- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Determination of parvovirus retention profiles in virus filter membranes using laser scanning microscopy
摘要： Virus filtration is a highly effective method in the downstream processing of biotherapeutic products to provide effective removal of potential infectious agents based on a size exclusion mechanism. The direct visualization of viruses retained inside the filter membrane represents a valuable tool to get a deeper understanding of the filtration process and to explain observations of virus breakthrough under particular operating conditions. Parvoviruses, which are used as worst-case models in validation studies, were purified and labeled with fluorescent dyes to detect their retention pattern inside the filter membrane using laser scanning microscopy. Critical factors influencing the reproducibility and accuracy of the approach were identified and optimized. The retention profiles revealed detectable differences between viruses, suggesting that the use of bacteriophages or nanoparticles as surrogates is limited in their applicability to accurately predict the behavior of parvoviruses in filter membranes. The established method enables a direct and quantitative analysis of the virus retention profile, adding a valuable tool to the conventional measurement of the viral load reduction to better understand the mechanism underlying the removal of viruses during nanofiltration of biotherapeutic products.
关键词： Parvovirus retention profile,Virus filtration,Nanofiltration,Laser scanning microscopy,Filter membrane
更新于2025-09-23 15:19:57
-
Process Monitoring of Virus-like Particle Reassembly by Diafiltration with UV/Vis Spectroscopy and Light Scattering
摘要： Virus-Like Particles (VLPs) have shown great potential as biopharmaceuticals on the market and in clinics. Non-enveloped, in vivo-assembled VLPs are typically dis- and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At industrial scale, Cross-Flow Filtration (CFF) is the method of choice for performing reassembly by diafiltration. Here, we developed an experimental CFF setup with on-line measurement loop for the implementation of Process Analytical Technology (PAT). The measurement loop included an Ultraviolet and Visible (UV/Vis) spectrometer as well as a light-scattering photometer. These sensors allowed for monitoring protein concentration, protein tertiary structure, and protein quaternary structure. The experimental setup was tested with three Hepatitis B core Antigen (HBcAg) variants. With each variant, three reassembly processes were performed at different Transmembrane Pressures (TMPs). While light scattering provided information on the assembly progress, UV/Vis allowed for monitoring the protein concentration and the rate of VLP assembly based on the microenvironment of Tyrosine-132. VLP formation was verified by off-line Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Furthermore, the experimental results provided evidence of aggregate-related assembly inhibition and showed that off-line Size-Exclusion Chromatography (SEC) does not provide a complete picture of the particle content. Finally, a Partial-Least Squares (PLS) model was calibrated to predict VLP concentrations in the process solution. Q2 values of 0.947 to 0.984 were reached for the three HBcAg variants. In summary, the proposed experimental setup provides a powerful platform for developing and monitoring VLP reassembly steps by CFF.
关键词： process analytical technology,self-assembly,cross-flow filtration,virus-like particles,downstream processing,spectroscopy
更新于2025-09-19 17:15:36
-
Electrospun CuS/PVP Nanowires and Superior Near-Infrared Filtration Efficiency for Thermal Shielding Applications
摘要： Selective filtration of near-infrared (NIR) region is of primary importance to energy saving via thermal shielding. However, uniform coating of highly effective nanomaterials on flexible substrates remains very challenging. Here, we introduce new materials processing and fabrication methodologies that manufacture electrospun copper sulfide/polyvinylpyrrolidone (CuS/PVP) nanowires for enhanced thermal shielding efficiency. Electrospinning offers well-dispersed CuS nanoparticles in a thermal shielding film, which is not achievable in typical solution coating processes. Directly deposited CuS/PVP nanowires on a flexible polymer membrane are enabled by a fluorination treatment that decreases interfacial electrostatic repulsion. Monitoring of in-situ temperature change of a box shielded, CuS/PVP nanowire film demonstrates excellent NIR shielding efficiency (87.15%). Direct integration of the film with a model car and exposure to direct sunlight demonstrates about twice-higher shielding efficiency than commercial tungsten-oxide films. Overall, the comprehensive study of nanomaterial preparation, surface treatment, and integration techniques allows to fabricate highly flexible and reliable thermal shielding films.
关键词： Near-infrared filtration,CuS/PVP nanowires,Thermal shielding,Electrospinning,and Flexible film
更新于2025-09-19 17:15:36
-
Neodymium Laser Treatment of IOP Rise Following Ex-press Glaucoma Device Implantation
摘要： To report on the use neodymium laser for treatment of eyes with IOP rise following Ex-Press glaucoma filtration device implantation. We retrospectively examined the medical records of 73 patients who underwent Ex-Press device implantation at four medical institutions between 2007 and 2015 and subsequently developed an IOP rise. Enrollment criteria included patients with POAG on whom post treatment IOP data is available. Indications for treatment with neodymium laser were an IOP above target and a flat bleb. In order to disrupt the presumed micro-blockage, the neodymium laser was aimed at the axial and relief ports of the Ex-Press device. Applanation tonometry measurements were followed up after neodymium treatment for variable time intervals. Success was defined as an IOP < 18 mm Hg at 6 months without further surgical or laser-based glaucoma interventions. 73 charts were reviewed. 20 patients were excluded due to insufficient data or a diagnosis other than POAG. Data from 53 eyes of the remaining 53 patients was analyzed. The mean duration between Ex-Press implantation and rise in IOP requiring neodymium intervention was 34.2 months (range, 1.1 – 67.2). We found a statistically significant immediate IOP lowering effect in all eyes, with a mean IOP drop of 13.34 +/- 8.99 mm Hg, and a mean post treatment IOP of 14.30 ± 8.57 mm Hg (P<0.0001). Of a subset of 43 eyes on which 6 months follow up IOP data was available, 11 eyes required further glaucoma intervention (surgery or laser based); four eyes had an IOP of 18 or greater at 6 months. In the remaining 28 successful eyes, a sustained IOP below 18 mm Hg was observed at 6 months, with a mean pressure of 11.39 ± 4.03 mm Hg (P < 0.0001). Hypotony (IOP < 5) occurred in 3 eyes immediately following treatment and self-resolved by 1 week. Our retrospective case series suggests that neodymium laser is a potential consideration in eyes with sustained IOP rise after Ex-Press device implantation.
关键词： intraocular pressure,neodymium laser,Ex-Press glaucoma filtration device,glaucoma
更新于2025-09-12 10:27:22
-
Features of Operation of a Brightness Amplifier on Copper Bromide Vapors in the Bistatic Scheme of a Laser Monitor
摘要： The influence of the brightness amplifier operation mode on images formed with a bistatic laser monitor is studied. The bistatic laser monitor is an active optical system with two active elements. A possibility of imaging remote (to more than 5 m) objects with this instrument is evaluated. It is shown that a change in the concentration of active substance (copper bromide) of the amplifier significantly affects the amplification of the input signal. The active substance temperature rise from 480 to 550°C increases the gain throughout the input signal range. A further increase in the temperature (up to 570°C) increases the gain only at a relatively weak input signal (less than 100 mW). The resulting amplification characteristics of the active optical system are described and compared with the parameters of images formed (distortion and brightness).
关键词： remote objects,bistatic scheme of a laser monitor,brightness amplifiers,gain,active filtration,imaging,laser monitor
更新于2025-09-12 10:27:22
-
An Integration of Photo-Fenton and Membrane Process for Water Treatment by a PVDF@CuFe2O4 Catalytic Membrane
摘要： Membrane fouling always decreases the separation efficiency and shortens the membrane life, which severely hinders the practical application of the membrane technology. The photo-Fenton process can degrade various foulants with the generation of hydroxyl radicals, and its integration with membrane filtration may become an efficient way to improve the antifouling property and filtration performance of the membrane. In this study, the CuFe2O4 particles were synthesized and doped in the PVDF@CuFe2O4 membranes with increasing concentration from 0 to 1.0%. The degradation measurement of methylene blue (MB) solution shows the optimal conditions for the photo-Fenton process as CuFe2O4 concentration of 1.0%, pH of 3.0, and H2O2 dosage of 400 μL. With the photo-Fenton cleaning process, the PVDF@CuFe2O4 membrane (1.0%) exhibits versatile antifouling property to different types of foulants, including organic dyes (e.g. MB and rhodamine B (RhB)), nature organic matter (e.g. humic acid (HA)), and protein (e.g. bovine serum albumin (BSA)). With the integration of photo-Fenton and membrane process, the PVDF@CuFe2O4 membrane (1.0% of CuFe2O4) dramatically enhanced the separation efficiency, with the results of 99.77% to MB, 81.02% to RhB, 36.35% to HA, and 82.94% to BSA. The flux and rejection have been increased respectively to threefold and double of the corresponding data from the membrane filtration alone. Moreover, even after fifteen cycles of experiments, the average MB rejection is still higher than 70%, which further indicates the good stability and reusability of the PVDF@CuFe2O4 membrane. Therefore, this study provides a promising methodology for the successful fabrication of high-performance membrane through the integration of photo-Fenton and membrane process, and further proposes a new strategy on the design and application of functional materials for new generation of catalytic membranes.
关键词： Membrane,Antifouling,Integration,Filtration,Photo-Fenton Catalysis,CuFe2O4
更新于2025-09-10 09:29:36
-
Patterned fiber formation
摘要： The ability of liquid crystalline materials to order spontaneously has driven many innovations, from display technologies to extremely tough polymer fibers. Cheng et al. exploited this preponderance toward long-range ordering to direct the growth of nonliquid crystalline polymers into sheets of highly ordered fibers. Small changes to the processing conditions could be used to tweak the arrangement of the liquid crystals to generate a wide range of polymer mats or sheets for potential use in sensing or filtration applications.
关键词： polymer fibers,liquid crystalline materials,sensing,filtration
更新于2025-09-10 09:29:36
-
Detectors of Circularly Polarized Radiation Based on Semiconductor Heterostructures with a CoPt Schottky Barrier
摘要： In this paper, we showed the possibility of practical realization of circularly polarized radiation detectors based on a planar photoresistor using the effect of magnetocircular dichroism in the CoPt layer, as well as based on structures using the spin filtration by the CoPt layer of photogenerated spin-polarized charge carriers. The spin filtration process is established to allow increasing the detection efficiency of up to 1.3%.
关键词： semiconductor heterostructures,spin filtration,magnetocircular dichroism,circularly polarized radiation detectors,CoPt layer
更新于2025-09-10 09:29:36