Comparative study on ignition delay time and burning rate of modified double-base propellant and fuel-rich propellant.

With the higher requirements of various tactical and technical indicators of the weapon systems, the current research on the ignition and combustion characteristics of different types of solid propellants is not comprehensive. In more complex and harsh environmental conditions, the pressure affects the ignition and combustion characteristics. Therefore, the paper studies the ignition and combustion characteristics of the modified double-base propellants (MDB propellants) and fuel-rich propellants (FR propellants) under low-pressure environment. Combining experiment and theory, the ignition delay time and burning rate of two kinds of solid propellants are compared and analyzed at low pressure by the laser ignition experimental device. The results displayed that the burning flames of the FR and MDB propellant presented evident V-shape and cylindrical, respectively. The flame brightness decreased with the decrease in pressure. With the increase of pressure and heat flux, the ignition delay time of the MDB propellant and the FR propellant decreased. By comparison, Model 2 of the ignition delay time was more effective for the estimation of the ignition delay time of the FR propellant. The experimental results are compared with the three burning rate models, which are the Vielle formula (Model 1), Summerfield formula (Model 2), and B-number burning rate formula (Model 3). The results showed the burning rate was more in accord with Model 3.

[Electroacupuncture at "Zusanli"(ST36) and "Xuanzhong"(GB39) improves inflammatory reactions and reduces levels of serum MMP-3 and MMP-9 in adjuvant arthritis rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Xuanzhong" (GB39) on joint inflammatory reactions and serum matrix metalloproteinase-3 (MMP-3) and MMP-9 contents in rats with adjuvant arthritis (AA), so as to explore its mechanism underlying improvement of AA. METHODS: Forty male SD rats were randomly divided into control, model, acupoint and non-acupoint groups (n=10 in each group). The arthritis model was established by hypodermic injection of complete Freund's adjuvant (0.1 mL) into the bilateral footpads. EA (2 Hz, 3 V) was applied to bilateral ST36 and GB39 or two non-acupoints (5 mm left to ST36 and GB39) for 15 min, once every other day for a total of 8 times. The arthritis index score was evaluated according to the severity of local erythema and swelling of the ankle joint, plantar joint, toe joint and foot metacarpal joint (0-4 points). The inflammatory conditions of the ankle joint were observed by H.E. staining, and the contents of serum MMP-3 and MMP-9 were assayed by ELISA. RESULTS: The arthritis index score and serum concentrations of MMP-3 and MMP-9 were significantly increased in the model group relevant to the control group (P<0.01), and obviously decreased after EA intervention on the 18th day (P<0.01). The therapeutic effect of acupoint EA was notably superior to non-acupoint EA in down-regulating the arthritis index score and serum MMP-3 and MMP-9 concentrations (P<0.01). Under light microscope, marked proliferation of the synovial cells, inflammatory cell infiltration and increase of newly blood vessels were observed in the ankle joint of the model group, which was relatively milder in the acupoint group. CONCLUSION: acupoint EA intervention can significantly alleviate the inflammatory reaction of AA rats, which may be related to its effects in reducing the levels of serum MMP-3 and MMP-9.

[Effects of Electroacupuncture on Joint Function in Rheumatoid Arthritis Patients of Liver- and Kidney-Yin Deficiency Type].

OBJECTIVE: To compare the effects between electroacupuncture (EA) plus western medicine and simple western medicine in improving clinical symptoms and local joint function of rheumatoid arthritis (RA) patients with yin deficiency of Liver and Kidney. METHODS: A total of 68 RA patients of yin deficiency of Liver and Kidney were equally randomized into EA+medication group and medication group (n=34 in each group). Both groups were given once-a-week methotrexate (7.5 mg/time) and once-a-day leflunomide (10 mg/time), while EA+medication group was additionally treated by EA at bilateral Ganshu (BL 18), Shenshu (BL 23), Xuanzhong (GB 39), Zusanli (ST 36), Taichong (LR 3), Hegu (LI 4) 3 times/week. The treatment lasted for 12 weeks. The visual analogue scale (VAS, for assessing rest pain), swollen joint count (SJC), tender joint count (TJC), patient's global assessment (PGA), physician's global assessment (PhGA), traditional Chinese medicine (TCM) symptom scoring, 28 joints activity index (disease activity score, DAS 28), American College of Rheumatology 20 (ACR 20, i.e. 20% of clinical improving rate), and health assessment questionnaire (HAQ) were assessed and erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) levels were examined for comparison. RESULTS: Statistical differences were observed in before-after-treatment comparisons in both groups in reducing rest pain, SJC, TJC, serum CRP content, PGA and PhGA, HAQ scoring and DAS 28 (P<0.05, P<0.01). The ESR in the medication group and TCM symptom scoring of the EA+medication group were also significantly decreased after the treatment (P<0.05).The effects of the EA+medication group were superior to those of the medication group in reducing rest pain, SJC, TJC, TCM symptom and HAQ score, and the total effetive rate (P<0.05,90.9% vs 66.67%). Adverse reactions as pharyngeal obstruction sensation, anorexia, abdominal distension, etc. can be reduced by EA therapy coordinated with western medicine. CONCLUSIONS: EA is effective in relieving symptom and joint function in RA patients with yin deficiency of Liver and Kidney.

Electroacupuncture attenuates collagen-induced arthritis in rats through vasoactive intestinal peptide signalling-dependent re-establishment of the regulatory T cell/T-helper 17 cell balance.

OBJECTIVE: Imbalance between T-helper 17 (Th17) cells and regulatory T (Treg) cells is causally linked to the development of rheumatoid arthritis (RA). In this study, we tested the hypothesis that electroacupuncture (EA) confers therapeutic benefits in RA through activation of vasoactive intestinal peptide (VIP)-dependent signalling and restoration of the Th17/Treg cell balance. MATERIALS AND METHODS: A collagen-induced arthritis (CIA) model was induced in Sprague-Dawley rats by injection of bovine type II collagen in incomplete Freund's adjuvant on day 0 and day 7. Three days after the second injection, EA was given at acupuncture points GB39 and ST36 three times per week for 4 weeks. To block VIP signalling, [D-P-Cl-Phe(6)-Leu(17)]-VIP, a VIP receptor antagonist, was administered intraperitoneally 30 min before EA. Inflammatory and pathological responses in the joint were assessed. Synovial VIP receptor mRNA levels and Treg and Th17 cell frequencies in the spleen were determined. RESULTS: EA significantly reduced the severity of CIA, as evidenced by reduced paw volumes, arthritis scores and inflammation scores. EA significantly increased mRNA expression of the VIP receptor VPAC1 and led to an elevation in CD4(+)FOXP3(+) Treg cell frequency and a reduction in CD4(+)IL17(+) Th17 cell frequency. Pre-injection of a VIP receptor antagonist significantly reversed EA-induced expansion of Treg cells, but did not alter the frequencies of Th17 cells. CONCLUSIONS: EA exerts anti-inflammatory effects in a collagen-induced rat model of arthritis. These effects appear to be mediated through activation of VIP signalling and re-establishment of the Th17/Treg cell balance.

Electroacupuncture inhibits inflammation reaction by upregulating vasoactive intestinal Peptide in rats with adjuvant-induced arthritis.

Acupuncture is emerging as an alternative therapy for rheumatoid arthritis (RA). However, the molecular mechanism underlying this beneficial effect of acupuncture has not been fully understood. Here, we demonstrated that electroacupuncture at acupoints Zusanli (ST36), Xuanzhong (GB39); and Shenshu (BL23) markedly decreased the paw swelling and the histologic scores of inflammation in the synovial tissue, and reduced the body weight loss in an adjuvant-induced arthritis rat model. However, the electrical stimulation at nonacupoint did not produce any beneficial effects against the experimental arthritis. Most interestingly, the electroacupuncture treatment resulted in an enhanced immunostaining for vasoactive intestinal peptide (VIP), a potent anti-inflammatory neuropeptide, in the synovial tissue. Moreover, the VIP-immunostaining intensity was significantly negatively correlated with the scores of inflammation in the synovial tissue (r = -0.483, P = .0026). In conclusion, these findings suggest that electroacupuncture may offer therapeutic benefits for the treatment of RA, at least partially through the induction of VIP expression.

[Effects of acupuncture on the number and degranulation ratio of mast cells and expression of tryptase in synovium of rats with adjuvant arthritis].

OBJECTIVE: To observe the effects of acupuncture on synovial pathology, synovial mast cell degranulation and tryptase expression and to investigate the relationship between the functions of mast cells and effects of acupuncture on early adjuvant arthritis in rats. METHODS: Forty-six male Wistar rats were randomly divided into normal control group (n=16), untreated group (n=15) and acupuncture group (n=15). Adjuvant arthritis was induced by injection of 0.1 mL Freund's complete adjuvant in right hind limb footpad. Normal control group and untreated group received no acupuncture treatment, while rats in the acupuncture group were treated with sterilized disposable stainless steel needles inserted perpendicularly as deep as 2 to 3 mm at Xuanzhong (GB39), 6 mm at Shenshu (BL23) and 7 mm at Zusanli (ST36) for eight times (15 min each time) every two days. Setting the modeling day as the 0 day of the experiment, the body weight and paw volume of the rats were measured every three days from the 0 day. In the end, synovial tissues of the right hind ankles were sampled and made into paraffin sections. Then they were firstly stained with hematoxylin-eosin for observing synovial pathology to evaluate the effects of acupuncture on adjuvant arthritis, then stained with toluidine blue for observing the number and degranulation ratio of synovial mast cells and finally detected by immunohistochemical staining method to investigate the expression of tryptase in synovium. RESULTS: Compared with the untreated group, the body weight of rats in the acupuncture group was increased significantly (P<0.05), while the paw volume decreased obviously (P<0.01). Hematoxylin-eosin staining showed that acupuncture significantly inhibited inflammatory cell infiltration, synovial cell hyperplasia, and synovial fibroplasia in synovium of rats with adjuvant arthritis as compared with the untreated group (P<0.05). Toluidine blue staining showed that acupuncture could significantly diminish the numbers of total and degranulated mast cells in rats with adjuvant arthritis (P<0.01), which were significantly higher in the untreated group than in the normal control group (P<0.01). Showing by immunohistochemical staining, the expression of tryptase in synovium in the acupuncture group was decreased as compared with the untreated group (P<0.01). Analyzed by Spearman's bivariate correlation, the number of mast cells and degranulation ratio of mast cells were positively correlated with the pathological scores (r=0.837, P<0.01; r=0.634, P<0.01). CONCLUSION: Acupuncture can improve pathological condition of inflammatory synovium in rats with early adjuvant arthritis by inhibiting the function of synovial mast cells, which may play an important underlying role in the immunoregulation of acupuncture on adjuvant arthritis.