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The Mitral Valve
Published in Theo Kofidis, Minimally Invasive Cardiac Surgery, 2021
Abdelghani et al. [5] described the transapical delivery fashion which utilizes a 0.035” or a 0.038” guidewire. This system is sheathless and made of polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) to reduce friction during deployment, during passage through the apex and through the mitral valve complex. For this construct, sizing is based on echocardiographic mitral valve orifice average dimension (i.e. [mediolateral dimension + anteroposterior dimension]/2), and the manufacturer recommends to oversize by 3 mm.
Prevention of Microbial Contamination during Manufacturing
Published in Philip A. Geis, Cosmetic Microbiology, 2020
With the exception of Polyvinylidene fluoride (PVDF) or Polytetrafluoroethylene (PTFE) and 316L stainless steel, plastic piping is known to be intolerant to the use of heat and ozone as a water system sanitizer (32). PVC piping is also incompatible with most chemical sanitizers. In addition, plasticizers (phthalates) can be leached from PVC piping and are able to serve as a microbial food source for the development and maintenance of a microbial biofilm. Furthermore, PVC piping joints cannot be heat welded but must be joined with couplings that use a solvent to partially dissolve the joints to form a rough weld unlike the smooth welds of stainless steel, PVDF and PTFE. These rough PVC welds are known to be excellent sites for the development of a microbial biofilm. If PVDF and PTFE piping is planned for use to distribute heated water, it needs to be supported and expansion sections will need to be built into the design because it will expand. Furthermore, PVDF and PTFE piping carrying hot water will need to be insulated.
Physics of Ultrasound
Published in Marvin C. Ziskin, Peter A. Lewin, Ultrasonic Exposimetry, 2020
Although ferroelectric ceramic transducers are nowadays by far the most commonly used in biomedical ultrasonics, there is much contemporary interest in prospects for using piezoelectric plastic transducers. Commercially available polyvinylidene difluoride (PVDF) film is usually in antipolar form.10 In order to make this material piezoelectric, a sequence of processes has to be performed. This film is first stretched (typically to a thickness of 50 to 100 μm) and then annealed. For thermal poling, a field of 500 to 800 kV cm1 is used. For corona poling, the saturation charge density is about 12 μC cm−2. Electrodes are deposited by evaporation, either before thermal poling, or, on the exposed surface, after corona poling.
Investigating potential TRPV1 positive feedback to explain TRPV1 upregulation in airway disease states
Published in Drug Development and Industrial Pharmacy, 2021
Jesse Xu, Maliheh Ghadiri, Maree Svolos, Brent McParland, Daniela Traini, Hui Xin Ong, Paul M. Young
Polyvinylidene fluoride (PVDF) membranes were stripped using ReBlot stripping buffer (Merck Millipore, Australia) as per manufacturer’s instructions, and blocked with 5% skim milk in T-TBS twice. Membranes were probed with primary polyclonal anti-rabbit alpha-tubulin antibody (0.5 µg/mL, 16 h, 4 °C, Abcam, Australia) before being washed with T-TBS thrice. A secondary Goat anti-rabbit antibody IgG was probed onto the membrane (0.5 µg/mL for 2 h, room temperature, ThermoFisher, Australia, cat#: 31460) before being washed four times with T-TBS. Signal was detected using an enhanced chemiluminescent substrate (Luminata Forte, Merck) as per the manufacturer’s instructions and imaged using a Kodak Image Station 4000MM (Molecular Imaging Systems, Carestream Health Inc., New Haven, CT, USA).
Optimization, characterization and evaluation of ZnO/polyvinylidene fluoride nanocomposites for orthopedic applications: improved antibacterial ability and promoted osteoblast growth
Published in Drug Delivery, 2020
Yanhai Xi, Wenming Pan, Dan Xi, Xue Liu, Jiangmin Yu, Mintao Xue, Ning Xu, Jiankun Wen, Weiheng Wang, Hailong He, Yanyan Liu, Yue He, Chunjing Guo, Daquan Chen, Xiaojian Ye
So far, there exists no natural material with all these properties, but there is promise. Polyvinylidene fluoride (PVDF) possessed good resistance to chemical corrosion, high temperature, oxidation, radiation and it also has piezoelectric, dielectric, thermoelectric and other special properties making it suitable for orthopedic applications. Moreover, the transformation among various PVDF crystal shapes can be achieved (Agarwal et al., 2008; Noriega et al., 2012) so that the PVDF materials with optimal crystal shapes can be prepared according to implant needs (Kumar & Periman, 1993; Lin et al., 2004). PVDF is considered as a potential bone tissue engineering material because of its piezoelectricity (just like bone) and biocompatibility, however, its applications in the body have been limited in that it has no ability to resist bacteria growth or infection (Rim et al., 2013).
Ursolic acid derivative UA232 evokes apoptosis of lung cancer cells induced by endoplasmic reticulum stress
Published in Pharmaceutical Biology, 2020
Wenfeng Gou, Na Luo, Huiqiang Wei, Hongying Wu, Xiaojun Yu, Yuqing Duan, Changfen Bi, Hongxin Ning, Wenbin Hou, Yiliang Li
The purity of UA232 was more than >98%. UA was purchased from MedChemExpress (Monmouth Junction, NJ). UA232 and UA were dissolved in dimethyl sulfoxide (DMSO). Crystal violet was purchased from Beyotime Biotechnology (Shanghai, China). Polyvinylidenedifluoride (PVDF) membrane was purchased from Millipore Bedford (Bedford, MA). Propidium iodide (PI), FITC-labeled Annexin V, and propidium iodide (PI) double-staining were purchased from KeyGen Biotech (Nanjing, China). Primary antibodies against cyclin D1, CDK4, Bax, Bcl-2, caspase-8, PARP1, and CHOP were purchased from Proteintech Group (Rosemont, IL). Antibodies for PERK, p-PERK, eIF2α, and p-eIF2α were purchased from Bioss (Beijing, China). β-actin and horseradish peroxidase (HRP)-conjugated secondary antibodies (goat-anti-mouse or goat-anti-rabbit) were obtained from ZSGB-BIO (Beijing, China).