Generation of V-point polarization singularity using single phase encoding with a spatial light modulator.

A liquid crystal Spatial Light Modulator (SLM) can be used in various ways to produce vector-vortices. Superposition of scalar vortices with orthogonal polarization is a common approach, while a more recent technique is to use dual-phase modulation. These approaches require modulation of at least two phase patterns with a SLM or multiple SLMs. In this paper, we propose a novel technique to produce vector-vortices by modulating orthogonal light components through a single phase pattern with a SLM. It does not require interferometric setups, and simplifies the generation of light beams with V-point polarization singularities. Because of compact and robustness of our experimental setup, it can be easily integrated to any device for applications of vector-vortices.

Self-referenced interferometry for single-shot detection of vector-vortex beams.

Vector-vortex (VV) beams are of significant interest for various applications. There have been substantial efforts toward developing a fast and efficient method for the characterization of generated VV beams which is crucial for their usage. Polarimetric approaches are commonly used to identify unknown VV beams but require multiple intensity recordings. This paper demonstrates a technique to detect VV beams and identify their parameters using the concept of self-referenced interferometry. The approach uses a single recorded interferogram to determine the beam parameters that allow rapid detection. The method even enables detection of VV beams having high-order optical vortices.

Nonlinear frequency conversion of 3D optical bottle beams generated using a single axicon.

We demonstrate a novel experimental scheme to generate and study the nonlinear frequency conversion of a three-dimensional (3D) optical Bessel bottle beam (BBB). Using a single axicon and standard optical components and controlling the spot size and divergence of the input Gaussian beam to the axicon, we have generated stable micron-size, high-power optical BBB with tunable spatial characteristics. The BBB has a series of low-intensity regions surrounded by high intensity with diameters of ∼30µm and 17 µm, respectively, at a variable period of 2.3 to 6.4 mm along with the beam propagation. Using the single-pass second harmonic generation (SHG) of femtosecond BBB at 1064 nm in a bismuth triborate nonlinear crystal, we have generated BBB at 532 nm with output power as high as 75 mW and single-pass SHG efficiency of 1.9%. We also observed the self-healing of the BBB at both pump and SHG wavelengths. It is interesting to note that the pump beam truncation shows self-healing in the SHG beam. Such observation proves the direct transfer of the pump's spatial characteristics to the SHG beam in the nonlinear process, potentially useful for imaging even in the turbid medium in biology. This generic scheme can be used at different wavelengths and timescales (continuous-wave to ultrafast).

Relation between Hypertrophy of Teres Minor Muscle and External Rotation Lag Sign in Patients with Rotator Cuff Pathology.

BACKGROUND: The purpose of this study was to determine the compensatory hypertrophy of the teres minor (TM) muscle in rotator cuff tears (RCTs) and also the relation between hypertrophy of TM muscle and external rotation lag sign (ERLS). METHODS: In the period between June 2017 and April 2018, forty patients with RCTs of the shoulder joint came to our institution. We determined the ERLS of all the RCT patients along with the TM occupation ratio in the magnetic resonance imaging (MRI) scan and correlated them together. The normal mean of TM occupational ratio was calculated from ten patients who have undergone MRI scan for other causes but with normal rotator cuff muscles. RESULTS: In our study, the mean TM occupational ratio of 10 normal rotator cuff patients was 0.277. Of 40 rotator cuff pathology patients, the mean occupational ratio of the TM in RCTs is 0.359. Sixteen of the 40 patients had ER lag positive and the remaining 24 patients had ER lag negative. Those who were ER lag negative have an TM occupational ratio >0.401. A positive correlation was found between hypertrophy of TM and ERLS. CONCLUSION: ERLS will be negative in patients with hypertrophy of TM in the setting of posterosuperior cuff tears. There is a strong correlation between cuff tears and hypertrophy of TM muscle, which helps in better prognosis and functional outcome of the patients treated with surgical intervention.

On-axis intensity modulation-free, segmented, zero-order Bessel beams with tunable ranges.

We propose and experimentally demonstrate a novel experimental scheme to generate high on-axis peak intensity, segmented, smooth, zero-order quasi-Bessel beams with tunable ranges. Illuminating the axicon with hollow Gaussian beams (HGBs) of different orders, we have generated Bessel beams of varying ranges at different positions away from the axicon. The presence of a dark core at the center of the HGBs removes the effect of imperfection in the axicon tip. As a result, the entire power of the input beam is transformed into a zero-order Bessel beam without any on-axis intensity modulation. We observe the decrease in range and increase in on-axis peak intensity of the zero-order Bessel beam with the order of HGBs. Controlling the superposition of the HGBs of different orders to the axicon, we have demonstrated the increase in the range of the Bessel beam. The current technique can also produce Bessel beams of different intensity distributions, including single-peak or multiple-peak Bessel beams. Using single-pass second-harmonic generation in nonlinear crystals of different lengths, we have further verified the increase of on-axis peak intensity of the Bessel beam with the order of the HGBs and the increase in the range of the Bessel beam due to the superposed HGBs.

Ultrasound Assisted Cu-catalyzed Synthesis of 1,2-Disubstituted Benzimidazoles as Potential Antibacterial Agents.

BACKGROUND: The ultrasound assisted synthesis and anti-bacterial evaluation of a series of compounds based on 1,2-disubstituted benzimidazole framework is reported here. The approach leading to the synthesis of these compounds involved the Cu-catalyzed coupling-cyclization of N-substituted 2-iodoanilines with benzamide derivatives in the presence of 2-aminoethanol as a ligand. CONCLUSION: A number of compounds were prepared using this methodology in acceptable yield. Two of these compounds showed promising antibacterial activities when tested against both Gram-positive and Gram-negative bacterial strains.

Electronic solutions for combating counterfeit drugs.

INTRODUCTION: The problem of counterfeiting of drugs is assuming alarming proportions and is getting difficult to combat due to its trans-national character. It is undermining the faith of people on health care system. Therefore, there is a need to adopt zero tolerance approach to combat the problem. THE WAY FORWARD: There are many solutions available which are being adopted in piece meal manner by individual manufacturers. However, for wholesalers and resellers it is getting difficult to maintain multiple solutions. Therefore, there is a need to adopt a unified solution preferably with the help of the government. CONCLUSIONS: This paper discusses the available solutions, their shortcomings and proposes a comprehensive solution where at each level in the supply chain the authenticity is verified preferable linking it with Unique identification.

Cardioprotective activity of chalcones in ischemia/reperfusion-induced myocardial infarction in albino rats.

BACKGROUND: There is a comprehensive body of experimental and clinical evidence suggesting that exogenous supplementation of natural antioxidants or augmentation of endogenous antioxidants attenuates the damage caused by myocardial infarction. OBJECTIVE: To evaluate the cardioprotective effects of Cl-chalcone and F-chalcone against ischemia/reperfusion (I/R)-induced myocardial infarction in rats. METHODS: Myocardial infarct size was measured using the staining agent 2,3,5-triphenyltetrazolium chloride. Malondialdehyde was measured in serum and heart tissue, and superoxide dismutase and catalase in heart tissue were measured spectrophotometrically. RESULTS: I/R resulted in significant cardiac necrosis, indicated by a rise in the end products of myocardial lipid peroxidation (malondialdehydes). A loss of antioxidative enzymes (superoxide dismutase and catalase) in heart tissue was also observed in animals subjected to in vivo myocardial I/R injury. DISCUSSION: The present study demonstrated that treatment with Cl-chalcone and F-chalcone significantly limited infarct size, partially but significantly attenuated the level of lipid peroxidation and moderated the loss of antioxidant reserves in rats subjected to 30 min coronary artery occlusion followed by a 4 h reperfusion in comparison with I/R groups. CONCLUSIONS: The results of the present study suggest that chalcones have cardioprotective activity against I/R-induced myocardial infarction in rats.

2-Amino-anilinium 2-chloro-acetate.

In the crystal structure of the title compound, C(6)H(9)N(2) (+)·ClCH(2)COO(-), prepared by the reaction of OPDA (orthophenelynediamine) with chloro-acetic -acid, N-H⋯O hydrogen bonds generate ladder-like chains and very weak inter-molecular C-H⋯Cl hydrogen-bonding inter-actions between the anions and cations lead to a supra-molecular network. C-H⋯O inter-actions also occur.

Medial swivel dislocation of the talonavicular joint.

Medial swivel dislocation, a variant of subtalar dislocation is uncommon. A 35 years old male presented after 6 weeks old injury to left ankle following motor cycle accident. He had pain, swelling around ankle and was unable to bear weight on left foot. Clinical examination revealed diffuse swelling and tenderness in mid foot region. His plain X rays and CT scan showed talonavicular dislocation with compression defect of the head of the talus. He was treated by open reduction and K-wire fixation. At 32 months follow up foot was painless, stable with normal range of ankle and subtalar motion.

Chiral synthesis of a mononuclear nickel(II) complex formed from an achiral tripodal amine ligand: spontaneous resolution.

A neutral chiral mononuclear Ni(II) complex cis-[Ni(NCS)(2)(tren)] (1) [tren = tris(2-aminoethyl)amine] has been isolated in a reaction of nickel(II) salt with an achiral ligand tren and NH(4)SCN in a MeOH-H(2)O (1:1) mixture. The crystal structure of 1 reveals the encapsulation of Ni(II) ions in a facial {NiN(6)} coordination environment that includes four nitrogen donors from the tetradentate chelate tren and two nitrogen donors from two cis-NCS (monodentate) ligands. The chirality of 1 arises from symmetry breaking of the cis-(NCS)(2)-Ni(II) octahedral complex by the tetradentate chelate tren. Compound 1 exhibits both its enantiomers in a DMF solution through a Pfeiffer effect when l- and d-arabinose are used as environment substances. The particular synthesis, described herein, offers total spontaneous resolution, as is evidenced from crystal structure and circular dichroism spectral studies.

Synthesis and evaluation of a new class of nifedipine analogs with T-type calcium channel blocking activity.

We have synthesized a novel series of 18 dialkyl 1,4-dihydro-4-(2'alkoxy-6'-pentadecylphenyl)-2,6-dimethyl-3,5 pyridine dicarboxylates from anacardic acid, a natural compound found in cashew nut shells, and investigated their blocking action on L- and T-type calcium channels transiently expressed in tSA-201 cells. The IC(50) values for L-type calcium channel block obtained with the series ranged from 1 to approximately 40 microM, with higher affinities being favored by increasing the size of the alkoxy group on the 4-phenyl ring and ester substituent in the 3,5 positions. A detailed analysis of the strongest L-type channel blocker of the series (PPK-12) revealed that block was poorly reversible and mediated an apparent speeding of the time course of inactivation. Moreover, in the presence of PPK-12, the midpoint of the steady state inactivation curve was shifted by 20 mV toward more hyperpolarized potentials, resulting in an increase in blocking efficacy at more depolarized holding potentials. Surprisingly, PPK-12 blocked T- and L-type calcium channels with similar affinities. One of the weakest L-type channel inhibitors (PPK-5) exhibited a T-type channel affinity that was similar to that seen with PPK-12, resulting in a 40-fold selectivity of PPK-5 for T- over L-type channels. Thus, dialkyl 1,4-dihydro-4-(2'alkoxy-6'-pentadecylphenyl)-2,6-dimethyl-3,5 pyridine dicarboxylates may serve as excellent candidates for the development of T-type calcium-channel specific blockers.