Impacts of anthropogenic emissions and meteorology on spring ozone differences in San Antonio, Texas between 2017 and 2021

San Antonio has been designated as ozone nonattainment under the current National Ambient Air Quality Standards (NAAQS). Ozone events in the city typically occur in two peaks, characterized by a pronounced spring peak followed by a late summer peak. Despite higher ozone levels, the spring peak has received less attention than the summer peak. To address this research gap, we used the Weather Research and Forecasting (WRF)-driven GEOS-Chem (WRF-GC) model to simulate San Antonio's ozone changes in the spring month of May from 2017 to 2021 and quantified the respective contributions from changes in anthropogenic emissions and meteorology. In addition to modeling, observations from the San Antonio Field Studies (SAFS), the Texas Commission on Environmental Quality (TCEQ) Continuous Ambient Monitoring Stations (CAMS), and the spaceborne TROPOspheric Monitoring Instrument (TROPOMI) are used to examine and validate changes in ozone and precursors. Results show that the simulated daytime mean surface ozone in May 2021 is 3.8 ± 0.6 ppbv lower than in May 2017, which is slightly less than the observed average differences of -5.3 ppbv at CAMS sites. The model predicted that the anthropogenic emission-induced changes contribute to a 1.4 ± 0.5 ppbv reduction in daytime ozone levels, while the meteorology-induced changes account for a 2.4 ± 0.6 ppbv reduction over 2017-2021. This suggests that meteorology plays a relatively more important role than anthropogenic emissions in explaining the spring ozone differences between the two years. We additionally identified (1) reduced NO2 and HCHO concentrations as chemical reasons, and (2) lower temperature, higher humidity, increased wind speed, and a stronger Bermuda High as meteorological reasons for lower ozone levels in 2021 compared to 2017. The quantification of the different roles of meteorology and ozone precursor concentrations helps understand the cause and variation of ozone changes in San Antonio over recent years.

Spatial and temporal analysis of HCHO response to drought in South Korea

Though drought is known to affect biogenic emissions of volatile organic compounds (BVOC), its effect on isoprene and formaldehyde (HCHO), a high yield product of isoprene, has not been investigated in East Asia where incidences of drought have increased in recent years. In this work, we analyzed the impact of drought on HCHO in the South Korea region during the summer period (June, July, and August) from 2005 to 2018 and found increased HCHO due to drought. The tropospheric HCHO column density retrieved by OMI increased by 8.02 % during extreme drought compared to the non-drought period, whereas no significant effect of drought on the NO₂ column was found. Regional variation of HCHO response to drought correlates significantly with the tree percentage of the region. This correlation indicates that the drought-led HCHO increases are most likely driven by the increase in isoprene emissions during drought. Indeed, model predicts isoprene emissions to be higher by 27.87 % during the extreme drought compared to the non-drought period in South Korea. From 2005 to 2018, the HCHO column has been increasing in South Korea by 0.16 × 10¹⁵ molecules/cm²/year (1.56 % per year) during summer months, correlated with the increasing incidences of drought. HCHO increase is linked to higher ozone as most of South Korea is in the NOx-saturated or transitional regime.

Infectious complications following abdominal hysterectomy in Karachi, Pakistan

OBJECTIVE

In this paper we studied the prevalence of post-operative infections after total abdominal hysterectomy in Karachi, Pakistan and their associated risk factors.

METHOD

A retrospective analysis was conducted by reviewing the case notes of 827 consecutive total abdominal hysterectomies.

RESULTS

The post-operative infection rate was 22%. Of the patients, 6% (49) developed operative site infections including wound and vaginal cuff infections and pelvic abscesses while 16% (133) developed non-operative site infections including urinary tract infections and thrombophlebitis. Six risk factors were found to be significantly associated with post-operative infections: a pre-operative hospitalization of more than 2 days (P<0.02); additional non-gynecological procedures performed intra-operatively (P<0.02); indwelling catheterization for more than 7 days (P<0.001); patient's age greater than 50 years (P<0.02); an underlying malignancy (P<0.0001); and developing a hematoma post-operatively (P<0.04).

CONCLUSION

The results of this study may serve as a baseline for future comparison and indicate interventions which may contribute to a reduction in the post-operative infection rate.

Placenta percreta with bladder invasion as a cause of life threatening hemorrhage

PURPOSE

Abnormal placental penetration through the myometrium with bladder invasion is a rare obstetric complication with potential for massive blood loss. Urologists are usually consulted after a life threatening emergency has already arisen. Their familiarity with this condition is crucial for effective management. We describe 2 cases of placenta percreta with bladder invasion to highlight the catastrophic nature of this clinical entity, and review the literature on current diagnostic and management strategies.

MATERIALS AND METHODS

Between 1986 and 1998, 250 cases of adherent placenta (0.9%) were identified in 25,254 births at our institution, including 2 (0.008%) of placenta percreta with bladder invasion. We treated these 2 multiparous women who were 33 and 30 years old, respectively. Each had undergone 2 previous cesarean sections.

RESULTS

Presenting symptoms were severe hematuria in 1 patient and prepartum hemorrhage with shock in the other. Ultrasound showed complete placenta previa in each with evidence of bladder invasion in 1 patient. Hysterectomy, bladder wall resection and repair, and bilateral internal iliac artery ligation were required to control massive intraoperative hemorrhage. The patients received 22 and 15 units of packed red blood cells, respectively. Fetal death occurred in each case. Convalescence was complicated by disseminated intravascular coagulation in patient 1 but subsequent recovery was uneventful.

CONCLUSIONS

A high index of suspicion for placenta percreta with bladder invasion is required when evaluating pregnant women with a history of cesarean delivery and placenta previa who present with hematuria and lower urinary tract symptoms. Ultrasonography and magnetic resonance imaging may assist in establishing the diagnosis preoperatively. With proper planning and a multidisciplinary approach fetal and maternal morbidity and mortality may be decreased.

Prevalence of chlamydial infection in females attending antenatal and family planning clinics in Karachi Pakistan

A prospective study was undertaken to investigate the relative prevalence of Chlamydia trachomatis in asymptomatic pregnant women of 2 socioeconomic groups and those attending the family planning clinics. Group 1 consisted of women attending the antenatal clinics of the Aga Khan University Hospital which caters to the affluent strata of our society (n = 100). Group 2 comprised women attending the antenatal clinics of Lady Dufferin Hospital which provides free obstetric care to women belonging to the lower socioeconomic groups of Karachi (n = 100). Group 3 consisted of sexually active women attending the family planning clinics of Lady Dufferin Hospital (n = 100). Endocervical swabs were taken from women assigned to each group. Chlamydiazyme, an enzyme linked immunoassay, was used to detect chlamydia antigen. The positive samples were retested by using the direct fluorescent monoclonal antibody technique. Chlamydia positive patients and their sexual partners were treated with Erythromycin stearate 500 mg 8-hourly for 7 days. These patients were retested after antibiotic therapy to assess the efficacy of the therapy. In groups 1 and 2, 2% and in Group 3, 12% of the females tested positive. Selective screening of sexually active women for chlamydial infection is advocated as a cost-effective public health measure.

Characteristics of menopause in three socioeconomic urban groups in Karachi, Pakistan

To determine age, symptoms and treatment choices in Pakistani women with spontaneous menopause, three groups in Karachi were interviewed using a structured questionnaire. The groups consisted of 250 poor slum dwellers, 250 middle class clinic attenders and 150 wives of retired military officers. Interviews were carried out in 1989 and 1990 by members of a team from the Aga Khan University consisting of a gynaecologist, a community health physician and two senior medical students. All interviewees had natural menopause at least 12 months previously. The results showed a mean age of 47 years for menopause in all groups. One in five women were symptomatic in the poorest group but one in two were in the other groups. Treatment was sought by 6% in the poor group, 26% of the middle class group and 38% of the most privileged group. Age at menopause was 4 years earlier than in most reports and fewer women had menopausal symptoms. These urban women may not represent the situation across the country but, as life expectancy in Pakistan is rising (now 56.4 years for women), menopausal problems may increase.

Indole Alkaloids from Trachelospermum jasminoides

The leaves and stems of T. JASMINOIDES have been found to contain indole alkaloids. Five indole alkaloids, coronaridine, voacangine, apparicine, conoflorine, and 19-epi-voacangarine have been isolated. The (13)C-NMR spectra of apparicine and 19-epi-voacangarine are also reported.