侧明151井φ139.7mm套管走向开窗侧钻小井眼技术的研究

侧明151井是中原油田φ139．7mm套管定向开窗侧钻小井眼技术攻关的第一口井。该井斜向器陀螺定向、φ139．7mm套管开窗、修窗一次成功，整个裸眼段φ116mm小井眼轨迹控制良好，完全达到设计要求，为中原油田老井侧钻、特别是小井眼套管定向开窗侧钻小井眼技术的提高打下了坚实的基础。文中详细介绍了该井的施工情况及技术特点。     

Torsion of wandering spleen: the whorled appearance of the splenic pedicle on CT

Congenital deficiency or acquired laxity of the suspensory ligaments of the spleen may result in extreme splenic mobility. This rare condition, which is termed wandering or ectopic spleen predisposes the elongated splenic pedicle to torsion. We present a case of splenic torsion with a new CT finding consisting of a whorled appearance of the splenic pedicle. To our knowledge this finding has not been described before.     

Patterns of chemical residues detected in US beef carcasses between 1991 and 1993

A study of data from 12 states in the Food Safety Inspection Service's Residue Violation Information System was conducted to describe patterns of violative chemical residues in US beef during 1991, 1992, and 1993. In 1991, 3,249 violative residues were found in 2,734 carcasses in the 12 states included in the study. In 1992, 3,132 violative residues were found in 2,813 carcasses, and in 1993, 2,317 violative residues were found in 2,051 carcasses. During each of the 3 years, the Calf Antibiotic and Sulfonamide Test and Swab Test On Premises projects detected most of the violative residues, and producers/independent growers and dairy farms were recorded as the responsible sources for most of the violations. Also, most of the animals found to have violative residues were bob calves and culled cows. In bob calves, neomycin was the most frequently identified violative chemical, followed by tetracycline, gentamicin, oxytetracycline, and penicillin. In culled cows, penicillin was the most frequently identified violative chemical and was the chemical most frequently found in combination with other chemicals in cows with multiple violative residues. Distribution patterns of violative chemical residues by slaughter class and residue type varied among the 5 Food Safety Inspection Service regions. These specific regional characteristics support the need for customized intervention, education, assessment, and prevention programs.     

Assessing the patient at risk for oral squamous cell carcinoma

Patients and health care workers require continuing education to promote knowledge of the signs, symptoms, and risk factors for oral cancer. This paper reviews the literature assessing diagnostic tools that are currently available or being developed, in order to assist in the biopsy site selection and subsequent diagnosis of patients at risk for oral cancer. There is a general consensus that oral examination of patients at risk for oral squamous cell carcinoma (SCC) should be conducted on a routine basis. However, there can be false-positive and false-negative findings. Toluidine blue has been shown to be useful as an adjunct to the clinical examination when used by experienced clinicians. Exfoliative cytology is not currently used as a routine measure for the evaluation of lesions of the oral mucosa, but further development and the application of biologic markers to cytologic specimens may increase its value. Fluorescent imaging of malignant lesions of the oral mucosa has been shown to be sensitive and specific in animal models but thus far has been reported in only one human trial. The sensitivity and specificity of these techniques when used by general practitioners need to be assessed. Further, none of the above procedures has yet been shown to be a cost-effective public health measure in screening for oral cancer.     

Engineering a change in metal-ion specificity of the iron-dependent superoxide dismutase from Mycobacterium tuberculosis-- X-ray structure analysis of site-directed mutants

We have refined the X-ray structures of two site-directed mutants of the iron-dependent superoxide dismutase (SOD) from Mycobacterium tuberculosis. These mutations which affect residue 145 in the enzyme (H145Q and H145E) were designed to alter its metal-ion specificity. This residue is either Gln or His in homologous SOD enzymes and has previously been shown to play a role in active-site interactions since its side-chain helps to coordinate the metal ion via a solvent molecule which is thought to be a hydroxide ion. The mutations were based on the observation that in the closely homologous manganese dependent SOD from Mycobacterium leprae, the only significant difference from the M. tuberculosis SOD within 10 A of the metal-binding site is the substitution of Gln for His at position 145. Hence an H145Q mutant of the M. tuberculosis (TB) SOD was engineered to investigate this residue's role in metal ion dependence and an isosteric H145E mutant was also expressed. The X-ray structures of the H145Q and H145E mutants have been solved at resolutions of 4.0 A and 2.5 A, respectively, confirming that neither mutation has any gross effects on the conformation of the enzyme or the structure of the active site. The residue substitutions are accommodated in the enzyme's three-dimensional structure by small local conformational changes. Peroxide inhibition experiments and atomic absorption spectroscopy establish surprisingly the H145E mutant SOD has manganese bound to it whereas the H145Q mutant SOD retains iron as the active-site metal. This alteration in metal specificity may reflect on the preference of manganese ions for anionic ligands.     

Determination of gestational age from lunar age assessments in human fetal remains

Occasionally forensic fetal remains are submitted to the office of the medical examiner for age determination. A variety of literature and many techniques are available for this assessment depending upon the overall condition of the remains. If one uses traditional forensic anthropological sources, then age is calculated in lunar months; if one uses other sources--embryological, anthropological and sonographic--then age is reported as gestational weeks. For comparison between ages derived from these various studies, especially in cases involving age assessments of incomplete fetal remains that may be partially damaged by taphonomic factors, it is necessary to convert between lunar age and gestational age. The objective of this study is to present a conversion table for exact correspondence between lunar months and gestational weeks from the point of conception to term. This information is useful for developing a forensic profile at any gestational age as well as providing a means to assess the probability of viability at the time of death.