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Conventional film processing
Published in Damian Tolan, Rachel Hyland, Christopher Taylor, Arnold Cowen, Get Through, 2020
Damian Tolan, Rachel Hyland, Christopher Taylor, Arnold Cowen
True – the developer reduces exposed silver bromide to metallic silver.False – oxidation of developer shortens its life. Preservatives (e.g. sodium sulphite) are added to the developer to minimise oxidation and its effects.False – this acts as an accelerator. Most developers have a pH 10–11.5.True – this explains why timing of development is crucial. The addition of a restrainer, typically potassium bromide, helps the unexposed silver bromide crystals to maintain a barrier of bromide ions around them, thus preventing reduction and fog formation.True – these act synergistically, another example is metol/hydroquinone.
Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
In general, HIO and its dissociation products are labile, more so in acidic and neutral than in alkaline solutions.20 However, above pH 10, they are again very unstable.10 The instability is due to the tendency to disproportionate according to Equation 7 in iodide and iodate at the ratio of 2:1. The cation seems to have some bearing on stability, for stability increases in the order of NalO <KIO < (NH4)IO.20 Pyridine also stabilizes aqueous hypoiodite. Disproportionation is not influenced by light, and it takes place more slowly in dilute solutions than in concentrated ones.
Detection And Identification of Drugs of Dependence
Published in S.J. Mulé, Henry Brill, Chemical and Biological Aspects of Drug Dependence, 2019
The detection and/or determination of barbiturates in biological material by ultraviolet spectroscopy has been adequately demonstrated.10,71,72 These techniques have usually utilized the difference in absorbance at pH 13/10 or pH 10/2 and have found wide application amongst toxi-cologists. The major difficulty with these methods was interference from other substances. Normally the biological materials were extracted at neutral or acidic pH into chloroform, with subsequent extraction in NaOH before UV spectrophotometry. Drugs73 likely to interfere with this assay were weak acids or ampholytes possessing similar physical properties and absorbing within the UV spectrum.
Anti-neuroinflammatory effects of alkaloid-enriched extract from Huperzia serrata on lipopolysaccharide-stimulated BV-2 microglial cells
Published in Pharmaceutical Biology, 2023
Thu Kim Dang, Seong-Min Hong, Vui Thi Dao, Phuong Thi Thu Tran, Hiep Tuan Tran, Giang Hoang Do, Thanh Nguyen Hai, Hang Thi Nguyet Pham, Sun Yeou Kim
As described in a previous article (Dang et al. 2022), HsAE, the alkaloid fraction of the total ethanol extract (HsE), was extracted and one of the main bioactive compounds in it was huperzine A. Aerial parts of H. serrata were collected from Da Lat, Lam Dong province, Vietnam, in September, 2019. The plant was identified by Master Nguyen Quynh Nga and Master Phan Van Truong at the Department of Medicinal Resources, National Institute of Medicinal Materials (NIMM), Hanoi, Vietnam. A voucher specimen (No. DL-100919) was deposited in the NIMM. The alkaloid-enriched extract was prepared as described in our previous article. In brief, dried H. serrata samples were extracted in 90% EtOH at room temperature, and then the extract was filtered and evaporated under vacuum. The residue was re-dissolved in the solution of 5% HCl and partitioned three times with ethyl acetate. Next, the acidic layer was adjusted to pH 10-11 by 20% NaOH and partitioned three times by dichloromethane. The organic layers were collected and evaporated to yield the HsAE.
An interview with Shawn Singh: Chief Executive Officer and Director of VistaGen Therapeutics (Nasdaq: VTGN)
Published in Expert Review of Neurotherapeutics, 2020
I am excited about the prospects across our entire pipeline. We have many potential clinical-stage shots on goal. Right now, we are preparing to begin our Phase 3 clinical development program for our neuroactive nasal spray PH94B as a potential game-changing therapy for SAD. As mentioned above, if successful in Phase 3 and approved, PH94B would become the first FDA-approved on-demand treatment for SAD. Self-administered in non-systemic microgram doses potential for with rapid-onset effects without sedation or risk of addiction, we also see exciting applications for PH94B in maternal mental health, such as postpartum anxiety, preoperative anxiety, and other anxiety-related disorders where current oral treatment options are systemic (which is a particular issue in maternal mental health indications), sedative and potentially addictive. I am also excited about the vast potential of PH10 for rapid-onset benefits in MDD, TRD, and suicidal ideation and AV-101’s potential as a new non-opioid, non-sedating option for the treatment of pain, and dyskinesia associated with levodopa therapy for Parkinson’s disease.
Proteomics for hematopoietic stem cell transplantation
Published in Expert Review of Proteomics, 2020
Eva M. Weissinger, Debora Basílio-Queirós, Jochen Metzger, Lisa M. Bieling, Arnold Ganser
CE-MS application for monitoring of urine samples collected after allogeneic HSCT has been applied for two decades to the prediction and diagnosis of complications developing post-HSCT. Body fluids (urine or plasma) are collected on ice, and cells and debris are removed by centrifugation (e.g. at 200 × g at 4°C for 5 to 10 min) prior to freezing of the samples at a minimum of −20°C [26,27]. Prior to analyses the pH is adjusted to pH 10 using ammonia and cleared by centrifugation for 10 min at 13,000 × g at 4°C. The supernatants are applied onto a Pharmacia C2-column (Amersham Bioscience, Buckinghamshire, UK). Polypeptides are eluted with 50% (v/v) acetonitrile (Sigma-Aldrich, Taufkirchen, Germany) in 20 μl HPLC-grade water (Roth, Karlsruhe, Germany) containing 0.5% (v/v) formic acid (Sigma-Aldrich). The eluate is lyophilized, and the pellet is suspended in 20 μl HPLC-grade water, sonicated for 1 min in an ultrasonic bath, centrifuged for 10 min at 13,000 × g, and injected into the CE. After separation of the peptides in the CE, high voltage is applied and the polypeptide mixture is sprayed directly into the electrospray ionization time of flight (ESITOF). The benefit of this approach lies in the potential of detecting new possible new disease-specific markers and therapeutic targets. CE-MS analysis detects a large number of polypeptides present in urine or plasma, without the necessity of specific antibodies. In addition, tandem-MS analyses allowed sequencing of aGvHD-specific markers forming the diagnostic polypeptide profile, aGvHD-MS17. This profile consists of 17 differentially excreted peptides, 10 of those have been sequenced to date [21–23].