Method for a deflection-type refractometer measuring the fringe shift by using linear Fresnel zone plates.

This study describes the design and performance of a deflection-type refractometer based on measuring the fringe shift from the Fresnel diffraction pattern to solve some major limitations of conventional differential refractometers, such as measurement range, resolution, zero balancing, and monitoring analysis. The refractometer apparatus comprises a coherent light source, linear Fresnel zone plate, measuring cell, and image capture device mounted on a movable platform. The distance measurement unit is configured to detect fringe deflection due to the difference in refractive index between the sample and the reference. To achieve this, distance measurements with an accuracy of a few nanometers by using the local frequency method and fringe shift measurement method are quite feasible. The uncertainty in this technique is determined by the smallest change in the longitudinal displacement of the image for which the CCD camera can detect a change in pixel position. The refractive index is obtained with a highly extended measurement range of at least ±0.4R I U and precision of the order of 2×10-4 R I U. A numerical comparison between computer simulation of the diffraction patterns that occur when the linear Fresnel zone plate is illuminated by a plane light traveling parallel to the z axis.

Design of a compact varifocal panoramic system based on the mechanical zoom method.

A compact varifocal panoramic annular lens (PAL) system based on the four-component mechanical zoom method is proposed, which solves the problem that the traditional PAL system cannot zoom in to the region of interest. By moving the zoom group and the compensation group, our design achieves continuous zooming, in which the focal length changes from 3.8 to 6 mm. It can keep the position of the image surface unchanged while maintaining a compact structure. The system has a field of view (FoV) of 25°-100° in wide-angle mode and an FoV of 25°-65° in telephoto mode. The modulation transfer function of the wide-angle view is higher than 0.22 at 147 lp/mm. The F-theta distortion is less than 3%, and the relative illuminance is higher than 0.9 in the zoom process. Compared with the zoom PAL system with multiple free-form aspheric surfaces, the proposed system uses multiple spherical lenses and only one Q-type asphere lens to achieve outstanding panoramic zoom imaging results. It is practical and straightforward, easy to manufacture, detect, and mass produce.

Dual-view catadioptric panoramic system based on even aspheric elements.

We propose a compact catadioptric imaging system based on even aspheric elements to solve some major limitations of conventional panoramic structure, such as field of view, blind spot, resolution, illumination, and less structure is introduced. The design includes a catadioptric front unit that is capable of providing a compression image of a panoramic scene and of relaying high-performance aspheric lenses to a decompression image. It is arranged to project two uncompressed images from two channels on a single sensor. Their optical paths do not interfere with each other, and there is no blind-spot image.

Combination of anti-tuberculosis drugs with vitamin C or NAC against different Staphylococcus aureus and Mycobacterium tuberculosis strains.

BACKGROUNDS: Hepatotoxicity due to anti tuberculosis drugs, rifampin and isoniazid, is a major problem in tuberculosis patients. Vitamin C, an antioxidant, and N-acetyl cysteine (NAC), a scavenger of active metabolites, reduce the hepatotoxicity. The aim of present study was to investigate the effect of vitamin C and NAC individually on the antibacterial activity of anti tuberculosis drugs against Mycobacterium tuberculosis and Staphylococcus aureus strains. METHODS: The MICs of each compound against all strains were determined in 96 wells plate. Rifampin was tested at serial two fold concentrations alone or in combination with NAC or vitamin C. RESULTS: The MIC of rifampin against different strains of S. aureus was 0.008-0.032 µg/ml. The MIC of rifampin and isoniazid against M. tuberculosis strains were 40 and 0.2 µg/ml, respectively. Vitamin C and NAC had no antibacterial activity against all strains. MIC of rifampin was reduced two fold by combination with vitamin C for all S. aureus strains, while NAC did not affect the antibacterial activity of rifampin. Vitamin C and NAC had remarkable effects on the antibacterial activity of anti-tuberculosis drugs against M. tuberculosis. CONCLUSIONS: Synergistic effects were observed between rifampin or isoniazid and vitamin C against all tested strains. However, combination therapy of rifampin and isoniazid with NAC was not being effective. This study highlighted the advantages of combination of anti-tuberculosis drugs and vitamin C to eradicate the microbial infections.

Effects of 8 Weeks of Balance Training, Virtual Reality Training, and Combined Exercise on Lower Limb Muscle Strength, Balance, and Functional Mobility Among Older Men: A Randomized Controlled Trial.

BACKGROUND: Poor muscle strength, balance, and functional mobility have predicted falls in older adults. Fall prevention guidelines recommend highly challenging balance training modes to decrease falls; however, it is unclear whether certain modes are more effective. The purpose of this study was to determine whether traditional balance training (BT), virtual reality balance training (VR), or combined exercise (MIX) relative to a waitlist control group (CON) would provoke greater improvements in strength, balance, and functional mobility as falls risk factor proxies for falls in older men. HYPOTHESIS: We hypothesized that 8 weeks of MIX will provoke the greatest improvements in falls risk factors, followed by similar improvements after BT and VR, relative to the CON. STUDY DESIGN: Single-blinded randomized controlled trial NCT02778841 (ClinicalTrials.gov identifier). LEVEL OF EVIDENCE: Level 2. METHODS: In total, 64 community-dwelling older men (age 71.8 ± 6.09 years) were randomly assigned into BT, VR, MIX, and CON groups and tested at baseline and at the 8-week follow-up. The training groups exercised for 40 minutes, 3 times per week, for 8 weeks. Isokinetic quadriceps and hamstrings strength on the dominant and nondominant legs were primary outcomes measured by the Biodex Isokinetic Dynamometer. Secondary outcomes included 1-legged stance on firm and foam surfaces, tandem stance, the timed-up-and-go, and gait speed. Separate one-way analyses of covariance between groups were conducted for each outcome using baseline scores as covariates. RESULTS: (1) MIX elicited greater improvements in strength, balance, and functional mobility relative to BT, VR, and CON; (2) VR exhibited better balance and functional mobility relative to BT and CON; and (3) BT demonstrated better balance and functional mobility relative to CON. CONCLUSION: The moderate to large effect sizes in strength and large effect sizes for balance and functional mobility underline that MIX is an effective method to improve falls risk among older adults. CLINICAL RELEVANCE: This study forms the basis for a larger trial powered for falls.

Comparing intravenous dexmedetomidine and clonidine in hemodynamic changes and block following spinal anesthesia with ropivacaine in lower limb orthopedic surgery: a randomized clinical trial.

Dexmedetomidine (DEX) can prolong duration of anesthesia and shorten onset of sensory and motor block relative to clonidine. This study attempted to compare the efficacy of intravenous DEX and clonidine for hemodynamic changes and block after spinal anesthesia with ropivacaine in lower limb orthopedic surgery. In a double-blind randomized clinical trial, 120 patients undergoing spinal anesthesia in lower limb orthopedic surgery were recruited and divided into three groups using balanced block randomization: DEX group (n = 40; intravenous DEX 0.2 µg/kg), clonidine group (n = 40; intravenous clonidine 0.4 µg/kg), and placebo group (n = 40; intravenous normal saline 10 mL) in which pain scores were assessed using visual analogue scales (at recovery, and 2, 4, 6, and 12 hours after surgery) and time to achieve and onset of sensory and motor block. Statistically significant differences were found in mean arterial pressure among the groups at all times except baseline (P = 0.001), with a less mean arterial pressure and a prolonged duration of sensory and motor block (P = 0.001) in the DEX group where pain relieved in patients immediately after surgery and at above mentioned time points (P = 0.001). Simultaneous administration of intravenous DEX with ropivacaine for spinal anesthesia prolongs the duration of sensory and motor block and relieves postoperative pain, and however, can decrease blood pressure. Although intravenous DEX as an adjuvant can be helpful during spinal anesthesia with ropivacaine, it should be taken with caution owing to a lowering of mean arterial pressure in patients especially in the older adults. This study was approved by Ethical Committee of Arak University of Medical Sciences (No. IR.Arakmu.Rec.1395.450) in March, 2017, and the trial was registered and approved by the Iranian Registry of Clinical Trials (IRCT No. IRCT2017092020258N60) in 2017.

Comparison of calcaneus joint internal and external fractures in open surgery and minimal invasive methods in patients.

Surgical management of calcaneal fractures has various complications. In recent years, minimally invasive surgeries have been utilized for a wide range of surgical procedures on different body parts significantly declining complications. This paper compares surgical outcomes of calcaneal fracture management between the open reduction and internal fixation technique (ORIF) and the MIS technique. In this randomized clinical trial forty patients with calcaneus fractures were randomly assigned to two equal groups; ORIF group and MIS group. Patients were followed for 1 year post-operatively. Gissane and Bohler's angles, AOFAS questionnaire, pain intensity, ability to conduct previous activities and various complications like wound healing complications and irritation with shoe wear were assessed in the final post-operative visit. Eventually data obtained from the two groups were compared. All patients obtained fracture union. Bohler's and Gissane angles significantly increased and decreased, respectively, after the operation in both groups (p˂0.05), however, no significant difference was found between the two research groups. AOFAS scores and pain intensity was similar in both groups, however, surgical duration in the MIS group was significantly less than the ORIF group (P=0.021). Only one patient from the ORIF group was not able to resume his previous occupation. 12 patients from the ORIF group and five patients from the MIS group experienced irritation from shoe wear (p=0.025). In the ORIF group, 4 patients suffered from wound healing complications, however, none of the patients of the MIS group had wound complications (p=0.035). In conclusion, based on the results, it can be concluded that the MIS technique demonstrated better functional and radiographic outcomes as well as a more favorable complication profile, thus, it is recommended for the management of calcaneus fractures.