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【Objective】 The asymmetric Venturi fertilizer injector is a device to simultaneously supply water and nutrients to crops through a drip irrigation system. Its performance is influenced by various factors. In this paper, we experimentally study the impact of the offset distance of the central axis in the diffusion section on fertilizer adsorption. 【Method】 Five asymmetric Venturi injectors with different diffusion sections were studied. Their fertilizer absorption was experimentally and numerically studied. The fertilizer absorption rate, critical pressure difference and the critical pressure at the inlet for fertilizer absorption were compared and analyzed between the five injectors. 【Result】 Under normal working conditions, the fertilizer absorption rate linearly increased with the inlet pressure. When the pressure difference between the inlet and outlet was 0.15 MPa, the fertilizer absorption rate maximized. The critical pressure difference and critical inlet pressure both increased with the increase in the outlet pressure. Compared with original asymmetric Venturi injector (F1), the asymmetric Venturi injector with eccentric downward diffusion section (F5) increased fertilizer absorption rate and efficiency by 13.03%~40.16% and 12.09%~39.13%, respectively. The increase, however, gradually decreased with the increase in the inlet pressure. Compared with F1, F5 increased the maximum fertilizer absorption rate by up to 13.03% and reduced the critical pressure difference by 7.69%. 【Conclusion】 When working at normal conditions, reducing the outlet pressure was beneficial to reducing the critical pressure at the inlet for fertilizer absorption. Moving the diffusion section away from the side of the fertilizer suction pipe can reduce local water head loss, make pressure at the throat more negative, thereby increasing the flow rate of fertilizer into the injector and reducing the critical pressure difference for fertilizer absorption. Our findings can help improve the design of the Venturi fertilizer injector for drip irrigation-fertigation systems.

Objective To analyze the clinical features of patients with pseudoretinitis pigmentosa (PRP). Methods We performed a retrospective case analysis among 26 patients with PRP admitted in our department between December, 2014 and October, 2018, with 30 age-matched patients with RP as the controls. The etiology, disease course, best corrected visual acuity (BCVA), fundus and full-field flash electroretinogram (FERG) changes were compared between the patients with RP and those with PRP. Results Of the 26 patients with PRP (including 12 male and 14 female patients aged from 26 to 56 years), 22 (84.6%) had unilateral PRP and 4 (15.4%) had bilateral PRP, and the disease course ranged from 6 months to 5 years. The BCVA of these patients ranged from no light perception to 1.2, and none of the patients complained of night blindness. The 30 control patients with RP included 13 male and 17 female patients with a mean disease duration of 27 years. The primary causes of PRP included uveitis (40.0%), retinal detachment (36.7%), ocular trauma (16.7%), and other factors (6.6%). The patients with RP and PRP had significantly different disease durations and BCVA (P < 0.05). The patients with PRP typically manifested a bilateral asymmetry of the fundus, with obvious differences in retinal color, pigment distribution and visual disc color change from patients with RP. FERG of the patients with PRP revealed synchronously decreased amplitudes of the waveforms in the bilateral eyes with obvious eye asymmetry, and the reduction of FERG amplitude was not consistent with the changes in the fundus of the affected eyes. Conclusion The causes of PRP are diverse, and the disease course is often short without night blindness. The changes in the fundus and FERG are the main indicators for differential diagnosis between PRP and RP.

Aiming at the current groove blasting problems of additional damage, the feasibility of double base propellant for groove blasting was explored. Based on the propellant gas release behavior, the pressure change of the double base propellant in the closed hole was calculated. Combined with high-speed photography and digital image correlation (DIC) method, two groups of experiments were carried out with propellant loading density of 0.84 and 0.96 g/cm³ to investigate the dynmic destruction process of granite slabs under the action of propellant. The results show that the granite slabs in the two groups of experiments were cracked along the groove direction at 100 μs after ignition, and the cracks penetrated through the slabs at 200 μs; the specimen with a charge density of 0.96 g/cm³ had a larger separation speed between the upper and lower slabs after fracture, and the upper and lower slabs were cracked by the friction of the blocking rubber and the inertia of the specimen, and the cracks were in the vertical direction at 2 500 μs. The grooves around the blast hole provide space for the effect of the propellant gas, and the grooves can effectively guide the direction of crack propagation, no crushing zone formed around the hole wall. The quasi-static pressure generated by the combustion of double-base propellant is the main driving force for crack initiation and propagation. The experimental results have some implications for the use of double base propellant in controlled rock blasting projects. [ABSTRACT FROM AUTHOR]

In order to explore the influence of calcination temperature on the mineral phase of cement clinker, the clinker was analyzed qualitative!)', quantitative!)' and morphologically by XRD, Rietveld and lithofacies method. The results show that Rietveld method can be used to measure the relative content of each mineral phase in the clinker quickly and accurately. According to the content of mineral phase calculated by Rietveld method, it can be seen that calcination temperature has a direct effect on the content of mineral phase in the clinker, especialy C3S and C2S. The results of mineral phase content obtained by Rietveld method are close to those obtained by Bague algorithm, but the content of C3A obtained by fitting is lower. This is due to the rapid cooling of clinker which makes C3A exist as glass phase. With the increase of calcination temperature, the crystal nucleation and development are more perfect, and the clinker shows better morphology. [ABSTRACT FROM AUTHOR]

Objective To observe the effects of Eldepryl on expressions of tyrosine hydroxylase (TH) and glial cell line-derived neurotrophic factor (GDNF) in substantia nigra and striatum in Parkinson's disease (PD) and to explore the protective mechanism of Eldepryl on dopaminergic neuron . Methods Healthy male Sprague-Dawley (SD) rats (n=72) were randomly divided into control group, model group and Eldepryl group (n=24 in each group). Each group was divided randomly into 2 subgroups as 4 day treatment group and 8 day treatment group (n=12 in each subgrop). Pakinson's disease model was established by injecting rotenone subcutaneously back the neck, rats in the control group were injected with an equal volume of sunflower oil subcutaneously at the same location. Rats in the Eldepryl group were then given Eldepryl 0.5 mg⋅kg-1 intragastrically every day for 4 or 8 consecutive days and rats in model group and control group were given an equal volume of saline instead. The expression of TH and GDNF in substantia nigra and striatum were detected by immunohistochemistry and Western blotting. Results Immunohistochemistry and Western blotting showed that strong expression of TH positive cells with little expression of GDNF positive cells were seen in substantia nigra and striatum in rats of control group, and there was no significant difference between subgroup of 8 day treatment and 4 day treatment within control group. The expression of TH cells and GDNF were both significantly reduced in model group compared with those in control group (both P < 0.05), and there was no significant difference between subgroup of 8 day treatment and 4 day treatment within each group. The expression of TH positive cells were significantly reduced in Eldepryl group compared with those in control group, and were significantly increased compared with those in model group. The expression of GDNF positive cells were significantly increased in Eldepryl group compared with those in control group and model group (all P<0.05). And there were significantly more expression of TH positive cells and GDNF positive cells at subgroup of 8 day treatment compared with those at subgroup of 4 day treatment within Eldepryl group with (all P < 0.05). Conclusion These data suggest that Eldepryl can protect the damage of dopaminergic neurons in substantia nigra and striatum of PD rats. And its therapeutic mechanism may be associated with increased expression of GDNF. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of chlamydiaphage virus protein 2(Vp2) on the recombinant virus and virus screening research, and it clinical value thereof. Methods To compare the Vp2 protein sequences to get the conservative region with COBALT. A phylogenetic tree was built with ProteinBlast of Distance tree. The amino acid sequence in the high conservative region was predicted by the methods of Gamier-Robson and Chou-Fasman, and its flexibe regions were predicted by Karplus method. The hydrophilicity plot was predicted by Kyte-Doolittle and Hopp-Woods method. The surface probability was analysed by Emini, and the antigenic index was analysed by Jameson-Wolf method. Results The six Chlamydiaphage Vp2 proteins were the highly conserved sequences. There were obvious differences between Chp1Vp2 and other 5 Vp2 proteins. There were the main structure-alpha helix and some cell epitopes in the high conserved region. Conclusion Vp2 protein is the important component of chlamydia phage capsid with the conservative nature. Vp2 protein has complicated structures and high conservative region with strong immunogenicity, playing a practical value of research in virus recombinantment and screening the wild strains of chlaymdia trachomatis phage. [ABSTRACT FROM AUTHOR]

Background The prevalence of inflammatory bowel disease (IBD) increases annually in China. The integrated traditional Chinese and western medicine is helpful to alleviate and control symptoms of IBD. Quality of life (QoL) is an important index to evaluate the clinical efficacy of IBD. However, there are few studies about IBD patient-reported outcomes (PROs) based on TCM theories. Objective To determine the framework and items, and then use them to develop the IBD PROs scale using TCM theories. Methods Under the guidance of the TCM theory of "body and mind harmony, and man's adaptation to his total environment" , literature review, core-group discussion and expert consultation were carried out. The conceptual framework and item pool of the draft of an IBD PROs scale were developed, then the corresponding items were determined, forming the draft of the IBD PROs scale. Then the draft scale was pre-tested in IBD patients treated in Department of Spleen and Stomach Diseases, the First Affiliated Hospital of Guangzhou University of Chinese Medicine from January to June 2021. The dispersion tendency, Cronbach's α and correlation analysis were used for further item selection. Results The final IBD PROs scale is composed of two domains: body and mind harmony (12 body-related items, and 9 mind-related items) and man's adaptation to his total environment (6 items) . Conclusion The IBD PROs scale developed based on theories of TCM could be used to evaluate the QoL of IBD patients. But further clinical research is still needed to verify its reliability and validity.

Objective: To investigate the contributions of human rods and cones pathway to different components of oscillatory potentials (OP) in time and frequency domain., Methods: Case-control study. Twenty subjects were divided into two groups, normal groups (NG) and cones pathway abnormal groups (CAG). All eyes were investigated by dark-adapted (DA) and light-adapted (LA) 3.0 ERG recommended by ISCEV. Data were output into the computer and processed and analyzed by the software Matlab7.0. First, to extract the OP by filter, then to get the frequency-amplitude relationship by FFT, after that the relationship was fitted by equations and lastly we statistic and analyze the parameters gotten from the equations., Results: Compared with normal group [(48.63 ± 4.29), (158.00 ± 32.75), (69.27 ± 30.31), (38.5 ± 15.28) µV], the amplitudes of the first two components of dark-adapted OP in the CAG [(4.12 ± 3.20), (71.25 ± 25.43), (48.96 ± 20.05), (36.84 ± 14.26) µV] were significant decreased (t = 16.68, 5.77, P < 0.01). Frequency domain of LA and DA OP in the two groups was comprised with two components (harmonic and subharmonic). Compared with normal group, harmonic components of CAG were dramatic decreased (t = 2.72, P < 0.05; Z = -2.24, P < 0.05). The value of subharmonic component in CAG was lowest in DA OP compared with NG (t = 4.20, P < 0.005)., Conclusions: Cones and rods pathway all contributed to the DA and LA OP Cones pathway mainly contributes to the earlier and faster components of OP while the rods pathway to the later and slower components.

A temporary demand pacemaker with electrocardiosignal display is introduced in this paper. Double way low-noise electrocardiosignal preamplifier, amplitude limiter, high and low pass filter, 50 Hz notch filter, TTL level generator and stimulating pulse formation circuit are components of the hardware electrocircuit. The demand pacing and the electrocardiosignal display are separately controlled by the software in which the double microcontrollers communications technique is used. In this study, liquid crystal display is firstly used in body surface electrocardiosignal display or intracardial electrophysiologic signal display when the temporary demand pacemaker is installed and put into use. The machine has proven clinically useful and can be of wide appliation.