准噶尔盆地滴南凸起一五彩湾地区天然气成因与成藏过程分析

一般认为天然气具有晚期成藏的特征,但通过对准噶尔盆地滴南凸起一五彩湾地区石炭系天然气成藏的研究则得到了不同的认识。研究区的天然气以湿气为主,干燥系数均值为0．92,非烃气体中N2含量均值为3．04％;而天然气的δ^13C1均值为-32．12‰,明显偏高,反映出天然气成熟度已经处于干气阶段。通过对研究区天然气成因与成藏分析,认为该地区具有“早期聚集、晚期保存”的天然气成藏过程,总体来说该地区经历了海西晚期、印支晚期和燕山中期的多期油气充注和成藏,但燕山中期是该地区成藏的关键时期,并且该时期主要聚集的是石炭系烃源岩在．Ro值达到0．8％～1．2％之后生成的天然气,这也是造成该地区天然气组分碳同位素值偏高的主要原因。     

新疆油田超稠油开发地面集输注汽工艺技术

超稠油由于其黏度高,开采技术难度大,一直难以实现经济开采。新疆油田通过试验研究,提出了多项优化、简化地面集输工艺的配套技术,运用了多通阀选井工艺、短半径注汽方式、称重式计量技术、计量接转注汽一体化建站模式等,使工人劳动强度有所降低,地面建设工程量和管理点减少,与常规计量站建设相比,节约投资约25%,稠油地面集输工艺水平有了较大提高。     

稀土离子与NaY分子筛的滤饼柱交换过程

研究了稀土离子与NaY分子筛滤饼柱的交换过程。结果表明，与间歇交换相比，采用分子筛滤饼柱进行稀土离子交换，可以在较短时间内得到较高的稀土离子交换度。调整稀土离子和NH4^ 在交换液中的比例，可以在滤饼柱上获得具有一定稀土离子交换度且稀土分布均匀的Y型分子筛产品。交换液温度对稀土与NH4^ 混合交换的稀土交换度影响较大，但可以通过调整稀土离子与NH4^ 在交换液中的比例弥补交换度的差异。用约3倍于分子筛量的去离子水以洗去分子筛上残余的Na^ 、稀土离子和Cl^-。     

CHARACTERIZATION OF STOMACH AND PYLORIC CAECA PROTEINASES OF TAMBAQUI (COLOSSOMA MACROPOMUM)

The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of crude extracts from the stomach, liver, pyloric caeca, and intestines of Colossoma macropomum were investigated. The highest acid and alkaline proteolytic activities were found in stomach and pyloric caeca, respectively. The optimum pH for the acid and alkaline proteases were 1.8 and 7.0–9.0, respectively, while the optimum temperatures were 35C and 65C. This alkaline protease thermal stability remained unaltered after 90 min incubation at 55C. A pepsin‐like protease was responsible for most of the acidic proteolytic activity (Pepstatin A inhibited approximately 90%), whereas PMSF inhibited about 40% of the alkaline protease. The alkaline proteolytic activity has attractive thermal properties for industrial applications.     

4-Defect repair of grade 4 cystocele

PURPOSE: The 4-defect repair of grade 4 cystocele corrects discrete and severe deficiencies of vesicourethral support. We describe this technique used during pelvic reconstruction in 130 women. MATERIALS AND METHODS: During a 3-year period 130 patients (age range 35 to 96 years) underwent repair of grade 4 cystocele using the 4-defect repair technique. Cystocele repair had been performed in 60 patients (46%) and hysterectomy had been performed in 85 (65%). A "goalpost incision" is used in the vaginal wall to facilitate separation of the wall from underlying perivesical fascia, entry into the retropubic space, and exposure of the urethropelvic ligament, cardinal ligament and perivesical fascia. The 4 polypropylene sutures are used to provide an anterior vaginal wall sling which is modified to incorporate perivesical fascia and cardinal ligaments. Central defect repair is achieved by approximation of the cardinal ligaments and midline plication of the perivesical fascia over absorbable mesh. RESULTS: A total of 112 patients were available for followup which ranged from 6 to 42 months (mean 21). Repair of grade 4 cystocele was accompanied by other transvaginal repairs in 94 patients (83%), including rectocele repair in 81, hysterectomy in 22 and enterocele repair in 31. Of the patients 92% had excellent objective and subjective results for anatomical cystocele repair. Of the patients with preoperative stress urinary incontinence 90% had excellent or good subjective results. De novo urge incontinence was seen in 7% of patients. CONCLUSIONS: The 4-defect repair technique relies on anatomical restoration of 4 distinct deficiencies of pelvic support and is highly effective for relief of symptoms of grade 4 cystocele.     

Ophthalmic findings with partial trisomy (duplication) of the long arm of chromosome 7

BACKGROUND: The sensitivity of diagnostic imaging of processes in the parotid gland has been increased by improved spatial resolution, yet specificity remains unchanged. The purpose of this study was to determine whether the low-flow color duplex technique alters the specificity of B-mode ultrasonography. PATIENTS AND METHODS: Forty-one patients with tumors of the parotid gland were examined by color duplex echography as well as histologically. Twenty-eight of the 41 patients had benign tumors and 13 had malignant disease. In 17 of 41 patients, color duplex ultrasonography failed to detect any vascularization within the tumor. Histopathological examination showed that 3 of these 17 tumors were malignant and 14 of 17 were benign. Intranodal vascularization was detected in 24 cases. Ten of these patients were found to have malignant tumors of the parotid gland; 14 had benign parotid tumors. RESULTS: Our present findings show that marked intratumoral vascularization especially appears in malignant tumors. In contrast to lymph nodes, the location and texture of intranodal blood vessels do not provide information about the nature of the neoplasm. CONCLUSIONS: Low flow duplex ultrasonography does not increase the specificity of preoperative examination in tumors of the parotid gland.     

Growth on urea can trigger death and peroxidation of the cyanobacterium Synechococcus sp. strain PCC 7002

Laboratory conditions have been identified that cause the rapid death of cultures of cyanobacteria producing urease. Once the death phase had initiated in the stationary growth phase, cells were rapidly bleached of all pigmentation. Null mutations in the ureC gene, encoding the alpha subunit of urease, were constructed, and these mutants were no longer sensitive to growth in the presence of urea. High levels of peroxides, including lipid peroxides, were detected in the bleaching cells. Exogenously added polyunsaturated fatty acids triggered a similar death response. Vitamin E suppressed the formation of peroxides and delayed the onset of cell bleaching. The results suggest that these cyanobacterial cells undergo a metabolic imbalance that ultimately leads to oxidative stress and lipid peroxide formation. These observations may provide insights into the mechanism of sudden cyanobacterial bloom disappearance in nature.