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membrane diffusing capacity

Hongmei Xia, Yinxiang Xu, Zhiqing Cheng, Yongfeng Cheng
Tetramethylpyrazine (TMP) was extracted from Ligusticum chuanxiong hort. The compound is known to have a variety of medicinal functions; in particular, it is used for the treatment of cerebral ischemic diseases. TMP-loaded hydrogels offer an excellent preparation with the capacity to bypass the blood-brain barrier, allowing treatment of the brain through intranasal administration. We prepared TMP-loaded hydrogels using carbomer 940 and evaluated the release of TMP from the hydrogel. We determined the release rate using Franz-type diffusion cell experiments with a subcutaneous-mucous-membrane model and also by a molecular dynamics (MD) simulation...
October 14, 2016: AAPS PharmSciTech
Longsheng Zhang, Wei Fan, Tianxi Liu
It is still very challenging to achieve effective combination of carbon nanofibers and graphene sheets. In this study, a novel and facile method is developed to prepare flexible graphene/carbon nanofiber (GCNF) membranes with every carbon nanofiber wrapped by conductive graphene sheets, resulting in a remarkable improvement of their electrical conductivity. This method only entails a moderate process of soaking the pre-oxidized electrospun polyacrylonitrile (oPAN) nanofiber membranes in graphene oxide (GO) aqueous dispersion, and subsequent carbonization of the GO/oPAN hybrid membranes...
September 15, 2016: Nanoscale
Daniel Pliquett, Peter S Schulz, Frank W Heinemann, Angela Bause, Peter Wasserscheid
A series of silver tris(perfluoroethyl)trifluorophosphate (Ag[FAP]) complexes with various ligands (acetonitrile ACN, chloroacetonitrile Cl-ACN, acrylonitrile acryl-CN, pyridine py, ethylenediamine en and propene C3H6) have been synthesized starting from Ag[NO3] and K[FAP] using three different routes. Physicochemical properties as well as crystal structures ([Ag(ACN)2/4][FAP], [Ag(py)2][FAP]) were determined and the suitability of such Ag salts for propene/propane separation processes was investigated. The investigated silver complexes exhibit either low melting points or form liquid complexes when contacted with gaseous propene at 30 °C...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
M El Khalifi, J Bentin, E Duverger, T Gharbi, H Boulahdour, F Picaud
The behavior of confined anticancer carboplatin (CPT) molecules in a single (10, 10) boron nitride nanotube (BNNT) was studied by means of molecular dynamics simulations. Our study revealed a very large storage capacity of BNNT. Analysis of the energy profiles depending on the number of confined molecules, and on their spatial organization allowed us to quantify the ability of BNNT to vectorize CPT. Indeed, BNNT despite its small radius presented a large inner volume that favored stable encapsulation of multiple active anticancer molecules...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Tom Trapphoff, Martyna Heiligentag, Jenny Simon, Nora Staubach, Thorsten Seidel, Kathrin Otte, Thomas Fröhlich, Georg J Arnold, Ursula Eichenlaub-Ritter
STUDY QUESTION: Can supplementation of media with a glutathione (GSH) donor, glutathione ethyl ester (GEE), prior to vitrification protect the mouse oocyte from oxidative damage and critical changes in redox homeostasis, and thereby improve cryotolerance? SUMMARY ANSWER: GEE supplementation supported redox regulation, rapid recovery of spindle and chromosome alignment after vitrification/warming and improved preimplantation development of mouse MII oocytes. WHAT IS KNOWN ALREADY: Cryopreservation may affect mitochondrial functionality, induce oxidative stress, and thereby affect spindle integrity, chromosome segregation and the quality of mammalian oocytes...
September 7, 2016: Molecular Human Reproduction
Egidio Beretta, Francesca Lanfranconi, Simone Grasso Gabriele, Manuela Bartesaghi, Alemayehu Hailu Kinfu, Giuseppe Miserocchi
DLCO measured in hypoxia must be corrected due to the higher affinity (increase in coefficient θ) of CO with Hb. We propose an adjustment accounting for individual changes in the equation relating DLCO to subcomponents Dm (membrane diffusive capacity) and Vc (lung capillary volume): 1/DLCO=1/Dm+1/θVc. We adjusted the individual DLCO measured in hypoxia (HA, 3269m) by interpolating the 1/DLCO to the sea level (SL) 1/θ value. Nineteen healthy subjects were studied at SL and HA. Based on the proposed adjustment, DLCO increased in HA in 53% of subjects, reflecting the increase in Dm that largely overruled the decrease in Vc...
September 2, 2016: Respiratory Physiology & Neurobiology
Mohammad Taghi Taghizadeh, Morteza Vatanparast
Zirconium dioxide (ZrO2) nanoparticles were fabricated successfully via ultrasonic-assisted method using ZrO(NO3)2·H2O, ethylenediamine and hydrazine as precursors in aqueous solution. Morphology, structure and composition of the obtained products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and diffuse reflectance spectroscopy (DRS). Then, the synthesized nanoparticles were used to prepare Nafion/ZrO2 nanocomposite membranes...
December 1, 2016: Journal of Colloid and Interface Science
Muhammad Imran, Anne-Marie Revol-Junelles, Grégory Francius, Stéphane Desobry
Application of nano-biotechnology to improve the controlled release of drugs or functional agents is widely anticipated to transform the biomedical, pharmaceutical, and food safety trends. The purpose of the current study was to assess and compare the release rates of fluorescently labeled antimicrobial peptide nisin (lantibiotic/biopreservative) from liposomal nanocarriers. The elevated temperature, high electrostatic attraction between anionic bilayers and cationic nisin, larger size, and higher encapsulation efficiency resulted in rapid and elevated release through pore formation...
August 24, 2016: ACS Applied Materials & Interfaces
Julien Alassimone, Satoshi Fujita, Verónica G Doblas, Maritza van Dop, Marie Barberon, Lothar Kalmbach, Joop E M Vermeer, Nelson Rojas-Murcia, Luca Santuari, Christian S Hardtke, Niko Geldner
Casparian strips are precisely localized and aligned ring-like cell wall modifications in the root of all higher plants. They set up an extracellular diffusion barrier analogous to animal tight junctions, and are crucial for maintaining the homeostatic capacity of plant roots. Casparian strips become localized because of the formation of a highly stable plasma membrane domain, consisting of a family of small transmembrane proteins called Casparian strip membrane domain proteins (CASPs). Here we report a large-scale forward genetic screen directly visualizing endodermal barrier function, which allowed us to identify factors required for the formation and integrity of Casparian strips...
2016: Nature Plants
Pranjal Taskar, Akshaya Tatke, Soumyajit Majumdar
INTRODUCTION: Ocular drug delivery is presented with many challenges, taking into account the distinctive structure of the eye. The prodrug approach has been, and is being, employed to overcome such barriers for some drug molecules, utilizing a chemical modification approach rather than a formulation-based approach. A prodrug strategy involves modification of the active moiety into various derivatives in a fashion that imparts some advantage, such as membrane permeability, site specificity, transporter targeting and improved aqueous solubility, over the parent compound...
July 21, 2016: Expert Opinion on Drug Delivery
Umma Habiba, Amalina M Afifi, Areisman Salleh, Bee Chin Ang
In this study, chitosan/polyvinyl alcohol (PVA)/zeolite nanofibrous composite membrane was fabricated via electrospinning. First, crude chitosan was hydrolyzed with NaOH for 24h. Afterward, hydrolyzed chitosan solution was blended with aqueous PVA solution in different weight ratios. Morphological analysis of chitosan/PVA electrospun nanofiber showed a defect-free nanofiber material with 50:50 weight ratio of chitosan/PVA. Subsequently, 1wt.% of zeolite was added to this blended solution of 50:50 chitosan/PVA...
June 30, 2016: Journal of Hazardous Materials
Marco Morosin, Carlo Vignati, Angela Novi, Elisabetta Salvioni, Fabrizio Veglia, Marina Alimento, Guido Merli, Susanna Sciomer, Gianfranco Sinagra, Piergiuseppe Agostoni
In chronic heart failure (HF), the alveolar-capillary membrane undergoes a remodeling process that negatively affects gas exchange. In case of alveolar-capillary gas diffusion impairment, arterial desaturation (SaO2) is rarely observed in HF patients. At play are 3 factors: overall pulmonary diffusing capacity (assessed as lung diffusion for CO, DLCO), global O2 consumption (VO2) and alveolar (A) to arterial (a) pO2 gradient (AaDO2). In 100 consecutive stable HF patients, DLCO, resting respiratory gases and arterial blood gases were measured to determine VO2, paO2, pAO2 and AaDO2...
July 1, 2016: Respiratory Physiology & Neurobiology
Qing-wen Wu, Liang Meng, Zhi-hao Zhang, Qi-shi Luo, Jie Yang
The purpose of this study was to investigate the sorption characteristics of phenanthrene (PHE) and 1, 1-dichloroethene (1, 1-DCE) onto reed straw biochar at 500 degrees C in aquatic solutions. The sorption mechanisms and effects of solution pH and biochar mass on sorption intensity were discussed. The results showed that the time required to reach sorption equilibrium was 60 min and 480 min for PHE and 1, 1-DCE, respectively, with maximum removal rates of 81, 87% and 90.18%. The sorption kinetics of both PHE and 1, 1-DCE fitted the pseudo-second-order model well, but the pseudo-second-order reaction rate of PHE was higher than that of 1, 1-DCE...
February 15, 2016: Huan Jing Ke Xue= Huanjing Kexue
Marc Prudhomme, Mathieu Berge, Bernard Martin, Patrice Polard
Bacteria have evolved various inducible genetic programs to face many types of stress that challenge their growth and survival. Competence is one such program. It enables genetic transformation, a major horizontal gene transfer process. Competence development in liquid cultures of Streptococcus pneumoniae is synchronized within the whole cell population. This collective behavior is known to depend on an exported signaling Competence Stimulating Peptide (CSP), whose action generates a positive feedback loop...
June 2016: PLoS Genetics
Li-Ming Chen, Mei Liu, Ying Liu
Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity...
June 25, 2016: Sheng Li Xue Bao: [Acta Physiologica Sinica]
Zhamshid Okhunov, Renai Yoon, Alberto Perez Lanzac, Michael Sgroi, Wei Ling Lau, Michael Del Junco, Michael Ordon, Austin Drysch, Christina Hwang, Simone L Vernez, Roy Fujitani, Nii-Kabu Kabutey, Kamyar Kalantar-Zadeh, Jaime Landman
OBJECTIVES: We attempted to create a surgical model to evaluate the retroperitoneal space for the ability to transfer solutes through the retroperitoneal membrane. Our dual objectives were to develop a technique to assess the feasibility of retroperitoneal dialysis (RPD) in a porcine model. METHODS: We incorporated two 35-kg Yorkshire pigs for this pilot study. In the first animal, we clamped renal vessels laparoscopically. In the second animal, we embolized renal arteries...
August 2016: Clinical Nephrology
José A L Calbet, Carsten Lundby, Robert Boushel
In the oxygen (O2) cascade downstream steps can never achieve higher flows of O2 than the preceding ones. At the lung the transfer of O2 is determined by the O2 gradient between the alveolar space and the lung capillaries and the O2 diffusing capacity (DLO2). While DLO2 may be increased several times during exercise by recruiting more lung capillaries and by increasing the oxygen carrying capacity of blood due to higher peripheral extraction of O2, the capacity to enhance the alveolocapillary PO2 gradient is more limited...
2016: Advances in Experimental Medicine and Biology
Shijun Wang, Chun-Hsien Chu, Mingri Guo, Lulu Jiang, Hui Nie, Wei Zhang, Belinda Wilson, Li Yang, Tessandra Stewart, Jau-Shyong Hong, Jing Zhang
BACKGROUND: Misfolded α-synuclein (α-Syn) aggregates participate in the pathogenesis of synucleinopathies, such as Parkinson's disease. Whereas much is known about how the various domains within full-length α-Syn (FL-α-Syn) contribute to the formation of α-Syn aggregates and therefore to their neurotoxicity, little is known about whether the individual peptides that can be generated from α-syn, possibly as intermediate metabolites during degradation of misfolded α-Syn aggregates, are neurotoxic themselves...
2016: Journal of Neuroinflammation
Thomas P Olson, Bruce D Johnson, Barry A Borlaug
OBJECTIVES: The purpose of this study was to compare measures of gas exchange at rest and during exercise in patients with heart failure and preserved ejection fraction (HFpEF) with age- and sex-matched control subjects. BACKGROUND: Patients with HFpEF display elevation in left heart pressures, but it is unclear how this affects pulmonary gas transfer or its determinants at rest and during exercise. METHODS: Patients with HFpEF (n = 20) and control subjects (n = 26) completed a recumbent cycle ergometry exercise test with simultaneous measurement of ventilation and gas exchange...
June 2016: JACC. Heart Failure
Rasha A Khallaf, Heba F Salem, Ahmed Abdelbary
CONTEXT: The effective treatment of skin carcinoma is warranted for targeting the chemotherapeutic agents into tumor cells and avoiding unwanted systemic absorption. OBJECTIVE: This work was dedicated to the purpose of engineering highly penetrating shell-enriched nanoparticles, which were loaded with a hydrophilic chemotherapeutic agent, 5-FU. METHODS: Varying ratios of lecithin and poloxamer188 were used to produce shell enriched nanoparticles by enabling the formation of reversed micelles within this region of the SLN...
May 31, 2016: Drug Delivery
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