Epitaxial growth of graphene on 6H-silicon carbide substrate by simulated annealing method.

We grew graphene epitaxially on 6H-SiC(0001) substrate by the simulated annealing method. The mechanisms that govern the growth process were investigated by testing two empirical potentials, namely, the widely used Tersoff potential [J. Tersoff, Phys. Rev. B 39, 5566 (1989)] and its more refined version published years later by Erhart and Albe [Phys. Rev. B 71, 035211 (2005)]. Upon contrasting the results obtained by these two potentials, we found that the potential proposed by Erhart and Albe is generally more physical and realistic, since the annealing temperature at which the graphene structure just coming into view at approximately 1200 K is unambiguously predicted and close to the experimentally observed pit formation at 1298 K within which the graphene nucleates. We evaluated the reasonableness of our layers of graphene by calculating carbon-carbon (i) average bond-length, (ii) binding energy, and (iii) pair correlation function. Also, we compared with related experiments the various distance of separation parameters between the overlaid layers of graphene and substrate surface.

Detection of a noble gas molecular ion, 36ArH+, in the Crab Nebula.

Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5- and 1234.6-gigahertz J = 1-0 and 2-1 rotational lines of (36)ArH(+) at several positions in the Crab Nebula, a supernova remnant known to contain both molecular hydrogen and regions of enhanced ionized argon emission. Argon-36 is believed to have originated from explosive nucleosynthesis in massive stars during core-collapse supernova events. Its detection in the Crab Nebula, the product of such a supernova event, confirms this expectation. The likely excitation mechanism for the observed (36)ArH(+) emission lines is electron collisions in partially ionized regions with electron densities of a few hundred per centimeter cubed.

Investigating stillbirths using a simplified obstetric events-based protocol.

INTRODUCTION: A stillbirth remains a distressing enigma to parents and clinicians alike as the cause often remains elusive. Few papers describe a protocol for the investigation of stillbirths. We evaluate the first obstetric events-based protocol designed for local use with an aim to adequately investigate stillbirths in a cost-effective manner. METHODS: A prospective cohort study was performed on 61 stillbirths at KK Women's and Children's Hospital. There were a total of 16,980 births in the year 2000. RESULTS: 37.7 percent of cases remained unexplained. There was protocol compliance in 51 cases (83.6 percent) with deviation in 10 cases (16.4 percent). The protocol helped to minimise costs in 18 cases (29.5 percent) as selected investigations were performed in view of obvious causes. The overall postmortem rate was 27.9 percent with the lowest rates in the Malay population. CONCLUSION: An obstetric events-based protocol allows clinicians to tailor their investigations easily and appropriately. It helps to provide optimal investigations and minimise unnecessary costs. It could be further fine-tuned by initiating detailed serum investigations only after delivery so as to exclude an obvious cause, like cord accidents, where full investigations are unnecessary.

Routine screening for Chlamydia trachomatis in subfertile women--is it time to start?

UNLABELLED: Genital Chlamydia trachomatis infection has long been recognised as the major cause of pelvic disease and subsequently infertility. The diagnosis of this infection has traditionally relied on tissue culture. The availability of DNA amplification methods like ligase chain reaction promises faster and more sensitive results. This study was conducted to evaluate the prevalence of chlamydial infection in a subfertile population subgroup. AIM: A case control longitudinal study of 100 subfertile women in a tertiary teaching hospital were analyzed for the prevalence of genital Chlamydia trachomatis infection using ligase chain reaction test kit. RESULTS: A prevalence rate of 8% was detected, the majority being 25 years old or less (33.3%), p = 0.007. All patients gave no prior history of abnormal PAP smears, hospitalisation for pelvic inflammatory disease or abnormal vaginal discharge at the time of investigation. CONCLUSION: Our infertile group of patients has a relatively high incidence of silent genital Chlamydia trachomatis infection. This being highest in the below 25 years old age group. This finding indicates that screening for chlamydia may be necessary for the subfertile couple presenting to clinic. This is especially so if the patient is of the younger age group.

Uterine papillary serous carcinoma--the KK Hospital experience.

A review of 355 cases of endometrial cancer treated at the KK Gynaecological Cancer Centre from June 1987 to June 1997 revealed 19 cases (5.3%) of uterine papillary serous carcinoma (UPSC), a clinically aggressive and pathologically distinct variant of adenocarcinoma which closely resembles ovarian papillary serous carcinoma. The majority of UPSC presented as late stage disease with 79% showing extrauterine disease. Twelve of 15 patients also had lymphovascular space invasion. Of the 19 cases, 15 had total hysterectomy and bilateral salpingo-oophorectomy with or without omentectomy and lymphadenectomy. Two had omental biopsy only and another 2 had dilatation and curettage only. The overall median survival in the series was 15 months. Twelve patients had died of disease (67%). Early stage disease seemed to confer a better prognosis. The poor prognosis is frequently ascribed to its tendency to present at a late stage.

Ureteral injuries in an obstetric and gynaecology teaching hospital.

Between November 1994 to May 1996, there was a total of eight ureteric injuries out of 2495 major gynaecologic operations and one ureteric injury out of 4146 caesarean sections at the Kandang Kerbau Hospital, giving the incidence to be 0.3% and 0.02% respectively. Antecedent operations were four abdominal hysterectomies, two Werthiem's hysterectomies, one laparoscopic-assisted vaginal hysterectomy and one caesarean section. All operations were performed by qualified specialists. Three patients had previous abdominal operations and five patients had procedures complicated by dense adhesions. Only one injury was detected intraoperatively and the rest presented with uretero-vaginal fistula. One presented with immediate postoperative anuria. The average time interval for diagnosis ranged between one day and twenty-three days (average 10.7 days). The commonest damage was transection of the ureter. Double J stents were used in all repairs with two cases requiring reimplantation with psoas hitch, and two cases of ureteroneocystostomies and one case of primary reanastomosis. There were no mortality in our series.