Application of stable isotope technique to authenticate the geographical origin of imported apple products

Journal of Radioanalytical and Nuclear Chemistry - This research aimed to authenticate the geographical origin of imported fresh apples using isotopic techniques. The results show that the...     

Dissipative and generative fractional electric elements in modeling $${\varvec{RC}}$$ RC and $${\varvec{RL}}$$ RL circuits

Nonlinear Dynamics - Two types of constitutive equations consisting of instantaneous and power type hereditary contributions are proposed in order to model generalized capacitor (inductor). The...     

On the efficacy of charging a battery using a chaotic energy harvester

Nonlinear Dynamics - Introduction of stiffness nonlinearities to broaden the frequency bandwidth of vibratory energy harvesters has the adverse influence of complicating the response behavior of...     

Protein tyrosine phosphatase 1B inhibitors from a marine-derived fungal strain aspergillus sp. SF-5929

Abstract

In the course of our continuing investigation of bioactive secondary metabolites from marine-derived fungal strains, a racemate of a novel diphenolic derivative named (±)-tylopilusin D (1) along with ten previously known secondary metabolites (2–11) were isolated from a marine-derived fungal strain Aspergillus sp. SF-5929. Their structures were elucidated mainly by analysis of NMR and MS data. In addition, the inhibitory effects of the isolated compounds against protein tyrosine phosphatase 1B (PTP1B) activity were evaluated, and compounds 1, 2, and 5–7 inhibited PTP1B activity with IC₅₀ values ranging from 3.3 to 8.1?µM. Kinetics studies suggested that compounds 1, 2, and 5 had noncompetitive inhibitory effects against PTP1B.     

Reinforced Supramolecular Hydrogels from Attapulgite and Cyclodextrin Pseudopolyrotaxane for Sustained Intra‐Articular Drug Delivery

Injectable hydrogels for nonsteroidal anti‐inflammatory drugs’ (NSAIDs) delivery to minimize the side effects of NSAIDs and achieve long‐term sustained release at the targeted site of synovial joint are attractive for osteoarthritis therapy, but how to improve its mechanical strength remains a challenge. In this work, a kind of 1D natural clay mineral material, attapulgite (ATP), is introduced to a classical cyclodextrin pseudopolyrotaxane (PPR) system to form a reinforced supramolecular hydrogel for sustained release of diclofenac sodium (DS) due to its rigid, rod‐like morphology, and unique structure, which has great potential in tissue regeneration, repair, and engineering. Investigation on the interior morphology and rheological property of the obtained hydrogel points out that the ATP distributed in PPR hydrogel plays a role similar to the “reinforcement in concrete” and exhibits a positive effect on improving the mechanical properties of PPR hydrogel by regulating their interior morphology from a randomly distributed style to the well‐ordered porous frame structure. The hybrid hydrogels demonstrate good shear‐thinning and thixotropic properties, excellent biocompability, and sustained release behavior both in vitro and in vivo. Furthermore, preliminary in vivo treatment in an acute inflammatory rat model reveals that the ATP hybrid hydrogels present sustained anti‐inflammatory effect.     

Flocking Dynamics of the Inertial Spin Model with a Multiplicative Communication Weight

In this paper, we study a flocking dynamics of the deterministic inertial spin (IS) model. The IS model was introduced for the collective dynamics of active particles with an internal angular momentum, or spin. When the generalized moment of inertia becomes negligible compared to spin dissipation (overdamped limit) and mutual communication weight is a function of a relative distance between interacting particles, the deterministic inertial spin model formally reduces to the Cucker–Smale (CS) model with constant speed constraint whose emergent dynamics has been extensively studied in the previous literature. We present several sufficient frameworks leading to the asymptotic mono-cluster flocking, in which spins and relative velocities tend to zero asymptotically. We also provide several numerical simulations for the decoupled and coupled inertial spin models to see the effect of the C–S velocity flocking and compare them with our analytical results.

     

Acetyl Methyl Torsion in N‐Ethylacetamide: A Challenge for Microwave Spectroscopy and Quantum Chemistry

The gas‐phase structures and parameters describing acetyl methyl torsion of N‐ethylacetamide are determined with high accuracy, using a combination of molecular beam Fourier‐transform microwave spectroscopy and quantum chemical calculations. Conformational studies at the MP2 level of theory yield four minima on the energy surface. The most energetically favorable conformer, which possesses C₁ symmetry, is assigned. Due to the torsional barrier of 73.4782(1) cm^?1 of the acetyl methyl group, fine splitting up to 4.9 GHz is found in the spectrum. The conformational structure is not only confirmed by the rotational constants, but also by the orientation of the internal rotor. The ¹⁴N quadrupole hyperfine splittings are analyzed and the deduced coupling constants are compared with the calculated values.     

Trichosanthes kirilowii ameliorates cisplatin-induced nephrotoxicity in both in vitro and in vivo

The aim of this study was to explore the protective effects of Trichosanthes kirilowii ethanol extract (TKE) against cisplatin-induced acute renal failure (ARF). In the in vitro study, TKE-pretreated porcine kidney cells (PK15) exhibited enhanced cell viability after cisplatin (15 μg mL^? 1) treatment in both MTT and crystal violet assays. PK15 cells pretreated with TKE (50 μg mL^? 1) exhibited increased glutathione content, decreased reactive oxygen species production and ameliorated p53 expression. In vivo study, rats were administered with TKE for 4 weeks before cisplatin (5 mg kg^? 1) injection. TKE (100 mg kg^? 1) decreased blood urea nitrogen and creatinine levels by 24% and 47%, respectively, in comparison with cisplatin-alone group. In addition, TKE pretreatment ameliorated cisplatin-induced oxidative stress, as evidenced by increased antioxidative enzyme levels and decreased lipid peroxidation levels. Moreover, TKE pretreatment reduced histopathological alterations in the kidney with decreased apoptotic cells. Taken together, TKE might be beneficial in treating cisplatin-induced ARF.     

Diversity‐Oriented Approach for Chemical Biology

Synthetic molecules that modulate and probe biological events are critical tools in chemical biology. Utilizing combinatorial and diversity‐oriented synthetic strategies, access to large numbers of small molecules is becoming more and more feasible, and research groups in this field can take advantage of the power of chemical diversity. Since the majority of early studies were focused on the discovery of compounds that perturb protein functions, diversity‐based approaches are often considered as therapeutic lead discovery tactics. However, the diversity‐oriented approach can also be applied to advance distinct aims, such as target protein identification, or the development of imaging probes and sensors. This review provides a personal perspective of the chemical‐diversity‐based approach and how this principle can be adapted to various chemical biology studies.