Comparison of Climate Impact, Clinical Outcome, and Cost-Efficiency of Pediatric Transumbilical Laparoscopic Assisted Appendectomy vs Standard 3-Port Laparoscopic Appendectomy.

BACKGROUND: Healthcare is responsible for 8.5% of US greenhouse gas emissions. These impacts must be mitigated while maintaining clinical excellence. This study compares clinical outcomes, cost-efficiency, and climate impact of trans-umbilical laparoscopic assisted appendectomy (TULAA) versus 3-port laparoscopic appendectomy (LA). STUDY DESIGN: Institutional Review Board approval was obtained. Appendectomies performed between Jan 1, 2020 and December 31, 2022 at a tertiary children's hospital were reviewed. Data abstracted included clinical characteristics, operative approach and findings, supplies and equipment utilized, and complications. For analysis TULAA was combined with cases converted to LA (TULAA+C). To determine a surgical site infection (SSI) increase of ≤ 2.5%, a minimum sample size of 479 patients per group was needed to achieve a power of 80%. A composite supply list for each approach was determined by averaging supplies from cases reviewed. The composite was used to calculate cost-efficiency and climate impact. Life cycle assessment was used to determine the carbon footprint (according to ISO 14067) of supplies and equipment. RESULTS: Analysis was performed on 1,611 appendectomies: 497 LA and 1,114 TULAA+C (932 TULAA, 182 converted). Except for BMI, there were no clinically significant differences between groups. SSI did not increase with TULAA+C (n=15, 1.3%) versus LA (n=6, 1.2%), p=0.81. TULAA+C ($369.21/case) was more cost efficient than LA ($879.30/case) and TULAA+C (24.8 kg CO2e) produced fewer emissions than LA (27.4 kg CO2e). CONCLUSIONS: While patient safety and excellent clinical outcomes must remain the top priority in healthcare, the current environmental crisis demands consideration of climate impacts. When clinical non-inferiority can be demonstrated, treatment options with a fewer greenhouse gas emissions should be chosen.

The Carbon Catalogue, carbon footprints of 866 commercial products from 8 industry sectors and 5 continents.

Product carbon footprints (PCFs) are playing an increasing role in decisions around sustainability for companies and consumers. Using data reported to CDP, we have previously built a dataset of 866 PCFs, from 145 companies, 30 industry groups, and 28 countries, showing trends of how upstream and downstream emissions vary by industry and how life cycle assessment (LCA) appears to aid companies in achieving steeper carbon reductions through improvements throughout a product's value chain. Here, we present the greenhouse gas emissions and respective meta data for every product in this dataset. The Carbon Catalogue provides each product with name and description, PCF (in kg CO2e) and the respective LCA protocol/standard, product weight, as well as the name, industry, and country of incorporation of its manufacturer. For a subset of 421 products, the Carbon Catalogue further includes the PCF's reported breakdown into two to nine separate stages of the product's life cycle. For another subset of 250 products, the Carbon Catalogue includes how the respective PCFs changed and why the changes occurred.

Impacts of COVID-19 related stay-at-home restrictions on residential electricity use and implications for future grid stability.

"Stay-at-home" orders and other health precautions enacted during the COVID-19 pandemic have led to substantial changes in residential electricity usage. We conduct a case study to analyze data from 390 apartments in New York City (NYC) to examine the impacts of two key drivers of residential electricity usage: COVID-19 case-loads and the outdoor temperature. We develop a series of regression models to predict two characteristics of residential electricity usage on weekdays: The average occupied apartment's consumption (kWh) over a 9am-5pm window and the hourly peak demand (Watt) over a 12pm-5pm window. Via a Monte Carlo simulation, we forecast the two usage characteristics under a possible scenario in which stay-at-home orders in NYC, or a similar metropolitan region, coincide with warm summer weather. Under the scenario, the 9am-5pm residential electricity usage on weekdays is predicted to be 15% - 24% higher than under prior, pre-pandemic conditions. This could lead to substantially higher utility costs for residents. Additionally, we predict that the residential hourly peak demand between 12pm and 5pm on weekdays could be 35% - 53% higher than that under pre-pandemic conditions. We conclude that the projected increase in peak demand - which might arise if stay-at-home guidelines coincided with hot weather conditions - could pose grid management challenges, especially for residential feeders. We also note that, if there is a longer lasting shift towards work and study-from-home, utilities will have to rethink load profile considerations. The applications of our predictive models to managing future smart-grid technology are also highlighted.

MFRED, 10 second interval real and reactive power for groups of 390 US apartments of varying size and vintage.

Building electricity is a major component of global energy use and its environmental impacts. Detailed data on residential electricity use have many interrelated research applications, from energy conservation to non-intrusive load monitoring, energy storage, integration of renewables, and electric vs. fossil-based heating. The dataset presented here, Multifamily Residential Electricity Dataset (MFRED), contains the electricity use of 390 apartments, ranging from studios to four-bedroom units. All apartments are located in the Northeastern United States (IECC-climate-zone 4 A), but differ in their heating/cooling system and construction year (early to late 20th century). To adhere to privacy guidelines, data were averaged across 15 apartments each, based on annual electricity use. MFRED includes real and reactive power, at 10-second resolution, for January to December 2019 (246 million data points). The annual average real power per apartment is 343 W (3.27 W/m2 of floor area), with strong variation between seasons and apartment size. Considering its large number of apartments, high time resolution, real and reactive power, and 12-month duration, MFRED is currently unique for the multifamily-sector.

Carbon emissions embodied in product value chains and the role of Life Cycle Assessment in curbing them.

Life cycle-based analyses are considered crucial for designing product value chains towards lower carbon emissions. We have used data reported by companies to CDP for public disclosure to build a database of 866 product carbon footprints (PCFs), from 145 companies, 30 industries, and 28 countries. We used this database to elucidate the breakdown of embodied carbon emissions across products' value chains, how this breakdown varies by industry, and whether the reported emission reductions vary with the granularity of the PCF. For the 866 products, on average 45% of total value chain emissions arise upstream in the supply chain, 23% during the company's direct operations, and 32% downstream. This breakdown varies strongly by industry. Across their lifecycle, the 866 products caused average total emissions of 6 times their own weight, with large variation within and across industries. Reported achievements to reduce emissions varied depending on whether a company had reported a PCF's breakdown to life cycle stages or only the total emissions (10.9% average reduction with breakdown versus 3.7% without). We conclude that a sector-level understanding of emissions, absent of individual PCFs, is insufficient to reliably quantify carbon emissions, and that higher reported emission reductions go hand in hand with more granular PCFs.

A Life Cycle Assessment Case Study of Coal-Fired Electricity Generation with Humidity Swing Direct Air Capture of CO2 versus MEA-Based Postcombustion Capture.

Most carbon capture and storage (CCS) envisions capturing CO2 from flue gas. Direct air capture (DAC) of CO2 has hitherto been deemed unviable because of the higher energy associated with capture at low atmospheric concentrations. We present a Life Cycle Assessment of coal-fired electricity generation that compares monoethanolamine (MEA)-based postcombustion capture (PCC) of CO2 with distributed, humidity-swing-based direct air capture (HS-DAC). Given suitable temperature, humidity, wind, and water availability, HS-DAC can be largely passive. Comparing energy requirements of HS-DAC and MEA-PCC, we find that the parasitic load of HS-DAC is less than twice that of MEA-PCC (60-72 kJ/mol versus 33-46 kJ/mol, respectively). We also compare other environmental impacts as a function of net greenhouse gas (GHG) mitigation: To achieve the same 73% mitigation as MEA-PCC, HS-DAC would increase nine other environmental impacts by on average 38%, whereas MEA-PCC would increase them by 31%. Powering distributed HS-DAC with photovoltaics (instead of coal) while including recapture of all background GHG, reduces this increase to 18%, hypothetically enabling coal-based electricity with net-zero life-cycle GHG. We conclude that, in suitable geographies, HS-DAC can complement MEA-PCC to enable CO2 capture independent of time and location of emissions and recapture background GHG from fossil-based electricity beyond flue stack emissions.

Local routes revisited: the space and time dependence of the Ca2+ signal for phasic transmitter release at the rat calyx of Held.

During the last decade, advances in experimental techniques and quantitative modelling have resulted in the development of the calyx of Held as one of the best preparations in which to study synaptic transmission. Here we review some of these advances, including simultaneous recording of pre- and postsynaptic currents, measuring the Ca2+ sensitivity of transmitter release, reconstructing the 3-D anatomy at the electron microscope (EM) level, and modelling the buffered diffusion of Ca2+ in the nerve terminal. An important outcome of these studies is an improved understanding of the Ca2+ signal that controls phasic transmitter release. This article illustrates the spatial and temporal aspects of the three main steps in the presynaptic signalling cascade: Ca2+ influx through voltage-gated calcium channels, buffered Ca2+ diffusion from the channels to releasable vesicles, and activation of the Ca2+ sensor for release. Particular emphasis is placed on how presynaptic Ca2+ buffers affect the Ca2+ signal and thus the amplitude and time course of the release probability. Since many aspects of the signalling cascade were first conceived with reference to the squid giant presynaptic terminal, we include comparisons with the squid model and revisit some of its implications. Whilst the characteristics of buffered Ca2+ diffusion presented here are based on the calyx of Held, we demonstrate the circumstances under which they may be valid for other nerve terminals at mammalian CNS synapses.

Calcium secretion coupling at calyx of Held governed by nonuniform channel-vesicle topography.

Phasic transmitter release at synapses in the mammalian CNS is regulated by local [Ca2+] transients, which control the fusion of readily releasable vesicles docked at active zones (AZs) in the presynaptic membrane. The time course and amplitude of these [Ca2+] transients critically determine the time course and amplitude of the release and thus the frequency and amplitude tuning of the synaptic connection. As yet, the spatiotemporal nature of the [Ca2+] transients and the number and location of release-controlling Ca2+ channels relative to the vesicles, the "topography" of the release sites, have remained elusive. We used a time-dependent model to simulate Ca2+ influx, three-dimensional buffered Ca2+ diffusion, and the binding of Ca2+ to the release sensor. The parameters of the model were constrained by recent anatomical and biophysical data of the calyx of Held. Comparing the predictions of the model with previously measured release probabilities under a variety of experimental conditions, we inferred which release site topography is likely to operate at the calyx: At each AZ one or a few clusters of Ca2+ channels control the release of the vesicles. The distance of a vesicle to the cluster(s) varies across the multiple release sites of a single calyx (ranging from 30 to 300 nm; average approximately 100 nm). Assuming this topography, vesicles in different locations are exposed to different [Ca2+] transients, with peak amplitudes ranging from 0.5 to 40 microm (half-width approximately 400 microsec) during an action potential. Consequently the vesicles have different release probabilities ranging from <0.01 to 1. We demonstrate how this spatially heterogeneous release probability creates functional advantages for synaptic transmission.