Obstetric hysterectomy in a tertiary centre: a 3-year retrospective study

Background: Obstetric hysterectomy (OH) is a life-saving procedure and involves removal of uterus in cases of intractable hemorrhage. This study includes 21 cases of OH in a period of 3 years at a tertiary centre. We sought to understand the prevalence, indications and outcomes of emergency obstetric hysterectomy. Methods: This is a retrospective, observational study, conducted with the means of hospital delivery records in a tertiary care centre in Navi Mumbai. We included all patients who underwent obstetric hysterectomy in a span of 3 years between 1st April 2020 to 31st March 2023, in Dr. D.Y. Patil Hospital, Navi Mumbai, India. Results: Twenty- one OH were done in the period of study. The incidence of obstetric hysterectomy was 0.45% (452 OH per 100,000 deliveries). It was more prevalent in patients with caesarean section compared to vaginal delivery. Women between the age 25-35 years group comprised of 57.15% cases. Out of the 21 women in the study 7 women were primigravida (33.33%). Most common cause for OH was observed to be uterine atony (42.85%) followed by adherent placenta (28.57%). Maternal morbidity like admission to intensive care unit and need for blood and blood product transfusion was noted in most patients, mortality was observed in only 1 case. Neonatal mortality was nil in this study but, admission to neonatal intensive care unit was required in 7 patients. Conclusions: Although, obstetric hysterectomy kills the future reproductive prospect for a woman, it is life saving for her. Timely decision for OH can not only prevent mortality but, also morbidity for the woman. Previous caesarean section and multigravida have higher incidence of OH. Atonicity is the predominant cause for obstetric hysterectomy in this study

Experimental investigation of heat transfer during LOCA with failure of emergency cooling system

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The pressure tubes (PT) in the Indian Pressurized Heavy Water Reactor (PHWR) are kept concentrically inside horizontal calandria tube (CT), which is submerged in a moderator pool. During postulated loss-of-coolant accident (LOCA) without emergency core cooling system, the temperature of PT could rise significantly. At elevated temperature, the weight of the PT with the weight of fuel pins could cause it to sag. Before sagging heat transfer from the PT to CT is mainly by convection. Once the PT sags and touches the CT, heat transfer mode changes to conduction. Direct contact between the PT and CT increases heat transfer and checks the temperature rise of the PT and limit the fuel heatup and subsequent degradation of the reactor core. An experimental set-up is designed and fabricated at Indian Institute of Technology Roorkee (IITR) to simulate the LOCA in the Indian PHWR. From the experimental investigation, it is found that the contact between the PT and CT occurred at around 300 seconds after the initiation of the simulation with corresponding temperature of the PT at around 680°C. The experiment was continued after the contact between the PT and CT and it is found that the temperature rise of the PT was within 800°C. This work demonstrates the inherent safety feature of Pressurised Heavy Water Reactor.cs201

Artificial Light at Night: A Global Threat to Plant Biological Rhythms and Eco-Physiological Processes

Light is crucial environmental factor for primary resource and signalling in plants and provide optimum fitness under fluctuating environments from millions of year. However, due to urbanization, and human development activities lot of excess light generated in environment during night time and responsible for anthropogenic generated pollution (ALAN; artificial night light pollution). This pollution has cause for serious problem in plants as it affects their processes and functions which are under the control of light or diurnal cycle. Plant biorhythms mostly diurnal rhythms such as stomatal movements, photosynthetic activity, and many more metabolic processes are under the control of period of light and dark, which are crucially affected by artificial light at night. Similarly, the crucial plant processes such as pollination, flowering, and yield determining processes are controlled by the diurnal cycle and ALAN affects these processes and ultimately hampers the plant fitness and development. To keep in mind the effect of artificial light at night on plant biorhythm and eco-physiological processes, this chapter will focus on the status of global artificial night light pollution and the responsible factors. Further, we will explore the details mechanisms of plant biorhythm and eco-physiological processes under artificial light at night and how this mechanism can be a global threat. Then at the end we will focus on the ANLP reducing strategies such as new light policy, advanced lightening technology such as remote sensing and lightening utilisation optimisation

Direct synthesis of Pt-free catalyst on gas diffusion layer of fuel cell and usage of high boiling point fuels for efficient utilization of waste heat

Gas diffusion layers (GDL) and electrocatalysts are integral parts of fuel cells. It is, however, a challenging task to grow Pt-free robust electrocatalyst directly on GDL for oxygen reduction reaction (ORR) - a key reaction in fuel cells. Here, we demonstrate that boron-doped carbon nanotubes (BCNTs) grown directly on gas-diffusion layer (which avoid the need of ionomer solution used for catalyst loading) can be used as efficient Pt-free catalyst in alcohol fuel cells. Increase in boron concentration improves the electrochemical ORR activity in terms of onset and ORR peak positions, half-wave potentials and diffusion-limited current density that ensure the optimization of the device performance. The preferential 4e(-) pathway, excellent cell performance, superior tolerance to fuel crossover and long-term stability makes directly grown BCNTs as an efficient Pt-free cathode catalyst for cost-effective fuel cells. The maximum power density of the fuel cell is found to increase monotonically with boron concentration. In addition to the application of BCNTs in fuel cell, we have introduced the concept of hot fuels so that waste heat can effectively be used and external power sources can be avoided. The fuel is passed through a hot bath for the realization of hot fuel which eventually increases the operating temperature of the cell (for example: 60 degrees C for methanol and 80 degrees C for ethyleneglycol, avoids the requirement of heating arrangement) and hence, the performance. Overall, different strategies to design ultimate fuel cells for their commercial adoption and effective utilization of waste heat have been outlined

Excellent performance of Pt-free cathode in alkaline direct methanol fuel cell at room temperature

We report the room temperature cell performance of alkaline direct methanol fuel cells (ADMFCs) with nitrogen-doped carbon nanotubes (NCNTs) as cathode materials. NCNTs show excellent oxygen reduction reaction activity and methanol tolerance in alkaline medium. The open-circuit-voltage (OCV) as well as the power density of ADMFCs first increases and then saturates with NCNT loading. Similarly, the OCV initially increases and reaches saturation with the increase in the concentration of methanol feed stock. Overall, NCNTs exhibit excellent catalytic activity and stability with respect to Pt based cathodes