Relation between axial length and ocular parameters

AIM: To investigatethe relation between axial length(AL), age and ocular parameters.<p>METHODS: A total of 360 subjects(360 eyes)with emmetropia or myopia were recruited. Refraction, center corneal thickness(CCT), AL, intraocular pressure(IOP)were measured by automatic-refractor, Pachymeter, A-mode ultrasound and non-contact tonometer, respectively. Corneal curvature(CC), anterior chamber depth(ACD)and white-to-white distance(WWD)were measured by Orbscan II. Three dimensional frequency domain coherent optical tomography(3D-OCT)was used to examine the retinal nerve fiber layer thickness(RNFLT). The Pearson correlation coefficient(<i>r</i>)and multiple regression analysis were performed to evaluate the relationship between AL, age and ocular parameters.<p>RESULTS: The average AL was 24.15±1.26mm. With elongation of the AL, spherical equivalent(SE)(<i>r</i>=-0.742,<i>P</i><0.01), CC(<i>r</i>=-0.395, <i>P</i><0.01)and RNFLT(<i>r</i>=-0.374, <i>P</i><0.01)all decreased, while the mean ACD(<i>r</i>=0.411, <i>P</i><0.01)increased. On the contrary, there was not statistical significan with CCT(<i>r</i>=0.099, <i>P</i>=0.060)and WWD(<i>r</i>=0.061, <i>P</i>=0.252). There was also a significant correlation between AL and age(<i>P</i>=0.001), SE(<i>P</i><0.001), ACD(<i>P</i><0.001), CC(<i>P</i><0.001)in Multiple linear regression analysis.<p>CONCLUSION: In longer eyes, there is a tendency toward myopia, a flatter cornea, a deeper ACD and a thinner RNFLT. Age is an influencing factor for the AL as well

Numerical Analysis of Cold Injury of Skin in Cryogen Spray Cooling for Laser Dermatologic Surgery

In laser dermatologic surgery, cryogen spray cooling (CSC) is used to avoid unwanted thermal damage such as scars from skin burning due to the melanin absorption of the laser beam. As the cryogen is fully atomized from the nozzle, temperature of the droplets can quickly drop below -60 oC because of evaporation. Such low temperature may lead to cold injury of skin. Therefore, spray cooling process should be accurately controlled during clinical practice to achieve sufficient protection and avoid cold injury. This study presents a numerical analysis for cold injury of skin in cryogen spray cooling for dermatologic laser surgery by a newly developed hest transfer model. For the freezing of skin cells, heat conduction equation was used to describe frozen and unfrozen zones, and heat capacity method was utilized for mushy zone to consider the phase change of tissue. A realistic boundary condition was implemented to simulate the cooling effect during cryogen spray cooling by a generalized correlation for the dynamic heat transfer coefficient. By tracking the front of the tissue phase change, the model can be used to predict the movement of the harmful isothermals. With this model, the severity of cold injury is quantified under various clinical conditions and the effects of initial temperature as well as the spurt duration on possible cold injury of skin are investigated. The results show that 100~150ms spray cooling duration is appropriate to avoid non-uniform cooling along the radial direction and also prevent potential cold injury. Lower room temperature (10~20oC) is recommended to achieve a deep penetration protection. Further development of new candidate cryogens with lower boiling point (e.g. R407C or R404a) are highly recommended to achieved a better cooling effect

BiCl3-catalyzed propargylic substitution reaction of propargylic alcohols with C-, O-, S- and N-centered nucleophiles

A general and efficient BiCl3-catalyzed substitution reaction of propargylic alcohols with carbon and heteroatom-centered nucleophiles such as allyl trimethylsilane, alcohols, aromatic compounds, thiols and amides, leading to the construction of C - C, C - O, C - S and C - N bonds, has been developed

An Overview of Kinematic and Calibration Models Using Internal/External Sensors or Constraints to Improve the Behavior of Spatial Parallel Mechanisms

This paper presents an overview of the literature on kinematic and calibration models of parallel mechanisms, the influence of sensors in the mechanism accuracy and parallel mechanisms used as sensors. The most relevant classifications to obtain and solve kinematic models and to identify geometric and non-geometric parameters in the calibration of parallel robots are discussed, examining the advantages and disadvantages of each method, presenting new trends and identifying unsolved problems. This overview tries to answer and show the solutions developed by the most up-to-date research to some of the most frequent questions that appear in the modelling of a parallel mechanism, such as how to measure, the number of sensors and necessary configurations, the type and influence of errors or the number of necessary parameters

Pretreatment and enzymatic hydrolysis optimization of lignocellulosic biomass for ethanol, xylitol, and phenylacetylcarbinol co-production using Candida magnoliae

Cellulosic bioethanol production generally has a higher operating cost due to relatively expensive pretreatment strategies and low efficiency of enzymatic hydrolysis. The production of other high-value chemicals such as xylitol and phenylacetylcarbinol (PAC) is, thus, necessary to offset the cost and promote economic viability. The optimal conditions of diluted sulfuric acid pretreatment under boiling water at 95°C and subsequent enzymatic hydrolysis steps for sugarcane bagasse (SCB), rice straw (RS), and corn cob (CC) were optimized using the response surface methodology via a central composite design to simplify the process on the large-scale production. The optimal pretreatment conditions (diluted sulfuric acid concentration (% w/v), treatment time (min)) for SCB (3.36, 113), RS (3.77, 109), and CC (3.89, 112) and the optimal enzymatic hydrolysis conditions (pretreated solid concentration (% w/v), hydrolysis time (h)) for SCB (12.1, 93), RS (10.9, 61), and CC (12.0, 90) were achieved. CC xylose-rich and CC glucose-rich hydrolysates obtained from the respective optimal condition of pretreatment and enzymatic hydrolysis steps were used for xylitol and ethanol production. The statistically significant highest (p ≤ 0.05) xylitol and ethanol yields were 65% ± 1% and 86% ± 2% using Candida magnoliae TISTR 5664. C. magnoliae could statistically significantly degrade (p ≤ 0.05) the inhibitors previously formed during the pretreatment step, including up to 97% w/w hydroxymethylfurfural, 76% w/w furfural, and completely degraded acetic acid during the xylitol production. This study was the first report using the mixed whole cells harvested from xylitol and ethanol production as a biocatalyst in PAC biotransformation under a two-phase emulsion system (vegetable oil/1 M phosphate (Pi) buffer). PAC concentration could be improved by 2-fold compared to a single-phase emulsion system using only 1 M Pi buffer

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

The Genomes of Oryza sativa: A History of Duplications

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family