Interfacial-interaction induced modifications in segmental dynamics and free volume of the poly(ethyleneimine) canopy in nanoparticle-organic hybrid materials: an investigation by temperature dependent broadband dielectric and positron annihilation spectroscopy.

Broadband dielectric spectroscopy, positron annihilation lifetime spectroscopy and differential scanning calorimetry are used to investigate the molecular dynamics, free volume and thermal behaviour of a poly(ethyleneimine), PEI, canopy in liquid-like nanoparticle-organic hybrid materials (NOHMs) consisting of alumina nanoparticles and nanorods as inorganic nanocores. It is confirmed that the highly branched PEI canopy in liquid-like NOHMs possesses an ordered structure having less entanglements of the side chains as compared to neat PEI. The size of the free volumes associated with the PEI canopy for nanoparticle- and nanorod-based NOHMs is larger and smaller, respectively, as compared to neat PEI. The time scales characterizing the segmental dynamics and side chain relaxations of the canopy in the nanorod-based NOHM are slowed down drastically as compared to the nanoparticle-based NOHM and neat PEI. These results confirm that the shape of the inorganic cores plays a deterministic role toward the structural arrangement (free volume) and segmental dynamics of the canopy polymer in liquid-like NOHMs.

Capture of Volatile Iodine Gas and Identification of Adsorption Sites in the Pore Network of Unsubstituted Imidazole Linker-Incorporated Zeolitic Imidazolate Framework-8.

The incorporation of unsubstituted imidazole (Im) in zeolitic imidazolate framework-8 (ZIF-8) crystallized in sodalite topology is proposed to improve gas capture and gas separation performance drastically. However, the incorporation of unsubstituted Im in ZIF-8 has remained challenging due to the thermodynamic instability of zinc and Im bonding in sodalite topology. We have incorporated up to 24.4 (mol %) Im linker in highly crystalline ZIF-8 with similar morphology and sodalite topology using a delayed linker addition strategy at room temperature. Im incorporation brings significant tuning to the pore architecture of ZIF-8, as confirmed by positron annihilation lifetime spectroscopy. The modifications in the pore architecture are primarily due to linker defects produced in the frameworks during crystallization and the elimination of steric hindrance due to the absence of a methyl group on Im. The Im-incorporated ZIF-8 shows significant enhancement in iodine capture as well as higher crystal structure stability under iodine vapor exposure as compared to pristine ZIF-8. Through ortho-positronium interaction with the adsorbed molecular iodine in the pore network of the frameworks, it is confirmed that iodine is preferentially adsorbed at cavity and intercrystalline voids, whereas aperture sites remain unoccupied by iodine molecules.

Corrigendum: Serological and molecular prevalence of Brucella spp. among livestock species in Rajasthan, India.

[This corrects the article DOI: 10.3389/fvets.2023.1157211.].

Bimetallic Zeolitic Imidazole Frameworks for Improved Stability and Performance of Intrusion-Extrusion Energy Applications.

Hydrophobic flexible zeolitic imidazole frameworks (ZIFs) represent reference microporous materials in the area of mechanical energy storage, conversion, and dissipation via non-wetting liquid intrusion-extrusion cycle. However, some of them exhibit drawbacks such as lack of stability, high intrusion pressure, or low intrusion volume that make them non-ideal materials to consider as candidates for real applications. In this work, we face these limitations by exploiting the hybrid ZIF concept. Concretely, a bimetallic SOD-like ZIF consisting of Co and Zn ions was synthesized and compared with Co-ZIF (ZIF-67) and Zn-ZIF (ZIF-8) showing for the first time that the hybrid ZIF combines the good stability of ZIF-8 with the higher water intrusion volume of ZIF-67. Moreover, it is shown that the hybrid-ZIF approach can be used to tune the intrusion/extrusion pressure, which is crucial for technological applications.

Serological and molecular prevalence of Brucella spp. among livestock species in Rajasthan, India.

A seroprevalence and molecular study was carried out in six districts of the state of Rajasthan, India to detect brucellosis in major livestock species. This study involves the testing of 3,245 livestock samples using the Rose Bengal Plate Test (RBPT), Indirect Enzyme-Linked Immunosorbent Assay (i-ELISA), and genus-specific polymerase chain reaction (PCR) markers for molecular diagnosis of the disease. In the tested samples, seroprevalence was 5.06% (CI: 1.96-8.15) using the RBPT test and 6.88% (CI: 1.98-11.78) using the i-ELISA test, while the cumulative seroprevalence (RBPT and i-ELISA) was 3.63% (CI: 0.44-6.83). The prevalence of the disease was 1.27% (CI: 0.56-3.11) when tested using molecular markers. The highest prevalence of brucellosis was detected in Cattle (7.00, 3.22%), followed by camels (5.50, 2.50%), buffalo (2.66, 0.00%), sheep (2.43, 0.41%), and goats (0.58, 0.23%) when serological (cumulative) and molecular diagnosis were considered preferred methods of detection. Cattle (3.22%) and camels (2.50%) also showed a high prevalence of disease when tested using molecular markers. The results of this study reveal that cattle, camel, and sheep brucellosis is prevalent in the study areas.

Fine-Tuning of the Pore Aperture and Framework Flexibility of Mixed-Metal (Zn/Co) Zeolitic Imidazolate Framework-8: An In Situ Positron Annihilation Lifetime Spectroscopy Study under CO2 Gas Pressure.

The mixed-metal (Zn/Co) strategy has been used to enhance the gas separation selectivity of zeolitic imidazolate framework-8 (ZIF-8)-based membranes. The enhancement in selectivity has been attributed to possible modifications in the grain boundary structure, pore architecture, and flexibility of the frameworks. In the present study, we used in situ positron annihilation lifetime spectroscopy (PALS) under varying CO2 pressure to investigate the tuning of the pore architecture and framework flexibility of mixed-metal (Zn/Co) ZIF-8 frameworks with varying Co contents. The random distribution of Zn and Co metal nodes within the highly crystalline frameworks having an SOD topology was established using electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The inherent aperture as well as cavity size of the frameworks, and the pore interconnectivity to the outer surface, were observed to vary with the Co content in ZIF-8 due to the random distribution of Zn and Co metal nodes in the frameworks. The aperture size is reduced with the incorporation of an additional metal (Zn or Co) in ZIF-67 or ZIF-8, respectively. The aperture size remains the smallest for a lower Co content (∼0.20) in ZIF-8. The framework flexibility determined by in situ PALS measurements under CO2 pressure continuously reduces with increasing Co content in ZIF-8. A smaller aperture size as well as low flexibility of ZIF-8 with a low Co content is seen to be directly correlated to a higher separation selectivity of membranes prepared with this mixed-metal composition.

Flexibility of Mixed Ligand Zeolitic Imidazolate Frameworks (ZIF-7-8) under CO2 Pressure: An Investigation Using Positron Annihilation Lifetime Spectroscopy.

Fine tuning of the pore architecture and flexibility of zeolitic imidazolate frameworks (ZIFs) is highly crucial for realizing their applications in molecular gas separation. Mixed ligand frameworks (ZIF-7-8) synthesized by mixing 2-methylimidazole (2meIm) and benzimidazole (bIm) ligands show enhanced gas separation performance, attributable to pore and flexibility tuning. In the present study, positron annihilation lifetime spectroscopy (PALS) measurements under CO2 pressure have been used to experimentally investigate the tuning of the pore architecture and flexibility of mixed ligand frameworks ZIF-7-8 having a ZIF-8 structure and similar morphology with varying bIm content up to 18.2%. The aperture and cavity of frameworks begin to open up with an increasing bIm ligand content followed by a decrease at a higher content. On the contrary, flexibility of the frameworks indexed from PALS measurements carried out under CO2 pressure shows a decreasing trend followed by an increase. The present study shows that mixed ligand frameworks having a larger aperture size are less flexible as a result of inherent open configurations of ligands in the framework lattice. On the other hand, frameworks having a comparatively smaller aperture size show higher flexibility as a result of a possibility of twisting of the ligands under CO2 pressure, resulting in aperture opening. The pore-opening phenomenon as a result of lattice flexibility under CO2 pressure is observed to be fully reversible for ZIF-7-8.

Developments in the Catalytic Asymmetric Synthesis of Agrochemicals and Their Synthetic Importance.

Catalytic asymmetric synthesis has become an essential tool for the enantioselective synthesis of pharmaceuticals, natural products, and agrochemicals (mainly fungicides, herbicides, insecticides, and pheromones). With continuous growing interest in both modern agricultural chemistry and catalytic asymmetric synthesis chemistry, this review provides a comprehensive overview of some earlier reports as well as the recent successful applications of various catalytic asymmetric syntheses methodologies, such as enantioselective hydroformylation, enantioselective hydrogenation, asymmetric Sharpless epoxidation and dihydroxylation, asymmetric cyclopropanation or isomerization, organocatalyzed asymmetric synthesis, and so forth, which have been used as key steps in the preparation of chiral agrochemicals (on R&D, piloting, and commercial scales). Chiral agrochemicals can also lead the new generation of such chemicals having specific and novel modes of action for achieving sustainable crop protection and production. Some perspectives and challenges for these catalytic asymmetric methodologies in the synthesis of chiral agrochemicals are also briefly discussed in the final section of the manuscript. This review will provide the insight regarding understanding, development, and evaluation of catalytic asymmetric systems for the synthesis of chiral agrochemicals among the agrochemists.

Sensitive impedimetric detection of troponin I with metal-organic framework composite electrode.

Metal-organic frameworks (MOFs) are promising materials for biosensing applications due to their large surface to volume ratio, easy assembly as thin films, and better biocompatibility than other nanomaterials. Their application in electrochemical biosensing devices can be realized by integrating them with other conducting materials, like polyaniline (PANI). In the present research, a composite of a copper-MOF (i.e., Cu3(BTC)2) with PANI has been explored to develop an impedimetric sensor for cardiac marker troponin I (cTnI). The solvothermally synthesized Cu3(BTC)2/PANI composite has been coated as a thin layer on the screen-printed carbon electrodes (SPE). This electroconductive thin film was conjugated with anti-cTnI antibodies. The above formed immunosensor has allowed the impedimetric detection of cTnI antigen over a clinically important concentration range of 1-400 ng mL-1. The whole process of antigen analysis could be completed within 5 min. The detection method was specific to cTnI even in the co-presence of other possibly interfering proteins.

Effects of Lycopene and Sodium Valproate on Pentylenetetrazol-Induced Kindling in Mice.

Sodium valproate and tomato extract have been studied in different experimental models of epilepsy individually. The aim of the present study was to evaluate the effect of lycopene on the antiepileptic effects of sodium valproate against pentylenetetrazol-induced kindling in mice. Swiss albino mice of either sex were randomly divided into 5 groups, with each group containing 8 mice. These groups were treated with pentylenetetrazol (45 mg/kg on days 8, 10, and 12 and 70 mg/kg on day 14 day, i.p.); sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; lycopene (2 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; and lycopene (4 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol, for 14 days, respectively. After treatment, the animals were observed for 30 minutes for behavioral analysis. Subsequently, the animals were sacrificed, and their brain was removed for the biochemical estimations of thiobarbituric acid reactive substances, catalase, superoxide dismutase activity, reduced glutathione, and gamma-aminobutyric acid. Significant pentylenetetrazol-induced seizure was characterized by alteration in the seizure score and latency as well as a significant increase in the levels of brain thiobarbituric acid reactive substances and a significant decrease in reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels. Treatment with sodium valproate and lycopene significantly restored the seizure score, latency, thiobarbituric acid reactive substance, reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels near to normal compared to pentylenetetrazol. The present study provides experimental evidence that a combination therapy of lycopene along with sodium valproate attenuated seizure and oxidative stress against pentylenetetrazol-induced kindling in mice.

Polymorphism in spa gene of Staphylococcus aureus from bovine subclinical mastitis.

AIM: The virulence-associated protein-A of Staphylococcus aureus, encoded by spa gene shows a variation in length in different strains. In this study, the spa gene variation in S. aureus strains was studied which were isolated from subclinical cases of bovine mastitis. MATERIALS AND METHODS: About 38 isolatesof S. aureus were recovered from Holstein-Friesian (HF) crossbred (n=16) and Rathi cattle (n=22) with subclinical mastitis as per standard procedures, and these isolates were subjected to amplification of spa gene (X-region) by polymerase chain reaction and calculation of number of tandem repeats were done. RESULTS: Of the 16 isolates from H-F crossbred cattle, all with the exception of one isolate produced spa amplicon. Seven isolates produced amplicons of 200 bp, one produced 160 bp, and other seven produced spa amplicon of 150 bp with calculated number of 6, 5, and 4 repeats, respectively, whereas nine different types of amplicons were produced by 22 S. aureus isolates from Rathi cattle, viz., 280, 250, 240, 200, 190, 180, 170, 150, and 140 bp with 10, 8, 8, 6, 6, 6, 5, 4, and 4 repeats, respectively. One of the isolates from Rathi cattle produced two spa amplicons (150 and 190 bp). CONCLUSION: A greater polymorphism was observed in the S. aureus isolates from Rathi cattle than from H-F crossbreds with subclinical mastitis.

Typing of Staphylococcus aureus obtained from mastitic milk of cattle and buffalo on the basis of two virulence-associated genes (spa and clfA).

AIM: The present study was undertaken to type Staphylococcus aureus isolates from cattle and buffalo mastitic milk on the basis of spa (X-region) and clfA genes, both responsible for producing virulence factors. MATERIAL AND METHODS: In the present investigation S. aureus isolates were isolated as per standard protocols. Typing of S. aureus was carried out by molecular detection of spa and clfA gene by polymerase chain reaction. RESULTS: All the 32 isolates from cattle (16) and buffalo (16) were divisible into seven spa types with amplicon sizes ranging between 120 and 380bp. The cattle isolates produced seven different spa amplicons of 120, 150, 200, 250, 280, 300, and 330 bp with 3, 4, 6, 8, 10, 11 and 12 number of tandem repeats, respectively whereas buffalo isolates were divisible into five spa types with amplicons of 150, 200, 250, 330 and 380 bp having calculated number of repeats of 5, 7, 9, 12, and 14, respectively. Of the total isolates, 24 were considered pathogenic on the basis of more than seven number of tandem repeats. In the present investigation, clfA gene was amplified in 27 isolates from cattle and buffalo producing two different amplicons of 900 and 1000 bp sizes showing polymorphism. The most (71.80%) of the isolates produced amplicons of 900 bp while amplicon size of 1000 bp was produced by four (12.5%) of the isolates. CONCLUSION: The presence of these genes with a wide degree of polymorphism confirmed the pathogenic potential of S. aureus and their association with clinical manifestations in mastitis among cattle and buffalo.

GroEL and CCT are catalytic unfoldases mediating out-of-cage polypeptide refolding without ATP.

Chaperonins are cage-like complexes in which nonnative polypeptides prone to aggregation are thought to reach their native state optimally. However, they also may use ATP to unfold stably bound misfolded polypeptides and mediate the out-of-cage native refolding of large proteins. Here, we show that even without ATP and GroES, both GroEL and the eukaryotic chaperonin containing t-complex polypeptide 1 (CCT/TRiC) can unfold stable misfolded polypeptide conformers and readily release them from the access ways to the cage. Reconciling earlier disparate experimental observations to ours, we present a comprehensive model whereby following unfolding on the upper cavity, in-cage confinement is not needed for the released intermediates to slowly reach their native state in solution. As over-sticky intermediates occasionally stall the catalytic unfoldase sites, GroES mobile loops and ATP are necessary to dissociate the inhibitory species and regenerate the unfolding activity. Thus, chaperonin rings are not obligate confining antiaggregation cages. They are polypeptide unfoldases that can iteratively convert stable off-pathway conformers into functional proteins.

Pyrrolidine based chiral organocatalyst for efficient asymmetric Michael addition of cyclic ketones to ß-nitrostyrenes.

An efficient asymmetric Michael addition of cyclic ketones to ß-nitrostyrenes using secondary diamine as an organocatalyst derived from l-proline and (R)-α-methylbenzyl amine has been described. This pyrrolidine based catalyst 1 was found to be very effective to synthesize various γ-nitrocarbonyl compounds in good yield (up to 81%) with excellent stereoselectivity (up to >99:1 dr and >99% ee).

Synthesis, antimicrobial, anticancer evaluation and QSAR studies of 6-methyl-4-[1-(2-substituted-phenylamino-acetyl)-1H-indol-3-yl]-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl esters.

A series of 6-methyl-4-[1-(2-substituted-phenylamino-acetyl)-1H-indol-3-yl]-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl esters (1-16) were synthesized and evaluated in vitro for their antimicrobial and anticancer potential. 6-Methyl-4-{1-[2-(4-nitro-phenylamino)-acetyl]-1H-indol-3-yl}-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl ester (15, pMIC(ec) = 2.50 µM/mL) was found to be almost equipotent to the standard drug, norfloxacin (pMIC(ec) = 2.61 µM/mL) against Escherichia coli and emerged as most potent antimicrobial agent (pMIC(am) = 1.84 µM/mL). 4-{1-[2-(2-Chloro-4-nitro-phenylamino)-acetyl]-1H-indol-3-yl}-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl ester (4, IC(50) = 5 µg/mL) was more potent than the standard drug 5-fluorouracil (IC(50) = 6 µg/mL) against HCT-116 a colon cancer cell line, and emerged as the most potent anticancer agent. The QSAR studies demonstrated the importance of topological parameter, Balaban index (J) followed by lipophillic parameter, log P in describing the antimicrobial activity of the synthesized compounds.

Effect of water on glass transition in starch/sucrose matrices investigated through positron annihilation lifetime spectroscopy: a new approach.

Glass transition is studied through positron annihilation lifetime spectroscopy (PALS) in maize starch matrices containing 10 (batch STS10) and 20 (STS20) w/w% sucrose, as a function of temperature (T) and water content (c(w)). To circumvent important losses of water upon heating while recording the PALS spectra, a new method is developed: instead of a series of measurements of τ(3), the triplet positronium lifetime, at different T, the latter is kept constant and the series relates to c(w), which is left to decrease at a constant rate. Similarly to the changes in τ(3) with T, the τ(3)vs. c(w) plots obtained show a smooth linear increase until a break, denoting the occurrence of glass transition, followed by a sharper increase. The gradients appear to be independent of T. The variation of the glass transition temperature, T(g), with c(w) shows a broad sigmoid with a large linear central part; as expected from the plasticising effect of sucrose, the plot for STS20 lies some 10 K below that for STS10. Results from differential scanning calorimetry for STS20 yield T(g) values some 15 K higher than from PALS. On the basis of the general shape of the τ(3)vs. T variations, a general equation is set for τ(3)(T, c(w)), leading one to expect a similar shape for τ(3)vs. c(w), as experimentally observed.

Clinical Evaluation of Xylazine-Butorphanol-Guaifenesin-Ketamine as Short-Term TIVA in Equines.

Xylazine (1.1 mg/kg), butorphanol (0.02 mg/kg), guaifenesin 5% (20 mg/kg), and ketamine (2.2 mg/kg) combinations were able to induce short-term surgical anaesthesia for 23.33 ± 2.57 min in Spiti ponies with excellent to good muscle relaxation and analgesia. Urination and neighing was a constant feature during recovery period. Biphasic P wave, biphasic T wave, and depressed PR segment were common electrocardiographic findings. Biochemical attributes were within physiological limits except a significant increase in ALT values during anaesthesia. The values returned to normal during recovery ruling out any renal or hepatic toxicity. Occasionally, negative T wave, notched P wave, and sinus block were noticed. It is recommended that the anaesthetic combinations xylazine-butorphanol-guaifenesin-ketamine can be safely used for short-term total intravenous anaesthesia (TIVA) in equines under field conditions.

Characterization of a sucrose/starch matrix through positron annihilation lifetime spectroscopy: unravelling the decomposition and glass transition processes.

The triplet state of positronium, o-Ps, is used as a probe to characterize a starch-20% w/w sucrose matrix as a function of temperature (T). A two-step decomposition (of sucrose, and then starch) starts at 440 K as shown by a decrease in the o-Ps intensity (I(3)) and lifetime (τ(3)), the latter also disclosing the occurrence of a glass transition. Upon sucrose decomposition, the matrix acquires properties (reduced size and density of nanoholes) that are different from those of pure starch. A model is successfully established, describing the variations of both I(3) and τ(3) with T and yields a glass transition temperature, T(g) = (446 ± 2) K, in spite of the concomitant sucrose decomposition. Unexpectedly, the starch volume fraction (as probed through thermal gravimetry) decreases with T at a higher rate than the free volume fraction (as probed through PALS).