbate conditions were 78.67 % ± 12.90 %, 84.53 % ± 24.30 %, 85.59 % ± 16.98 %, and 93.74 % ± 7.44 %, respectively. The detectable Fe-virus flocculates collected by the PC membrane were approximately 101 WSSV DNA copies/mL of seawater, a value more than 10-fold higher than that compared to the PES membrane filter (102 WSSV DNA copies/mL), regardless of the resuspension buffer types. WSSV resuspended with oxalate buffer caused mass mortality among whiteleg shrimp (Litopenaeus vannamei), inducing the expression of the virus envelope protein, VP28, similar to that of a native virus, suggesting stable viral activity during the resuspension process. Based on the PES-Ascorbate, WSSV particles could be successfully concentrated in seawater from shrimp farms with white spot disease outbreaks (approximately 102 WSSV DNA copies/mL). Collectively, these findings indicate that the simple and efficient method of iron flocculation is sufficient to concentrate WSSV in seawater and could be used as a non-invasive approach and one of the reasonable diagnostic processes for white spot disease surveillance.

A New Method for Microplastics Identification in Copepods

This study investigates several methods to identify microplastics (MPs) of small size ranges (&amp;lt;10 µm) in the copepod Eurytemora affinis collected in the Seine estuary (France) and identified using epifluorescence microscopy and Raman microspectroscopy. In order to calibrate the methodology, copepods obtained from cultures were used. Firstly, we labelled three types of MPs (i.e., Polystyrene, Polyethylene, and Polylactic acid) with Nile Red and confirmed their ingestion by E. affinis with epifluorescence microscopy. Considering the convenient detection of Nile Red labelled MPs using epifluorescence observation, we tried to pair this method with Raman microspectroscopy. For this, we developed an enzymatic digestion method consisting of copepods digestion using Proteinase K followed by sonication in order to fragment their cuticle. The lysate was then vacuum filtered on black polycarbonate membrane filters that were the most appropriate for epifluorescence microscopy. Potential MPs were dyed with Nile Red directly on the filter, which allowed a relatively rapid visual detection. However, results showed that black polycarbonate membrane filters induced a significant background fluorescence during Raman identification of MPs and hence particles smaller than 10 µm could not be characterized. In this case, we were not able to link staining method with micro-Raman for the size range of MPs targeted in this study. Thus, aluminum oxide filters were tested, and staining method was replaced by a classical observation with stereomicroscopic magnifier to delimit areas of observation for Raman microscopic identification. Aluminum oxide filters induced less fluorescence, allowing the detection of MPs (as small as 1 µm diameter) on copepods from laboratory cultures exposed with MPs. We applied this method on copepods collected in the natural environment. Within a pool of 20 copepods of three replicates, we identified 17 MPs (average of 0.28 MPs/copepod) composed of eight different polymer types and six colors. These MPs corresponded to 59% of fibres with 14.1 ± 9.4 µm diameter and 391.6 ± 600.4 µm length along with 41% of fragments with an average diameter of 13.2 µm ± 9.5 µm. This study reports a novel approach to detect the presence of small particles of MPs ingested by copepods in the natural environment.

Advantages of filtration method for sperm-DNA genotyping in sexual assault cases.

Differential extraction (DE) is a conventional method to isolate sperms from forensic semen samples (e.g. vaginal swab containing semen) for sperm-DNA genotyping. Subsequent to selective digestion of somatic cells in a mixture sample, sperms are collected and purified as a pellet by repetitive centrifugation based on the specific gravity of sperm heads. However, the centrifugation operation requires a technical proficiency and an extensive time to prevent a loss of sperms from the pellet as much as possible. Therefore, we devised a "filtration method (FM)", in which a vacuum filtration operation based on the size of sperm heads is adapted, instead of DE, for isolation of sperms without any loss in principle. Sperms are collected and purified on a polycarbonate membrane filter. In this study, we have compared results of forensic assays by DE and FM for sperm-DNA genotyping from forensic semen samples. Consequently, FM had advantages of easy operation, timesaving, and high yield of sperms from semen samples compared with DE, although FM had a comparable ability to DE for a purification of sperms from mixture samples. Thus, we present that FM could simply lead to success of sperm-DNA genotyping and has a possibility to supersede DE as a gold-standard method.

A New Filter Based Cultivation Approach for Improving Aspergillus Identification using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) is widely used in clinical laboratories for routine identification of bacteria and yeasts. However, methodological difficulties are still apparent when applied to filamentous fungi. The liquid cultivation method recommended by Bruker Daltonics GmbH for identification of filamentous fungi by MALDI-TOF MS is labour intensive and time-consuming. In this study, growth of Aspergillus species on different (porous) surfaces was investigated with the aim to develop a more reliable, quicker and less laborious identification method using MALDI-TOF MS. Mycelial growth without sporulation mimicking liquid cultivation and reliable MALDI-TOF MS spectra were obtained when A. fumigatus strains were grown on and in between a polycarbonate membrane filter on Sabouraud dextrose agar. A database of in-house reference spectra was created by growing Aspergillus reference strains (mainly focusing on sections Fumigati and Flavi) under these selected conditions. A test set of 50 molecularly identified strains grown under different conditions was used to select the best growth condition for identification and to perform an initial validation of the in-house database. Based on these results, the cultivation method on top of a polycarbonate filter proved to be most successful for species identification. This method was therefore selected for the identification of two sets of clinical isolates that mainly consisted of Aspergilli (100 strains originating from Indonesia, 70 isolates from Qatar). The results showed that this cultivation method is reliable for identification of clinically relevant Aspergillus species, with 67% and 76% correct identification of strains from Indonesia and Qatar, respectively. In conclusion, cultivation of Aspergilli on top of a polycarbonate filter showed improved results compared to the liquid cultivation protocol recommended by Bruker in terms of percentage of correct identification, ease of MSP creation, time consumption, cost and labour intensity. This method can be reliably applied for identification of clinically important Aspergilli and has potential for identification of other filamentous fungi.

Synergistically enhanced Salmonella Typhimurium reduction by sequential treatment of organic acids and atmospheric cold plasma and the mechanism study

Salmonella, a foodborne pathogen, has been frequently associated with recalls of fresh food products, including poultry meat products. Atmospheric cold plasma (ACP) is a novel non-thermal technology, which has potential to reduce pathogens in food products. This study demonstrates the synergistic interactions of food grade organic acids (i.e., lactic acid (LA) or gallic acid (GA)) and ACP to inactivate Salmonella enterica Typhimurium ATCC 13311 inoculated on polycarbonate membrane filter paper and poultry meat surface. Organic acids were used in the form of a spray to enhance dispersion on samples surface. The sequential treatment of organic acid followed by ACP synergistically reduced S. Typhimurium on poultry meat surface. Irrespective of the type of organic acid, an average reduction of more than 3.5 log CFU/cm2 in S. Typhimurium on filter paper was obtained, when a combination of 10 mM LA or GA with an ACP exposure of 30 s was tested. However, the individual treatments of LA, GA, and ACP resulted in only 0.4, 0.3, 1.2 log CFU/cm2 reduction in S. Typhimurium, respectively. On poultry meat surface, a higher level of organic acid concentration (i.e., 50 mM) in combination with 30 s ACP was required to achieve more than 2.5 log CFU/cm2 reduction in S. Typhimurium. Our investigation on inactivation mechanisms revealed that the sequential treatment of LA or GA with ACP resulted in a significantly higher level of membrane permeability and membrane lipid peroxidation in S. Typhimurium cells. Additionally, the combined treatment significantly reduced the cell metabolic activity and affected the intracellular reactive oxygen species level of S. Typhimurium. In summary, this study demonstrated the potential synergistic benefits of combining organic acids and ACP to achieve a higher level of bacterial inactivation.

DEVELOPMENT OF A TECHNOLOGY FOR PRODUCING A STABLE INJECTABLE DOSAGE FORM OF A HYDROPHOBIC INDOLOCARBAZOLE DERIVATIVE

Objective: Development of a technology for the production of a stable injectable dosage form (IDF) of indolocarbazole derivative LHS-1269. Methods: LHS-1269 is an active pharmaceutical ingredient that was synthesized in the N. N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation. The IDF includes dimethyl sulfoxide (DMSO), 95% ethanol, Kollidon® 17PF and water for injection. Magnetic stirrer and overhead stirrer with a propeller stirring element were used to prepare the model solution of the IDF of LHS-1269. Sterilizing filtration of the solution was performed with 0.2−0.22 um polycarbonate, cellulose, polyvinylidene fluoride, polyethersulfone and nylon membrane filters. The aqueous solution of LHS-1269 was lyophilized in Edwards Minifast DO.2 freeze dryer. Assay of LHS-1269 was performed by spectrophotometry at 320±3 nm. Potentiometry was used to measure pH, a viscosimetry method was used to measure the viscosity of the solutions. The average weight was estimated by weighing a sample of 10 vials with the concentrate. Results: 0.5% aqueous solution of LHS-1269 was produced by mixing the solution of the active substance in DMSO and ethanol with an aqueous solution of polyvinylpyrrolidone gradually at the ratio of LHS-1269/DMSO/ethanol/Kollidon® of 1/11/32/40 by weight. The aqueous solution of the study substance cannot be lyophilized, so a sequence of technological operations was presented to produce an anhydrous concentrate “LHS-1269, concentrate for solution for injection and infusion 25 mg”. Conclusion: A technology was developed to produce a stable IDF of a hydrophobic indolocarbazole derivative LHS-1269, a high-potential antitumor drug.

Physicochemical Properties of Indoor and Outdoor Particulate Matter 2.5 in Selected Residential Areas near a Ferromanganese Smelter.

Particulate matter (PM) of different sizes and elemental composition is a leading contributor to indoor and outdoor air pollution in residential areas. We sought to investigate similarities between indoor and outdoor PM2.5 in three residential areas near a ferromanganese smelter in Meyerton to apportion the emission source(s). Indoor and outdoor PM2.5 samples were collected concurrently, using GilAir300 plus samplers, at a flow rate of 2.75 L/min. PM2.5 was collected on polycarbonate membrane filters housed in 37 mm cassettes coupled with PM2.5 cyclones. Scanning electron microscopy coupled with energy-dispersive spectroscopy was used to study the morphology, and inductively coupled plasma-mass spectroscopy was used to analyse the elemental composition of the PM2.5. Mean indoor and outdoor PM2.5 mass concentrations were 10.99 and 24.95 µg/m3, respectively. Mean outdoor mass concentration was 2.27-fold higher than the indoor concentration. Indoor samples consisted of irregular and agglomerated particles, ranging from 0.09 to 1.06 µm, whereas outdoor samples consisted of irregular and spherical particles, ranging from 0.10 to 0.70 µm. Indoor and outdoor PM2.5 were dominated by manganese, silicon, and iron, however, outdoor PM2.5 had the highest concentration of all elements. The ferromanganese smelter was identified as the potential main contributing source of PM2.5 of different physicochemical properties.

Co-Loaded Reversal Agent and Chemotherapeutic Nanoerythrosomes to Overcome Cancer Multidrug Resistance

The multidrug resistance (MDR) is still a major obstacle in cancer chemotherapeutic treatments. The purpose of this study is to challenge the MDR in tumors by using nanoerythrosomes (NEs) co-loaded P-glycoprotein (P-gp) inhibitor and a chemotherapeutic agent. Nanoerythrosomes were prepared by extrusion, in which the red blood cells (erythrocytes) ghost suspension is extruded through a polycarbonate membrane filter pore by 8-10 consecutive extrusions in an extrusion device. Then verapamil (Ver) and doxorubicin (Dox) were co-loaded into NEs with a hypotonic dialysis method (denoted as Ver/Dox/ NEs), which acted as a drug delivery system. The multidrug resistant leukemia K562/A02 cells were treated with the denoted Ver/Dox/ NEs. In vitro and in vivo, the reversal effect on MDR in human leukemic cells were evaluated by flow cytometer, Cell Counting Kit-8 assays, and Western blot analysis. Results demonstrated that Ver/Dox/NEs could inhibit the function of P-glycoprotein by Ver as reversal agent, significantly increase the uptake of Dox, enhance the sensitivity of the MDR cancer cells to the chemotherapeutic agent, and induce apoptosis while avoiding the toxic side effects. It was therefore concluded that Ver/Dox/ NEs could represent a promising approach in overcoming tumor MDR. DisclosuresNo relevant conflicts of interest to declare.

Estimation of unattached and aerosol-attached activities of airborne short-lived radon progeny in indoor environments

Inhalation of the airborne short-lived radon progeny is regarded as the most crucial way of internal exposure to the natural radiation dose delivered to the human lung. In this respect, this study aims to determine the unattached and aerosol-attached activities of radon progeny and to estimate some important physical parameters employed to assess the radiological impact of this radiation on humans. For this purpose, radioactive aerosol samples collected on polycarbonate membrane filters to measure total alpha activity by passive alpha dosimetric technique using CR-39 detectors in sixteen different locations including some houses and workplaces in El Jadida city, in Morocco. In addition, the room-specific parameters and aerosol physical processes that affect the unattached and attached activity concentrations were determined. The obtained experimental results by the three-count method and room model parameters were used as input data on a developed PC-based software that we have developed to solve mathematical equations and calculate required physical quantities. Accordingly, the individual activities of radon progeny namely 218Po, 214Pb, and 214Po as well as radon activity concentration were determined. Simultaneously, the unattached and aerosol-attached activity concentrations (Cju and Cja) of radon progeny were calculated based on the room model calculation. Consequently, some radiological quantities used in the calculation of the lung dose were estimated. The results showed that the indoor radon activity concentration in different targeted locations ranges between 38 and 143 Bq. m−3 with an average value of 84.8 ± 9.5 Bq. m−3. The average obtained values of the equilibrium-equivalent concentration (Ceq), unattached fraction (fp), and equilibrium factor (F) at low and good ventilation rates change respectively from (24 Bq. m−3, 0.08, and 0.25) to (34 Bq. m−3, 0.02, and 0.41). Under normal environmental conditions, the average obtained values of Ceq, fp, and F, in houses and at workplaces were (17 Bq. m−3, 0.07, and 0.25) and (32 Bq. m−3, 0.04, and 0.35) respectively. Depending on the different aerosol conditions and obtained values of unattached fraction fp, the calculated average values of dose conversion factors (DCFs) were 8.70 mSv.WLM−1 and 11 mSv.WLM−1 in houses and workplaces respectively. These values were in good agreement with the recommended values by ICRP, which are in the order of 9 mSv.WLM−1 and 12 mSv.WLM−1 for houses and workplaces respectively.

Scanning electrochemical microscopy and electrochemical impedance spectroscopy-based characterization of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase

In this research, scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were applied for the evaluation of surface characteristics of electrochemical (amperometric) biosensor based on two composite structures consisting of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase. The first structure consisted of the polycarbonate filter membrane, punctured by 400 nm holes (PCM) consequently modified with single walled carbon nanotubes (SWCNT) and graphene oxide (GO) layer (PCM/SWCNT/GO); and the other structure consisted of the same PCM, consequently modified with SWCNT and reduced graphene oxide (rGO) layer (PCM/SWCNT/rGO). These two composite structures were developed and applied in biosensor design. In order to form a biosensing surfaces the PCM/SWCNT/GO and PCM/SWCNT/rGO composite structures were modified by immobilized glucose oxidase (GOx). The surface of GOx modified PCM/SWCNT/GO composite structure (PCM/SWCNT/GO/GOx) was evaluated by SECM redox-competition mode at different glucose concentrations. It was determined that PCM/SWCNT/GO/GOx composite structure is suitable for the design of amperometric glucose biosensors, because SWCNT/GO layer facilitates electron transfer from GOx via the oxidation of formed catalyzed reaction product H 2 O 2 . Therefore, the PCM/SWCNT/GO/GOx structure is a promising material for the design of amperometric glucose biosensors and biofuel cells, which are useful for a wide variety of environmental purposes and green energy production using food-industry waste. • Punctured polycarbonate membrane (PCM) was modified by single walled carbon nanotubes (SWCNT). • PCM/SWCNT-based structure was modified by graphene oxide (GO) or reduced graphene oxide (rGO). • On the surface of PCM/SWCNT/GO and PCM/SWCNT/rGO structures glucose oxidase (GOx) was immobilized. • Scanning electrochemical microscopy (SECM) and impedance spectroscopy (EIS) were applied. • It was determined that PCM/SWCNT/GO/GOx structure is suitable for the design of glucose biosensor.

Review of Respirable Coal Mine Dust Characterization for Mass Concentration, Size Distribution and Chemical Composition

Respirable coal mine dust (RCMD) exposure is associated with black lung and silicosis diseases in underground miners. Although only RCMD mass and silica concentrations are regulated, it is possible that particle size, surface area, and other chemical constituents also contribute to its adverse health effects. This review summarizes measurement technologies for RCMD mass concentrations, morphology, size distributions, and chemical compositions, with examples from published efforts where these methods have been applied. Some state-of-the-art technologies presented in this paper have not been certified as intrinsically safe, and caution should be exerted for their use in explosive environments. RCMD mass concentrations are most often obtained by filter sampling followed by gravimetric analysis, but recent requirements for real-time monitoring by continuous personal dust monitors (CPDM) enable quicker exposure risk assessments. Emerging low-cost photometers provide an opportunity for a wider deployment of real-time exposure assessment. Particle size distributions can be determined by microscopy, cascade impactors, aerodynamic spectrometers, optical particle counters, and electrical mobility analyzers, each with unique advantages and limitations. Different filter media are required to collect integrated samples over working shifts for comprehensive chemical analysis. Teflon membrane filters are used for mass by gravimetry, elements by energy dispersive X-ray fluorescence, rare-earth elements by inductively coupled plasma-mass spectrometry and mineralogy by X-ray diffraction. Quartz fiber filters are analyzed for organic, elemental, and brown carbon by thermal/optical methods and non-polar organics by thermal desorption-gas chromatography-mass spectrometry. Polycarbonate-membrane filters are analyzed for morphology and elements by scanning electron microscopy (SEM) with energy dispersive X-ray, and quartz content by Fourier-transform infrared spectroscopy and Raman spectroscopy.

A Refined Method to Analyze Insoluble Particulate Matter in Ice Cores, and Its Application to Diatom Sampling in the Antarctic Peninsula

The insoluble particulate matter deposited on ice sheets provide key information to reconstruct past climate. The low concentration of some insoluble particulate matter, such as terrigenous particles and microfossils, challenges the efficiency of the recovery and the representativeness of the results. Here we present a new optimized method to extract, quantify and classify targeted low concentration insoluble particulate matter. Particle recovery rates and particle distribution were investigated using polystyrene particle standards filtered through Polycarbonate membrane filters and subsequently scanned in a scanning electron microscope. Experimental results in continuous and discrete sampling systems reveal consistent trends in the transport and removal of particulate material inside a filtration system. Statistical simulations are used to optimize the sample analyses required to achieve representative results. The analysis of diatoms in ice cores using this new method uncovered their potential to hold valuable climate records from the Antarctic Peninsula region. The data presented here evidence the presence of a measurable amount of marine diatoms with sub-annual variations, highlighting the potential of this record as a seasonal indicator. The new method presented provides an optimized and statistically representative approach for extracting, recovering and analyzing micrometre-sized, low-concentration insoluble particulate matter in ice.