Binding interaction between (−)-epigallocatechin-3-gallate (EGCG) of green tea and pepsin

Analysis of the binding interaction of (−)-epigallocatechin-3-gallate (EGCG) and pepsin is important for understanding the inhibition of digestive enzymes by tea polyphenols. We studied the binding of EGCG to pepsin using fluorescence spectroscopy, Fourier transform infrared spectroscopy, isothermal titration calorimetry, and protein-ligand docking. We found that EGCG could inhibit pepsin activity. According to thermodynamic parameters, a negative ΔG indicated that the interaction between EGCG and pepsin was spontaneous, and the electrostatic force accompanied by hydrophobic binding forces may play major role in the binding. Data from multi-spectroscopy and docking studies suggest that EGCG could bind pepsin with a change in the native conformation of pepsin. Our results provide further understanding of the nature of the binding interactions between catechins and digestive enzymes

Multi-neutron transfer coupling in sub-barrier 32S+90,96Zr fusion reactions

The role of neutron transfers is investigated in the fusion process below the Coulomb barrier by analyzing 32S+90Zr and 32S+96Zr as benchmark reactions. A full coupled-channel calculation of the fusion excitation functions has been performed for both systems by using multi-neutron transfer coupling for the more neutron-rich reaction. The enhancement of fusion cross sections for 32S+96Zr is well reproduced at sub-barrier energies by NTFus code calculations including the coupling of the neutron-transfer channels following the Zagrebaev semiclassical model. We found similar effects for 40Ca+90Zr and 40Ca+96Zr fusion excitation functions.Comment: Minor corrections, 11 pages, 4 figures, Fusion11 Conference, Saint Malo, France, 2-6 mai 201

Construction and Verification of the Constitutive Model of Pure Copper Deformation at Elevated Temperatures

The deformation behavior of pure copper was studied in hot compression tests in the temperature range of 773–1173 K and strain rate interval of 0.001–1.0 s⁻¹, the corresponding flow stress curves were plotted. The new method to calculate critical and saturation stresses was devised, quantitative analysis of strain hardening and dynamic softening was presented, a three-stage constitutive model was constructed to predict the flow stress of pure copper. As predicted and measured flow stress comparison indicate, the physical constitutive model can accurately characterize hot deformation of pure copper. With dynamic recovery and/or recrystallization. Numerical simulation of an upsetting process is carried out by implementing the constitutive model into commercial software. This model can be put to practical use and be quite promising for improving efficiency of a hot forging process for pure copper components.Изучено деформационное поведение чистой меди при испытании горячих проб на сжатие в диапазоне температур 773 1173 К и скорости деформации 0.001–1.0 с⁻¹, построены соответствующие кривые напряжения пластического течения. Разработан новый метод расчета критического напряжения и напряжения насыщения, представлен количественный анализ деформационного упрочнения и динамического разупрочнения, построена трехступенчатая определяющая модель прогнозирования напряжения пластического течения чистой меди. Как показывает сравнение прогнозируемого и измеренного напряжений пластического течения, с помощью такой модели можно точно описать горячее деформирование чистой меди при динамическом возврате и/или рекристаллизации. Выполнено численное моделирование процесса высадки путем реализации данной модели в рамках коммерческого программного обеспечения. Модель весьма перспективна и может использоваться для повышения эффективности процесса горячей ковки деталей из чистой меди.Вивчено деформаційне поведінку чистої міді при випробуванні гарячих проб на стиск в діапазоні температур 773-1173 К і швидкості деформації 0.001–1.0 с⁻¹, побудовані відповідні криві напружень пластичної течії. Розроблено новий метод розрахунку критичної напруги і напруги насичення, представлений кількісний аналіз деформаційного зміцнення і динамічного знеміцнення, побудована триступенева визначає модель прогнозування напружень пластичної течії чистої міді. Як показує порівняння прогнозованого і виміряного напружень пластичної течії, за допомогою такої моделі можна точно описати гаряче деформування чистої міді при динамічному поверненні і / або рекристалізації. Виконано чисельне моделювання процесу висадки шляхом реалізації даної моделі в рамках комерційного програмного забезпечення. Модель вельми перспективна і може використовуватися для підвищення ефективності процесу гарячого кування деталей з чистої міді

A self-consistent method to analyze the effects of the positive Q-value neutron transfers on fusion

AbstractConsidering the present limitation of the need for external parameters to describe the nucleus–nucleus potential and the couplings in the coupled-channels calculations, this work introduces an improved method without adjustable parameter to overcome the limitation and then sort out the positive Q-value neutron transfers (PQNT) effects based on the CCFULL calculations. The corresponding analysis for Ca+Ca, S,Ca+Sn, and S,Ca+Zr provides a reliable proof and a quantitative evaluation for the residual enhancement (RE) related to PQNT. In addition, the RE for S32,Ca40+Zr94 shows an unexpected larger enhancement than S32,Ca40+Zr96 despite the similar multi-neutron transfer Q-values. This method should rather strictly test the fusion models and be helpful for excavating the underlying physics

eEF2K enhances expression of PD-L1 by promoting the translation of its mRNA

Emerging advances in cancer therapy have transformed the landscape towards cancer immunotherapy regimens. Recent discoveries have resulted in the development of clinical immune checkpoint inhibitors that are 'game-changers' for cancer immunotherapy. Here we show that eEF2K, an atypical protein kinase that negatively modulates the elongation stage of protein synthesis, promotes the synthesis of PD-L1, an immune checkpoint protein which helps cancer cells to escape from immunosurveillance. Ablation of eEF2K in prostate and lung cancer cells markedly reduced the expression levels of the PD-L1 protein. We show that eEF2K promotes the association of PD-L1 mRNAs with translationally active polyribosomes and that translation of the PD-L1 mRNA is regulated by a uORF (upstream open reading-frame) within its 5'-UTR (5'-untranslated region) which starts with a non-canonical CUG as the initiation codon. This inhibitory effect is attenuated by eEF2K thereby allowing higher levels of translation of the PD-L1 coding region and enhanced expression of the PD-L1 protein. Moreover, eEF2K-depleted cancer cells are more vulnerable to immune attack by natural killer cells. Therefore, control of translation elongation can modulate the translation of this specific mRNA, one which contains an uORF that starts with CUG, and perhaps others that contain a similar feature. Taken together, our data reveal that eEF2K regulates PD-L1 expression at the level of the translation of its mRNA by virtue of a uORF in its 5'-region. This, and other roles of eEF2K in cancer cell biology (e.g., in cell survival and migration), may be exploited for the design of future therapeutic strategies.Yu Wu, Jianling Xie, Xin Jin, Roman V. Lenchine, Xuemin Wang, Danielle M. Fang ... et al

The σ\sigma pole in J/ψ→ωπ+π−J/\psi \to \omega \pi^+ \pi^-

Using a sample of 58 million $J/\psi$ events recorded in the BESII detector, the decay $J/\psi \to \omega \pi^+ \pi^-$ is studied. There are conspicuous $\omega f_2(1270)$ and $b_1(1235)\pi$ signals. At low $\pi \pi$ mass, a large broad peak due to the $\sigma$ is observed, and its pole position is determined to be $(541 \pm 39)$ - $i$ $(252 \pm 42)$ MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

Direct Measurements of the Branching Fractions for D0→K−e+νeD^0 \to K^-e^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

The absolute branching fractions for the decays $D^0 \to K^-e ^+\nu_e$ and $D^0 \to \pi^-e^+\nu_e$ are determined using $7584\pm 198 \pm 341$ singly tagged $\bar D^0$ sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged $\bar D^0$ meson, $104.0\pm 10.9$ events for $D^0 \to K^-e ^+\nu_e$ and $9.0 \pm 3.6$ events for $D^0 \to \pi^-e^+\nu_e$ decays are observed. Those yield the absolute branching fractions to be $BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)$ and $BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)$. The vector form factors are determined to be $|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03$ and $|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06$. The ratio of the two form factors is measured to be $|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07$.Comment: 6 pages, 5 figure

Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure