Using Rheo-Small-Angle Neutron Scattering to Understand How Functionalised Dipeptides Form Gels

We explore the use of rheo-small-angle neutron scattering as a method to collect structural information from neutron scattering simultaneously with rheology to understand how low-molecular-weight hydrogels form and behave under shear. We examine three different gelling hydrogel systems to assess what structures are formed and how these influence the rheology. Furthermore, we probe what is happening to the network during syneresis and why the gels do not recover after an applied strain. All this information is vital when considering gels for applications such as 3D-printing and injection

A comparative study of the electrochemical properties of vitamin B-6 related compounds at physiological pH

A comparative study of vitamin B6 group and related compounds in buffered solutions using electrochemical techniques has been performed at neutral pH. Irreversible bi- or tetra-electronic processes are observed for these substances, and the electron transfer coefficient (αn) calculated. It was concluded that either the first or second electron transfer were the rate determining step of the electrode process. The diffusion coefficient of these substances was calculated and the values given follow an inverse tendency to the molecular size. For aldehydes the values obtained were corrected of the hydration reaction. It is important to remark that catalytic waves were reported for the first time for these compounds. Using a model involving the nitrogen of the basic structure the kinetic constants were calculated for most of them

Lithium storage mechanisms in purpurin based organic lithium ion battery electrodes

Current lithium batteries operate on inorganic insertion compounds to power a diverse range of applications, but recently there is a surging demand to develop environmentally friendly green electrode materials. To develop sustainable and eco-friendly lithium ion batteries, we report reversible lithium ion storage properties of a naturally occurring and abundant organic compound purpurin, which is non-toxic and derived from the plant madder. The carbonyl/hydroxyl groups present in purpurin molecules act as redox centers and reacts electrochemically with Li-ions during the charge/discharge process. The mechanism of lithiation of purpurin is fully elucidated using NMR, UV and FTIR spectral studies. The formation of the most favored six membered binding core of lithium ion with carbonyl groups of purpurin and hydroxyl groups at C-1 and C-4 positions respectively facilitated lithiation process, whereas hydroxyl group at C-2 position remains unaltered

Using solution state NMR spectroscopy to probe NMR invisible gelators

Supramolecular hydrogels are formed via the self-assembly of gelator molecules upon application of a suitable trigger. The exact nature of this self-assembly process has been widely investigated as a practical understanding is vital for the informed design of these materials. Solution-state NMR spectroscopy is an excellent non-invasive tool to follow the self-assembly of supramolecular hydrogels. However, in most cases the self-assembled aggregates are silent by conventional 1H NMR spectroscopy due to the low mobility of the constituent molecules, limiting NMR spectroscopy to following only the initial assembly step(s). Here, we present a new solution-state NMR spectroscopic method which allows the entire self-assembly process of a dipeptide gelator to be followed. This gelator forms transparent hydrogels by a multi-stage assembly process when the pH of an initially alkaline solution is lowered via the hydrolysis of glucono-δ-lactone (GdL). Changes in the charge, hydrophobicity and relative arrangement of the supramolecular aggregates can be followed throughout the assembly process by measuring the residual quadrupolar couplings (RQCs) of various molecular probes (here, 14NH4+ and isopropanol-d8), along with the NMR relaxation rates of 23Na+. The initially-formed aggregates comprise negatively charged fibrils which gradually lose their charge and become increasingly hydrophobic as the pH falls, eventually resulting in a macroscopic contraction of the hydrogel. We also demonstrate that the in situ measurement of pH by NMR spectroscopy is both convenient and accurate, representing a useful tool for the characterisation of self-assembly processes by NMR

Hot or not? Discovery and characterization of a thermostable alditol oxidase from Acidothermus cellulolyticus 11B

We describe the discovery, isolation and characterization of a highly thermostable alditol oxidase from Acidothermus cellulolyticus 11B. This protein was identified by searching the genomes of known thermophiles for enzymes homologous to Streptomyces coelicolor A3(2) alditol oxidase (AldO). A gene (sharing 48% protein sequence identity to AldO) was identified, cloned and expressed in Escherichia coli. Following 6xHis tag purification, characterization revealed the protein to be a covalent flavoprotein of 47 kDa with a remarkably similar reactivity and substrate specificity to that of AldO. A steady-state kinetic analysis with a number of different polyol substrates revealed lower catalytic rates but slightly altered substrate specificity when compared to AldO. Thermostability measurements revealed that the novel AldO is a highly thermostable enzyme with an unfolding temperature of 84 °C and an activity half-life at 75 °C of 112 min, prompting the name HotAldO. Inspired by earlier studies, we attempted a straightforward, exploratory approach to improve the thermostability of AldO by replacing residues with high B-factors with corresponding residues from HotAldO. None of these mutations resulted in a more thermostable oxidase; a fact that was corroborated by in silico analysis

Human monoclonal antibodies targeting carbonic anhydrase IX for the molecular imaging of hypoxic regions in solid tumours

BACKGROUND: Hypoxia, which is commonly observed in areas of primary tumours and of metastases, influences response to treatment. However, its characterisation has so far mainly been restricted to the ex vivo analysis of tumour sections using monoclonal antibodies specific to carbonic anhydrase IX (CA IX) or by pimonidazole staining, after the intravenous administration of this 2-nitroimidazole compound in experimental animal models.METHODS: In this study, we describe the generation of high-affinity human monoclonal antibodies (A3 and CC7) specific to human CA IX, using phage technology.RESULTS: These antibodies were able to stain CA IX ex vivo and to target the cognate antigen in vivo. In one of the two animal models of colorectal cancer studied (LS174T), CA IX imaging closely matched pimonidazole staining, with a preferential staining of tumour areas characterised by little vascularity and low perfusion. In contrast, in a second animal model (SW1222), distinct staining patterns were observed for pimonidazole and CA IX targeting. We observed a complementary pattern of tumour regions targeted in vivo by the clinical-stage vascular-targeting antibody L19 and the anti-CA IX antibody A3, indicating that a homogenous pattern of in vivo tumour targeting could be achieved by a combination of the two antibodies.CONCLUSION: The new human anti-CA IX antibodies are expected to be non-immunogenic in patients with cancer and may serve as broadly applicable reagents for the non-invasive imaging of hypoxia and for pharmacodelivery applications. British Journal of Cancer (2009) 101, 645-657. doi: 10.1038/sj.bjc.6605200 www.bjcancer.com Published online 21 July 2009 (C) 2009 Cancer Research U

Relevance of the diploma section "Civil protection"

На сьогоднішньому етапі реформування вищої освіти навчальна дисципліна «Цивільний захист» вже не є нормативною і виключена з навчальних планів у вищих навчальних закладах, у тому числі технічного профілю. Але соціально-економічна ситуація в країні, нажаль, ускладнюється. Тому зростає необхідність і важливість питань захисту населення в умовах надзвичайних ситуацій.The discipline "Civil Protection" is not normative any more and excluded from the curriculum in higher educational institutions, including the technical profile at the present stage of reforming higher education. However, unfortunately, the socio-economic situation in the country is becoming more complicated. In these conditions, the need and importance of protecting the population in emergency situations is increasing

Activation of mammalian skeletal-muscle carbonic anhydrase III by arginine modification

Purified carbonic anhydrase isozymes I, II, and III (CA I, CA II, CA III) from various sources were treated with 2,3-butanedione and their bicarbonate dehydration reactions followed. The specific activities of human and bovine CA I and CA II and chicken CA III were not affected by the butanedione treatment, whereas the activities of human, gorilla, and bovine CA III were rapidly activated. These findings suggest that one, or both, of the two arginyl residues which appear to be unique to the active sites of the mammalian CA III isozymes are modified by butanedione.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44191/1/10540_2005_Article_BF01121914.pd

Novel inhibition of carbonic anhydrase isozymes I, II and III by carbamoyl phosphate

Carbamoyl phosphate has been shown to inhibit carbonic anhydrase (CA) isozymes CA I, CA II and CA III. This physiologically important molecule is the most potent, naturally occurring inhibitor of carbonic anhydrase yet found. It is also unique, among carbonic anhydrase inhibitors discovered hitherto, in that it inhibits the 3 isozymes with equal effect, despite their strikingly different properties. The results imply the participation of carbonic anhydrase in the regulation of substrate availability for the urea cycle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24933/1/0000360.pd