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Research insurance funds investment based on constant elasticity of variance (CEV) model, consider a model which the risky asset is modeled by CEV model and the aggregate claims are inodeled by a Brownian motion with drift. As employment of premium is different from ordinary, which means that the insurer should keep an eye on underwrite risk when he use insurance funds, assume that investment risk has a linear correlation with underwrite risk. According to stochastic control theory, derive the HJB equation related with insurance problem. This equation is non-linear partial differential equation, yet it is difficult to solve it, change primary problem to the dual problem by using Legendre transform. Through setting the parameter values, the optimal investment strategy for an insurer with CARA or CRRA utility flmction is presented and the relevant analysis is given, which provides important practical significance for an insurer to invest. [ABSTRACT FROM AUTHOR]

A new method for determination of trace iron in superconductor powder by ICP-AES was proposed. The instrument parameters were optimized, and the matrix effects as well as the method of eliminating interferences were also studied systemically. The results showed that matrix interference was serious when the amount of matrix increased, and the repeatability was poor, so it was necessary that separation and preconcentration were used to improve the accuracy and precision. In the experiment, complex was formed with Fe and phenanthroline after the matrix elements Bi and Cu were masked by triethanolamine in an appropriate acidity condition. Then the complex was quantitatively adsorbed by activated carbon, and desorbed by 1 : 1 HNO3. The enrichment conditions were investigated in detail. Under the optimal condition, an artificial sample was analysed, and the result was identical with reference values, with the RSD and detection limit being 2.42% and 0.033 microg x g(-1), respectively. The method was applied for the determination of trace iron in Bi-based superconductor powder samples with satisfactory results, in which the recoveries experiment was performed with the recovery coefficient falling in the range of 95.6% to 98.0%.

A new method for the determination of trace nickel in superconductor powder by ICP-AES was proposed. The instrument parameters were optimized, and the matrix effects as well as the method of eliminating interferences were also studied systemically. The results showed that matrix interference in the superconductor powder was serious when the amount of matrix increased, and the repeatability as well as the accuracy was poor, so it was necessary to used separation and preconcentration to improve the accuracy and precision. In this experiment, Ni-diacetyl dioxime complexes were enriched by toluene extraction in alkaline condition after eliminating the interference of major element Bi and partial Pb, Sr, Ca and Cu by eluting with anion exchange resin, then the Ni-complexes were back extracted by diluted hydrochloric acid. The enrichment conditions were investigated in detail and the recovery rate of Ni was higher than 95%. Under the optimal condition, an artificial sample was analysed, the result showed that the found values were identical with reference values, and the RSD and detection limit were 1.9% and 0.19 microg x g(-1), respectively. The method has been applied to the determination of trace nickel in Bi-based superconductor powder samples with satisfactory results.

Objective: To study the value of cervical length (CL) by transvaginal sonography in the mid-trimester and late-trimester for the prediction of preterm delivery., Methods: The CL was measured by transvaginal sonography for 5277 pregnant women between 22 - 24 weeks and 28 - 32 weeks gestation, who were prenatal cared and delivered at the First Hospital of Peking University from June 2008 to November 2009. The pregnancy outcomes were followed, and the relationship between CL and preterm delivery and preterm premature rupture of membrane was studied., Results: (1) The incidence of preterm delivery was 5.4% (289/5370) total, among of them the incidence of therapeutic preterm delivery was 1.7% (93/5370), spontaneously preterm delivery was 1.2% (62/5370), and preterm premature rupture of membrane was 2.5% (134/5370). There are 4 cases (4/5370) who occured late abortion. (2) Excluding the 93 women who had therapeutic preterm delivery, the mean CL of 22 - 24 weeks was (38.8 ± 4.0) mm. The relative risk for preterm delivery when the CL < 30 mm was 5.2, when CL < 25 mm, the relative risk was 11.1, and when CL < 15 mm the relative risk for preterm delivery was 13.8. The average CL during 28-32 weeks of gestation was (34.6 ± 4.8) mm, was significantly shorter than that of 22 - 24 weeks (P < 0.05). During this period the relative risk for preterm delivery when the CL < 30 mm was 6.9, when CL < 25 mm, the relative risk was 11.1, and when CL < 15 mm the relative risk for preterm delivery was 20.0. (3) A CL < 30 mm as the cut-off value for predicting preterm delivery during 22 - 24 weeks of gestation has only a 3% sensitivity and 19% positive predictive value, but had a 99% specificity and 96% negative predictive value. The sensitivity, positive predictive value, specificity and negative predictive value for a CL < 30 mm as the cut-off value for predicting preterm delivery during 28 - 32 weeks of gestation was 33%, 21%, 95% and 97% respectively. (4) The total number of preterm premature rupture of membrane pregnant women was 134 (2.5%), who had a mean CL of (38.4 ± 4.7) mm during 22 - 24 weeks of gestation, was similar with the women without preterm premature rupture of membrane (PPROM), but during 28 - 32 weeks of gestation the women who occured PPROM had a mean cervical length of (30.6 ± 8.1) mm, and was significantly shorter than that of women without PPROM (34.7 ± 4.6) mm., Conclusions: (1) CL in 28 - 32 weeks of gestation is significantly shorter than that of in the mid-gestation, but more than 90% of women has a CL ≥ 30 mm. (2) The shorter the CL is, the greater the relative risk of preterm delivery. According to different CL for clinical consulting objective relative risk could be provide. (3) The CL during 28 - 32 weeks of gestation can also predict preterm delivery, the sensitivity is obviously better than that of 22 - 24 weeks of gestation. (4) The CL during 28 - 32 weeks of gestation is valuable for predicting of PPROM.

Objective: To improve the diagnosis and treatment of paratesticular embryonal rhabdomyosarcoma (PER)., Methods: We retrospectively studied the clinical data of 5 cases of PER treated from 1997 to 2009 and reviewed the relevant literature, focusing on its clinical manifestations, diagnosis and treatment., Results: The 5 cases of PER, 2 involving the spermatic cord, 2 the testis and 1 the tunica vaginalis, were all treated by radical orchiectomy. Pathologically, 2 cases were classified as stage I, 1 as stage II and 2 as stage IV. Postoperatively, 2 of the patients received chemotherapy and the other 3 refused adjunctive therapy. The patients were followed up for 6, 12, 18 and 28 months, respectively. Four of them remained free from relapse and metastasis, and 1 stage IV patient died of multiple metastasis at 6 months., Conclusion: Early diagnosis, radical orchiectomy and adjunctive chemo- or radio-therapy are effective means to the treatment of PER.

Objective: To investigate the role of KAI1 gene expression and loss of heterozygosity (LOH) of KAI1 in metastatic potential and prognosis of pancreatic cancer., Methods: The expression of KAI1 gene was studied by immunohistochemistry for CD82 on paraffin-embedded tumor tissues. The LOH of KAI1 gene was detected by microdissection, polymerase chain reaction (PCR) and denaturing high performance liquid chromatography (DHPLC)., Results: The positivity rate of CD82 in primary pancreatic cancer was 76% (47/62). CD82 expression was significantly higher (P < 0.01) in earlier tumor stages (I and II), as compared to the advanced tumor stages ( III and IV) in which nodal or distant metastases were present. The expression rate of CD82 in patients who survived for more than one year was higher than that in patients who survived for less than one year (P < 0.05). The percentage of LOH at D11S1344 and D11S1326 loci was 17%., Conclusions: The abnormal expression of CD82 which participates in malignant progression of pancreatic cancer is probably associated with LOH of KAI1 gene. Detection of CD82 expression and LOH of KAI1 gene may carry potential clinical significance in evaluating the metastatic potential and prognosis of pancreatic cancer.