Nucleopore Research Articles

The Structural Influence of Airborne Particles on their Toxicity

This paper studies human exposure to microplastics in real-life situations. The concentration of the polyamide nano/microplastics in the proximity of textile workplaces was made by the device Laser Aerosol Spectrometer. The descriptive statistical analysis was elaborated for: variables TSC (total concentration µg/m3), PM10 (µg/m3), PM2.5 (µg/m3), PM1 (µg/m3) and TC (total number of particles, 1/l). The histograms of each variable highlight the asymmetry of the distribution, with the predominance of frequencies or variables; representation of level indicators (average, median) and dispersion-box-plot graphs were obtained. Collection of the particle made with TECORA-SKYPORT PM-HV and GilAirPlus pumps, by using Quartz and Nucleopore filters with different diameters highlighted that the highest mass (683µg) was collected by using GilAir Plus pump and Quartz filter 37mm. A strong correlation was obtained between the variable: "Collected mass/ Air concentration": r = 0997775 ÷ 0,999477 and "Collected mass/ Air volume", r = -0,97473 ÷ 0.80064. The prediction of the value of the collected mass as a function of the diameter of the filters, particle concentration, airflow, and total air volume was made by obtaining the regression equations. Optic microscope analyses highlighted the dimension of microfibres (50% are <10µm) and SEM the dimension: 25% < 68.47 nm and the spherical shape of particles. FT-IR, µRaman and TG-DSC analyses showed the presence of PA particles in the collected particles.

Rapid diagnosis of malaria by chemometric peak-free LIBS of trace biometals in blood

Laser Induced Breakdown Spectroscopy (LIBS) trace atomic species of diseased biofluids are subtle (peak-free) in complex spectra. Trace analysis requires a considerable push in analytical strategy. Enabling LIBS with chemometrics can help identify, extract, analyze and interpret the trace species’ spectral signatures to give an insight on the biophysiological status of the bodies from which the biofluids originate. We report on the trace quantitative performance of peak-free LIBS enabled by chemometrics modelling using principal components analysis (PCA) for direct artificial neural network (ANN)–based analysis of Cu, Zn, Fe and Mg in Plasmodium falciparum-infected blood in the context of rapid spectral diagnosis of malaria utilizing the biometals as the disease biomarkers. Only one standard is required in this method—to delineate the analyte spectral regions (feature selection) and to test for accuracy. Based on the alteration of the biometal levels and their multivariate and correlational patterns in cultured blood, peripheral finger blood drops dried directly on Nucleopore membrane filters was accurately discriminated as either malaria-infected or healthy. Further the morphological evolution of Plasmodium was accurately predicted using spectral features of the biometals wherein high negative correlations between Fe (− 0.775) and Zn (− 0.881) and high positive correlations between Cu (0.892) and Mg (0.805) with parasitemia were observed. During the first 96 h of malaria infection Cu increases profoundly (from 328 to 1999 ppb) while Fe, Zn and Mg decrease (from 1206 to 674 ppb), (from 1523 to 499 ppb) and (from 23,880 to 19,573 ppb) respectively. Compared with healthy, Plasmodium falciparum-infected blood has high Cu but low levels of Fe, Zn and Mg. Cu and Zn are highly (≥ 0.9) positively correlated while Fe and Cu as well as Zn and Cu are highly (≥ 0.9) negatively correlated. Chemometric peak-free LIBS showed the potential for direct rapid malaria diagnostics in blood based on the levels, alterations and multivariate associations of the trace biometals which are used as biomarkers of the disease.

Effect of a Polydisperse Hydrosol on the Spectral Properties of Light Scattering by Seawater at Forfard Angles

In this paper we discuss the problem how to analyze the results of spectral volume scattering function measurements in natural waters and artificial ones. Analytical predictions and experimental proves of the remarkable changes in the properties of the light scattering at small angles after a filtration of water sample are presented. It was proposed that a certain correlations in the positions of scattering centers always exist in the water which were resulted in the volume scattering function of any natural water was strong forward peaked. Based on Mie theory the sums of scattering amplitudes and scattering radiances were calculated for a power-law particle size distribution while the maximal radius was varied. The square of the sum of the scattering amplitudes was compared with the value of the classical term. It is shown that in the “blue” a significant compensation of the effect of spatial correlation of particles occurs with an increasing of the maximum radius of particles, starting from the radius is about 0.2 μm. The contribution of the additional term decreases faster at general angles region. The spectral properties of light scattering by seawater during sequential filtration through nucleopore filters with a pore diameter of 2, 1, and 0.45 μm have been measured. The volume scattering function data at scattering angles from 6 to 90 degrees were analyzed. Water samples were taken from the surface of the Black Sea at the beginning of October. The Secchi depths are varied from 16 up to 19m. It was found that after filtration through a filter with pores diameter equaled to 1 μm, the typical deep at 30° of spectral slope of volume scattering function was appeared. Such deep becomes stronger after the next stage of filtration, when diameter of pores was equal to 0.45 µm. It is shown that the angular dependence of the exponent of the spectral slope obtained as a result of processing the experimental data is in consistent with theoretical predictions.

Концентрирование ртути во взвешенном веществе пены и воды Чёрного моря

Способность взвешенного вещества концентрировать ртуть может быть превалирующим фактором в очищении водной толщи Чёрного моря. В результате седиментации взвешенные частицы выносят загрязнения из поверхностного слоя воды и в итоге могут депонировать их в донных осадках, участвуя таким образом в процессах самоочищения морской акватории. Взвешенное вещество как дисперсная фаза водной среды, рассматриваемой в качестве гетерогенной дисперсной системы, может быть более насыщено ртутью, чем сама вода как дисперсионная среда. В данной работе определён вклад растворённой и взвешенной форм ртути в её общее содержание и оценена концентрирующая способность взвешенного вещества в отношении ртути, обуславливающая биогеохимическое самоочищение вод от ртути. Все пробы воды разделяли на фильтрат и взвесь путём их фильтрации через нуклеопоровые фильтры с диаметром пор 0,45 мкм. Измерения содержания ртути проводили на анализаторе «Хиранума-1» методом атомно-абсорбционной спектрофотометрии. Концентрацию растворённой ртути в воде определяли в пересчёте на литр, а во взвешенном веществе — на литр и на грамм сухой массы. Выявлено превалирование растворённой формы ртути независимо от сезона года с варьированием её процентного содержания в диапазоне 66,3–85,8 % от общей (суммарной) концентрации ртути. Средняя концентрация взвешенной формы составила 14,2–33,7 % от её общего содержания. При этом значения концентрации взвешенного вещества (mвзв) варьировали от 0,1 до 15,0 мг·л−1 за весь исследованный период, а коэффициент накопления ртути взвешенным веществом (Кнвзв) изменялся в диапазоне от n·10³ до n·107. Определён значительный вклад взвешенной формы ртути в её общее содержание в морской пене, образованной в штормовую погоду. Так, при концентрации взвешенного вещества в морской воде 9,6 мг·л−1 концентрация растворённой формы ртути имела значение 55 нг·л−1, а взвешенной — 20 нг·л−1. В морской пене концентрация взвешенного осадочного вещества составила 895,2 мг·л−1, а концентрация ртути достигла 200 нг·л−1 в растворённой форме и 260 нг·л−1 — во взвешенной. Содержание общей (суммарной) ртути в морской пене при этом превышало предельно допустимую концентрацию (100 нг·л−1) для морской воды. В данном случае Кнвзв для морской воды был равен 3,8·104, а для пены — 1,5·103. Такое распределение ртути в морской взвеси, пене и воде, а также полученные значения коэффициента накопления свидетельствуют о большой важности взвешенного вещества в самоочищении морской акватории. При низком содержании ртути в воде концентрирующая способность взвешенного вещества, характеризуемая относительно высокими значениями его коэффициента накопления ртути, становится весьма значимым фактором в седиментационном самоочищении вод от ртути, однако при повышении загрязнения вод ртутью влияние этого фактора снижается.

STRUCTURAL AND FUNCTIONAL INDICATORS OF BACTERIOPLANKTON OF THE SOUTH STRETCH OF LAKE MUNOZERO (KARELIA)

In article are presented the results of the state of the pelagic part of the south stretch of Lake Munozero (Karelia) according to microbiological indicators for the growing season of 2018. In the furtherance of this goal, 27 water samples were chosen in May, July and September at different strata. Munozero Lake is one of the unique lakes of Karelia due to its high salinity (100 mg/l), low-nutrient water sand organic substances. The total number, cell size dimensional structure and biomass of bacteria were determination by method of luminescence microscopy, by means of filtration through black nucleopore track membranes, after coloration bacteria by acridine orange. The total abundance of bacteria varied from 0,66 to 1,85 million cells/ml, and the biomass from 0,13 to 0,66 g/m3. The average cell volume varied in the range 0,18-0,34 μm3. Coccus form of bacteria prevailed in numbers. The doubling time and bacterial production were determined by the method of isolated samples. Bacterial production varied between 0,01 and 0,07 g/(m3•day-1). Specific growth rates (day-1) ranged around 0,05-0,2, giving doubling times of 70-364 h. The average daily production for the growing season was 0,65 g/m3•day-1. The physiological activity of bacteria was greatest at the end of the growing season. During the research period, the abundance of saprophytic bacteria growing on fish peptone agar was in the range of 19-550 CFU/ml. the abundance of oligotrophic bacteria growing on from starvation agar variable 200 to 850 CFU/ml. During the study period Water of the south stretch of the Lake Munozero was estimated as clean - moderately polluted with an intermediate quality class of 2-3. The south stretch of the Munozero is characterized as a mesotrophic water body.

Characteristics of Spherical Organic Particles Emitted from Fixed-Bed Residential Coal Combustion

Residential coal combustion is one of the most significant sources of carbonaceous aerosols in the Highveld region of South Africa, significantly affecting the local and regional climate. This study investigated single coal-burning particles emitted when using different fire-ignition techniques (top-lit up-draft versus bottom-lit up-draft) and air ventilation rates (defined by the number of air holes above and below the fire grate) in selected informal braziers. Aerosol samples were collected on nucleopore filters at the Sustainable Energy Technology and Research Centre Laboratory, University of Johannesburg. The individual particles (~700) were investigated using a scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (EDX). Two distinct forms of spherical organic particles (SOPs) were identified, one less oxidized than the other. The particles were further classified into electronically dark and bright. The EDX analysis showed that 70% of the dark spherical organic particles had higher (~60%) relative oxygen content than in the bright SOPs. The morphology of spherical organic particles were quantified and classified into four categories: ~50% were bare single particles; ~35% particles were aggregated and formed diffusion accretion chains; 10% had inclusions, and 5% were deformed due to impaction on filter material during sampling. This study concludes that there are two distinct kinds of coal burning spherical organic particles and that dark SOPs are less volatile than bright SOPs. The authors also show that these spherical organic particles are similar in nature and characteristics to tar balls observed in biomass combustion and that they have the potential to absorb sunlight thereby affecting the earth’s radiative budget and climate. This study provides insights into the mixing states, morphology, and possible formation mechanisms of these organic particles from residential coal combustion in informal stoves.

Study on Bombykol Receptor Self-Assembly and Universality of G Protein Cellular Signal Amplification System.

The G protein cascade amplification system couples with several receptors to sense/amplify the cellular signal, implying universal application. In order to explore whether GPCRs can trigger G protein signal amplification in tissues/cells from different species, bombykol receptor was isolated and purified from antennas of male Bombyx mori, which subsequently self-assembled on the cell membrane in rat taste buds/rat vomeronasa/catfish tentacles/taste bud tissues of rabbits/pig/cattle in those lacking endogenous bombykol receptor, followed by immobilization between two sheets of nucleopore membranes fixed by sodium alginate-starch gel, forming the sandwich-type sensing membrane, which in turn was immobilized on the glass-carbon electrode. Thus, bombykol receptor sensors were established with different tissues. The response current of bombykol receptor sensor toward bombykol was measured with an electrochemical workstation. Every bombykol receptor sensor could sense bombykol based on enzyme-substrate kinetics. The double reciprocal plot and the activation constant values of bombykol receptor sensors assembled with rat taste buds, rat vomeronasa, catfish tentacles, rabbit taste buds, pig taste buds, and cattle taste buds were calculated. Approximately 2-3 receptors could trigger the G protein cascade amplification system and achieve the maximum signal output. Moreover, the detection lower limit indicated that the bombykol receptor self-assembled on the cell membranes of different tissues that transmitted and amplified the bombykol signal with hypersensitivity. Also, cattle taste bud tissues served as an ideal system for heterogeneous GPCRs self-assembly and signal sensing/amplification. This sensing technique and method had promising potential in studies of biological pest control, sex pheromone detection, and receptor structure and function.

Impact of Single Dose Praziquantel Treatment on Schistosoma haematobium Infection among School Children in an Endemic Nigerian Community.

Schistosomiasis is prevalent in Nigeria, and the foremost pathogen is Schistosoma haematobium, which affects about 29 million people. Single dose of the drug praziquantel is often recommended for treatment but the efficacy has not been documented in certain regions. Therefore, this study was designed to assess the impact of single dose praziquantel treatment on S. haematobium infection among school children in an endemic community of South-Western Nigeria. Urine samples were collected from 434 school children and 10 ml was filtered through Nucleopore filter paper before examination for egg outputs by microscopy. The prevalence was 24.9% at pre-treatment. There was no statistically significant difference for the prevalence of infection between males (14.7%) and females (10.2%), although the mean egg count for the females (9.87) was significantly more (P<0.05) than the males (6.06). At 6 and 12 months post-treatment there was 74.4% and 86.4% reduction in the mean egg count, respectively. Interestingly, an increased prevalence of infection from 2.1% at 6 months to 7.7% at 12 months post-treatment was observed, nonetheless the mean egg count was reduced to 0.27 at 12th month from 1.98 at 6 months post-treatment. Resurgence in the prevalence rate between 6 and 12 months post-treatment with praziquantel is herein reported and the need for a follow-up treatment in endemic areas for adequate impact on schistosomiasis control is discussed.

Efficacy and tolerability of treatment with single doses of diethylcarbamazine (DEC) and DEC plus albendazole (ABZ) for three consecutive years in lymphatic filariasis: a field study in India.

Lymphatic filariasis (LF) affects 73 countries, causes morbidity and impedes socioeconomic development. We had found no difference in safety and micro (Mf) and macro filarial action of single-dose diethylcarbamazine (DEC) and DEC + albendazole (ABZ) in an F01 study done in India (year 2000). There was a programmatic need to evaluate safety and efficacy of multiple annual treatments (F02). Subjects (155) from the F01 study, meeting inclusion-exclusion criteria, were enrolled in F02 and treated with further two annual doses of DEC or DEC + ABZ. Efficacy was evaluated for Mf positivity by peripheral smear (PS) and nucleopore (NP) filter, circulating filarial antigen (CFA) and filarial dance sign (FDS) positivity and Mf count at yearly follow-up. Safety was assessed for 5days after drug administration. Total of 139 subjects evaluated for efficacy (69 DEC and 70 DEC + ABZ group). Mf positivity prevalence declined progressively by 95% (PS), 66% (NP), and 95% (PS) and 86% (NP); CFA positivity prevalence declined by 15% and 9%; FDS by 100% each; Mf count declined by 75.5 and 76.9% with three annual treatment of DEC and DEC + ABZ, respectively. Addition of ABZ did not show any advantage over DEC given as three annual rounds for LF. DEC and DEC + ABZ were well tolerated. There was no correlation between result of CFA and FDS, (both claimed to be indicative of adult worm). Analysis of published studies and our data indicate that macrofilaricidal effect of DEC/DEC + ABZ may be seen in children and not adults, with three or more annual dosing.

TrackEtching — A Java based code for etched track profile calculations in SSNTDs

A java code incorporating a user friendly GUI has been developed to calculate the parameters of chemically etched track profiles of ion-irradiated solid state nuclear track detectors. Huygen’s construction of wavefronts based on secondary wavelets has been used to numerically calculate the etched track profile as a function of the etching time. Provision for normal incidence and oblique incidence on the detector surface has been incorporated. Results in typical cases are presented and compared with experimental data. Different expressions for the variation of track etch rate as a function of the ion energy have been utilized. The best set of values of the parameters in the expressions can be obtained by comparing with available experimental data. Critical angle for track development can also be calculated using the present code. Program summaryProgram Title: TrackEtchingProgram Files doi:http://dx.doi.org/10.17632/7wb6pvpbgh.1Licensing provisions: CC0 1.0Programming language: JavaNature of problem: Calculation of the etched track profiles in ion irradiated SSNTDs is important for the application in the field of nucleopore filters and for their use as templates for nano wire fabrication.Solution method: A numerical approach, based on Huygen’s method for optical wavefront calculations has been employed. At any etching time, the etching is assumed to proceed along the normal to the etched surface. Several analytical functions are tried for the variation of the track etch velocity along the ion track as a function of the depth inside the surface and the energy/stopping power of the ion in the medium.Additional comments including Restrictions and Unusual features: The program does not generate three-dimensional profile. Provision for double sided etching will be incorporated in a later version of the code.

Morphochemical characteristics and mixing state of long range transported wildfire particles at Ny-Ålesund (Svalbard Islands)

A prolonged and exceptionally intense air mass advection event transporting biomass burning aerosols generated in Alaska affected Ny-Ålesund in the mid of July 2015. This paper reports the morphochemical characteristics and mixing state of individual aerosol particles collected during the event. To this aim aerosol samples were collected on nucleopore polycarbonate membrane filters using a DEKATI 12-stage low volume impactor and analyzed by scanning electron microscopy (SEM) techniques. Results of SEM investigations depict a complex aerosol characterized by an external mixing between a main part of carbonaceous organic particles (tar balls and organic particles), lower ammonium sulfate and minor potassium chloride and mineral dust amounts. The carbonaceous particles are spherical to slightly elongated and the organic particles show an internal mixing of low density organics and/or ammonium sulfate upon denser nuclei. Most particles are in the accumulation mode size range although the size and the morphology of the chloride and the sulfate salts evidence the growth of these species both in the air and upon the sampling membranes. Individual particle analyses were complemented by aerosol size distribution (Aerodynamic Particle Sizer, Scanning Mobility Particle Sizer) and optical (Particle Soot Absorption Photometer, nephelometer) measurements at ground level in order to retrieve the optical and radiative properties of the aerosol in the atmosphere and to predict the fate and behaviour of particles upon deposition at ground level. Individual particle analyses were also compared with bulk chemical analyses on daily sampling filters and back-trajectory analyses of the air mass movement in order to enucleate distinct sources of the aerosol during the long range transport.

Flow Behavior Through Porous Media and Microdisplacement Performances of Hydrophobically Modified Partially Hydrolyzed Polyacrylamide

Summary To investigate the relationship between the flow behavior and microdisplacement performance and the molecular structures, especially associating monomer content, of hydrophobically modified partially hydrolyzed polyacrylamides (HMHPAMs) with varied associating monomer content, compared with that of partially hydrolyzed polyacrylamide (HPAM), a series of experiments were conducted that involved the filtration through screen viscometer, nucleopore membrane, and series-connection microporous membranes; the flow through three serial mounted artificial cores; and the displacement in the microetching model. The screen factors and the hydrodynamic sizes of polymers were obtained by screen viscometer and nucleopore membrane, respectively. The results show that the screen factors and hydrodynamic sizes of HMHPAMs were much-more sensitive to the polymer concentration, filtration pressure, and associating monomer content than HPAM. Moreover, the filtration experiment through series-connection microporous membranes indicates that there were moderate associating monomer content or greater flow pressure or pore size for HMHPAMs to easily pass and obtain equivalent differential pressure between membranes, which implies that the compatibility between the pore size and the hydrodynamic sizes of the microstructures is the most-important factor for the injectivity of HMHPAMs. The resistance factor (RF) established by HMHPAMs through three serial mounted artificial cores notably tended to be higher than HPAMs, and the HMHPAMs with higher associating monomer content could generate a greater RF. In contrast, when the associating monomer content was low enough and the permeability was high enough, the flow could obtain equilibrium easily and the RFs were almost in accordance, which indicate there was moderate associating monomer content for HMHPAMs to propagate deep into the cores. At the same viscosity, HMHPAMs had better microdisplacement efficiency than glycerol (no effect) and HPAM (a small portion) for displacing the residual oil trapped in the “dead” ends of flow channel. The pilot tests of the associative polymer AP-P4, which was developed for Bohai oil fields, have demonstrated the great application potential of HMHPAMs for enhanced oil recovery (EOR).

Molecular gut content analysis demonstrates that Calanus grazing on Phaeocystis pouchetii and Skeletonema marinoi is sensitive to bloom phase but not prey density

The seawater samples were stained with primuline (Direct Yellow 59, Sigma-Aldrich Co), fixed with a solution containing 3.6% (v/v) glutaraldehyde and 10% (v/v) glycerol (final concentrations), and gently filtered onto black-stained 25 mm diameter 0.4-µm pore-size Nucleopore filters. Filters were mounted on slides and analyzed by epifluorescence microscopy. The method is a modification from Grebecki (1962), Hobbie et al. (1977) and Caron (1983) with the glycerol added to reduce the damage of particularly small delicate protists during filtration as described in Sazhin et al. (2007). FlowCAM analysis of mesocosm seawater The FlowCAM was run in autoimage-mode, using 4x magnification to analyze particles ranging between 15 and 1000 µm. The water samples were kept in dim light at 4°C until analyzed, within 4 h after sampling. Each sample was run for ca. 30 min, corresponding to 5.7 ml of analyzed volume. The relevant context capture property chosen to do the analysis was distance to nearest neighbor = 50 µm. All the image collages were manually post-analyzed in order to identify the particles in question. Particle sizes were estimated from area-based diameter determined by the FlowCAM VISP 2.2 software following Jakobsen & Carstensen (2011). Colonies of P. pouchetii are composite clusters of cells spaced in colonies of various sizes. When the colonies are forming dense blooms, the FlowCAM cannot distinguish whether a cluster is a part of colony or if a cluster is a part of a neighbouring colony. The FlowCAM therefore captures clusters of colonies. S. marinoi and P. pouchetii are colonial structures of multiple cells, and we developed scaling relationships between colony area and cell number by manually counting the number of cells in either a diatom chain or a P. pouchetii colony (n > 100) and related the cell number to particle area. We further developed scaling relationships between cluster areas by manually counting the number of cells in P. pouchetii clusters (n > 100). The same procedure was used for estimating S. marinoi cells, where we manually counted the number of cells per chain. The cell numbers were related to either cluster area (P. pouchetii clusters) or chain length (S. marinoi), and the relationships were then used to estimate the total number of P. pouchetii or S. marinoi cells in colonies or chains, respectively, by sample. Cell concentrations were estimated by correcting for the analyzed volume. The resulting regression equation used for estimation the number of P. pouchetii cells in colonies and colony fragments was Cells = ABD 1.834 * 0.028 (R 2 = 0.83), where ABD (area base diameter) is an output parameter from

Functional and cytometric examination of different human lung epithelial cell types as drug transport barriers.

To develop inhaled medications, various cell culture models have been used to examine the transcellular transport or cellular uptake properties of small molecules. For the reproducible high throughput screening of the inhaled drug candidates, a further verification of cell architectures as drug transport barriers can contribute to establishing appropriate in vitro cell models. In the present study, side-by-side experiments were performed to compare the structure and transport function of three lung epithelial cells (Calu-3, normal human bronchial primary cells (NHBE), and NL-20). The cells were cultured on the nucleopore membranes in the air-liquid interface (ALI) culture conditions, with cell culture medium in the basolateral side only, starting from day 1. In transport assays, paracellular transport across all three types of cells appeared to be markedly different with the NHBE or Calu-3 cells, showing low paracellular permeability and high TEER values, while the NL-20 cells showed high paracellular permeability and low TEER. Quantitative image analysis of the confocal microscope sections further confirmed that the Calu-3 cells formed intact cell monolayers in contrast to the NHBE and NL-20 cells with multilayers. Among three lung epithelial cell types, the Calu-3 cell cultures under the ALI condition showed optimal cytometric features for mimicking the biophysical characteristics of in vivo airway epithelium. Therefore, the Calu-3 cell monolayers could be used as functional cell barriers for the lung-targeted drug transport studies.

Evaluation of Nuclepore Membrane Filteration Technique for Diagnosis of Schistosoma haematobium Infection

Shistosomiasis is a parasitic disease . It is one of the most important diseases of humans in tropical and subtropical parts of the world , rapid characterization of schistosome eggs considered as a key step for clinical management, diagnosis of Schistosoma haematobium is generally based on the detection of eggs in a single urine specimen, Urine filteration is one of the methods recommended by the WHO for the detection of S.haematobium. In 1976, Peters et al adapted nucleopore filter for the diagnosis of S.haematobium eggs . They used filter 13 mm in diameter with 8 µm pores ,In another study done by Peters et al (1976),they proved that under field conditions , filteration of two 5 ml aliquots using 8 µm pore filters was very practical , if eggs of S.haematobium are present (size 150 by 60 µm), they are unable to pass through the filter and can be observed and counted under a microscope fitted with a 10x objective. This study used both the microscopic examination techniques of urine, centrifugation sedimentation technique and Nuclepore membrane filteration technique to detect Schistosoma haematobium eggs in urine for 1000 patient samples, to evaluate each technique alone and the two techniques together . This study showed that nuclepore filteration method more valid than sedimentation centrifugation method, nuclepore filteration detect 77 infected cases with sensitivity of 97.5%, but sedimentation detect 64 infected cases with a sensitivity of 81%, in this study we considered the sum of nuclepore and sedimentation as a gold standard, they detected 79 infected cases to compare them with another methods.

A Three-Step Scenario Involved in Particle Capture on a Pore Edge

A scenario is proposed to describe the capture of a spherical particle around a cylindrical pore. This geometry, "ideal" as far as the problem of particle capture on a filtration membrane is concerned, is clearly relevant in view of the pore-scale geometry of nucleopore or microsieve filtration membranes, and also of some microfluidic systems used to perform fluid-particle separation. The present scenario consists of three successive steps: particle deposition on the membrane away from the pore, subsequent reentrainment of some of the deposited particles by rolling on the membrane surface, and final arrest by a stabilizing van der Waals torque when the particle rolls over the pore edge. A modeling of these three steps requires the hydrodynamic and physicochemical particle-membrane interactions to be detailed close to the singular pore edge region and raises questions concerning the role of particle surface roughness. The relevance and robustness of such of a scenario for rough micrometer-sized latex particles is emphasized and comparisons are made with existing experimental data.

High resolution particle characterization to expedite development and regulatory acceptance of nanomedicines.

The pharmaceutical industry as well as European and US governing agencies have indicated the need for more accurate, high resolution, characterization of complex drug materials, nanomedicines, to facilitate their development and eventual approval. In particular, accurately measuring the size, zeta-potential, and concentration of nanomedicines is desired. Herein we demonstrate the comprehensive and high resolution analysis capabilities of tunable resistive pulse sensing (TRPS) on the most widely approved nanomedicines to-date, liposomal particles. The number-based size distribution, concentration and volume fraction of liposomes formed by extrusion through a 100 nm or 200 nm Nucleopore filter membrane are shown as well as how freeze-thaw aggregation changes individual liposomes and the overall size distribution. In addition, the simultaneous size and zeta-potential analysis capabilities of TRPS is used to characterize the homogeneity and difference between liposomes made with and without the addition of PEGylated phospholipids.

Evaluation of the kinetics and mechanism of action of anti-integration host factor-mediated disruption of bacterial biofilms.

The extracellular polymeric substance produced by many human pathogens during biofilm formation often contains extracellular DNA (eDNA). Strands of bacterial eDNA within the biofilm matrix can occur in a lattice-like network wherein a member of the DNABII family of DNA-binding proteins is positioned at the vertex of each crossed strand. To date, treatment of all biofilms tested with antibodies directed against one DNABII protein, Integration Host Factor (IHF), results in significant disruption. Here, using non-typeable Haemophilus influenzae as a model organism, we report that this effect was rapid, IHF-specific and mediated by binding of transiently dissociated IHF by anti-IHF even when physically separated from the biofilm by a nucleopore membrane. Further, biofilm disruption fostered killing of resident bacteria by previously ineffective antibiotics. We propose the mechanism of action to be the sequestration of IHF upon dissociation from the biofilm eDNA, forcing an equilibrium shift and ultimately, collapse of the biofilm. Further, antibodies against a peptide positioned at the DNA-binding tips of IHF were as effective as antibodies directed against the native protein. As incorporating eDNA and associated DNABII proteins is a common strategy for biofilms formed by multiple human pathogens, this novel therapeutic approach is likely to have broad utility.

Induction of resistance to Staphylococcus aureus in an environmental marine biofilm

The study of environmental biofilms is complicated by the difficulty of working with them under lab conditions. Nonetheless, knowledge of cellular activity and interactions within environmental biofilms could lead to novel biomedical applications. As a first step in this direction we propose a novel technique for inducing resistance to Staphylococcus aureus (S. aureus) in an intact environmental biofilm. Agar plates were prepared with or without the addition of 20% S. aureus spent culture media and immersed in coastal seawater (Boston Harbor, Massachusetts, USA) for four days to grow up an environmental biofilm. Nucleopore filters inoculated with an overnight culture of S. aureus were then applied to the surface of the agar plates with the environmental biofilms, incubated 4h at 37°C, removed and subsequently stained and analyzed. Marine environmental biofilms grown on agar containing S. aureus spent culture media were significantly more inhibitory of S. aureus growth than were marine environmental biofilms grown on plain agar.

Using the AD12-ICT rapid-format test to detect Wuchereria bancrofti circulating antigens in comparison to Og4C3-ELISA and nucleopore membrane filtration and microscopy techniques

Lymphatic filariasis (LF) continues to be a major source of permanent disability and an impediment to socio-economic development in 73 countries where more than 1 billion people are at risk and over 120 millions are infected. The global drive to eliminate LF necessitates an increasing demand for valid, reliable and rapid diagnostic tests. This study aimed to assess the performance of the AD12 rapid format immunochromatographic test (ICT) to detect Wuchereria bancrofti circulating antigens, against the combined gold standard: TropBio Og4C3-ELISA (enzyme-linked immunosorbent assay) which detects circulating filarial antigen (CFA) and the nucleopore membrane filtration and microscopic examination. This prospective case-control study involved 647 asymptomatic migrant workers from filariasis-endemic countries. Of these specimens, 32 were positive for microfilaremia using the membrane filtration and microscopy, 142 positive by ELISA (of which 32 had microfilaremia), and 128 positive by the ICT (of which 31 had microfilaremia). The performance of the ICT was calculated against 32 true-positive and 90 true-negative cases. For the detection of CFA, the ICT had a sensitivity of 97% (95% confidence interval [CI] 91-103), specificity 100% (95% CI 100-100), Positive Predictive Value (PPV) 100% (95% CI 100-100), Negative Predictive Value (NPV) 99% (95% CI 97-101); and the total accuracy of the test was 99% (95% CI 98-101). The agreement between ICT and ELISA in detecting W. bancrofti antigens was excellent (kappa = 0.934; p = 0.000). In conclusion, the AD12-ICT test for the detection of W. bancrofti-CFA was sensitive and specific and comparable to the performance of ELISA. The ICT would be a useful additional test to facilitate the proposed strategies for control and elimination of LF. Because it is rapid, simple to perform, and does not require the use of special equipment, the ICT may be most appropriate in screening programs and in monitoring the possible risk of introducing the disease to the non-endemic countries.