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1.
Clin Orthop Relat Res ; 481(3): 542-549, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35901432

RESUMO

BACKGROUND: Surgical wound-healing complications after tumor resections in tissue that has been preoperatively radiated are a major clinical problem. Most studies have reported that complications occur in more than 30% of patients undergoing such resections in the lower extremity. There is currently no available method to predict which patients are likely to have a complication. Transcutaneous oximetry has been identified in preliminary studies as potentially useful, but the available evidence on its efficacy for this application thus far is inconclusive. QUESTIONS/PURPOSES: (1) Does transcutaneous oximetry measurement below 25 mmHg at any location in the surgical wound bed predict a wound-healing complication? (2) Does recovery (increase) in transcutaneous oxygen measurement during the rest period between the end of radiation and the time of surgery protect against wound-healing complications? METHODS: A prospective, multi-institution study was coordinated to measure skin oxygenation at three timepoints in patients undergoing surgery for a lower extremity soft tissue sarcoma after preoperative radiation. Between 2016 and 2020, the five participating centers treated 476 patients for lower extremity soft tissue sarcoma. Of those, we considered those with a first-time sarcoma treated with radiation before limb salvage surgery as potentially eligible. Based on that, 21% (98 of 476) were eligible; a further 12% (56 of 476) were excluded because they refused to participate or ultimately, they were treated with a flap, amputation, or skin graft. Another 1% (3 of 476) of patients were lost because of incomplete datasets or follow-up less than 6 months, leaving 8% (39 of 476) for analysis here. The mean patient age was 62 ± 14 years, 62% (24 of 39) of the group were men, and 18% (7 of 39) of patients smoked cigarettes; 87% (34 of 39) of tumors were intermediate/high grade, and the most common histologic subtype was undifferentiated pleomorphic sarcoma. In investigating complications, a cutoff of 25 mmHg was chosen based on a pilot investigation that identified this value. All patients were assessed for surgical wound-healing complications, which were defined as: those resulting in a return to the operating room, initiation of oral or IV antibiotics, intervention for seroma, or prolonged wound packing or dressing changes. To answer the first research question, we compared the proportion of patients who developed a wound-healing complication between those patients who had any reading below 25 mmHg (7 of 39) and those who did not (32 of 39). To answer the second question, we compared the group with stable or decreased skin oxygenation (22 of 37 patient measurements [two patients missed the immediate postoperative measurement]) to the group that had increased skin oxygen measurement (15 of 37 measurements) during the period between the end of radiation and the surgical procedure; again, the endpoint was the development of a wound-healing complication. This study was powered a priori to detect an unadjusted odds ratio for wound-healing complications as small as 0.71 for a five-unit (5 mmHg) increase in TcO 2 between the groups, with α set to 0.05, ß set to 0.2, and a sample size of 40 patients. RESULTS: We found no difference in the odds of a wound-healing complication between patients whose transcutaneous oxygen measurements were greater than or equal to 25 mmHg at all timepoints compared with those who had one or more readings below that threshold (odds ratio 0.27 [95% confidence interval (CI) 0.05 to 1.63]; p = 0.15). There was no difference in the odds of a wound-healing complication between patients who had recovery of skin oxygenation between radiation and surgery and those who did not (OR 0.63 [95% CI 0.37 to 5.12]; p = 0.64). CONCLUSION: Transcutaneous oximetry cannot be considered a reliable test in isolation to predict wound-healing complications. This may be a function of the fact that transcutaneous oximetry samples a relatively small portion of the landscape in which a wound-healing complication could potentially arise. In the absence of a reliable diagnostic test, clinicians must still use their best judgment regarding surgical timing and work to address modifiable risk factors to avoid complications. The unanswered question that remains is whether there is a skin perfusion or oxygenation issue at the root of these complications, which seems likely. Alternative approaches that can assess the wound more broadly and in real time, such as fluorescent probes, may be deserving of further investigation. LEVEL OF EVIDENCE: Level II, diagnostic study.


Assuntos
Sarcoma , Ferida Cirúrgica , Masculino , Humanos , Pessoa de Meia-Idade , Idoso , Feminino , Cicatrização , Monitorização Transcutânea dos Gases Sanguíneos/efeitos adversos , Estudos Prospectivos , Extremidade Inferior/patologia , Sarcoma/radioterapia , Sarcoma/cirurgia , Oxigênio , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/diagnóstico , Estudos Retrospectivos
2.
Int J Phytoremediation ; 21(12): 1197-1204, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31099254

RESUMO

Electrokinetic-enhanced phytoremediation is an effective technology to decontaminate heavy metal contaminated soil. In this study, we examined the effects of electrokinetic treatments on plant uptake and bioaccumulation of U from soils with various U sources. Redistribution of uranium in soils as affected by planting and electrokinetic treatments was investigated. The soil was spiked with 100 mg kg-1 UO2, UO3, and UO2(NO3)2. After sunflower and Indian mustard grew for 60 days, 1 voltage of direct-current was applied across the soils for 9 days. The results indicated that U uptake in both plants were significantly enhanced by electrokinetic treatments from soil with UO3 and UO2(NO3)2. U was more accumulated in roots than in shoots. Electrokinetic treatments were effective on lowering soil pH near the anode region. Overall, uranium (U) removal efficiency reached 3.4-4.3% from soils with UO3 and uranyl with both plants while that from soil with UO2 was 0.7-0.8%. Electrokinetic remediation treatment significantly enhanced the U removal efficiency (5-6%) from soils with UO3 and uranyl but it was 0.8-1.3% from soil with UO2, indicating significant effects of U species and electrokinetic enhancement on U bioaccumulation. This study implies the potential feasibility of electrokinetic-enhanced phytoremediation of U soils with sunflower and Indian mustard.


Assuntos
Helianthus , Poluentes do Solo , Urânio , Biodegradação Ambiental , Mostardeira , Solo
3.
Microchem J ; 139: 242-249, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30245530

RESUMO

In this paper, we examined three different sequential coprecipitation schemes based on Mg(OH)2 and CaF2 precipitation using triethylamine (TEA) and hydrofluoric acid (HF), respectively, for determination of cadmium (Cd) impurities from multivitamin/mineral (MVM) supplements by isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS). The schemes involved three-step coprecipitation with either TEA alone or in combination with HF and are designated as Scheme 1 (TEA-TEA-TEA), Scheme 2 (TEA-HF-TEA) and Scheme 3 (HF-TEA-TEA) according to the addition sequence of each reagent. Experiments were carried out with MVM solutions spiked with 60 µg L-1 Cd from a multielement standard solution. All schemes provided quantitative separation of Cd from MVM matrix. Scheme 1 was the least effective in removal of interfering concomitant elements, molybdenum (Mo) and tin (Sn). Scheme 2 performed better for Sn, but failed in eliminating Mo. Scheme 3 was the most effective in eliminating both Mo and Sn. Mo levels in test MVM solutions reduced from 4.3 µg mL-1 to as low as 0.014 µg mL-1 while that for Sn decreased from 0.5 µg mL-1 to 0.018 µg mL-1 allowing interference-free determination of Cd to be achieved. Salt-matrix due to Mg, Ca, P and K along with the essential elements (Mn, Fe, Cu and Zn) levels was also reduced significantly. Reagent blanks from HF and TEA were insignificant (0.008 µg L-1) allowing a limit of detection of 0.004 µg L-1 or 0.26 ng g-1 Cd to be achieved (3σ, n = 6). The performance of the coprecipitation method (Scheme 3) was validated by determination of Cd in multivitamin/multielement tablets certified reference material (SRM 3280) by ID-ICP-MS. Experimental results (ng g-1) and recoveries were 78.8 ± 4.7 (98.5%), 77.9 ± 5.2 (97.4%) and 76.5 ± 4.8 (95.6%) for 110Cd, 111Cd and 114Cd isotopes, respectively. Several commercial MVM supplements were analyzed using the method. Mean Cd concentration ranged from 21.4 ng g-1 to 93.3 ng g-1. These values are much lower than those reported to date for various MVM supplements by ICP-MS determinations without chemical separation.

4.
Postgrad Med J ; 91(1077): 373-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26069217

RESUMO

OBJECTIVE: To investigate the barriers to access to eye health services for patients with glaucoma in Tanzania with the aim of identifying key areas for improvement and further research. DESIGN: Qualitative investigation using face-to-face semi-structured interviews with patients recruited from the Kilimanjaro Christian Medical Centre (KCMC) outpatient eye clinic. This project is part of the international strategy of the Research into Glaucoma and Ethnicity (ReGAE) programme. METHODS: Interviews were conducted with the help of a translator; all data were transcribed in Swahili and then translated into English. Manual coding and qualitative analysis was used to identify major themes and relevant concepts. Data were collected during May and June 2013. MAIN OUTCOME MEASURES: Qualitative data on glaucoma awareness and access to healthcare. RESULTS: 12 patients (7 men, 5 women) of mean age 67.5 years (range 53-86 years) were interviewed. All participants had a previous diagnosis of glaucoma and no other eye conditions. The understanding of glaucoma was limited and the capacity for healthcare providers to improve glaucoma knowledge seemed underused. Participants had particular difficulty in understanding the aetiology and chronicity of the disease. Socioeconomic factors also posed significant barriers to service usage. CONCLUSIONS: Among many barriers to access to health services for patients with glaucoma, knowledge of the condition was identified as a key issue. Enhancing the understanding of glaucoma may improve access by triggering earlier presentation, informing those at risk and improving adherence to treatment. This is an area for further research with potential for improving service provision.


Assuntos
Atenção à Saúde/organização & administração , Glaucoma/prevenção & controle , Acessibilidade aos Serviços de Saúde/organização & administração , Optometria/organização & administração , Adulto , Idoso , Conscientização , Feminino , Glaucoma/diagnóstico , Glaucoma/epidemiologia , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Atenção Primária à Saúde/organização & administração , Pesquisa Qualitativa , Tanzânia/epidemiologia
5.
Clin Orthop Relat Res ; 473(2): 695-702, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25224820

RESUMO

BACKGROUND: There are few data on the types of procedures orthopaedic oncologists perform in their first years of practice. Because fellowships are graduating fellows each year and the number of tumor patients is limited, defining the practice patterns of early-career orthopaedic oncologists may help diminish early employment discontent and enhance workforce discussions. QUESTIONS/PURPOSES: The aim of the study was to use the objective case log volumes of a cross-section of early career orthopaedic oncologists to describe (1) the number of operations performed annually; (2) the proportion of tumor, trauma, adult reconstruction, and other operations for individual participants, (3) individual practice characteristics that were associated with the number of tumor procedures; and (4) the sources of satisfaction and challenges in each individual's career and surgical practice. METHODS: Fifteen fellowship-trained orthopaedic oncologists out of a potential pool of 33 (45%) in their first 4 years of practice responded to a survey by submitting complete operative case lists for a 2-year period. We recorded the type of procedure and determined associations between the annual number of tumor operations and total operative caseload, years in practice, and some details of individual practice patterns. Each participant completed a survey regarding practice-related sources of stress and satisfaction. A total of 5611 surgical cases were available for review. For the entire cohort, there were 3303 (59%) tumor procedures, 973 (17%) trauma, 890 (16%) adult reconstruction, and 445 (8%) other. RESULTS: The median annual number of total operations was 214 (range, 63-356) and median annual number of tumor operations was 135 (range, 47-216). The median proportion of tumor operations in an individual practice was 56% (range, 43%-94%). The annual number of tumor operations correlated with the total annual number of operations (r = 0.73, p < 0.001). Sources of stress and satisfaction were similar to the general membership of the Musculoskeletal Tumor Society (MSTS), apart from more early-career surgeons regarding case volume as important (29 of 104 [28%] of MSTS versus 11 of 15 [73%] of early-career, p < 0.001). CONCLUSIONS: The typical early-career orthopaedic tumor surgeon had fewer than 60% of his or her operative procedures directly related to the subject of his or her fellowship training in orthopaedic oncology. Overall, the challenges and rewards of clinical practice are similar to oncologic surgeons later in their career. This study is a first step in assessing early practice characteristics and may be of value to the prospective orthopaedic oncologist, fellowship educators, and the society in workforce discussions. Early-career practice patterns have not been previously presented, to our knowledge, for any subspecialty of orthopaedic surgery, and we hope that this study will stimulate similar efforts throughout the field. LEVEL OF EVIDENCE: Level IV, economic and decision analyses. See Guidelines for Authors for a complete description of levels of evidence.


Assuntos
Neoplasias Ósseas/cirurgia , Competência Clínica , Ortopedia/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Adulto , Humanos , Satisfação no Emprego
6.
Clin Orthop Relat Res ; 473(3): 868-74, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24777726

RESUMO

BACKGROUND: Patients often receive advanced imaging before referral to an orthopaedic oncologist. The few studies that have evaluated the value of these tests have been single-center studies, and there were large discrepancies in the estimated frequencies of unnecessary use of diagnostic tests. QUESTIONS/PURPOSES: (1) Is there regional variation in the use of advanced imaging before referral to an orthopaedic oncologist? (2) Are these prereferral studies helpful to the treating orthopaedic oncologist in making a diagnosis or treatment plan? (3) Are orthopaedic surgeons less likely to order unhelpful studies than other specialties? (4) Are there any tumor or patient characteristics that are associated with the ordering of an unhelpful study? METHODS: We performed an eight-center prospective analysis of patients referred for evaluation by a fellowship-trained orthopaedic oncologist. We recorded patient factors, referral details, advanced imaging performed, and presumptive diagnosis. The treating orthopaedic oncologist determined whether each study was helpful in the diagnosis or treatment of the patient based on objective and subjective criteria used in prior investigations. We analyzed the data using bivariate methods and logistic regression to determine regional variation and risk factors predictive of unhelpful advanced imaging. Of the 371 participants available for analysis, 301 (81%) were referred with an MRI, CT scan, bone scan, ultrasound, or positron emission tomography scan. RESULTS: There were no regional differences in the use of advanced imaging (range of patients presenting with advanced imaging 66%-88% across centers, p = 0.164). One hundred thirteen patients (30%) had at least one unhelpful study; non-MRI advanced imaging was more likely to be unhelpful than MRIs (88 of 129 [68%] non-MRI imaging versus 46 of 263 [17%] MRIs [p < 0.001]). Orthopaedic surgeons were no less likely than nonorthopaedic surgeons to order unhelpful studies before referral to an orthopaedic oncologist (56 of 179 [31%] of patients referred by orthopaedic surgeons versus 35 of 119 [29%] referred by primary care providers and 22 of 73 [30%] referred by nonorthopaedic specialists, p = 0.940). After controlling for potential confounding variables, benign bone lesions had an increased odds of referral with an unhelpful study (59 of 145 [41%] of benign bone tumors versus 54 of 226 [24%] of soft tissue tumors and malignant bone tumors; odds ratio, 2.80; 95% confidence interval, 1.68-4.69, p < 0.001). CONCLUSIONS: We found no evidence that the proportion of patients referred with advanced imaging varied dramatically by region. Studies other than MRI were likely to be considered unhelpful and should not be routinely ordered by referring physicians. Diligent education of orthopaedic surgeons and primary care physicians in the judicious use of advanced imaging in benign bone tumors may help mitigate unnecessary imaging. LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.


Assuntos
Neoplasias Ósseas/diagnóstico , Diagnóstico por Imagem , Padrões de Prática Médica , Encaminhamento e Consulta , Feminino , Humanos , Masculino , Ortopedia , Estudos Prospectivos
8.
Ground Water ; 62(1): 60-74, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37945376

RESUMO

Categorical parameter distributions consisting of geologic facies with distinct properties, for example, high-permeability channels embedded in a low-permeability matrix, are common at contaminated sites. At these sites, low-permeability facies store solute mass, acting as secondary sources to higher-permeability facies, sustaining concentrations for decades while increasing risk and cleanup costs. Parameter estimation is difficult in such systems because the discontinuities in the parameter space hinder the inverse problem. This paper presents a novel approach based on Traveling Pilot Points (TRIPS) and an iterative ensemble smoother (IES) to solve the categorical inverse problem. Groundwater flow and solute transport in a hypothetical aquifer with a categorical parameter distribution are simulated using MODFLOW 6. Heads and concentrations are recorded at multiple monitoring locations. IES is used to generate posterior ensembles assuming a TRIPS prior and an approximate multi-Gaussian prior. The ensembles are used to predict solute concentrations and mass into the future. The evaluation also includes an assessment of how the number of measurements and the choice of the geological prior determine the characteristics of the posterior ensemble and the resulting predictions. The results indicate that IES was able to efficiently sample the posterior distribution and showed that even with an approximate geological prior, a high degree of parameterization and history matching could lead to parameter ensembles that can be useful for making certain types of predictions (heads, concentrations). However, the approximate geological prior was insufficient for predicting mass. The analysis demonstrates how decision-makers can quantify uncertainty and make informed decisions with an ensemble-based approach.


Assuntos
Água Subterrânea , Humanos , Geologia , Modelos Teóricos , Soluções , Movimentos da Água
9.
Aesthet Surg J ; 33(5): 681-90, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23813397

RESUMO

BACKGROUND: Aesthetic breast augmentation can be fraught with postoperative complications, particularly capsular contracture (CC), skin surface irregularities, and implant or inframammary fold malposition. Similar complications have been addressed successfully in reconstructive breast surgery with acellular dermal matrix (ADM) products. OBJECTIVE: The authors present their initial experience with porcine ADM (PADM) in aesthetic breast augmentation. METHODS: Retrospective chart review was performed for 93 consecutive patients (179 breasts) who underwent revisionary cosmetic breast augmentation with or without mastopexy between May 2009 and September 2012. Porcine ADM (Strattice; Lifecell Corp, Branchburg, New Jersey) was placed bilaterally in 74 patients and unilaterally in 19 patients. All patients were operated upon by 1 surgeon (J.N.P.). Product use description and complications were recorded, including infection, extrusion, CC, and implant malposition. RESULTS: Average follow-up was 12 months (range, 1-39 months). There were 2 major complications (1.6% of breasts): an infection in 1 breast that required implant explantation approximately 2 weeks postoperatively and an extrusion that required PADM removal. Two additional patients had high-riding implants resulting from folded PADM that required revision; both cases were corrected by excising the folded PADM segment. Seven other patients required office procedures to correct minor imperfections. Two CC recurrences were suspected (1 patient) in the 76 breasts that underwent capsulectomy and PADM placement. CONCLUSIONS: Porcine ADM demonstrated great utility as an adjunct in revisionary cosmetic breast surgery. The product helped to provide good aesthetic outcomes with low complication rates. Prospective, randomized trials may prove helpful in defining the role of PADM further in these challenging cases.


Assuntos
Implantes de Mama/efeitos adversos , Mamoplastia/efeitos adversos , Procedimentos de Cirurgia Plástica/métodos , Derme Acelular , Adulto , Idoso , Animais , Estudos de Coortes , Estética , Feminino , Sobrevivência de Enxerto , Humanos , Contratura Capsular em Implantes/cirurgia , Mamoplastia/métodos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/cirurgia , Reoperação/métodos , Estudos Retrospectivos , Medição de Risco , Retalhos Cirúrgicos , Suínos , Resultado do Tratamento , Adulto Jovem
10.
Ground Water ; 61(1): 131-138, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36594877

RESUMO

We present a contaminant treatment system (CTS) package for MODFLOW 6 that facilitates the simulation of pump-and-treat systems for groundwater remediation. Using the "nonintrusive" MODFLOW 6 application programming interface (API) capability, the CTS package can balance flows between extraction and injection wells within the outer flow solution loop and applies blended concentration/mass treatment efficiency within the outer transport solution loop. The former can be important when the requested extraction rate cannot be satisfied by the current simulated groundwater system conditions, while the latter can be important for simulating incomplete/imperfect treatment schemes. Furthermore, the CTS package allows users to temporally vary all aspects of a simulated CTS system, including the configuration and location of injection and extraction wells, and the CTS efficiency. This flexibility combined with the API-based implementation provide a generic and general CTS package that can be applied across the wide range of MODFLOW 6 simulation options and that evolves in step with MODFLOW 6 code modifications and advancements without needing to update the CTS package itself.


Assuntos
Água Subterrânea , Modelos Teóricos , Movimentos da Água , Simulação por Computador , Software
11.
J Orthop Case Rep ; 13(11): 122-128, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38025377

RESUMO

Introduction: Calcific myonecrosis is a rare soft-tissue disease where a single muscle or muscle compartment is replaced with central liquefaction and peripheral calcification. This disease usually occurs in a single limb after trauma. Until now, bilateral muscle involvement has not been previously reported. Case Report: A 73-year-old woman presented with symptomatic masses in the soft tissues of bilateral anterior thighs. She had no known history of trauma but recalled a specific tearing sensation episode in both her legs while squatting when weightlifting in the distant past. The patient had calcified masses that had replaced the rectus femoris muscle bilaterally with associated effects on hip and knee range of motion. The patient underwent excision of a portion of calcific myonecrosis and two locations of rectus femoris tenotomies in one leg and only a simple rectus femoris tenotomy on the contralateral leg. The patient subsequently experienced a significant improvement in hip and knee motion and a reduction in associated pain on both sides. Conclusion: Historical and radiographic information are key in making the diagnosis of calcific myonecrosis. Treatment decisions should be based on the patient's symptoms balanced with the morbidity of the expected procedures. Symptomatic patients should be considered for excision of the symptomatic involved areas. A tenotomy may be a viable option if a limitation in motion is the primary complaint. Asymptomatic patients with a stable lesion and imaging should undergo conservative management due to the high risk of infection and wound healing problems.

12.
Can J Neurol Sci ; 39(3): 343-6, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22547515

RESUMO

PURPOSE: To compare North American Symptomatic Carotid Endarterectomy Trial (NASCET) stenosis values and NASCET grade categorization (mild, moderate, severe) of semi-automated vessel analysis software versus manual measurements on computed tomography angiography (CTA). METHODS: There were four observers. Two independently analyzed 81 carotid artery CTAs using semi-automated vessel analysis software according to a blinded protocol. The software measured the narrowest stenosis in millimeters (mm), distal internal carotid artery (ICA) in mm, and calculated percent stenosis based on NASCET criteria. One of these two observers performed this task twice on each carotid, the second analysis was delayed two months in order to mitigate recall bias. Two other observers manually measured the narrowest stenosis in mm, distal ICA in mm, and calculated NASCET percent stenosis in a blinded fashion. The calculated NASCET stenoses were categorized into mild, moderate, or severe. Chi square and analysis of variance (ANOVA) were used to test for statistical differences. RESULTS: ANOVA did not find a statistically significant difference in the mean percent stenosis when comparing the two manual measurements, the two semi-automated measurements, and the repeat semi-automated. Chi square demonstrated that the distribution of grades of stenosis were statistically different (p<0.05) between the manual and semiautomated grades. Semi-automated vessel analysis tended to underestimate the degree of stenosis compared to manual measurement. CONCLUSION: The mean percentage stenosis determined by semi-automated vessel analysis is not significantly different from manual measurement. However, when the data is categorized into mild, moderate and severe stenosis, there is a significant difference between semi-automated and manual measurements. The semi-automated software tends to underestimate the stenosis grade compared to manual measurement.


Assuntos
Angiografia/métodos , Estenose das Carótidas/diagnóstico por imagem , Processamento Eletrônico de Dados/métodos , Tomografia Computadorizada por Raios X , Idoso , Método Duplo-Cego , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Estudos Retrospectivos , Software
13.
Sensors (Basel) ; 12(10): 13284-94, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23201996

RESUMO

Measurement by impedance spectroscopy of the changes in intrazeolitic cation motion of pressed pellets of zeolite particles upon adsorption of dimethylmethylphosphonate (DMMP) provides a strategy for sensing DMMP, a commonly used simulant for highly toxic organophosphate nerve agents. In this work, two strategies for improving the impedance spectroscopy based sensing of DMMP on zeolites were investigated. The first one is the use of cerium oxide (CeO(2)) coated on the zeolite surface to neutralize acidic groups that may cause the decomposition of DMMP, and results in better sensor recovery. The second strategy was to explore the use of zeolite Y membrane. Compared to pressed pellets, the membranes have connected supercages of much longer length scales. The zeolite membranes resulted in higher sensitivity to DMMP, but recovery of the device was significantly slower as compared to pressed zeolite pellets.

14.
Ecol Evol ; 12(1): e8523, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35127033

RESUMO

Granivorous rodents are important components of ecosystems not only because they consume seeds but also because some aid in seed dispersal through seed-caching behaviors. Some rodents bury seeds in shallow pits throughout territories, called scatterhoards, that individuals recover, pilfer, or transfer to other caches. We suspect some single-seed caches in environments represent missed seeds from reclaiming or pilfering caches. We documented the sloppiness of seed removal from scatterhoards of soapweed yucca (Yucca glauca) seeds by Ord's kangaroo rats (Dipodomys ordii). We quantified the frequency and location of seeds remaining. In an experiment with artificial caches of three sizes, kangaroo rats harvested 51% of caches after one night, and 53% had incomplete recovery with at least one seed remaining. The greater the number of seeds in caches, the greater frequency of incomplete recovery. In another experiment with natural and artificial caches, 75% of caches were excavated after 8 days, with at least 70% having at least one seed remaining. Regardless of original cache size, a single seed represented the mode for seeds remaining. Incomplete recovery of seeds likely benefits plant establishment, potentially significantly in some systems. Remaining seeds, especially those buried at bottoms of caches, likely will stay undetected in landscapes, yielding propagules for subsequent plant generations. Soapweed yucca has large but light, flat wind-dispersed seeds, and removal of caches with smaller seeds might have greater frequency of missed seeds during recovery and pilfering by rodents. Our results suggest that scatter-hoarding granivores also contribute to plant establishment by leaving limited numbers of seeds behind when removing caches, at least in some systems.

15.
Ground Water ; 60(1): 71-86, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34463959

RESUMO

Environmental water management often benefits from a risk-based approach where information on the area of interest is characterized, assembled, and incorporated into a decision model considering uncertainty. This includes prior information from literature, field measurements, professional interpretation, and data assimilation resulting in a decision tool with a posterior uncertainty assessment accounting for prior understanding and what is learned through model development and data assimilation. Model construction and data assimilation are time consuming and prone to errors, which motivates a repeatable workflow where revisions resulting from new interpretations or discovery of errors can be addressed and the analyses repeated efficiently and rigorously. In this work, motivated by the real world application of delineating risk-based (probabilistic) sources of water to supply wells in a humid temperate climate, a scripted workflow was generated for groundwater model construction, data assimilation, particle-tracking and post-processing. The workflow leverages existing datasets describing hydrogeology, hydrography, water use, recharge, and lateral boundaries. These specific data are available in the United States but the tools can be applied to similar datasets worldwide. The workflow builds the model, performs ensemble-based history matching, and uses a posterior Monte Carlo approach to provide probabilistic capture zones describing source water to wells in a risk-based framework. The water managers can then select areas of varying levels of protection based on their tolerance for risk of potential wrongness of the underlying models. All the tools in this workflow are open-source and free, which facilitates testing of this repeatable and transparent approach to other environmental problems.

16.
Br J Sports Med ; 45(2): 140-6, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20966035

RESUMO

At the end of this article, the reader should be able to (1) recognise normal anatomy and anatomical variants of the extensor mechanism of the knee on various imaging modalities, including plain film, ultrasound and MRI; (2) diagnose a broad spectrum of EM injuries in adult and paediatric patients including patellar and quadriceps tendinopathy, Osgood-Schlatter disease, Sindig-Larsen-Johansson syndrome, chondromalacia patellae and patellar fractures on various imaging modalities; and (3) appreciate the important role of imaging in the diagnosis of musculoskeletal injuries.


Assuntos
Traumatismos do Joelho/diagnóstico , Adulto , Bursite/diagnóstico , Criança , Diagnóstico por Imagem/métodos , Feminino , Fraturas Ósseas/diagnóstico , Humanos , Articulação do Joelho/anatomia & histologia , Masculino , Osteocondrose/diagnóstico , Patela/lesões , Luxação Patelar/diagnóstico , Ligamento Patelar/anatomia & histologia , Músculo Quadríceps/lesões , Ruptura/diagnóstico , Tendinopatia/diagnóstico , Traumatismos dos Tendões/diagnóstico
17.
Aesthet Surg J ; 31(6): 634-42, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21813876

RESUMO

Chin augmentation is an extremely rewarding cosmetic operation, particularly when performed as an adjunct to rhinoplasty and rhytidectomy. There has been much debate regarding the ideal surgical approach and whether implant placement or osseous genioplasty is the superior operation. Regardless of the technique, all surgery carries an inherent risk for complications, and it is the surgeon's responsibility to learn which techniques will work best in his or her hands for each patient. Certain complications can be almost unavoidable, but a solid foundation in anatomy and a review of the existing literature can help minimize the risk of certain problems while providing an improved understanding of how to recognize and manage them when they occur. The authors present a comprehensive review of genioplasty and chin implant complications, how they might be avoided, and management methods if they occur.


Assuntos
Queixo/cirurgia , Procedimentos de Cirurgia Plástica/efeitos adversos , Complicações Pós-Operatórias/prevenção & controle , Queixo/anormalidades , Humanos , Complicações Pós-Operatórias/etiologia , Próteses e Implantes , Implantação de Prótese/efeitos adversos , Implantação de Prótese/métodos , Procedimentos de Cirurgia Plástica/métodos
18.
Ground Water ; 59(4): 571-580, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33495991

RESUMO

A popular and contemporary use of numerical groundwater models is to estimate the discrete relation between groundwater extraction and surface-water/groundwater exchange. Previously, the concept of a "capture map" has been put forward as a means to effectively summarize this relation for decision-making consumption. While capture maps have enjoyed success in the environmental simulation industry, they are deterministic, ignoring uncertainty in the underlying model. Furthermore, capture maps are not typically calculated in a manner that facilitates analysis of varying combinations of extraction locations and/or reaches. That is, they are typically constructed with focus on a single reach or group of reaches. The former of these limitations is important for conveying risk to decision makers and stakeholders, while the latter is important for decision-making support related to surface-water management, where future foci may include reaches that were not the focus of the original capture analysis. Herein, we use the concept of a response matrix to generalize the theory of the capture-map approach to estimate spatially discrete streamflow depletion potential. We also use first-order, second-moment uncertainty estimation techniques with the concept of "risk shifting" to place capture maps and streamflow depletion potential in a stochastic, risk-based framework. Our approach is demonstrated for an integrated groundwater/surface-water model of the lower San Antonio River, Texas, USA.


Assuntos
Água Subterrânea , Rios , Incerteza , Água , Movimentos da Água
19.
Ground Water ; 59(6): 788-798, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33866566

RESUMO

Realistic environmental models used for decision making typically require a highly parameterized approach. Calibration of such models is computationally intensive because widely used parameter estimation approaches require individual forward runs for each parameter adjusted. These runs construct a parameter-to-observation sensitivity, or Jacobian, matrix used to develop candidate parameter upgrades. Parameter estimation algorithms are also commonly adversely affected by numerical noise in the calculated sensitivities within the Jacobian matrix, which can result in unnecessary parameter estimation iterations and less model-to-measurement fit. Ideally, approaches to reduce the computational burden of parameter estimation will also increase the signal-to-noise ratio related to observations influential to the parameter estimation even as the number of forward runs decrease. In this work a simultaneous increments, an iterative ensemble smoother (IES), and a randomized Jacobian approach were compared to a traditional approach that uses a full Jacobian matrix. All approaches were applied to the same model developed for decision making in the Mississippi Alluvial Plain, USA. Both the IES and randomized Jacobian approach achieved a desirable fit and similar parameter fields in many fewer forward runs than the traditional approach; in both cases the fit was obtained in fewer runs than the number of adjustable parameters. The simultaneous increments approach did not perform as well as the other methods due to inability to overcome suboptimal dropping of parameter sensitivities. This work indicates that use of highly efficient algorithms can greatly speed parameter estimation, which in turn increases calibration vetting and utility of realistic models used for decision making.


Assuntos
Água Subterrânea , Algoritmos , Calibragem , Mississippi , Modelos Teóricos
20.
Ground Water ; 59(4): 581-596, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33901297

RESUMO

A numerical surface-water/groundwater model was developed for the lower San Antonio River Basin to evaluate the responses of low base flows and groundwater levels within the basin under conditions of reduced recharge and increased groundwater withdrawals. Batch data assimilation through history matching used a simulation of historical conditions (2006-2013); this process included history-matching to groundwater levels and base-flow estimates at several gages, and was completed in a high-dimensional (highly parameterized) framework. The model was developed in an uncertainty framework such that parameters, observations, and scenarios of interest are envisioned stochastically as distributions of potential values. Results indicate that groundwater contributions to surface water during periods of low flow may be reduced from 6% to 25% with a corresponding 25% reduction in recharge and a 25% increase in groundwater pumping over an 8-year planning period. Furthermore, results indicate groundwater-level reductions in some hydrostratigraphic units are more likely than in other hydrostratigraphic units over an 8-year period under drought conditions with the higher groundwater withdrawal scenario.


Assuntos
Água Subterrânea , Rios , Texas , Incerteza
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