A microfabricated low-profile wideband antenna array for terahertz communications.

While terahertz communications are considered to be the future solutions for the increasing demands on bandwidth, terahertz equivalents of radio frequency front-end components have not been realized. It remains challenging to achieve wideband, low profile antenna arrays with highly directive beams of radiation. Here, based on the complementary antenna approach, a wideband 2 × 2 cavity-backed slot antenna array with a corrugated surface is proposed. The approach is based on a unidirectional antenna with a cardiac radiation pattern and stable frequency characteristics that is achieved by integrating a series-resonant electric dipole with a parallel-resonant magnetic dipole. In this design, the slots work as magnetic dipoles while the corrugated surface radiates as an array of electric dipoles. The proposed antenna is realized at 1 THz operating frequency by stacking multiple metallized layers using the microfabrication technology. S-parameter measurements of this terahertz low-profile metallic antenna array demonstrate high efficiency at terahertz frequencies. Fractional bandwidth and gain are measured to be 26% and 14 dBi which are consistent with the simulated results. The proposed antenna can be used as the building block for larger antenna arrays with more directive beams, paving the way to develop high gain low-profile antennas for future communication needs.

Extended subcutaneous tunnelling technique for external ventricular drainage.

Infection is a serious complication of external ventricular drain (EVD) and various strategies have been adopted to minimize its occurrence. The use of an extended subcutaneous tunnel (50-60 cm) was previously described, but has since received little attention in the literature. The authors reviewed their experience with this technique, with emphasis on the rate of infection and predisposing risk factors. This is a retrospective review of 114 patients who received EVD with extended subcutaneous tunnel ('long EVD'). Fourteen of the 114 patients underwent more than one insertion, and a total of 133 cases of 'long EVD' were included. The mean duration of drainage was 20 days. One-hundred-and-three cases started without pre-existent infection and seven became infected, yielding an overall infection rate of 6.8%. The majority of infections were found within the first 5 days and in the third week of drainage. There was, however, no statistically significant difference in daily infection risks between the first, second and third weeks. Only intraventricular instillation of urokinase was identified as a statistically significant risk factor. Non-infective complications occurred in 17 cases (12.8%). In the present study, the overall infection rate of the 'long EVD' was comparable with that of conventional EVD, as reported by other authorities in the literature. The extended subcutaneous tunnel technique did not affect the daily infection risk on a week-to-week basis. The 'long EVD' does not appear to offer any distinct advantage over the standard tunnelling technique in our unit. However, this is essentially an audit within a single centre, and the findings should be interpreted with caution and with the understanding that individual institutions may have their unique patterns and risks of EVD infection.

Retrospective prevalence of snakebites from Hospital Kuala Lumpur (HKL) (1999-2003).

A hospital based retrospective study of the prevalence of snakebite cases at Hospital Kuala Lumpur was carried out over a five-year period from 1999 to 2003. A total of 126 snakebite cases were recorded. The highest admission for snakebites was recorded in 2001 (29 cases). The majority of cases were admitted for three days or less (79%). Most of the snakebite cases were reported in the 11-30 years age group (52%). The male:female ratio was 3:1. The majority of cases were Malaysians (80%, 101 cases). Of the non-Malaysians, Indonesians constituted the most (56%, 14 cases). Bites occurred most commonly on the lower limbs (49%), followed by upper limbs (45%) and on other parts of the body (6%). No fatal cases were detected and complications were scarce. In 60% (70 cases) the snake could not be identified. Of the four species of snakes that were identified, cobra (both suspected and confirmed) constituted the largest group (25%), followed by viper (10%), python (4%) and sea snake (1%). The most common clinical presentations were pain and swelling, 92% (116 cases). All patients were put on snakebite charts and their vital signs were monitored. Of the snakebite cases, 48% (61 cases) were treated with cloxacillin and 25% (32 cases) were given polyvalent snake antivenom.

The incidence of pregnancy-induced hypertension among patients with carbohydrate intolerance.

OBJECTIVE: To determine the association between pregnancy-induced hypertension (PIH) and carbohydrate intolerance in pregnancy. METHODS: Data on singleton pregnancies were retrieved from the obstetric database of University Hospital, Kuala Lumpur. Gestational impaired glucose tolerance (GIGT) and gestational diabetes mellitus (GDM) were defined according to the World Health Organization criteria. Established diabetes mellitus (EDM) was defined as diabetes mellitus diagnosed prior to pregnancy. PIH was diagnosed according to the criteria of the International Society for the Study of Hypertension in Pregnancy. Maternal characteristics were compared between groups using analysis of variance (ANOVA) and incidence counts using the chi-squared test. Logistic regression analysis using the presence of PIH as the response variable was used to study the association among GDM, GIGT, EDM, and PIH, controlling for maternal factors. MAIN OUTCOME MEASURES: To determine the incidence of PIH among patients with glucose intolerance and the independent risk factors for the development of PIH. RESULTS: There were 24,290 singleton pregnancies retrieved from the database. Both the prevalence of carbohydrate intolerance and the incidence of PIH differed among the three principal ethnic groups (p < 0.0001). There was a significant association between PIH and both a higher maternal age (OR = 1.04, p < 0.0001) and a higher maternal body mass index (BMI) at delivery (OR = 1.14 per unit increment, p < 0.0001). After adjusting for maternal age, BMI, parity, and ethnic origin, using logistic regression, there was a significant residual risk of PIH among individuals with GIGT, GDM, or EDM. CONCLUSIONS: Patients with carbohydrate intolerance of varying severity are at increased risk of developing PIH. Our findings lend credence to the theory that carbohydrate intolerance and PIH share a common etiology.

Colonization and transmission of Ureaplasma urealyticum and Mycoplasma hominis from mothers to full and preterm babies by normal vaginal delivery.

A prospective study was carried out among pregnant women and their newborn babies in the University Hospital, Kuala Lumpur from January 1996 to June 1997. The maternal cervical colonization rates of Ureaplasma urealyticum (UU) and Mycoplasma hominis (MH) were found to be 57.5% and 15.8% respectively while the isolation rates from nasopharyngeal secretions of the newborns were 50.8% for UU and 6.6% for MH. The overall transmission rates were 88.4% for UU and 42.1% for MH. There was no significant difference in the transmission rates of either organism from mothers to their respective newborn babies by the maturity of pregnancy. In preterm babies, the nasopharyngeal isolation rates of UU and MH were not influenced by the babies' gestational age and birth weight nor by the maternal history of abortion or parity. However, there was a tendency for UU to persist in the nasopharyngeal secretion of preterm babies especially those of birth weight below 2 kg. None of the babies contaminated with mycoplasmas at birth developed respiratory symptoms during six to eight weeks of follow-up.

Ureaplasma urealyticum and Mycoplasma hominis isolation from cervical secretions of pregnant women and nasopharyngeal secretions of their babies at delivery.

BACKGROUND: A prospective study was carried out at the University Hospital, Kuala Lumpur to determine the cervical carriage rate of Ureaplasma urealyticum and Mycoplasma hominis among healthy pregnant women at delivery and the incidence of nasopharyngeal colonisation among their infants. PATIENTS: Sixty mother and baby pairs were examined. RESULTS: Cervical colonisation among the mothers was found to be 56.7% for U.urealyticum and 17.7% for M.hominis. The transmission rate to their infants was 88.2% and 30% for U.urealyticum and M.hominis respectively. CONCLUSION: There was no statistically significant difference in the maternal colonisation rates according to ethnic group, parity and past history of abortion. All U.urealyticum isolates in our study were sensitive to erythromycin but about one-third were resistant to tetracycline and ciprofloxacin and 26.5% were resistant to minocycline.

Vertical transmission of dengue.

Dengue, an important mosquito-borne flavivirus infection, is endemic in Southeast Asia. We describe two mothers who had acute dengue 4 and 8 days before the births of their infants. One mother had worsening of her proteinuric pregnancy-induced hypertension, liver dysfunction, and coagulopathy and required multiple transfusions of whole blood, platelets, and fresh frozen plasma. Her male infant was ill at birth, developed respiratory distress and a large uncontrollable left intracerebral hemorrhage, and died of multiorgan failure on day 6 of life. Dengue virus type 2 was isolated from the infant's blood, and IgM antibody specific to dengue virus was detected in the mother's blood. The second mother had a milder clinical course; she gave birth to a female infant who was thrombocytopenic at birth and had an uneventful hospitalization. Dengue virus type 2 was recovered from the mother's blood, and IgM antibody specific to dengue virus was detected in the infant's blood. This report highlights not only the apparently rare occurrence of vertical transmission of dengue virus in humans but also the potential risk of death for infected neonates.

The predictive value of extremes of birth weight, mother's height and ethnic origin on the likelihood of emergency caesarean section.

We reviewed the deliveries in a teaching hospital in a multiracial community over the period of one year (1988), and investigated the relationship between maternal height, ethnic origin, and the extremes of birth weight with the likelihood of emergency lower segment caesarean section (LSCS). After excluding patients with obvious indications for LSCS, 5,050 patients were entered in the study. Chi-square analysis showed that the risk of emergency LSCS is significantly higher in the Indians compared to Chinese and Malays, but does not differ significantly between the latter two groups. Logistic regression analysis showed that birth weight of less than 2,500 g or greater than 3,500 g is the most significant association with emergency LSCS rate. Conditional logistic regression showed that, provided the individuals conformed to the characteristics of the cohort in this study, risk of emergency LSCS for a 150 cm (25th centile) tall Indian pregnant lady is almost twice that of a 158 cm (75th centile) tall non-Indian).

The adverse effect of fibrin-clot inhibiting drugs on intravesical bacillus Calmette-Guérin efficacy for superficial bladder cancer.

Bacillus Calmette-Guérin (BCG) is currently thought to act as a biological immune modifier in effecting antitumour activity. Recent evidence suggests that BCG binding to fibronectin (FN), a tissue glycoprotein, may be a prerequisite step in initiating this response. Drugs inhibiting the availability of exposed FN in the bladder after urothelial disruption may adversely affect the efficacy of BCG. Data are presented of 45 patients with tumour limited to mucosa (pTa) or carcinoma in situ (CIS) given intravesical BCG therapy, with (group 1) or without (group 2) fibrin clot-inhibiting drugs concurrently during treatment. The success rate of 11.1% for group 1 (1/9) patients was significantly less than that of 69.4% for group 2 (25/36), (chi 2 = 7.79, P < 0.01 Fisher's exact test) supporting the suggestion that the concurrent administration of fibrin-clot inhibiting drugs may adversely affect the outcome of BCG therapy.

Ruptured subcapsular haematoma of the liver in pregnancy; a case report.

A case of ruptured subcapsular haematoma of the liver, a rare and potentially lethal complication of pre-eclampsia, is presented. The lack of characteristic signs and symptoms is highlighted. This case serves to remind clinicians of the high maternal and perinatal mortality rates associated with complications of hypertension in pregnancy.