Unveiling the Potential of Diffraction Gratings for Precision Separation of Higher-Harmonics in Non-Linear Acoustics.

Diffraction gratings, with their periodically ordered structures, have been critical components in acoustics, optics, and spectroscopy for over a century. The classical grating equation describes the emergence of diffraction phenomena by gratings, considering the groove periodicity and the characteristics of the incident wave. These gratings find extensive applications in communication, spectroscopy, architectural acoustics, and underwater research, and they are foundational to pioneering investigations in Phononic Crystals and Meta-materials. While much attention has been given to understanding the diffraction behavior of linear acoustics concerning gratings, the literature lacks research regarding the influence of high-amplitude ultrasonic waves, which introduce observable non-linear effects. This experimental inquiry presents a pioneering methodology for isolating higher harmonics from these non-linear phenomena. We have developed a spatial filtering apparatus with a single-frequency transducer and a specially designed grating profile, enabling precise frequency selection or rejection.

Ultrasonic examination of a thin, textured metal plate with Penrose tile structure consisting of pitched indentations.

A feasibility study is presented on the experimental application of ultrasound to examine rolled stainless steel plates having equidistant surface textures in two directions in the form of Penrose tiles. The specific problem of interest is investigating surface profile quality in terms of its equidistance and depth to monitor the manufacturing process. The goal is to eventually replace current time-consuming optical examination procedures with a reliable and rapid ultrasonic inspection technique. Two practical experimental setups are discussed and compared in this work: examining frequency spectra obtained from normal incidence pulse-echo measurements, and those obtained at Laue angle incidence. A thorough survey of ultrasonic methods precedes the experimental results to investigate such surfaces from a historical perspective.

Thiourea-Mediated Halogenation of Alcohols.

The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.

Oxidative C-C bond formation and C-N bond cleavage catalyzed by complexes of copper(i) with acridine based (E N E) pincers (E = S/Se), recyclable as a catalyst.

Copper(i) complexes of 4,5-bis((phenylthio/seleno)methyl)acridine, [CuLBr] (C1 and C2) (L = L1/L2; pincer type (E N E) ligand), were synthesized and found to be thermally stable, and moisture and air insensitive. The complexes and ligands were characterized by multinuclei NMR and single crystal X-ray diffraction. In both complexes C1 and C2, ligands L1 and L2 coordinate with Cu in a pincer mode furnishing two six-membered chelate rings, with the distorted tetrahedral geometry of donor atoms around Cu. The Cu-S and Cu-Se bond lengths (Å) are 2.2482(17)-2.2979(16) and 2.3603(14)-2.4177(13) respectively. These complexes served as efficient catalysts for cross dehydrogenative coupling of unactivated tertiary amines with unactivated terminal alkynes, and cleavage of the benzylic (C-N) bond of N,N dimethylbenzylamines under oxidative solvent-free conditions. The reactions were found to be highly selective, and no over-oxidation to acid was observed. A low catalytic loading of 1.0 mol% was good enough to bring about both these transformations with recyclability up to five times.

GO-Cu7S4 catalyzed ortho-aminomethylation of phenol derivatives with N,N-dimethylbenzylamines: site-selective oxidative CDC.

Copper chalcogenide nanoparticles (Cu7S4) supported on graphene oxide (GO) have been synthesized for the first time from Cu2S, and used as highly efficient heterogeneous catalysts for oxidative ortho-selective C-H aminomethylation of phenols with N,N-dimethylbenzylamines. The NPs (30-80 nm) have been characterized by HRTEM, SEM-EDX, PXRD, FTIR, Raman, ICP-AES and XPS analyses. The NP catalyzed sp2-sp3 cross dehydrogenative coupling (CDC) features a broad substrate scope, excellent functional group tolerance, high yields, use of an inexpensive and reusable copper catalyst, mild conditions, and no need for pre-functionalization of substrates.

Base free N-alkylation of anilines with ArCH2OH and transfer hydrogenation of aldehydes/ketones catalyzed by the complexes of η5-Cp*Ir(iii) with chalcogenated Schiff bases of anthracene-9-carbaldehyde.

The condensation of anthracene-9-carbaldehyde with 2-(phenylthio/seleno)ethylamine results in Schiff bases [PhS(CH2)2C[double bond, length as m-dash]N-9-C14H9](L1) and [PhSe(CH2)2C[double bond, length as m-dash]N-9-C14H9] (L2). On their reaction with [(η5-Cp*)IrCl(µ-Cl)]2 and CH3COONa at 50 °C followed by treatment with NH4PF6, iridacycles, [(η5-Cp*)Ir(L-H)][PF6] (1: L = L1; 2: L = L2), result. The same reaction in the absence of CH3COONa gives complexes [(η5-Cp*)Ir(L)Cl][PF6] (3-4) in which L = L1(3)/L2(4) ligates in a bidentate mode. The ligands and complexes were authenticated with HR-MS and NMR spectra [1H, 13C{1H} and 77Se{1H} (in the case of L2 and its complexes only)]. Single crystal structures of L2 and half sandwich complexes 1-4 were established with X-ray crystallography. Three coordination sites of Ir in each complex are covered with η5-Cp* and on the remaining three, donor atoms present are: N, S/Se and C-/Cl-, resulting in a piano-stool structure. The moisture and air insensitive 1-4 act as efficient catalysts under mild conditions for base free N-alkylation of amines with benzyl alcohols and transfer hydrogenation (TH) of aldehydes/ketones. The optimum loading of 1-4 as a catalyst is 0.1-0.5 mol% for both the activations. The best reaction temperature is 80 °C for transfer hydrogenation and 100 °C for N-alkylation. The mercury poisoning test supports a homogeneous pathway for both the reactions catalyzed by 1-4. The two catalytic processes are most efficient with 3 followed by 4 > 1 > 2. The mechanism proposed on the basis of HR-MS of the reaction mixtures of the two catalytic processes taken after 1-2 h involves the formation of an alkoxy and hydrido species. The real catalytic species proposed in the case of iridacycles results due to the loss of the Cp* ring.

Trinuclear complexes of palladium(ii) with chalcogenated N-heterocyclic carbenes: catalysis of selective nitrile-primary amide interconversion and Sonogashira coupling.

3-Methyl-1-(2-(phenylthio/seleno)ethyl)-1H-benzo[d]imidazol-3-ium iodide (L1/L2), a precursor of sulfated/selenated N-heterocyclic carbene, was synthesized by the reaction of benzimidazole with 1,2-dichloroethane followed by treatment with PhS/SeNa and MeI. The reaction of L1/L2 with Ag2O followed by treatment with [Pd(CH3CN)2Cl2] (metal to ligand ratio 3 : 2), i.e. transmetallation, resulted in trinuclear palladium(ii) complexes [Pd3(L1/L2-HI)2(CH3CN)Cl6] (1-2). The complexes were characterized with 1H, 13C{1H} and 77Se{1H} NMR (2 only), elemental analyses, HR-MS and single-crystal X-ray diffraction. The geometry of three Pd atoms in each complex is nearly square planar. The Pd-S/Se, Pd-C, Pd-N and Pd-Cl bond distances (Å) in 1/2 are 2.3179(19)/2.4312(10), 1.968(7)/1.952(4), 2.073(8)/2.079(4) and 2.2784(19)-2.298(2)/2.292(2)-2.3003(15), respectively. In both the complexes, all Cl are trans to each other. For the central Pd atom, two benzimidazole rings are also trans to each other. The C-HCl non-covalent interactions result in a three-dimensional network. The moisture and air insensitive trinuclear Pd(ii) complexes 1 and 2 are thermally stable and efficient as a catalyst for nitrile-amide interconversion and amine-free Sonogashira C-C coupling (in the presence of CuI). The optimum temperature is 80 °C for the interconversion and 110 °C for the coupling. The catalytic protocols are applicable to both aliphatic and aromatic amides/nitriles. The optimum catalyst loading is 1 mol% for the C-C coupling and 0.5 to 1 mol% for the interconversion. K2CO3 as a base gives the best result for Sonogashira C-C coupling. In the conversion of nitriles to amides, the formation of an acid was not detected. After using once, 1/2 can carry out the conversion of ten fresh lots of nitriles to amides with almost the same efficiency. The real catalytic species for the interconversion and coupling appear to be based on Pd(ii) and Pd(0), respectively.

Identification and molecular characterization of border disease virus (BDV) from sheep in India.

Pestiviruses isolated from sheep and goats in India thus far have been bovine viral diarrhoea virus 1 (BVDV-1) or BVDV-2. During routine genetic typing of pestiviruses in the years 2009-10, border disease virus (BDV) was detected in eight Indian sheep of a flock showing clinical signs of BD by real time RT-PCR. All the samples yielded positive virus isolates in cell culture but were found negative by a BVDV antigen ELISA. A representative BDV isolate was characterized at genetic and antigenic level. Phylogenetic analysis carried out in 5'-UTR, N(pro) and E2 regions of genome typed the Indian BDV isolate as BDV-3. A more detailed analysis in N(pro) and entire region coding structural proteins showed that the N(pro) (168), C (100 aa), E(rns) (227 aa), E1 (195 aa) and E2 (373 aa) proteins were of size characteristic for BDV reference strain X818. Antigenic differences were evident between the BDV-3 isolate and previously reported BDV-1, BDV-5 and BDV-7 strains. Although origin of BDV-3 in India is not clear, the results reflect probable introduction through trade in sheep between India and other countries or BDV-3 may be more widely distributed. Additionally, this study suggests that for diagnosis of BDV infection, the commercial BVDV Ag-ELISA should be used with caution. This is the first identification of BDV in sheep in India which highlights the need for continued pestivirus surveillance and assessing its impact on sheep and goat production.

In vitro and in vivo evaluation of PEGylated nanoparticles of bendamustine for treatment of lung cancer.

The purpose of this study was to develop PEGylated nanoparticles of bendamustine (BM) to improve therapeutic efficiency of drug and reduce the side-effects. The nanoparticles were prepared by a modified diffusion-emulsification method. The particle size and zeta potential of optimized BM-loaded PEGylated NPs were found to be 256 nm and -29.1 mV. The in vitro release showed biphasic behavior, with initial burst release followed by slow sustained delivery. The anti-tumor activity was determined using the A- 549 cell line, by the MTT assay. The stability study revealed that the nanoparticles prepared were stable for 3 months at both 25°C and 4°C.

Development of a RT-PCR ELISA for simultaneous detection of BVDV-1, BVDV-2 and BDV in ruminants and its evaluation on clinical samples.

The aim of this study was to develop a reverse transcription polymerase chain reaction ELISA (RT-PCR ELISA) for detection of ruminant pestiviruses and to evaluate its diagnostic performance on clinical samples obtained from cattle, sheep and goats. Optimization was carried out by serial dilution of home-made digoxygenin-labelled RT-PCR product standards obtained from pestivirus isolates and pestivirus infected animals. The detection limit of the assay was 10TCID50/ml, similar to virus isolation and real-time RT-PCR but 10-fold higher than RT-PCR. The assay had high analytical specificity along with a good reproducibility. When the assay was evaluated on the samples obtained from animals infected experimentally with BVDV and from the field using virus isolation as standard, it showed a high diagnostic sensitivity (95.9%) and specificity (98.6%) and there was strong agreement (97.5% concordance) between the two tests. However, it displayed an increased diagnostic specificity and sensitivity over RT-PCR. Additionally, when a few samples (n=26) were tested by RT-PCR ELISA and real-time RT-PCR, 100% concordance was obtained between them. Our results showed that RT-PCR ELISA can be a rapid, cost effective and alternative molecular diagnostic test for simultaneous detection of BVDV-1, BVDV-2 and BDV in ruminants in ordinary laboratory settings.

Ceramic nanocarriers: versatile nanosystem for protein and peptide delivery.

INTRODUCTION: Proteins and peptides have been established to be the potential drug candidate for various human diseases. But, delivery of these therapeutic protein and peptides is still a challenge due to their several unfavorable properties. Nanotechnology is expanding as a promising tool for the efficient delivery of proteins and peptides. Among numerous nano-based carriers, ceramic nanoparticles have proven themselves as a unique carrier for protein and peptide delivery as they provide a more stable, bioavailable, readily manufacturable, and acceptable proteins and polypeptide formulation. AREAS COVERED: This article provides an overview of the various aspects of ceramic nanoparticles including their classification, methods of preparation, latest advances, and applications as protein and peptide delivery carriers. EXPERT OPINION: Ceramic nanocarriers seem to have potential for preserving structural integrity of proteins and peptides, thereby promoting a better therapeutic effect. This approach thus provides pharmaceutical scientists with a new hope for the delivery of proteins and peptides. Still, considerable study on ceramic nanocarrier is necessary with respect to pharmacokinetics, toxicology, and animal studies to confirm their efficiency as well as safety and to establish their clinical usefulness and scale-up to industrial level.

Phylogenetic analysis of recent classical swine fever virus (CSFV) isolates from Assam, India.

Classical swine fever (CSF), a highly contagious viral disease of pigs, is endemic in India. As there is no information concerning the accurate genetic typing of classical swine fever virus (CSFV) isolates in India, 16 CSF viruses isolated during 2005-2007 from domestic pigs in different districts of Assam were typed in 5' UTR (150 nucleotides). To confirm the genetic typing results and to study the genetic variability, selected viruses were also analyzed in E2 (190 nt) and NS5B gene (409 nt) regions. Phylogenetic analysis revealed that all the 16 CSFV isolates analyzed belonged to group 1 and subgroup 1.1 in contrast to the situation in other Asian countries. Additionally, analysis in E2 and NS5B region placed the Indian isolates in a clearly separated clade within subgroup 1.1. The results suggest that subgroup 1.1 CSF viruses are currently circulating in India, which is important for epidemiology and control of CSF.