Journal articles: 'Gamma bond'

1

Gorman, C. B., and S. R. Marder. "An investigation of the interrelationships between linear and nonlinear polarizabilities and bond-length alternation in conjugated organic molecules." Proceedings of the National Academy of Sciences 90, no. 23 (December 1, 1993): 11297–301. http://dx.doi.org/10.1073/pnas.90.23.11297.

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A computational method was devised to explore the relationship of charge separation, geometry, molecular dipole moment (mu), polarizability (alpha), and hyperpolariz-abilities (beta, gamma) in conjugated organic molecules. We show that bond-length alternation (the average difference in length between single and double bonds in the molecule) is a key structurally observable parameter that can be correlated with hyperpolarizabilities and is thus relevant to the optimization of molecules and materials. By using this method, the relationship of bond-length alternation, mu, alpha, beta, and gamma for linear conjugated molecules is illustrated, and those molecules with maximized alpha, beta, and gamma are described.

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Abaza, Engy Fahmy, Ahmed Abbas Zaki, Haytham Samir Moharram, Amal Alaa El Din El Batouti, and Asmaa Aly Yassen. "Influence of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in Er, Cr:YSGG laser-prepared cavities." European Journal of Dentistry 12, no. 03 (July 2018): 338–43. http://dx.doi.org/10.4103/ejd.ejd_305_17.

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ABSTRACT Objective: To evaluate the effect of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in laser-prepared cavities. Materials and Methods: Twenty-eight flat buccal dentin surfaces were prepared for microshear bond strength test. Er, Cr:YSGG laser was used to prepare another 28 Class V cavities on the buccal surfaces of the molars. All teeth were divided into four groups; 1st group: Application of Filtek Z350 nanocomposite material, 2nd group: As the 1st group and then exposure to gamma radiation, 3rd group: Application of Ketac N100 nanoglass ionomer, and the 4th group: As the 3rd group and then gamma irradiated. The bond strength test was performed after storage in artificial saliva for 24 h. For the nanoleakage test, teeth were submerged in a solution of ammoniacal silver nitrate, sectioned, and then examined under a scanning electron microscope. The collected data were statistically analyzed. Results: Nanocomposite showed higher bond strength values than nanoglass ionomer. Despite the fact that gamma radiation did not decrease nanocomposite bond strength, it decreased nanoglass ionomer bond strength. Nanoglass ionomer-restored cavities showed higher silver ion penetration than nanocomposite in both control and gamma-irradiated groups. Conclusion: Gamma radiation has no effect on bond strength and nanoleakage of nanocomposite so that it can be placed before radiotherapy. On the other hand, the bond strength of nanoglass ionomer was adversely affected by gamma radiation.

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Chairunnnisa, Ubudia Hiliaily, Abdul Hoyyi, and Hasbi Yasin. "PEMODELAN TRANSFORMASI FAST-FOURIER PADA VALUASI OBLIGASI KORPORASI (Studi Kasus: PT. Bank Danamon Tbk, PT. Bank CIMB Niaga Tbk, dan PT. Bank UOB Indonesia Tbk)." Jurnal Gaussian 10, no. 1 (February 28, 2021): 85–93. http://dx.doi.org/10.14710/j.gauss.v10i1.30937.

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The basic assumption that is often used in bond valuations is the assumption on the Black-Scholes model. The practical assumption of the Black-Scholes model is the return of assets with normal distribution, but in reality there are many conditions where the return of assets of a company is not normally distributed and causing improperly developed bond valuation modeling. The Fast-Fourier Transform model (FFT) was developed as a solution to this problem. The Fast-Fourier Transformation Model is a Fourier transformation technique with high accuracy and is more effective because it uses characteristic functions. In this research, a modeling will be carried out to calculate bond valuations designed to take advantage of the computational power of the FFT. The characteristic function used is the Variance Gamma, which has the advantage of being able to capture data return behavior that is not normally distributed. The data used in this study are Sustainable Bonds I of Bank Danamon Phase I Year 2019 Series B, Sustainable Bonds II of Bank CIMB Niaga II Phase IV Year 2018 Series C, Sustainable Subordinated Bonds II of Bank UOB Indonesia Phase II 2019. The results obtained are FFT model using the Variance Gamma characteristic function gives more precise results for the return of assets with not normal distribution. Keywords: Bonds, Bond Valuation, Black-Scholes, Fast-Fourier Transform, Variance Gamma

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Janatova, J. "Detection of disulphide bonds and localization of interchain linkages in the third (C3) and the fourth (C4) components of human complement." Biochemical Journal 233, no. 3 (February 1, 1986): 819–25. http://dx.doi.org/10.1042/bj2330819.

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Disulphide bonds contribute significantly to the maintenance of structural/functional integrity of many proteins. Therefore it was of interest to study the distribution and the effect of disulphides on conformation of complement components C3 and C4. These proteins are precursors of several fragments with various binding sites and distinct physiological functions. The constituents of C3c (beta, alpha 27, alpha 43) and those of C4c (beta, alpha 27, alpha 16, gamma) were investigated, since other fragments of C3 or C4 do not participate in interchain linkages. Inter-and intra-chain disulphide bonds in C3c and C4c were localized by using a modification of conventional SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis such that the change in mobility of disulphide-bond-containing proteins can be detected throughout the transition from a non-reduced to a fully reduced state. Several forms of the alpha 43 fragment from C3, and of the gamma-chain of C4, with different mobilities can exist, depending on the number of intra-chain disulphide bonds reduced. The intermediates (heterodimers) generated by a partial reduction of C3c or C4c were characterized by two-dimensional SDS/polyacrylamide-gel electrophoresis performed in the absence, then in the presence, of beta-mercaptoethanol. The inter-chain linkages in C3c were determined to be beta-alpha 27 and alpha 27- alpha 43, thus indicating the presence of only one interchain bond in C3. The two interchain bonds in C4c are beta-alpha 27 and alpha 16-gamma. The third interchain bond in C4 (alpha 27-gamma, tentative) remains to be determined.

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Seya, T., S. Nagasawa, and J. P. Atkinson. "Location of the interchain disulfide bonds of the fourth component of human complement (C4): evidence based on the liberation of fragments secondary to thiol-disulfide interchange reactions." Journal of Immunology 136, no. 11 (June 1, 1986): 4152–56. http://dx.doi.org/10.4049/jimmunol.136.11.4152.

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Abstract Treatment of human C4 with chemical denaturants and heat produces rapid, autolytic peptide bond cleavage of the alpha-chain. These alpha-chain fragments are linked to the parent C4 molecule through disulfide bonds. On more prolonged heating, however, there is liberation of several peptides, including the beta-chain, the gamma-chain, and a C-terminal alpha-chain fragment. This reaction is inhibited by iodoacetamide. By using a fluorescent thiol reagent and 14C-iodoacetamide, the thiol group present on each peptide was analyzed. The results suggest that the thiol residue exposed by cleavage of the thioester bond induces thiol-disulfide interchange reactions to liberate the peptides. Based on the identification of fragments liberated, the kinetics of their appearance, their sulfhydryl content, and the reported primary structure of human C4, a model of the interchain disulfide bonds is proposed in which the amino terminal portion of the alpha-chain is disulfide-linked to both the beta- and gamma-chains, whereas the carboxyl terminal portion of the alpha-chain is disulfide-linked to only the gamma-chain.

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Faulmann, E. L., M. Young, and M. D. Boyle. "Inactivation of the proteolytic activity of mouse nerve growth factor by human C1(activated)-inhibitor." Journal of Immunology 138, no. 12 (June 15, 1987): 4336–40. http://dx.doi.org/10.4049/jimmunol.138.12.4336.

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Abstract The interaction between the serine protease gamma subunit of NGF (gamma-NGF) and human C1(activated)-inhibitor (C1-Inh) has been studied. C1-Inh inactivates the protease activity of gamma-NGF as measured by its ability to cleave the synthetic substrate benzoyl-arginine-p-nitroanilide (L-BAPNA). Experiments in which gamma-NGF and C1-Inh were mixed at differing molar ratios indicated that inhibition was due to the formation of a 1:1 stoichiometric complex. Analysis of the interaction of 125I-labeled gamma-NGF with C1-Inh by SDS-PAGE and autoradiography indicated that a covalent bond was formed between gamma-NGF and C1-Inh. The covalent bond was hydrolyzed by hydroxylamine, which suggested that the two proteins were linked via an acyl linkage. The formation of this complex was time dependent and required the proteolytic activity of the gamma-NGF.

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Cheng, Min, and Yubo Li. "Convertible Bond Pricing Based on Variance Gamma Model." Saudi Journal of Economics and Finance 4, no. 6 (June 24, 2020): 287–92. http://dx.doi.org/10.36348/sjef.2020.v04i06.015.

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8

Stevenson, G. T., V. A. Anderson, K. S. Kan, and A. T. Worth. "Conjugation of human Fc gamma in closed-hinge or open-hinge configuration to Fab'gamma and analogous ligands." Journal of Immunology 158, no. 5 (March 1, 1997): 2242–50. http://dx.doi.org/10.4049/jimmunol.158.5.2242.

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Abstract We describe a method for linking human normal Fc gamma1, via stable thioether bonds emerging from its hinge, to any molecule expressing a free sulfhydryl (SH) group. The Fc hinge may be closed by a disulfide (SS) bond or left open. Preparation begins with reduction of the Fc hinge to release four SH groups from its two parallel inter-gamma SS bonds. When the Fc is required in normal closed-hinge configuration, one SH group is alkylated with N-ethylmaleimide under limiting conditions, and one of the inter-gamma SS bonds is reconstituted by SS interchange. The residual SH group, to be used for linking, is left as a 4-dithiopyridyl group suitable for storage. When the Fc is required for conjugation the 4-dithiopyridyl is replaced by a metastable maleimidyl group, which reacts rapidly with SH on the partner molecule to form a tandem thioether link. If the partner is Ab Fab'gamma, linking to cysteines in the Fab'gamma hinge yields derivatives such as FabFc and FabFc2. Chimeric FabFc Abs (mouse Fab'gamma/human Fc gamma1) invoked cellular cytotoxicity in vitro, using human cell lines as targets and human lymphocytes as effectors, whether the Fc hinge was open or closed. The same Abs could kill the same targets by activating human complement, but only when the Fc hinge was closed. Both effector functions were enhanced by the presence of a second Fc in FabFc2. This method of Fc addition can be used to predict the performance of recombinant chimeric Abs and to provide novel molecular geometries.

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9

Bulleid, N. J., and R. B. Freedman. "The transcription and translation in vitro of individual cereal storage-protein genes from wheat (Triticum aestivum, cv. Chinese Spring). Evidence for translocation of the translation products and disulphide-bond formation." Biochemical Journal 254, no. 3 (September 15, 1988): 805–10. http://dx.doi.org/10.1042/bj2540805.

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Genes coding for the high-Mr [‘high-molecular-weight’ (HMW)] glutenin subunit 12 and for a gamma-gliadin from wheat (Triticum aestivum, cv. Chinese Spring) were subcloned into transcription-translation vectors. In each case transcription in vitro yielded a RNA transcript which when added to a rabbit reticulocyte cell-free translation system directed the synthesis of a polypeptide of appropriate Mr by SDS/polyacrylamide-gel electrophoresis (SDS/PAGE). When dog pancreatic microsomal vesicles were added to the translation system, translocation of the newly synthesized polypeptides occurred, as judged by protection from proteolysis. When translation and translocation of the gamma-gliadin was carried out under conditions favouring the formation of disulphide bonds, a polypeptide was synthesized which had a faster mobility on SDS/PAGE carried out under non-reducing conditions than under reducing conditions. This suggests that the processed and translocated gamma-gliadin forms an intramolecular disulphide bond or bonds during synthesis in vitro.

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10

Metcalfe, Clive, Peter Cresswell, and A. Neil Barclay. "Interleukin-2 signalling is modulated by a labile disulfide bond in the CD132 chain of its receptor." Open Biology 2, no. 1 (January 2012): 110036. http://dx.doi.org/10.1098/rsob.110036.

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Certain disulfide bonds present in leucocyte membrane proteins are labile and can be reduced in inflammation. This can cause structural changes that result in downstream functional effects, for example, in integrin activation. Recent studies have shown that a wide range of membrane proteins have labile disulfide bonds including CD132, the common gamma chain of the receptors for several cytokines including interleukin-2 and interleukin-4 (IL-2 and IL-4). The Cys 183 –Cys 232 disulfide bond in mouse CD132 is susceptible to reduction by enzymes such as thioredoxin (TRX), gamma interferon-inducible lysosomal thiolreductase and protein disulfide isomerase, which are commonly secreted during immune activation. The Cys 183 –Cys 232 disulfide bond is also reduced in an in vivo lipopolysaccharide (LPS)-induced acute model of inflammation. Conditions that lead to the reduction of the Cys 183 –Cys 232 disulfide bond in CD132 inhibit proliferation of an IL-2-dependent T cell clone and concomitant inhibition of the STAT-5 signalling pathway. The same reducing conditions had no effect on the proliferation of an IL-2-independent T cell clone, nor did they reduce disulfide bonds in IL-2 itself. We postulate that reduction of the Cys 183 –Cys 232 disulfide in CD132 inhibits IL-2 binding to the receptor complex. Published data show that the Cys 183 –Cys 232 disulfide bond is exposed at the surface of CD132 and in close contact with IL-2 and IL-4 in their respective receptor complexes. In addition, mutants in these Cys residues in human CD132 lead to immunodeficiency and loss of IL-2 binding. These results have wider implications for the regulation of cytokine receptors in general, as their activity can be modulated by a ‘redox regulator’ mechanism caused by the changes in the redox environment that occur during inflammation and activation of the immune system.

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11

Tomas, Michael J., and Jun Yu. "An Asymptotic Solution for Call Options on Zero-Coupon Bonds." Mathematics 9, no. 16 (August 14, 2021): 1940. http://dx.doi.org/10.3390/math9161940.

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We present an asymptotic solution for call options on zero-coupon bonds, assuming a stochastic process for the price of the bond, rather than for interest rates in general. The stochastic process for the bond price incorporates dampening of the price return volatility based on the maturity of the bond. We derive the PDE in a similar way to Black and Scholes. Using a perturbation approach, we derive an asymptotic solution for the value of a call option. The result is interesting, as the leading order terms are equivalent to the Black–Scholes model and the additional next order terms provide an adjustment to Black–Scholes that results from the stochastic process for the price of the bond. In addition, based on the asymptotic solution, we derive delta, gamma, vega and theta solutions. We present some comparison values for the solution and the Greeks.

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Anggraini, Dian, and Yasir Wijaya. "Obligasi Bencana Alam Dengan Suku Bunga Stokastik Dan Pendekatan Campuran." Al-Jabar : Jurnal Pendidikan Matematika 7, no. 1 (June 16, 2016): 49–62. http://dx.doi.org/10.24042/ajpm.v7i1.130.

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This study contains the group claims model as discussed by (Lee, 2007) for the pricing of natural disaster bonds. This research was conducted with several stages. First make the formula of bond price with stochastic interest rate and disaster event following non homogeneous poisson process. It further estimates the parameters of disaster loss data from the Insurance Information Institute (III) from 1989 to 2012 and interest rates from the Federal Reserve Bank. Because the determination of aggregate distribution is difficult to be exact, numerical calculation is done by mixed approach method (Gamma and Inverse Gaussian) to determine the solution of natural disaster bond price. Finally, shows how the impact of financial risk and disaster risk on the price of natural disaster bonds.

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Al-Ghamdi, Hanan, Aljawhara Almuqrin, and Hamoud Kassim. "Effect of Gamma Irradiation on the Structural, Optical, Electrical, and Ferroelectric Characterizations of Bismuth-Modified Barium Titanate Ceramics." Materials 15, no. 12 (June 19, 2022): 4337. http://dx.doi.org/10.3390/ma15124337.

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Materials with ferroelectric properties, low bandgap energies, high polarization, low loss, and thermal stability are essential for future solar-cell applications. Researchers have attempted to obtain such materials by using several approaches. In this vein, a novel approach is reported in this work using gamma ray irradiation. The effect of gamma radiation on the structural, optical, and ferroelectric characterizations of bismuth (Bi)-doped barium titanate (BaTiO3 (BT)), namely Ba0.95Bi0.05TiO3 ceramics (abbreviated as (Bi:BT)), was investigated. X-ray diffraction, structure refinement, and Raman study revealed the presence of a perovskite structure with a tetragonal phase in all investigated samples. Morphological study revealed a nonuniform grain size and some porosity. Gamma irradiation-induced combined effects were proved by a detailed analysis of bond lengths, bond angles, octahedral distortions, oxygen vacancies, and charge compensations. Electron paramagnetic resonance (EPR) study gave direct evidence of oxygen vacancies in the irradiated samples. After gamma irradiation, UV–vis study indicated a decrease in the bandgap from 3.14 to 2.80 eV and a significant increase in visible light absorption. Cole–Cole plots confirm as an increase in gamma-ray dose results in higher levels of electron hopping. Study of the P–E hysteresis loop demonstrated that ferroelectric properties could be maintained after gamma irradiation, with a slight decrease in remnant polarization. The behaviour of the P–E was correlated with increasing gamma dose in the investigated ceramics, demonstrating a strong gamma dependence in the loops’ profile. We guess that the present approach may be a promising technique for enhancing the multifunctionality of electronic devices.

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Haslip, Gareth G., and Vladimir K. Kaishev. "Pricing of Reinsurance Contracts in the Presence of Catastrophe Bonds." ASTIN Bulletin 40, no. 1 (May 2010): 307–29. http://dx.doi.org/10.2143/ast.40.1.2049231.

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AbstractA methodology for pricing of reinsurance contracts in the presence of a catastrophe bond is developed. An important advantage of this approach is that it allows for the pricing of reinsurance contracts consistent with the observed market prices of catastrophe bonds on the same underlying risk process.Within the proposed methodology, an appropriate financial pricing formula is derived, under a market implied risk neutral probability measure for both a catastrophe bond and an aggregate excess of loss reinsurance contract, using a generalised Fourier transform. Efficient numerical methods for the evaluation of this formula, such as the Fast Fourier transform and Fractional Fast Fourier transform, are considered.The methodology is illustrated on several examples including Pareto and Gamma claim severities.

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YU, ERIC C. K., and WILLIAM T. SHAW. "ON THE VALUATION OF DERIVATIVES WITH SNAPSHOT RESET FEATURES." International Journal of Theoretical and Applied Finance 11, no. 08 (December 2008): 905–41. http://dx.doi.org/10.1142/s0219024908005081.

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We propose a general approach that requires only a simple change of variable that keeps the valuation of call and put options (convertible bonds) with strike (conversion) price resets two-dimensional in the classical Black–Scholes setting. A link between reset derivatives, compound options and "discrete barrier" type options, when there is one reset is then discussed, from which we analyze the risk characteristics of reset derivatives, which can be significantly different from their vanilla counterparts. We also generalize the prototype reset structure and show that the delta and gamma of a convertible bond with reset can both be negative. Finally, we show that the "waviness" property found in the delta and gamma of some reset derivatives is due to the discontinuous nature of the reset structure, which is closely linked to digital options.

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Landge, Vinod G., Ayisha Parveen, Avanashiappan Nandakumar, and Ekambaram Balaraman. "Pd(ii)-Catalyzed gamma-C(sp3)–H alkynylation of amides: selective functionalization of R chains of amides R1C(O)NHR." Chemical Communications 54, no. 54 (2018): 7483–86. http://dx.doi.org/10.1039/c8cc03445a.

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17

Jiang, Bo, Zhi Hong Wu, Jing Ying Zeng, Jian Lu, Qing Rong Wei, Xing Dong Zhang, and Zhong Wei Gu. "Collagenous Molecule Immobilization on Hydroxyapatite Surface." Key Engineering Materials 330-332 (February 2007): 741–44. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.741.

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Collagenous molecule was successfully immobilized to hydroxyapatite (HA) surface through a molecular bridge (2-Hydroxyethyl acrylate, HEMA) that was grafted to the surface with covalent bond by gamma irradiation. Hydroxyapatite modified by atelocollagen had been characterized by several surface sensitive techniques, such as FT-IR, SEM, XPS. The investigations showed that the collagen, a bioactive macromolecule, was immobilized on the HA surface through covalent bond.

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Tulga DDS, PhD, Ayça, Fatma Ayşe Şanal DDS, PhD, and Doğu Ömür Dede DDS, PhD. "Does Sterilization Affect the Push Out Bond Strength of Experimental Dentin Posts?" Odovtos - International Journal of Dental Sciences 21, no. 2 (March 12, 2019): 63–72. http://dx.doi.org/10.15517/ijds.v21i2.36506.

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The purpose of this preliminary study is to evaluate the push-out bond strength (PBS) of experimental dentin posts (EDPs) obtained from human and bovine teeth sterilized by autoclaving and gamma radiation. Eighty-four mandibulary premolars were obturated and divided into three post groups: the glass fiber group (Fb) human EDP group (Hm) and the bovine EDP group (Bv). Three subgroups (n=12) were obtained for each EDP groups according to the sterilization methods; no sterilization (Cnt), steam autoclaving (Aut), and gamma radiation (Rad) a total dose of 25 kGy. All posts were cemented to root canals using a dual cured resin cement (Panavia SA). After the micro slices (1mm in thickness) were obtained of each subgroup, PBS test was performed. Data were analyzed using two-way ANOVA and Tukey’s multiple comparison tests (α=.05). The post type and sterilization method was significantly effective on the PBS values according to the ANOVA (P<.001). No sterilization apllied EDP groups showed significantly higher PBS values than the sterilized groups (P<.001). Bv_Cnt (9.42 ±1.31) showed significantly lower PBS values than both Fb (12.36 ±1.54) and Hm_Cnt (11.06 ±1.38) groups (P<.001). Both steam autoclaving and gamma radiation affect the PBS values and fracture modes of EDPs negatively. The bovine EDPs are not as effective as human EDPs with regard to the PBS to the root dentin.

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Haynes, J. A., K. A. Unocic, M. J. Lance, and B. A. Pint. "Influences of Superalloy Composition and Pt Content on the Oxidation Behavior of Gamma–Gamma Prime NiPtAl Bond Coatings." Oxidation of Metals 86, no. 5-6 (September 13, 2016): 453–81. http://dx.doi.org/10.1007/s11085-016-9646-8.

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Kozlova, Maria I., Daria N. Shalaeva, Daria V. Dibrova, and Armen Y. Mulkidjanian. "Common Mechanism of Activated Catalysis in P-Loop Fold Nucleoside Triphosphatases—United in Diversity." Biomolecules 12, no. 10 (September 22, 2022): 1346. http://dx.doi.org/10.3390/biom12101346.

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To clarify the obscure hydrolysis mechanism of ubiquitous P-loop-fold nucleoside triphosphatases (Walker NTPases), we analysed the structures of 3136 catalytic sites with bound Mg-NTP complexes or their analogues. Our results are presented in two articles; here, in the second of them, we elucidated whether the Walker A and Walker B sequence motifs—common to all P-loop NTPases—could be directly involved in catalysis. We found that the hydrogen bonds (H-bonds) between the strictly conserved, Mg-coordinating Ser/Thr of the Walker A motif ([Ser/Thr]WA) and aspartate of the Walker B motif (AspWB) are particularly short (even as short as 2.4 ångströms) in the structures with bound transition state (TS) analogues. Given that a short H-bond implies parity in the pKa values of the H-bond partners, we suggest that, in response to the interactions of a P-loop NTPase with its cognate activating partner (which are analysed in the first article, reference, Biomolecules-1832854), a proton relocates from [Ser/Thr]WA to AspWB. The resulting anionic [Ser/Thr]WA alkoxide withdraws a proton from the catalytic water molecule, and the nascent hydroxyl attacks the gamma phosphate of NTP. When the gamma-phosphate breaks away, the trapped proton at AspWB passes by the Grotthuss relay via [Ser/Thr]WA to beta-phosphate and compensates for its developing negative charge that is thought to be responsible for the activation barrier of hydrolysis.

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Carvalho, Fabíola Galbiatti de, Suzana Beatriz Portugal de Fucio, Fernanda Miori Pascon, Kamila Rosamilia Kantovitz, Lourenço Correr-Sobrinho, and Regina Maria Puppin-Rontani. "Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials." Brazilian Dental Journal 20, no. 2 (2009): 122–26. http://dx.doi.org/10.1590/s0103-64402009000200006.

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This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm² area). G1 and G3 were sterilized with a 14.5 KGy dose at 27ºC for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (α=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials.

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Khair-el-Din, T. A., S. C. Sicher, M. A. Vazquez, W. J. Wright, and C. Y. Lu. "Docosahexaenoic acid, a major constituent of fetal serum and fish oil diets, inhibits IFN gamma-induced Ia-expression by murine macrophages in vitro." Journal of Immunology 154, no. 3 (February 1, 1995): 1296–306. http://dx.doi.org/10.4049/jimmunol.154.3.1296.

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Abstract Decreased Ia expression by macrophages may account for the increased susceptibility of fetuses and neonates to infection. We chose to investigate the role of docosahexaenoic acid (DHA), an omega-3 fatty acid, on Ia expression in vitro, because neonatal serum concentrations of DHA (100-150 microM) are approximately 50 times higher than in the adult. In addition, DHA is a major component of fish-oil diets that ameliorate some autoimmune diseases and prevent renal allograft rejection. DHA inhibited IFN-gamma-induced Ia expression with a half-maximal inhibitory concentration of 25 microM. The inhibition was not caused by nonspecific damage, because oxidative metabolism via the mitochondrial electron-transport chain was not inhibited. There were strict biochemical requirements for inhibition of Ia expression. Polyenoic fatty acids with 22 carbons were more inhibitory than those with 20 carbons. Among 22-carbon fatty acids, those with more double bonds, and, in particular, with a double bond in the omega-3 position, were more inhibitory. Although DHA is known to inhibit cyclooxygenase and thus the production of eicosanoids, indomethacin did not inhibit Ia expression. This indicated that inhibition of cyclooxygenase was not responsible for inhibition of Ia expression. We divided induction of Ia expression by IFN-gamma into four phases, with IFN-gamma being present only during the second phase. DHA was most inhibitory when given before or with the IFN-gamma. This indicated that DHA inhibited early steps in IFN-gamma-induced Ia expression. Consistent with this idea, we found that DHA inhibited the increase in mRNA transcripts for Ia beta b, as assayed by Northern blotting. In summary, we found that DHA, a major component of fetal and neonatal sera as well as fish-oil diets, inhibited IFN-gamma-induced macrophage Ia expression in vitro by preventing increases in Ia mRNA transcripts.

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Nguyen, Thanh Long, and Quang Luan Le. "Study on the immuno stimulation of radiation degraded β-glucan in swiss mice." Nuclear Science and Technology 5, no. 4 (December 30, 2015): 9–15. http://dx.doi.org/10.53747/jnst.v5i4.201.

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The mixtures β-glucan extracted from the yeast cell wall were irradiated under gamma rays from a Co-60 source at doses of 100, 200 and 300 kGy in order to prepare water-soluble β-glucan. Yields of the water soluble β-glucan produced are 25.9, 49.1, 66.71%, and their molecular weights (Mw) are 30.5, 24.9 and 10.8 kDa, respectively. There are no any new peak in the IR spectra of the irradiated β-glucan samples, but the intensity ratio between the peaks at wavenumber of 1156 cm-1 (assigned to C-O-C bond) and of 1040 cm-1 (assigned to C-C bond) in glycosidic linkages was reduced with irradiation dose. These results revealed that gamma irradiation did not cause any change in the β-glucan structure except the scissions of glycosidic linkages. In this study, immuno stimulation of the irradiated b-glucan was also investigated for the Swiss mice. After 28 days supplying with the irradiated b-glucan, not only cellular indexes (white blood cell, neutrophils and lymphocytes counts), but also humoral immunity indexes (IgA and IgM) of the mice significantly increased and the highest effects was obtained for the mice supplied with the oligoβ-glucan prepared by gamma irradiation at 200 kGy. Thus, the water soluble oligoβ-glucan with Mw ~ 24.9 kDa prepared by gamma radiation much stimulated the natural immune system (non-specific immunity) in mice including both the cellular and humoral immunities. Particularly, the irradiated b-glucan is a very promising product for preparation of functional foods aiming at cancer prevention.

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Wiegand, Benjamin C., Per E. Uvdal, J. G. Serafin, and Cynthia M. Friend. "Selective .gamma. carbon-hydrogen bond cleavage in alkoxides: 2-propanol on molybdenum(110)." Journal of the American Chemical Society 113, no. 17 (August 1991): 6686–87. http://dx.doi.org/10.1021/ja00017a057.

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Friedrich, Thomas, Burkhard Kroger, Wolfgang Koerwer, Karl-Hermann Strube, Thomas Meyer, and Siegfried Bialojan. "An isopeptide bond splitting enzyme from Hirudo medicinalis similar to gamma-glutamyl transpeptidase." European Journal of Biochemistry 256, no. 2 (September 1998): 297–302. http://dx.doi.org/10.1046/j.1432-1327.1998.2560297.x.

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Shim, Ha-Eun, Byoung-Min Lee, Dae-Hee Lim, You-Ree Nam, Pyung-Seok Choi, and Hui-Jeong Gwon. "A Comparative Study of Gamma-Ray Irradiation-Induced Oxidation: Polyethylene, Poly (Vinylidene Fluoride), and Polytetrafluoroethylene." Polymers 14, no. 21 (October 28, 2022): 4570. http://dx.doi.org/10.3390/polym14214570.

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Radiation techniques are used to modify the physical, chemical and biological properties of polymers. This induces crosslinking and degradation reactions of polymers by utilizing radicals generated through ionizing radiation. However, oxidation products (such as carbonyl) can be formed because oxidation occurs by chain scission in the presence of oxygen. Herein, we demonstrate the gamma-ray irradiation-induced oxidation with and without fluorine using polyethylene, polyvinylidene fluoride and polytetrafluoroethylene under the same conditions. In this study, changes in element-content and chemical-bond structures were analyzed before and after gamma-ray irradiation under air atmosphere. As a result, polytetrafluo-roethylene showed less oxidation and excellent thermal properties after the absorbed dose of 500 kGy. This can be attributed to the generation of stable perfluoroalkylperoxy radicals after gamma ray irradiation in the PTFE structure containing only CF2 groups, thereby hindering the oxidation reaction.

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PINTOUX, CAROLINE, and NICOLAS PRIVAULT. "A DIRECT SOLUTION TO THE FOKKER–PLANCK EQUATION FOR EXPONENTIAL BROWNIAN FUNCTIONALS." Analysis and Applications 08, no. 03 (July 2010): 287–304. http://dx.doi.org/10.1142/s0219530510001655.

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The solution of the Fokker–Planck equation for exponential Brownian functionals usually involves spectral expansions that are difficult to compute explicitly. In this paper, we propose a direct solution based on heat kernels and a new integral representation for the square modulus of the Gamma function. A financial application to bond pricing in the Dothan model is also presented.

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Gobara, Mohammed, and Ahmad Baraka. "Tartrazine Solution as Dosimeter for Gamma Radiation Measurement." International Letters of Chemistry, Physics and Astronomy 33 (May 2014): 106–17. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.33.106.

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In this study, Tartrazine aqueous solution was investigated as a simple low-dose dosimeter in the range of 20-500 Gy for the high ionizing radiation, gamma ray. Gradual bleaching of Tartarzine solution was observed with dose by measuring the absorbance of Tartarzine-solutions at specified wavelength, λmax = 428 nm. Tartrazine concentration (10–4, 5 ×10–4 and 10–3 M) and solution-initial pH value (5, 7 and 9) were considered as factors affecting degree of bleaching. It was found that Tartarzine-solution color was diminished gradually with selected dose range due to breakdown of the azo bond. The rate of bleaching increases with the increase of solution-initial pH. Increase of Tartarzine-concentration causes widening of range to which solution is susceptible. The post-irradiated effect (24 hours) was found to cause more bleaching. The sensitivity of Tartrazine solution is not regular with the Tartarzine-concentration and regular with pH.

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Gobara, Mohammed, and Ahmad Baraka. "Tartrazine Solution as Dosimeter for Gamma Radiation Measurement." International Letters of Chemistry, Physics and Astronomy 33 (May 11, 2014): 106–17. http://dx.doi.org/10.56431/p-b52d76.

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In this study, Tartrazine aqueous solution was investigated as a simple low-dose dosimeter in the range of 20-500 Gy for the high ionizing radiation, gamma ray. Gradual bleaching of Tartarzine solution was observed with dose by measuring the absorbance of Tartarzine-solutions at specified wavelength, λmax = 428 nm. Tartrazine concentration (10–4, 5 ×10–4 and 10–3 M) and solution-initial pH value (5, 7 and 9) were considered as factors affecting degree of bleaching. It was found that Tartarzine-solution color was diminished gradually with selected dose range due to breakdown of the azo bond. The rate of bleaching increases with the increase of solution-initial pH. Increase of Tartarzine-concentration causes widening of range to which solution is susceptible. The post-irradiated effect (24 hours) was found to cause more bleaching. The sensitivity of Tartrazine solution is not regular with the Tartarzine-concentration and regular with pH.

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Yao, Wei Wei, Zhi Wu Liu, Hong Gen Yi, and Jian Nan Wang. "Structure and Mechanical Property of Silk Fiber under Gamma Radiation." Advanced Materials Research 175-176 (January 2011): 85–89. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.85.

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An attempt to change the structure of silk fibers and their properties for the biological application was studied by utilizing gamma radiation in various Co60 intensities (0 kGy, 30 kGy, 50 kGy, 100 kGy, 200 kGy, 500 kGy, 1000 kGy, 2000 kGy, 3000 kGy). With the increase of the gamma radiation intensity, SEM result shows that cracks and fragments were formed between microfibrils of the irradiated fiber significantly. Simultaneously SDS-PAGE results give the evidence that the molecular weight of the fibroin diminished. Furthermore, the breaking strength and elongation of irradiated fibers decreased gradually with the increasing Co60 intensity. Although no significant changes of the molecular conformations were found by FTIR and X-ray diffraction, the effects on molecular interactions of the silk fibroin, such as peptide bonding, hydrogen bond and intermolecular bonding force, were obviously observed and enhanced gradually with the increase of gamma radiation intensity.

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Ahuja, B. L., Anil Gupta, and B. K. Department of Physics, M. Regional. "Compton Profile of Boron Nitride." Zeitschrift für Naturforschung A 48, no. 1-2 (February 1, 1993): 310–14. http://dx.doi.org/10.1515/zna-1993-1-258.

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Abstract The Compton profile of hexagonal boron nitride has been measured using 59.54 keV gamma rays and a planar Ge detector. The results are compared with theoretical Compton profiles calculated for various ionic arrangements and with those available from a bond orbital model, LCAO and SC canonical HF calculations. The LCAO calculation is in relatively good agreement with the present measurement.

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Chull An, Byung, Seung Sik Lee, Eun Mi Lee, Seung Gon Wi, Woojun Park, and Byung Yeoup Chung. "Global analysis of disulfide bond proteins inPseudomonas aeruginosaexposed to hydrogen peroxide and gamma rays." International Journal of Radiation Biology 86, no. 5 (April 16, 2010): 400–408. http://dx.doi.org/10.3109/09553000903567953.

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CHEN, Danni, Naoko OHTA, Mari UKAI, Mihoko MASUDA, and Toshihisa YOTSUYANAGI. "Binding and Aggregation of Human .GAMMA.-Globulin by cis-Diamminedichloroplatinum(II) through Disulfide Bond." Biological & Pharmaceutical Bulletin 17, no. 12 (1994): 1561–66. http://dx.doi.org/10.1248/bpb.17.1561.

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Hogan, Victoria, and Welkin E. Johnson. "Unique Structure and Distinctive Properties of the Ancient and Ubiquitous Gamma-Type Envelope Glycoprotein." Viruses 15, no. 2 (January 18, 2023): 274. http://dx.doi.org/10.3390/v15020274.

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After the onset of the AIDS pandemic, HIV-1 (genus Lentivirus) became the predominant model for studying retrovirus Env glycoproteins and their role in entry. However, HIV Env is an inadequate model for understanding entry of viruses in the Alpharetrovirus, Gammaretrovirus and Deltaretrovirus genera. For example, oncogenic model system viruses such as Rous sarcoma virus (RSV, Alpharetrovirus), murine leukemia virus (MLV, Gammaretrovirus) and human T-cell leukemia viruses (HTLV-I and HTLV-II, Deltaretrovirus) encode Envs that are structurally and functionally distinct from HIV Env. We refer to these as Gamma-type Envs. Gamma-type Envs are probably the most widespread retroviral Envs in nature. They are found in exogenous and endogenous retroviruses representing a broad spectrum of vertebrate hosts including amphibians, birds, reptiles, mammals and fish. In endogenous form, gamma-type Envs have been evolutionarily coopted numerous times, most notably as placental syncytins (e.g., human SYNC1 and SYNC2). Remarkably, gamma-type Envs are also found outside of the Retroviridae. Gp2 proteins of filoviruses (e.g., Ebolavirus) and snake arenaviruses in the genus Reptarenavirus are gamma-type Env homologs, products of ancient recombination events involving viruses of different Baltimore classes. Distinctive hallmarks of gamma-type Envs include a labile disulfide bond linking the surface and transmembrane subunits, a multi-stage attachment and fusion mechanism, a highly conserved (but poorly understood) “immunosuppressive domain”, and activation by the viral protease during virion maturation. Here, we synthesize work from diverse retrovirus model systems to illustrate these distinctive properties and to highlight avenues for further exploration of gamma-type Env structure and function.

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Рогинский, Е. М., and М. Б. Смирнов. "Электронная структура и нелинейная диэлектрическая восприимчивость γ-фазы оксида теллура." Физика твердого тела 62, no. 4 (2020): 547. http://dx.doi.org/10.21883/ftt.2020.04.49117.641.

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The structural electronic and nonlinear optical properies of the γ-TeO2 crystal is studied by ab inito quantum mechanical calculations. The incluence of 5d electrons localization effect is taken into account in calculations by using Habbard-like correction term (LDA+U approximation). The obtained within such approach structural parameters are obtained in a good agreement with experimental data. The electronic bund structure is studied within quasiparticle G0W0 approximation, which is known as the most accurate method. It was found that the γ-TeO2 crystal is wide gap semiconductor with non-direct band gap. The analysis of the chemical bond is performed using Maximaly Localized Wannier functions. It is established that the valence electrons of ozigen atoms are belong to sp3-hybridization states and valence of tellurium atoms are equal to four.

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36

Ergun, Ece, Ümit Ergun, and Betül Kalıpçılar. "A comparative study of heat-cured and gamma-cured fiber-reinforced denture-base acrylic resins: Residual monomer and flexural strength." Polymers and Polymer Composites 28, no. 8-9 (November 16, 2019): 530–40. http://dx.doi.org/10.1177/0967391119887834.

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This study was performed to determine and compare the effect of heat and gamma-ray polymerization methods on the residual monomer and flexural strength of polyethylene fiber-reinforced denture-base acrylic resins. Four groups ( n = 10) of specimens of polyethylene fiber-reinforced denture-base material were prepared in the form of thin disks. The first group was subjected to heat-curing and the other three groups were polymerized with gamma irradiation at doses of 15, 25, and 35 kGy, respectively. Fourier-transform infrared (FTIR) spectrometer was used to monitor the corresponding polymerization processes. The analysis of residual monomer was carried out by high-performance liquid chromatography–photodiode array detector. A three-point bending test was used to evaluate the flexural strength of the samples. The one-way analysis of variance test was performed to determine the significant differences between the groups. The absence of the bands related to carbon–carbon double bond in the FTIR spectra of all test groups was an evidence of polymerization. The mean weight percentage of residual monomer was successively ranked from highest to lowest in; heat-cured, gamma-cured at 15–35 kGy. However, no significant difference ( p = 0.462) was found between gamma-cured samples at 25 and 35 kGy. Mechanical test results revealed that heat-cured samples had higher flexural strength than gamma-cured specimens ( p < 0.001). Within the limitations of this study, polymerization with gamma-rays at 15 kGy was proposed as a promising technique in terms of the residual monomer and flexural strength results.

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Darojati, Harum Azizah, Sebastianus Dani Ganesha, and Dhita Ariyanti. "Pengaruh Variasi Dosis Iradiasi Gamma pada Pemisahan Komponen Penyusun Biomassa Lignoselulosa Sabut Kelapa." JURNAL SELULOSA 12, no. 01 (June 30, 2022): 23. http://dx.doi.org/10.25269/jsel.v12i01.359.

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The Effect of Gamma Iradiation Dosage Variation on The Separation of Coconut Coir Lignocellulose Biomass ComponentsAbstractIndonesia has the potential for lignocellulosic biomass in the form of coconut coir, which is very abundant. The components of coconut coir are lignocellulosic biomass, which consists of cellulose, hemicellulose, and lignin and can be separated from one another. This study was conducted to determine the effect of variations in the dose of gamma-ray irradiation on the structure of each component so that it was expected that the utilization of coconut coir lignocellulosic biomass could be more comprehensive. The separation was carried out using wet irradiation with a 5% H2O2 solution as the initiator, where 15 grams of coco coir sample was dissolved in 60 ml of 5% H2O2 solution. Gamma irradiation dose variations were 0 kGy, 50 kGy, 100 kGy, 150 kGy, and 200 kGy. Based on the research, the optimal dose to obtain glucose was obtained at an irradiated dose of 100 kGy with a glucose level of 5.09 mg. The optimal gamma irradiation dose for lignin separation is 50 kGy with a lignin separation percentage of 34.95%. Based on the FTIR analysis, it can be seen that as a result of the chemical bond resulting from the separation, there is a decrease in the effect of the gamma IR radiation. This study showed that the separation of lignocellulosic coconut coir biomass using gamma irradiation could produce higher levels of glucose and lignin separation and affect the chemical structure of cellulosic biomass

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Lamotte-Brasseur, J., G. Dive, O. Dideberg, P. Charlier, J. M. Frère, and J. M. Ghuysen. "Mechanism of acyl transfer by the class A serine β-lactamase of Streptomyces albus G." Biochemical Journal 279, no. 1 (October 1, 1991): 213–21. http://dx.doi.org/10.1042/bj2790213.

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Optimization by energy minimization of stable complexes occurring along the pathway of hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase has highlighted a proton shuttle that may explain the catalytic mechanism of the beta-lactamases of class A. Five residues, S70, S130, N132, T235 and A237, are involved in ligand binding. The gamma-OH group of T235 and, in the case of benzylpenicillin, the gamma-OH group of S130 interact with the carboxylate group, on one side of the ligand molecule. The side-chain NH2 group of N132 and the carbonyl backbone of A237 interact with the exocyclic CONH amide bond, on the other side of the ligand. The backbone NH groups of S70 and A237 polarize the carbonyl group of the scissile beta-lactam amide bond. Four residues, S70, K73, S130 and E166, and two water molecules, W1 and W2, perform hydrolysis of the bound beta-lactam compound. E166, via W1, abstracts the proton from the gamma-OH group of S70. While losing its proton, the O-gamma atom of S70 attacks the carbonyl carbon atom of the beta-lactam ring and, concomitantly, the proton is delivered back to the adjacent nitrogen atom via W2, K73 and S130, thus achieving formation of the acyl-enzyme. Subsequently, E166 abstracts a proton from W1. While losing its proton, W1 attacks the carbonyl carbon atom of the S70 ester-linked acyl-enzyme and, concomitantly, re-entry of a water molecule W'1 replacing W1 allows E166 to deliver the proton back to the same carbonyl carbon atom, thus achieving hydrolysis of the beta-lactam compound and enzyme recovery. The model well explains the differences found in the kcat. values for hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase. It also explains the effects caused by site-directed mutagenesis of the Bacillus cereus beta-lactamase I [Gibson, Christensen & Waley (1990) Biochem J. 272, 613-619].

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Concas, Giorgio, Giorgio Spano, Marzia Carrada, Marco Bettinelli, and Adolfo Speghini. "Local Structure of Europium Sites in Oxide Glasses by Nuclear Gamma Resonance." Zeitschrift für Naturforschung A 54, no. 8-9 (September 1, 1999): 539–44. http://dx.doi.org/10.1515/zna-1999-8-916.

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The symmetry and disorder of the Eu3+ site was investigated in some phosphate and borate glasses by means of 151Eu Mössbauer spectroscopy. The quadrupole interaction parameter, which is due to the distortion of the Eu site compared to a cubic symmetry, has been measured together with the asymmetry parameter, which points out the absence of a threefold or fourfold axis of symmetry at the rare earth site. The correlation of the isomer shift with the optical basicity of the glass indicates a covalent component with 6s character in the Eu-O bond. The axial component of the electric field gradient at the Eu site is also correlated with the optical basicity.

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Huber, Christian, and Karl Deix. "Comparison of Calculation Methods of Elastic Bonding: Limits of the Gamma Method Using an Example of a Wood–Concrete Composite Floor with Single Loads." Materials 14, no. 23 (November 26, 2021): 7211. http://dx.doi.org/10.3390/ma14237211.

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Various methods are available for the calculation of timber–concrete composite floors. The gamma method, which is important in construction practice, as well as the differential equation method, are based on the simplified assumption of a continuous bond between wood and concrete. This makes it possible to analytically calculate the internally statically indeterminate partial section sizes and deformation sizes, analogous to the force size method. In this paper, two typical load situations of concentrated loads (central and off-centre) were analytically and numerically evaluated and compared using the above-mentioned methods (gamma and differential equation), with a discrete method for the case of a timber beam reinforced with a concrete slab using screws as fasteners. The calculation results show significant deviations, which speak for the application of discrete methods in certain load situations and thus limit the usability of the gamma method under certain conditions. For the problem of deflection determination, which is not dealt with in the literature for the discrete method, a numerical method is described in the present work, which was first developed and presented by the first author.

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Tie, Jian-Kie, Mei-Yan Zheng, Darrel W. Stafford, and David L. Straight. "Expression of a Two Chain Gamma-Glutamyl Carboxylase: Importance of Disulfide Bond Formation and Transmembrane Domain Interactions." Blood 108, no. 11 (November 16, 2006): 1694. http://dx.doi.org/10.1182/blood.v108.11.1694.1694.

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Abstract The vitamin K-dependent carboxylase is an integral membrane protein with five transmembrane domains (TMDs). It catalyzes the post-translational modification of specific glutamic acid residues of vitamin K-dependent proteins to gamma-carboxyglutamic acid residues. This posttranslational modification is critical for the biological functions of blood coagulation. The native enzyme is a single chain molecule with one disulfide bond. In this study, we have expressed carboxylase as two chains: residues 1–345 and 346–758 in the same insect cells. Our results show that these two fragments are assembled into a fully active enzyme and are joined by a disulfide. Affinity purification of the carboxylase C-terminal fragment (346–758) results in co-purification of the N-terminal fragment (1–345) even under reducing condition. This indicates that, in addition to the disulfide linkage between these two fragments, they are also linked by non-covalent interactions. One possibility is that the hydrophobic interactions between the TMDs play a role. According to carboxylase membrane topology, there are four TMDs (1–4) in the N-terminal fragment and one TMD (fifth) in the C-terminal fragment. The C-terminal fragment contains all glycosylation sites. When we introduced two prolines to disrupt the transmembrane helix in the wild type carboxylase’s fifth TMD, glycosylation was eliminated. This indicates that the domain is not inserted into the lumen of the ER, but remains in the cytoplasm. Therefore, as our results demonstrate, in the two chain carboxylase with its fifth TMD disrupted, the two chains do not form a disulfide bound nor do they associate through essential non-covalent TMD interactions. While proline residues can disrupt membrane helices as described above, they often occur at the interface between the membrane and the lumenal surface of ER; these prolines appear to affect the chain orientation as it exits the membrane. There is a proline at residue 378 near the lumenal surface of the fifth TMD helix of carboxylase. To examine P378’s effect on disulfide bond formation, we mutated it to leucine. Results show that less disulfide bond formed in the two chain mutant carboxylase and the protein was significantly degraded when compared to the unmutated two chain molecule. Based on our results, we conclude the following: 1) the two chain carboxylase is assembled into a single molecule in vivo and the two chains are joined by a disulfide bond, the enzyme carboxylates gla-containing substrates and binds propeptide with affinity similar to that of wild type enzyme. Therefore, this molecule is a good model for structural studies of TMD interactions and disulfide bond formation; 2) TMD association in the membrane is important for the orientation of the N- and C-terminal portions of carboxylase to be assembled into the active enzyme; 3) and finally proline residue 378 at the lumenal interface of the fifth TMD plays a key role in the conformation which promotes disulfide formation.

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Rappaport, J., and R. Weinmann. "Purine triphosphate beta-gamma bond hydrolysis requirements for RNA polymerase II transcription initiation and elongation." Journal of Biological Chemistry 262, no. 36 (December 1987): 17510–15. http://dx.doi.org/10.1016/s0021-9258(18)45410-5.

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Molina, Pamela, Samantha Borja, Vladimir Valle, Lisbeth Mena, and Francisco Cadena. "Dual Modification of Starch Via Gamma Irradiation and Subsequent Chemical Treatment with Urea for the Development of Adhesives." Revista Politécnica 46, no. 1 (August 3, 2020): 39–46. http://dx.doi.org/10.33333/rp.vol46n1.04.

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This research evaluates achira starch modification via gamma radiation, chemical modification and the subsequent adhesives formulation. Native starch was irradiated using a linear accelerator; the mean dose rate used was 19.5 kGy/min at ambient temperature and normal pressure. The chemical modification of irradiated starch consisted of a hydrolysis process, followed by the obtention of carbamates from the hydrolyzed starch with urea, sulphuric acid and ethanol. In order to prepare adhesives; native, modified and dual-modified starches were tested in different proportions with a polyvinyl alcohol (PVA) solution. Fourier Transformed Infrared Spectroscopy (FTIR) analysis showed all modified starches had a lower intensity in the band between 1100 and 900 cm-1 due to the damage in the glycosidic bonds. Only single modified starches evidenced a characteristic band at 1715 cm-1, which corresponds to the group carbonyl (C=O) of carbamates. The viscosity of native starch adhesives increased with the starch-PVA, unlike, single and dual-modified starch adhesives. The shear bond strength did not change significantly in the adhesives formulated either with starch modified by urea or electron beam irradiation. The combination of hydrolysis with gamma radiation caused strong damage in the starch structure. However, despite the molecular destruction of polysaccharide, the adhesion capacity for non-irradiated starches is similar in all cases.

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Witting, J. I., P. Bourdon, D. V. Brezniak, J. M. Maraganore, and J. W. Fenton. "Thrombin-specific inhibition by and slow cleavage of hirulog-1." Biochemical Journal 283, no. 3 (May 1, 1992): 737–43. http://dx.doi.org/10.1042/bj2830737.

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Hirulog-1 [D-Phe-Pro-Arg-Pro-[Gly]4-desulphohirudin-(53-64) (HV1)] was designed to bind by its first four and last 12 residues to the alpha-thrombin catalytic site and anion-binding exosite for fibrin(ogen) recognition respectively, with a [Gly]4 bridge and an Arg-Pro bond at the scissional position. Human alpha-, gamma- and zeta-thrombins, as well as bovine trypsin, readily hydrolyse Spectrozyme-TH (D-hexahydrotyrosyl-Ala-Arg p-nitroanilide) at pH 7.4 and approx. 23 degrees C. Both alpha- and zeta-thrombins, which have high fibrinogen-clotting activities (greater than 3000 kunits/g), were inhibited with this substrate by hirulog-1 [Ki = 2.56 +/- 0.35 nM (n = 3) and 1.84 +/- 0.15 nM (n = 3) respectively] and slowly cleaved the inhibitor [k = 0.326 +/- 0.082 min-1 (n = 12) and 0.362 +/- 0.056 min-1 (n = 18) respectively], whereas gamma-thrombin, which has essentially no clotting activity (approx. 4 kunits/g), and trypsin were not inhibited with greater than 1000-fold molar excess of hirulog-1. Similar inhibition parameters were also obtained for hirulog-1 incubated with alpha-thrombin or zeta-thrombin at approx. 23 degrees C and by measuring thrombin activity with fibrinogen in the clotting assay at 37 degrees C. Cleavage of the Arg-3-Pro-4 bond in hirulog-1 by either alpha- or zeta-thrombin was shown by identical cleavage products of either thrombin on h.p.l.c. and by sequence analysis of the alpha-thrombin products. These data demonstrate that hirulog-1 is a specific inhibitor of thrombin forms with high fibrinogen-procoagulant activities and that its Arg-3-Pro-4 bond is slowly cleaved by these thrombin forms.

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Noritake, Tatsuo, Masakazu Aoki, Shin-ichi Towata, Tsunehiro Takeuchi, and Uichiro Mizutani. "Structure determination of structurally complex Ag36Li64 gamma-brass." Acta Crystallographica Section B Structural Science 63, no. 5 (September 14, 2007): 726–34. http://dx.doi.org/10.1107/s0108768107039092.

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The crystal structure of the Ag36Li64 gamma-brass was determined by analyzing the powder diffraction pattern taken using a synchrotron radiation beam with wavelength 0.50226 Å. It turned out that the compound contained 52 atoms in its unit cell with the space group I\bar 43m and that the Li atom enters exclusively into inner tetrahedral (IT) and cubo-octahedral (CO) sites, whereas the Ag atom enters into those on outer tetrahedral (OT) and octahedral (OH) sites in the 26-atom cluster. Small amounts of Li also exist in OT and OH sites, resulting in chemical disorder. We discovered that the volumes of the IT and CO polyhedra shrink, while those of the OT and OH polyhedra expand relative to those of the corresponding polyhedra in the original b.c.c. (body-centered cubic) structure. This feature is universal and is found in other gamma-brasses such as Cu5Zn8 and Al8V5, for which the structure data are available. Among these gamma-brasses, we revealed the unique bond-length distribution for pairs connecting the atom on OH sites and that on CO sites, depending on the degree of d–p orbital hybridization between the transition metal elements such as Ag, Cu and V on OH sites, and the non-transition metal elements such as Li, Zn and Al on CO sites. It is suggested that this may hold a clue to resolving why some gamma-brasses such as the present Ag–Li and Cu–Zn possess a finite solid solution, but others such as Al8V5 and Mn3In exist as line compounds.

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Yonekawa, O., M. Voskuilen, and W. Nieuwenhuizen. "Localization in the fibrinogen γ-chain of a new site that is involved in the acceleration of the tissue-type plasminogen activator-catalysed activation of plasminogen." Biochemical Journal 283, no. 1 (April 1, 1992): 187–91. http://dx.doi.org/10.1042/bj2830187.

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In previous publications [e.g. Voskuilen, Vermond, Veeneman, Van Boom, Klasen, Zegers & Nieuwenhuizen (1987) J. Biol. Chem. 262, 5944-5946] we have shown that fibrin(ogen) chain fragment A alpha-(148-160) contains a site that contributes to the acceleration of Glu-plasminogen activation by tissue-type plasminogen activator (t-PA). In contrast with fibrin, this peptide, however, does not enhance the rate of mini-plasminogen activation. Therefore, possibly more stimulatory sites than A alpha-(148-160) are present in fibrin. In the present investigation we have localized a possible second type of stimulatory site in the fibrin(ogen) molecule. A whole CNBr digest of fibrinogen was applied to a Bio-Gel P-2 column run in water, pH 4. Two peaks with stimulatory activity were observed, one at the void volume and one between the void volume and the total volume. The former contained the previously described stimulating fragment FCB-2 [which comprises A alpha-(148-160)]; the latter had not been observed before and was characterized further. The stimulating material in the low-M(r) fraction of the Bio-Gel P-2 column was precipitated at pH 8.3 in a virtually pure form. It has a high tryptophan content, and an M(r) of 6500 as assessed by SDS/PAGE. On reduction, a main band of M(r) 2500 is seen, plus a weakly staining band of M(r) 4000. These properties plus the amino acid sequence data identify the fragment as FCB-5. FCB-5 consists of two chains, i.e. gamma-(311-336) and gamma-(337-379), linked by a single disulphide bond between Cys-gamma-326 and Cys-gamma-339. Both these chains and the disulphide bond appear to be essential for rate enhancement. FCB-5 enhances the activation rates of Glu-, mini- and micro-plasminogen, with all five kringles, only kringle V and without kringles respectively. FCB-5 binds t-PA, but none of the plasminogen forms binds to FCB-5. This indicates that the rate enhancements induced by FCB-5 are due to an effect on t-PA.

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47

Almuqrin, Aljawhara H., Badriah Albarzan, O. I. Olarinoye, Ashok Kumar, Norah Alwadai, and M. I. Sayyed. "Mechanical and Gamma Ray Absorption Behavior of PbO-WO3-Na2O-MgO-B2O3 Glasses in the Low Energy Range." Materials 14, no. 13 (June 22, 2021): 3466. http://dx.doi.org/10.3390/ma14133466.

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The Makishima and Mackenzie model has been used to determine the mechanical properties of the PbO-WO3-Na2O-MgO-B2O3 glass system. The number of bonds per unit volume of the glasses (nb) increases from 9.40 × 1022 to 10.09 × 1022 cm−3 as the PbO content increases from 30 to 50 mol%. The Poisson’s ratio (σ) for the examined glasses falls between 0.174 and 0.210. The value of the fractal bond connectivity (d) for the present glasses ranges from 3.08 to 3.59. Gamma photon and fast neutron shielding parameters were evaluated via Phy-X/PSD, while that of electrons were calculated via the ESTAR platform. Analysis of the parameters showed that both photon and electron attenuation ability improve with the PbO content. The fast neutron removal cross section of the glasses varies from 0.094–0.102 cm−1 as PbO molar content reduced from 50–30 mol%. Further analysis of shielding parameters of the investigated glass system showed that they possess good potential to function in radiation protection applications.

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48

Olliges, J., A. Lötz, J. Voitländer, H. Barfuss, G. Böhnlein, F. Gubitz, W. Ittner, G. Lanzendorfer, W. Kreische, and B. Röseler. "Boron, Nitrogen, and Fluorine Nuclear Quadrupole Coupling and the Electronic Structure of the Boron—Nitrogen Single Bond." Zeitschrift für Naturforschung A 41, no. 1-2 (February 1, 1986): 203–5. http://dx.doi.org/10.1515/zna-1986-1-234.

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The 11B and 19F nuclear quadrupole couplings in F3BNHx(CH3)3-x compounds are reported. The boron quadrupole couplings were measured by quadrupole perturbed NMR in the solid state. The fluorine quadrupole couplings were obtained by the time-differential observation of the angular distribution of the gamma radiation after excitation of the fluorine nuclei with accelerated protons (TDPAD). The results are discussed in connection with the nitrogen quadrupole couplings in F3BNHxR3-x compounds, and the nitrogen and boron quadrupole couplings in H3BNHxR3-x: compounds which were previously determined by nuclear quadrupole double resonance. In the F3BNHxR3-x series of compounds, the donor-acceptor character of the B -N bond appears to be less im portant than in the H3BNHxR3-x compounds in favour of a more ionic character of the bond with a higher negative charge on nitrogen.

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He, Xiao, Xiaomin Wang, and Peter Jensen. "Deficiency in Ab response to insulin in gamma-IFN-inducible lysosomal thiol reductase (GILT) knock-out mice (100.29)." Journal of Immunology 186, no. 1_Supplement (April 1, 2011): 100.29. http://dx.doi.org/10.4049/jimmunol.186.supp.100.29.

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Abstract The γ-IFN-inducible lysosomal thiol reductase (GILT) is a unique thiol reductase with optimal activity at low pH, and is expressed in Ag presenting cells (APC). GILT is critical to processing protein Ag by catalyzing disulfide bond reduction, thus facilitating the unfolding of native Ag containing disulfide bonds for further processing. GILT-/- mice are defective in processing exogenous protein Ag. However the role of GILT in Ab response is not clear. Here we report that after immunization, GILT-/- mice failed to produce Ab to exogenous bovine insulin (bIns), which has A and B chains and contains both inter and intra-chain disulfide bonds, while Ab response to OVA was normal in both GILT-/- and wt B6 mice. GILT-/- APC was able to present bIns to an insulin B chain peptide-specific T hybridoma, although it produced less amounts of IL2, compared to when using B6 APC. IL2 production was MHC-II mediated (could be blocked by α-mouse, but not α-human, MHC-II Ab) and the reduced IL2 production of GILT-/- cells was bIns-specific since GILT-/- APC could not present HEL, another Ag containing disulfide bonds, to an HEL-specific T hybridoma to produce IL2. This data indicates that the T cell response to bIns is only partially affected in GILT-/- mice, which was further supported by the fact that CFSE labeled, in vivo bIns primed, GILT-/- CD4 cells proliferated equally well as wt B6 CD4 cells upon restimulation by bIns. Our data indicates a novel role of GILT in Ab response to insulin.

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Tawancy, H. M. "On the Evolution of Microstructure of Gamma Prime + Gamma Platinum Bond Coats Deposited on Ni-Based Superalloys and Their Oxidation Resistance: Role of Superalloy Substrate." Metallography, Microstructure, and Analysis 6, no. 4 (June 15, 2017): 315–23. http://dx.doi.org/10.1007/s13632-017-0364-7.

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Journal articles on the topic 'Gamma bond'

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