Combinatorial Crystal Synthesis: Structural Landscape of Phloroglucinol:1,2‐bis(4‐pyridyl)ethylene and Phloroglucinol:Phenazine

A large number of crystal forms, polymorphs and pseudopolymorphs, have been isolated in the phloroglucinol‐dipyridylethylene (PGL:DPE) and phloroglucinol‐phenazine (PGL:PHE) systems. An understanding of the intermolecular interactions and synthon preferences in these binary systems enables one to design a ternary molecular solid that consists of PGL, PHE, and DPE, and also others where DPE is replaced by other heterocycles. Clean isolation of these ternary cocrystals demonstrates synthon amplification during crystallization. These results point to the lesser likelihood of polymorphism in multicomponent crystals compared to single‐component crystals. The appearance of several crystal forms during crystallization of a multicomponent system can be viewed as combinatorial crystal synthesis with synthon selection from a solution library. The resulting polymorphs and pseudopolymorphs that are obtained constitute a crystal structure landscape.     

Trypsin Inhibitor from Edible Mushroom Pleurotus floridanus Active against Proteases of Microbial Origin

Protease inhibitors can be versatile tools mainly in the fields of medicine, agriculture and food preservative applications. Fungi have been recognized as sources of protease inhibitors, although there are only few such reports on mushrooms. This work reports the purification and characterization of a trypsin inhibitor from the fruiting body of edible mushroom Pleurotus floridanus (PfTI) and its effect on the activity of microbial proteases. The protease inhibitor was purified up to 35-fold by DEAE-Sepharose ion exchange column, trypsin-Sepharose column and Sephadex G100 column. The isoelectric point of the inhibitor was 4.4, and its molecular mass was calculated as 37 kDa by SDS-PAGE and 38.3 kDa by MALDI-TOF. Inhibitory activity confirmation was by dot-blot analysis and zymographic activity staining. The specificity of the inhibitor toward trypsin was with Ki of 1.043?×?10^?10 M. The inhibitor was thermostable up to 90 °C with maximal stability at 30 °C, active over a pH range of 4–10 against proteases from Aspergillus oryzae, Bacillus licheniformis, Bacillus sp. and Bacillus amyloliquefaciens. Results indicate the possibility of utilization of protease inhibitor from P. floridanus against serine proteases.     

Kinetics and thermoluminescence glow curve study of Ba2MgSi2O7:Eu3+, Dy3+

This paper reports thermoluminescence glow curves of Eu³⁺, Dy³⁺-doped Ba₂MgSi₂O₇ phosphor for different UV exposure times. Kinetic data were evaluated by the peak-shape method. The glow curves shift toward higher intensity with increasing exposure time to UV at 365 nm. When the heating rate was 5 °C s^?1, peaks were observed at 101.76, 109.69, 102.67, and 104.05 °C, respectively, after UV exposure for 5, 10, 15, and 20 min. The glow peaks are indicative of second-order kinetics. Different kinetic data, i.e. trap depth, order of kinetics, activation energy, and frequency factor were also calculated. To evaluate the persistence characteristics of the luminescence of the phosphor, the lifetime of the charge in the trap was calculated; it was 348, 660, 368, and 428 s for UV exposure of 5, 10, 15, and 20 min, which indicates the luminescence of the phosphor is persistent.     

Efficient Chemical Protein Synthesis using Fmoc-Masked N-Terminal Cysteine in Peptide Thioester Segments

We report an operationally simple method to facilitate chemical protein synthesis by fully convergent and one-pot native chemical ligations utilizing the fluorenylmethyloxycarbonyl (Fmoc) moiety as an N-masking group of the N-terminal cysteine of the middle peptide thioester segment(s). The Fmoc group is stable to the harsh oxidative conditions frequently used to generate peptide thioesters from peptide hydrazide or o-aminoanilide. The ready availability of Fmoc-Cys(Trt)-OH, which is routinely used in Fmoc solid-phase peptide synthesis, where the Fmoc group is pre-installed on cysteine residue, minimizes additional steps required for the temporary protection of the N-terminal cysteinyl peptides. The Fmoc group is readily removed after ligation by short exposure (<7 min) to 20 % piperidine at pH 11 in aqueous conditions at room temperature. Subsequent native chemical ligation reactions can be performed in presence of piperidine in the same solution at pH 7.     

Application of Coherent States to Anharmonic,Time-Dependent and Damped Oscillator Systems

The present review deals with coherent states, its application to various problems in physics, chemistry and biology and its important applications to anharmonic, time-dependent and damped oscillator systems. It is seen that use of these states overcomes certain theoretical difficulties.     

Temporal Instability of Acoustic Wave in a Semiconductor Plasma Medium under Momentum Mismatched Condition

Physics of the Solid State - Temporal instability of acoustic wave is investigated in an infinite semiconductor plasma using classical hydrodynamic approach. We consider a homogeneous semiconductor...     

Triazoles as complexing agents: Synthesis and structural studies of some bivalent metal ion complexes with Bi- and tridentate ligands

Summary Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of 4-amino-5-mercapto-3-trifluoromethyl-s-triazole (AMTT) and 5-mercapto-4-salicylideneamino-3-trifluoromethyl-s-triazole (MSTT) have been synthesized and characterized on the basis of elemental analyses, magnetic measurements, infrared and electronic spectral data. The ligandsAMTT andMSTT were characterized by elemental analyses, infrared and¹H NMR spectral studies.AMTT, involving N and S as donor atoms, andMSTT, involving N, O and S as donor atoms, act as bi- and tridentate ligands, respectively. The geometry of the complexes has been assigned on the basis of magnetic and electronic spectral data. EPR parameters for copper (II) complexes have been calculated. Thermal stabilities of the complexes are also reported. Due to insolubility in water and common organic solvents and infusibility at higher temperatures, all the complexes are thought to be polymeric in nature.

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Triazole als Komplexierungs-Agentien: Synthese und Strukturuntersuchungen an einigen bivalenten Metallionenkomplexen mit zwei- und dreizähnigen Liganden

Zusammenfassung Es wurden Co(II)-, Ni(II)-, Cu(II)-, Zn(II)- und Cd(II)-Komplexe von 4-Amino-5-mercapto-3-trifluormethyl-s-triazol (AMTT) und 5-Mercapto-4-salizylidenamino-3-trifluormethyl-s-triazol (MSTT) hergestellt und mittels Elementaranalyse, magnetischen Messungen, Infrarot- und Elektronenspektroskopie charakterisiert. Die LigandenAMTT undMSTT wurden elementaranalytisch und spektroskopisch (IR und¹H-NMR) charakterisiert.AMT wirkt über die N-und S-Donoratome als zweizähniger Ligand,MSTT über N, O und S als dreizähniger Ligand. Die Geometrie der Komplexe wurde auf der Basis von magnetischen und elektronenspektroskopischen Daten zugeordnet. Für die Cu(II)-Komplexe wurden die EPR-Parameter berechnet. Die thermischen Stabilitäten der Komplexe wurde ebenfalls untersucht. Wegen ihrer Unlöslichkeit in Wasser und gängigen organischen Lösungsmitteln und der Unschmelzbarkeit bei höheren Temperaturen wird eine polymere Natur der Komplexe angenommen.

     

Towards CRISPR powered electrochemical sensing for smart diagnostics

Even though global health has been steadily improved, the global disease burden associated with communicable and non-communicable diseases extensively increased healthcare expenditure. The present COVID-19 pandemic scenario has again ascertained the importance of clinical diagnostics as a basis to make life-saving decisions. In this context, there is a need for developing next-generation integrated smart real-time responsive biosensors with high selectivity and sensitivity. The emergence of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas biosensing systems has shown remarkable potential for developing next-generation biosensors. CRISPR/Cas integrated electrochemical biosensors (E-CRISPR) stands out with excellent properties. In this opinionated review, we illustrate the rapidly evolving applications for E-CRISPR-integrated detection systems towards biosensing and the future scope associated with E-CRISPR based diagnostics.     

An estimation of fracture stress in a brittle solid

The present paper reports for the first time an exact analytic expression that can be used for obtaining fracture stress σ_F, when fracture occurs in the elastic limit and also when fracture occurs after general yield (σ_F > σ_Y) in a brittle solid. The present paper may provide a new basis to fracture-safe design of brittle materials.