Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-32603870

RESUMO

OBJECTIVE: To demonstrate our technique for robotic assisted laparoscopic ectopic pregnancy excision and concomitant scar revision. DESIGN: We present a stepwise narrated demonstration of our primary laparoscopic technique. SETTING: Although cesarean scar pregnancy is rare, it leads to life-threatening complications and often emergent hysterectomy. Because of its rarity there is a scarcity of centers with high volume experience with its treatment, and no standardized diagnostic or management guidelines are yet available. Recent evidence suggests that primary surgical management may be superior to medical or radiologic management as the latter methods carry a high reintervention rate. An additional consideration while selecting a treatment method is a patient's plans for future fertility, as cesarean scar defects are associated with secondary infertility. Evidence shows that repair of cesarean scar defects decreases the likelihood of future recurrence and secondary infertility, thus it may be pertinent to select a management strategy that allows accomplishment of both ectopic pregnancy removal and defect revision. We present our primary laparoscopic approach to ectopic pregnancy excision and revision of the cesarean scar defect utilizing techniques rooted in evidence and robust experience. INTERVENTIONS: Robotic assisted laparoscopic excision of a cesarean scar ectopic pregnancy with concomitant scar revision demonstrating key strategies to minimize blood loss and preserve future fertility. 1. A laparoscopic approach allows for concomitant ectopic pregnancy removal followed by cesarean scar revision. 2. Generous use of dilute vasopressin and purposeful application of electrosurgical energy provides hemostasis without the use of more invasive measures such as vascular clips or uterine artery balloons. 3. A multilayer closure is associated with a lower risk of wedge defect formation and uterine rupture. 4. Diagnostic hysteroscopy is a useful tool for identifying the location of the scar defect, assessing for an adequate repair, and identifying potential additional uterine pathology. CONCLUSION: Primary laparoscopic management is not only the most effective method with lowest complication rates but is an approach that allows for simultaneous repair and revision of the cesarean scar defect. We demonstrate easily adaptable techniques for maintaining hemostasis, minimizing injury to normal myometrium, and creating multilayer closures which lead to successful revisions with minimal impact to subsequent fertility.

2.
J Am Chem Soc ; 142(24): 10806-10813, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32431151

RESUMO

Accurately characterizing isoprene ozonolysis continues to challenge atmospheric chemists. The reaction is believed to be a spontaneous, concerted cycloaddition. However, little information is available about the entrance channel and isoprene-ozone complexes thought to define the long-range portion of the reaction coordinate. Our coupled cluster and auxiliary field quantum Monte Carlo calculations predict multiple stable isoprene-ozone van der Waals complexes for trans-isoprene in the gas phase with moderate association energies. These results indicate that long-range dynamics in the isoprene-ozone entrance channel can impact the overall reaction in the troposphere and provide the spectroscopic information necessary to extend the microwave characterization of isoprene ozonolysis to prereactive complexes. At the air-water interface, Born-Oppenheimer molecular dynamics simulations indicate that the cycloaddition reaction between ozone and trans-isoprene follows a stepwise mechanism, which is quite distinct from our proposed gas-phase mechanism and occurs on a femtosecond time scale. The stepwise nature of isoprene ozonolysis on the aqueous surface is more consistent with the DeMore mechanism than with the Criegee mechanism suggested by the gas-phase calculations, suggesting that the reaction media may play an important role in the reaction. Overall, these predictions aim to provide a missing fundamental piece of molecular insight into isoprene ozonolysis, which has broad tropospheric implications due to its critical role as a nighttime source of hydroxyl radicals.

3.
J Minim Invasive Gynecol ; 27(1): 160-165, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30926368

RESUMO

STUDY OBJECTIVE: To determine whether incorporation of operative hysteroscopy with biopsy of products of conception, in conjunction with a suction curettage for a first trimester missed abortion, affected the rate of maternal cell contamination when chromosomal analysis was performed on the products of conception, and to determine the rates of retained products of conception with incorporation of hysteroscopy after suction curettage. DESIGN: Retrospective chart study. SETTING: Private, minimally invasive surgery and infertility practice with academic-community hospital affiliation. PATIENTS: Infertility patients undergoing evacuation of products of conception for documented first trimester miscarriages between 2006 and 2017. INTERVENTIONS: Suction curettage or hysteroscopic biopsy and suction curettage, followed by chromosomal analysis of products of conception for determination of fetal genetics. MEASUREMENTS AND RESULTS: A total of 264 charts were analyzed. Patients were categorized into 2 groups based on surgical collection of products of conception: group 1 (N = 174), suction curettage only, and group 2 (N = 90), a single procedure consisting of operative hysteroscopy with biopsy of products of conception followed by suction curettage and then diagnostic hysteroscopy to look for retained products. Data for chromosome detection and retained products of conception were available for 246 and 239 patients, respectively. No significant differences were detected between the groups for age, body mass index, ethnicity, gravida, parity, primary infertility, secondary infertility, spontaneous conception, single or multiple gestation, and surgical complications. Fetal chromosome detection was significantly higher without maternal contamination in group 2 (88.5%) compared with group 1 (64.8%) (p < .001). There was no significant between-group difference in postoperative retained products of conception. CONCLUSION: Obtaining fetal genetics can be useful when planning for a future successful pregnancy. The addition of operative hysteroscopy to biopsy the gestational sac, chorionic villi, and/or fetus significantly decreases the risk of maternal contamination and increases the ability to detect fetal chromosomes for genetic analysis without an increased risk of surgical complications. Despite the low risk of surgical complications, immediate second-look hysteroscopy after the completion of suction evacuation does not reduce the risk of postoperative retained products of conception.

4.
J Clin Endocrinol Metab ; 105(3)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31650182

RESUMO

CONTEXT: Elagolix is an oral gonadotropin-releasing hormone (GnRH) antagonist recently approved for the treatment of endometriosis-associated pain and being developed for heavy menstrual bleeding associated with uterine fibroids. OBJECTIVE: The objective was to evaluate the effects of elagolix on ovulation and ovarian sex hormones. DESIGN AND SETTING: This was a randomized, open-label, multicenter study. PARTICIPANTS: Participants were healthy ovulatory women aged 18 to 40 years. INTERVENTIONS: Elagolix was administered orally for 3 continuous 28-day dosing intervals at 100 to 200 mg once daily (QD), 100 to 300 mg twice daily (BID), and 300 mg BID plus estradiol/norethindrone acetate (E2/NETA) 1/0.5 mg QD. MAIN OUTCOME MEASURES: The main outcomes measures were ovulation rates measured by transvaginal ultrasound, progesterone concentrations, and hormone suppression. RESULTS: Elagolix suppressed ovulation in a dose-dependent manner. The percentage of women who ovulated was highest at 100 mg QD (78%), intermediate at 150 and 200 mg QD and 100 mg BID (47%-57%), and lowest at 200 and 300 mg BID (32% and 27%, respectively). Addition of E2/NETA to elagolix 300 mg BID further suppressed the ovulation rate to 10%. Elagolix also suppressed luteinizing hormone and follicle stimulating hormone in a dose-dependent manner, leading to dose-dependent suppression of estradiol and progesterone. Elagolix had no effect on serum biomarker of ovarian reserve, and reduced endometrial thickness compared to the screening cycle. CONCLUSION: Women being treated with elagolix may ovulate and should use effective methods of contraception. The rate of ovulation was lowest with elagolix 300 mg BID plus E2/NETA 1/0.5 mg QD.

5.
Nature ; 575(7781): 180-184, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695210

RESUMO

Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide1,2. Unique opportunities for mitigation are presented by point-source emitters-surface features or infrastructure components that are typically less than 10 metres in diameter and emit plumes of highly concentrated methane3. However, data on point-source emissions are sparse and typically lack sufficient spatial and temporal resolution to guide their mitigation and to accurately assess their magnitude4. Here we survey more than 272,000 infrastructure elements in California using an airborne imaging spectrometer that can rapidly map methane plumes5-7. We conduct five campaigns over several months from 2016 to 2018, spanning the oil and gas, manure-management and waste-management sectors, resulting in the detection, geolocation and quantification of emissions from 564 strong methane point sources. Our remote sensing approach enables the rapid and repeated assessment of large areas at high spatial resolution for a poorly characterized population of methane emitters that often appear intermittently and stochastically. We estimate net methane point-source emissions in California to be 0.618 teragrams per year (95 per cent confidence interval 0.523-0.725), equivalent to 34-46 per cent of the state's methane inventory8 for 2016. Methane 'super-emitter' activity occurs in every sector surveyed, with 10 per cent of point sources contributing roughly 60 per cent of point-source emissions-consistent with a study of the US Four Corners region that had a different sectoral mix9. The largest methane emitters in California are a subset of landfills, which exhibit persistent anomalous activity. Methane point-source emissions in California are dominated by landfills (41 per cent), followed by dairies (26 per cent) and the oil and gas sector (26 per cent). Our data have enabled the identification of the 0.2 per cent of California's infrastructure that is responsible for these emissions. Sharing these data with collaborating infrastructure operators has led to the mitigation of anomalous methane-emission activity10.


Assuntos
Monitoramento Ambiental , Metano/análise , Gerenciamento de Resíduos , California , Efeito Estufa , Esterco , Metano/química , Metano/metabolismo , Gás Natural , Indústria de Petróleo e Gás/métodos , Petróleo , Águas Residuárias
6.
Sci Adv ; 4(7): eaao1167, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30009255

RESUMO

The contemporary Arctic carbon balance is uncertain, and the potential for a permafrost carbon feedback of anywhere from 50 to 200 petagrams of carbon (Schuur et al., 2015) compromises accurate 21st-century global climate system projections. The 42-year record of atmospheric CO2 measurements at Barrow, Alaska (71.29 N, 156.79 W), reveals significant trends in regional land-surface CO2 anomalies (ΔCO2), indicating long-term changes in seasonal carbon uptake and respiration. Using a carbon balance model constrained by ΔCO2, we find a 13.4% decrease in mean carbon residence time (50% confidence range = 9.2 to 17.6%) in North Slope tundra ecosystems during the past four decades, suggesting a transition toward a boreal carbon cycling regime. Temperature dependencies of respiration and carbon uptake suggest that increases in cold season Arctic labile carbon release will likely continue to exceed increases in net growing season carbon uptake under continued warming trends.

7.
Popul Health Manag ; 21(S1): S13-S20, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29649369

RESUMO

The primary objective of this study was to describe surgical treatment patterns among women with newly diagnosed uterine fibroids (UF). A secondary objective was to estimate the medical costs associated with other common surgical interventions for UF. Claims-based commercial and Medicare data (2011-2016) were used to identify women aged ≥30 years with continuous enrollment for at least 12 months before and after a new diagnosis of UF. Receipt of a surgical or radiologic procedure (hysterectomy, myomectomy, endometrial ablation, uterine artery embolization, and curettage) was the primary outcome. Health care resource utilization and costs were calculated for women with at least 12 months of continuous enrollment following a UF surgical procedure. Among women who met selection criteria, 31.7% of patients underwent a surgical procedure; 20.9% of these underwent hysterectomy. An increase was observed over time in the percentage of women undergoing outpatient hysterectomy (from 27.0% to 40.2%) and hysteroscopic myomectomy (from 8.0% to 11.5%). The cost analysis revealed that total health care costs for hysteroscopic myomectomy ($17,324) were significantly lower (P < 0.001) than those for women who underwent inpatient hysterectomy ($24,027) and those for women undergoing the 3 comparison procedures. Hysterectomy was the most common surgical intervention. Patients undergoing inpatient hysterectomy had the highest health care costs. Although less expensive, minimally invasive approaches are becoming more common; they are performed infrequently in patients with newly diagnosed UF. The results of this study may be useful in guiding decisions regarding the most appropriate and cost-effective surgical treatment for UF.


Assuntos
Custos de Cuidados de Saúde/estatística & dados numéricos , Leiomioma , Adulto , Técnicas de Ablação Endometrial/economia , Técnicas de Ablação Endometrial/estatística & dados numéricos , Feminino , Humanos , Histerectomia/economia , Histerectomia/estatística & dados numéricos , Leiomioma/economia , Leiomioma/epidemiologia , Leiomioma/cirurgia , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Embolização da Artéria Uterina/economia , Embolização da Artéria Uterina/estatística & dados numéricos
8.
Curr Opin Obstet Gynecol ; 30(1): 69-74, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29194076

RESUMO

PURPOSE OF REVIEW: This review was written in an effort to describe the evolution of power morcellation equipment from their creation to their current state. In addition, this review addresses the continuously evolving equipment involved with power morcellation and looks to describe where the field is headed in the future. In addition, recent professional and federal recommendations have changed the way power morcellation is being approached and has led to the development of contained morcellation systems, which, although in their infancy, are also being proven to be well tolerated options. RECENT FINDINGS: This article will review the most current research on electronic power morcellation and the multiple attempts to prove superiority from the many different types of equipment, and also the many different approaches to morcellation. In addition, with the adaptation to contained morcellation, this review will cover research focused on optimizing a containment system and the techniques involved. SUMMARY: In summary, this review is aimed at describing many of the currently available power morcellation products and contained morcellation systems in an effort to allow physicians to understand the different options available, and to discuss well tolerated, effective, and clinically proven techniques that can lead to improved surgical outcomes in the future.


Assuntos
Desenho de Equipamento/história , Morcelação/história , Morcelação/instrumentação , Contraindicações de Procedimentos , Diagnóstico Tardio/história , Desenho de Equipamento/tendências , Feminino , Doenças dos Genitais Femininos/história , Doenças dos Genitais Femininos/cirurgia , Neoplasias dos Genitais Femininos/diagnóstico , Neoplasias dos Genitais Femininos/história , Neoplasias dos Genitais Femininos/cirurgia , História do Século XX , História do Século XXI , Humanos , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/prevenção & controle , Laparoscopia/efeitos adversos , Laparoscopia/tendências , Morcelação/efeitos adversos , Morcelação/tendências , Segurança do Paciente , Estados Unidos , United States Food and Drug Administration
9.
Science ; 358(6360)2017 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-29026015

RESUMO

Spaceborne measurements by NASA's Orbiting Carbon Observatory-2 (OCO-2) at the kilometer scale reveal distinct structures of atmospheric carbon dioxide (CO2) caused by known anthropogenic and natural point sources. OCO-2 transects across the Los Angeles megacity (USA) show that anthropogenic CO2 enhancements peak over the urban core and decrease through suburban areas to rural background values more than ~100 kilometers away, varying seasonally from ~4.4 to 6.1 parts per million. A transect passing directly downwind of the persistent isolated natural CO2 plume from Yasur volcano (Vanuatu) shows a narrow filament of enhanced CO2 values (~3.4 parts per million), consistent with a CO2 point source emitting 41.6 kilotons per day. These examples highlight the potential of the OCO-2 sensor, with its unprecedented resolution and sensitivity, to detect localized natural and anthropogenic CO2 sources.

10.
Curr Opin Obstet Gynecol ; 29(4): 257-265, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28598911

RESUMO

PURPOSE OF REVIEW: The purpose of this review is to understand the minimally invasive approach to the excision and repair of an isthmocele. RECENT FINDINGS: Previous small trials and case reports have shown that the minimally invasive approach by hysteroscopy and/or laparoscopy can cure symptoms of a uterine isthmocele, including abnormal bleeding, pelvic pain and secondary infertility. A recent larger prospective study has been published that evaluates outcomes of minimally invasive isthmocele repair. Smaller studies and individual case reports echo the positive results of this larger trial. SUMMARY: The cesarean section scar defect, also known as an isthmocele, has become an important diagnosis for women who present with abnormal uterine bleeding, pelvic pain and secondary infertility. It is important for providers to be aware of the effective surgical treatment options for the symptomatic isthmocele. A minimally invasive approach, whether it be laparoscopic or hysteroscopic, has proven to be a safe and effective option in reducing symptoms and improving fertility. VIDEO ABSTRACT: http://links.lww.com/COOG/A37.


Assuntos
Cicatriz/diagnóstico , Cicatriz/cirurgia , Laparoscopia , Procedimentos Cirúrgicos Minimamente Invasivos , Aderências Teciduais/diagnóstico , Aderências Teciduais/cirurgia , Adulto , Cesárea/efeitos adversos , Cicatriz/etiologia , Feminino , Hemorragia , Humanos , Histeroscopia , Infertilidade Feminina/etiologia , Infertilidade Feminina/prevenção & controle , Imagem por Ressonância Magnética , Dor Pélvica/patologia , Gravidez , Complicações na Gravidez , Fatores de Risco , Aderências Teciduais/etiologia , Resultado do Tratamento , Ultrassonografia , Doenças Uterinas/cirurgia , Útero/cirurgia
11.
Proc Natl Acad Sci U S A ; 114(21): 5361-5366, 2017 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-28484001

RESUMO

High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

12.
JSLS ; 21(1)2017.
Artigo em Inglês | MEDLINE | ID: mdl-28352146

RESUMO

BACKGROUND AND OBJECTIVES: The well-known advantages of minimally invasive surgery make the approach well suited for hysterectomy and other gynecological procedures. The removal of specimens excised during surgery has been a challenge that has been answered by the use of power morcellation. With this study we sought to assess the feasibility of power morcellation within a specimen bag. METHODS: This was a retrospective cohort study including patients from a private practice in suburban Chicago, Illinois, who underwent contained electromechanical power morcellation during a laparoscopic or robot-assisted hysterectomy or myomectomy from May 2014 through December 2015. Contained power morcellation was performed with the Espiner EcoSac 230 (Espiner Medical Ltd., North Somerset, United Kingdom) specimen bag. Descriptive statistics were performed for both categorical and continuous data. RESULTS: Of the 187 procedures performed, 73.8% were myomectomies, and 26.2% were hysterectomies. The patients' mean age was 40 (range, 25-54) years and mean body mass index was 28.7 (range, 17.3-57.6). The average specimen weight was 300 g, with the largest weighing 2134 g. Estimated blood loss averaged 98.4 mL. The postoperative admission rate was 12.3%, most of which were due to nausea and urinary retention. Seventeen patients (9.1%) had postoperative complications, most of which were minor, and 4 (2.1%) were readmitted. There were no bag failures or complications that were due to the use of the specimen bag or to power morcellation. CONCLUSIONS: Performing electromechanical power morcellation within the Espiner EcoSac 230 specimen bag was successfully performed in 187 patients with no bag-related complications. This method of contained power morcellation is feasible, reliable, and reproducible, even for a large specimen.


Assuntos
Histerectomia/métodos , Laparoscopia/métodos , Morcelação/instrumentação , Procedimentos Cirúrgicos Robóticos/métodos , Miomectomia Uterina/métodos , Adulto , Estudos de Viabilidade , Feminino , Humanos , Histerectomia/instrumentação , Pessoa de Meia-Idade , Morcelação/métodos , Avaliação de Resultados em Cuidados de Saúde , Estudos Retrospectivos , Miomectomia Uterina/instrumentação
13.
Artigo em Inglês | MEDLINE | ID: mdl-30984251

RESUMO

We report continuous surface observations of carbon dioxide (CO2) and methane (CH4) from the Los Angeles (LA) Megacity Carbon Project during 2015. We devised a calibration strategy, methods for selection of background air masses, calculation of urban enhancements, and a detailed algorithm for estimating uncertainties in urban-scale CO2 and CH4 measurements. These methods are essential for understanding carbon fluxes from the LA megacity and other complex urban environments globally. We estimate background mole fractions entering LA using observations from four "extra-urban" sites including two "marine" sites located south of LA in La Jolla (LJO) and offshore on San Clemente Island (SCI), one "continental" site located in Victorville (VIC), in the high desert northeast of LA, and one "continental/mid-troposphere" site located on Mount Wilson (MWO) in the San Gabriel Mountains. We find that a local marine background can be established to within ~1 ppm CO2 and ~10 ppb CH4 using these local measurement sites. Overall, atmospheric carbon dioxide and methane levels are highly variable across Los Angeles. "Urban" and "suburban" sites show moderate to large CO2 and CH4 enhancements relative to a marine background estimate. The USC (University of Southern California) site near downtown LA exhibits median hourly enhancements of ~20 ppm CO2 and ~150 ppb CH4 during 2015 as well as ~15 ppm CO2 and ~80 ppb CH4 during mid-afternoon hours (12:00-16:00 LT, local time), which is the typical period of focus for flux inversions. The estimated measurement uncertainty is typically better than 0.1 ppm CO2 and 1 ppb CH4 based on the repeated standard gas measurements from the LA sites during the last 2 years, similar to Andrews et al. (2014). The largest component of the measurement uncertainty is due to the single-point calibration method; however, the uncertainty in the background mole fraction is much larger than the measurement uncertainty. The background uncertainty for the marine background estimate is ~10 and ~15 % of the median mid-afternoon enhancement near downtown LA for CO2 and CH4, respectively. Overall, analytical and background uncertainties are small relative to the local CO2 and CH4 enhancements; however, our results suggest that reducing the uncertainty to less than 5 % of the median mid-afternoon enhancement will require detailed assessment of the impact of meteorology on background conditions.

14.
Astrobiology ; 16(7): 539-50, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27315136

RESUMO

UNLABELLED: The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the martian environment and its potential for life, as the current theories do not entail any geological source or sink of methane that varies sub-annually. In particular, the 10-fold elevation during the southern winter indicates episodic sources of methane that are yet to be discovered. Here we suggest a near-surface reservoir could explain this variability. Using the temperature and humidity measurements from the rover, we find that perchlorate salts in the regolith deliquesce to form liquid solutions, and deliquescence progresses to deeper subsurface in the season of the methane spikes. We therefore formulate the following three testable hypotheses. The first scenario is that the regolith in Gale Crater adsorbs methane when dry and releases this methane to the atmosphere upon deliquescence. The adsorption energy needs to be 36 kJ mol(-1) to explain the magnitude of the methane spikes, higher than existing laboratory measurements. The second scenario is that microorganisms convert organic matter in the soil to methane when they are in liquid solutions. This scenario does not require regolith adsorption but entails extant life on Mars. The third scenario is that deep subsurface aquifers produce the bursts of methane. Continued in situ measurements of methane and water, as well as laboratory studies of adsorption and deliquescence, will test these hypotheses and inform the existence of the near-surface reservoir and its exchange with the atmosphere. KEY WORDS: Mars-Methane-Astrobiology-Regolith. Astrobiology 16, 539-550.


Assuntos
Meio Ambiente Extraterreno/química , Marte , Metano/análise , Metano/química , Adsorção , Atmosfera/química , Exobiologia , Umidade , Modelos Teóricos , Solo/química , Temperatura , Termodinâmica , Água/análise
15.
Proc Natl Acad Sci U S A ; 113(28): 7733-8, 2016 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-27354511

RESUMO

With rapid changes in climate and the seasonal amplitude of carbon dioxide (CO2) in the Arctic, it is critical that we detect and quantify the underlying processes controlling the changing amplitude of CO2 to better predict carbon cycle feedbacks in the Arctic climate system. We use satellite and airborne observations of atmospheric CO2 with climatically forced CO2 flux simulations to assess the detectability of Alaskan carbon cycle signals as future warming evolves. We find that current satellite remote sensing technologies can detect changing uptake accurately during the growing season but lack sufficient cold season coverage and near-surface sensitivity to constrain annual carbon balance changes at regional scale. Airborne strategies that target regular vertical profile measurements within continental interiors are more sensitive to regional flux deeper into the cold season but currently lack sufficient spatial coverage throughout the entire cold season. Thus, the current CO2 observing network is unlikely to detect potentially large CO2 sources associated with deep permafrost thaw and cold season respiration expected over the next 50 y. Although continuity of current observations is vital, strategies and technologies focused on cold season measurements (active remote sensing, aircraft, and tall towers) and systematic sampling of vertical profiles across continental interiors over the full annual cycle are required to detect the onset of carbon release from thawing permafrost.

16.
Eur J Obstet Gynecol Reprod Biol ; 201: 135-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27124666

RESUMO

OBJECTIVE(S): The ultrasonic advanced energy study device (AH device) is the first surgical device indicated to seal vessels up to and including 7mm using ultrasonic technology alone. This study assesses clinical experience during total laparoscopic hysterectomy (TLH) using advanced hemostasis mode (AHM). STUDY DESIGN: This was a prospective, non-randomized, single arm, multicenter, observational study which did not modify or influence current surgeon technique for elective TLH for benign disease. Each surgeon assessed hemostasis, defined as the hemostatic transection of the uterine vasculature (left/right) with at least one use of the AH device in AHM without the use of additional hemostatic measures other than the AH device. Patients were followed for 4-6 weeks after surgery. Vessel sealing performance was quantitatively assessed for transection and sealing of the uterine artery (UA), the uterine pedicle (UP; defined as cases where the UA could not be 'isolated') and the ovarian pedicle (OP) (when indicated). Adverse events (AEs) related to the AH device or procedures were collected. RESULTS: Forty patients underwent the procedure. Mean age was 49 years and mean body mass index was 28kg/m(2). Mean surgical duration was 88min. None required conversion to open procedure. Using only the AH device, hemostasis was achieved and maintained in 119 (94.4%) transections (both left and right sides of the UA/UP and OP). Additional hemostasis was achieved in 5 patients using conventional bipolar (4) or monopolar (1) energy. No patient required a blood transfusion postoperatively. Only one adverse event of pain was considered to be related to the use of the ultrasonic AH device during this study. CONCLUSION: These results support that the AH device with its AHM has clinical utility in sealing named vessels in TLH. The new algorithm to deliver energy in the AHM has the potential to reduce the need for additional hemostatic devices or products as well as the potential to reduce the need for multiple instrument changes during surgery.


Assuntos
Perda Sanguínea Cirúrgica/prevenção & controle , Hemostasia Cirúrgica/instrumentação , Histerectomia/métodos , Laparoscopia/métodos , Adulto , Idoso , Feminino , Hemostasia Cirúrgica/métodos , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Ultrassom
17.
Global Biogeochem Cycles ; 30(10): 1441-1453, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28066129

RESUMO

Methane (CH4) fluxes from Alaska and other arctic regions may be sensitive to thawing permafrost and future climate change, but estimates of both current and future fluxes from the region are uncertain. This study estimates CH4 fluxes across Alaska for 2012-2014 using aircraft observations from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) and a geostatistical inverse model (GIM). We find that a simple flux model based on a daily soil temperature map and a static map of wetland extent reproduces the atmospheric CH4 observations at the state-wide, multi-year scale more effectively than global-scale, state-of-the-art process-based models. This result points to a simple and effective way of representing CH4 flux patterns across Alaska. It further suggests that contemporary process-based models can improve their representation of key processes that control fluxes at regional scales, and that more complex processes included in these models cannot be evaluated given the information content of available atmospheric CH4 observations. In addition, we find that CH4 emissions from the North Slope of Alaska account for 24% of the total statewide flux of 1.74 ± 0.44 Tg CH4 (for May-Oct.). Contemporary global-scale process models only attribute an average of 3% of the total flux to this region. This mismatch occurs for two reasons: process models likely underestimate wetland area in regions without visible surface water, and these models prematurely shut down CH4 fluxes at soil temperatures near 0°C. As a consequence, wetlands covered by vegetation and wetlands with persistently cold soils could be larger contributors to natural CH4 fluxes than in process estimates. Lastly, we find that the seasonality of CH4 fluxes varied during 2012-2014, but that total emissions did not differ significantly among years, despite substantial differences in soil temperature and precipitation; year-to-year variability in these environmental conditions did not affect obvious changes in total CH4 fluxes from the state.

18.
Proc Natl Acad Sci U S A ; 113(1): 40-5, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26699476

RESUMO

Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥ 50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y(-1), ∼ 25% of global emissions from extratropical wetlands, or ∼ 6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.


Assuntos
Temperatura Baixa , Metano/análise , Tundra , Regiões Árticas , Monitoramento Ambiental , Modelos Teóricos , Estações do Ano , Solo , Áreas Alagadas
19.
J Minim Invasive Gynecol ; 22(2): 160, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25460317

RESUMO

STUDY OBJECTIVE: To show a technique of power morcellation within a rip-stop nylon specimen bag. DESIGN: Step-by-step explanation of the technique. BACKGROUND: The Food and Drug Administration recently warned against the use of electromechanical power morcellation for hysterectomy and myomectomy because of potential tissue dissemination within the abdomen and pelvis. If the tumor is malignant, this technique increases the staging of the patient and may further warrant re-operation and chemotherapy. If the tumor is benign, the patient is at risk for parasitic myomas that may lead to, but are not limited to, pain and/or bowel obstruction. INTERVENTION: To reduce the preceding risks, we reviewed the techniques of power morcellation within a specimen bag used by other surgeons across the United States. This technique was modified to incorporate a more durable bag made out of rip-stop nylon. Laparoscopic supracervical hysterectomy during power morcellation was performed, along with an introduction to incorporating power morcellation of multiple myomas during a laparoscopic myomectomy. CONCLUSION: This technique of power morcellation within a rip-stop nylon bag minimizes the risk of inadvertent tissue spread. This allows the patient an opportunity to undergo minimally invasive surgery for hysterectomy and myomectomy.


Assuntos
Histerectomia , Complicações Intraoperatórias , Laparoscopia , Leiomioma , Instrumentos Cirúrgicos , Miomectomia Uterina , Abdome/patologia , Abdome/cirurgia , Feminino , Humanos , Histerectomia/efeitos adversos , Histerectomia/instrumentação , Histerectomia/métodos , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/prevenção & controle , Laparoscopia/efeitos adversos , Laparoscopia/instrumentação , Laparoscopia/métodos , Leiomioma/patologia , Leiomioma/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos , Nylons , Pelve/patologia , Pelve/cirurgia , Risco Ajustado , Estados Unidos , Miomectomia Uterina/efeitos adversos , Miomectomia Uterina/instrumentação , Miomectomia Uterina/métodos , Neoplasias Uterinas/patologia , Neoplasias Uterinas/cirurgia
20.
JSLS ; 18(4)2014.
Artigo em Inglês | MEDLINE | ID: mdl-25516706

RESUMO

BACKGROUND AND OBJECTIVES: In our clinical experience, there seemed to be a correlation between cervical stump bleeding and adenomyosis. Therefore, we wanted to conduct a study to determine whether there was an actual correlation and to identify other risk factors for persistent bleeding after a laparoscopic supracervical hysterectomy. METHODS: The study included women who underwent laparoscopic supracervical hysterectomy from January 1, 2003, through December 31, 2012. Data were collected on age, postmenopausal status, body mass index (BMI), uterine weight, indication for hysterectomy, concomitant bilateral salpingo-oophorectomy (BSO), presence of endometriosis, surgical ablation of the endocervix, adenomyosis, presence of endocervix in the specimen, and postoperative bleeding. RESULTS: The study included 256 patients, of whom 187 had no postoperative bleeding after the operation, 40 had bleeding within 12 weeks, and 29 had bleeding after 12 weeks. The 3 groups were comparable in BMI, postmenopausal status, uterine weight, indication for hysterectomy, BSO, surgical ablation of the endocervix, adenomyosis, and the presence of endocervix. However, patients who had postoperative bleeding at more than 12 weeks were significantly younger (P = .002) and had a higher rate of endometriosis (P < .001). CONCLUSIONS: Risks factors for postoperative bleeding from the cervical stump include a younger age at the time of hysterectomy and the presence of endometriosis. Therefore, younger patients and those with endometriosis who desire to have no further vaginal bleeding may benefit from total hysterectomy over supracervical hysterectomy. All patients who are undergoing supracervical hysterectomy should be counseled about the possible alternatives, benefits, and risks, including continued vaginal bleeding from the cervical stump and the possibility of requiring future treatment and procedures.


Assuntos
Histerectomia/efeitos adversos , Laparoscopia/efeitos adversos , Hemorragia Pós-Operatória/etiologia , Hemorragia Uterina/cirurgia , Adulto , Endometriose/cirurgia , Feminino , Humanos , Histerectomia/métodos , Incidência , Pessoa de Meia-Idade , Hemorragia Pós-Operatória/epidemiologia , Estados Unidos/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA