Predictive Factors for Intraoperative Determination for the Need of Femoral Osteochondroplasty After Periacetabular Osteotomy for Acetabular Dysplasia.

Background: Determination of need for osteochondroplasty (OCP) during periacetabular osteotomy (PAO) commonly relies on intraoperative assessment of internal rotation at 90° flexion (IRF). Performing an OCP helps decrease the risk of iatrogenic femoroacetabular impingement from PAO reduction. Avoiding impingement helps decrease risks of accelerated secondary osteoarthritis. The literature is limited for factors that predict need for OCPs during PAOs. The purpose of this study was to (1) define the characteristics of patients needing concurrent OCP and provide OCP rate based on IRF and femoral version and (2) identify predictive factors (clinical, radiographic) associated with need for OCP during PAO. As some surgeons determine need for OCP pre-operatively, predictive factors would aid decision making. Methods: This was a prospective cohort of 224 hips (207 patients) who underwent PAO for symptomatic acetabular dysplasia, of which 154 hips (69%) underwent OCP between years 2013 and 2017. Patients underwent OCP if they had restrictions in motion or impingement intra-operatively. Pre-operative factors such as age, sex, BMI, and CT findings were recorded that underwent univariate and multivariable analyses. Multivariable analysis found predictors that were described using odds ratios and 95% confidence intervals. IRF>30° and femoral version 10°-25° were used as the reference groups during categorical analysis. P-values ≤0.05 were considered significant. Results: Alpha angles >55° (OR= 2.20, CI: 1.08-4.52, p= 0.03), IRF≤20° (OR: 9.52, CI: 3.87-23.40, p<0.001), IRF >20°-30° (OR: 2.68, CI: 1.08-6.62, p=0.03), and femoral version <10° (OR: 5.26, CI: 1.09-25.30, p=0.04) were associated with increased odds of OCP. On continuous modeling, decreasing femoral version (OR: 1.07, CI: 1.02-1.12, p=0.002) and IRF (OR: 1.06, CI: 1.03-1.09, p<0.001) were associated with increased chance of OCP. For 5° changes, the chance of OCP increased by 40% (OR: 1.40, CI: 1.13-1.73, p=0.002) and 35% (OR: 1.35, IC: 1.16-1.57, p<0.001), respectively. Conclusion: Awareness of need for OCP may be valuable in peri-operative planning for these patients especially since some surgeons perform this technique arthroscopically before PAO. Factors associated with increased chances of OCP were alpha angles >55°, decreased IRF, and decreased femoral version. More studies in the future would help determine how OCP affects patient outcomes. Level of Evidence: III.

Patients' Perceptions of Remote Monitoring and App-Based Rehabilitation Programs: A Comparison of Total Hip and Knee Arthroplasty.

BACKGROUND: Remote monitoring rehabilitation programs are new technologies growing in popularity for patients undergoing lower extremity total joint arthroplasty. The purpose of this study was to assess the patients' perceptions of these technologies. METHODS: Patients who underwent total hip arthroplasty (THA), total knee arthroplasty arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA) from September 2020 to February 2022, and participated in a clinical study utilizing remote monitoring and an app-based rehabilitation program were given a questionnaire 3 months postoperatively to assess their perceptions of these technologies. There were 166 patients who completed the survey (42 THA; 106 TKA; 18 UKA). RESULTS: There were 92% of patients who found the technology easy to use. A majority of patients felt the technologies motivated them. The TKA/UKA patients felt more strongly that these technologies allowed the surgeon to monitor their recovery closely (81.9% versus 65.9%; P = .009). There were 85% of THA patients and 94.5% of TKA/UKA patients recommended these technologies. The THA patients felt more strongly that digital rehabilitation could completely replace in-person physical therapy compared to TKA/UKA patients (85.4% versus 41.3%; P < .001). A majority (83%) of patients recommended a combination of inpatient and technology-assisted rehabilitation (THA 90.2%; 84.4% TKA/UKA). CONCLUSION: The THA and TKA/UKA patients found remote monitoring rehabilitation easy to use, increased motivation, and recommend it to other patients undergoing lower extremity arthroplasty. They recommend a combination of technology and in-person rehabilitation postoperatively. The THA patients felt these technologies could replace in-person rehabilitation programs. LEVEL OF EVIDENCE: IV.

Factors that impact recruitment and retention of veterinarians in emergency practice.

OBJECTIVE: To examine factors that impact emergency veterinarians' decisions in selecting a place of employment and their perceptions of factors important in fostering a work environment conducive to long-term employment. SAMPLE: 433 Veterinary Information Network members who reported practicing emergency medicine in the US and were not diplomates of the American College of Veterinary Emergency and Critical Care. PROCEDURES: An electronic survey distributed via the Veterinary Information Network data collection portal, made available from May 25, 2022, through June 15, 2022. RESULTS: Factors rated as most important in selecting a place of employment included working with a highly trained support staff and collegiality of coworkers. Factor analysis was used to extract factors that can influence emergency medicine practitioners' views of a work environment conducive to long-term employment. The factor found to be most important was leadership. All factors, except for professional growth, were rated as more important by female practitioners when compared to male practitioners. CLINICAL RELEVANCE: Aspects promoted in emergency medicine veterinarian recruitment efforts should include, in addition to the innate nature of the position, the elements identified as most attractive to current practitioners. By better understanding the impact of gender, children status, and years practicing emergency medicine on the relative importance in creating workplace environments conducive to long term employment, hospitals can be better equipped to meet the needs of both their current employees as well as potential new hires.

An automated technique for double staining of bone and cartilage in fetal mouse skeletal specimens using alizarin red S and Alcian blue.

Automated methods exist for double staining bone and cartilage in fetal rat, rabbit and mice using alizarin red S and Alcian blue. None of the published methods produce consistently stained bone and cartilage in mouse fetuses. Consequently, we modified an automated staining method for use with mouse fetuses. Methanol replaced 95% industrial denatured alcohol, and 5% glacial acetic acid was used instead of 20%. We describe here our new protocol, which has been used successfully to stain specimens for regulatory prenatal developmental toxicity studies.

The impact of sarcopenia and acute muscle mass loss on long-term outcomes in critically ill patients with intra-abdominal sepsis.

BACKGROUND: Sarcopenia is a known risk factor for poor outcomes across many chronic diseases. The impact on outcomes of both pre-existing sarcopenia and acute muscle wasting (AMW) in acute critical illness caused by sepsis remain unclear. METHODS: We conducted a prospective longitudinal cohort study of critically ill patients with intra-abdominal sepsis utilizing abdominal computed tomography at sepsis onset to determine baseline skeletal muscle index (SMI). Biomarkers of inflammation and catabolism were measured through 28 days while hospitalized. We performed follow-up evaluations of strength and physical function at 3, 6, and 12 months, with interval CT analyses at 3 and 12 months to evaluate changes in muscle mass. Measured clinical outcomes included development of chronic critical illness (≥14 days in intensive care with persistent organ dysfunction), long-term functional status, and 1 year mortality. RESULTS: Among 47 sepsis patients enrolled (mean age 53 ± 14 years), half (n = 23; 49%) were sarcopenic at baseline. Overall, sepsis patients exhibited acute and persistent muscle wasting with an average 8% decrease in SMI from baseline at 3 months (P = 0.0008). Sarcopenic (SAR) and non-sarcopenic (NSAR) groups were similar in regards to age and comorbidity burden. SAR patients had greater acute physiologic derangement (APACHE II, 18 vs. 12.5), higher incidence of multiple organ failure (57% vs. 17%), longer hospital (21 vs. 12 days) and intensive care unit length of stays (13 vs. 4 days), and higher inpatient mortality (17% vs. 0%; all P < 0.05). Pre-existing SAR was a strong independent predictor of early death or developing chronic critical illness (odds ratio 11.87, 95% confidence interval CI 1.88-74.9; P = 0.009, area under the curve 0.880) and was associated with significantly higher risk of 1-year mortality (34.9% vs. 4.2%, p = 0.007). Lower baseline SMI was also predictive of poor functional status at 12 months (OR 0.89, 95% confidence interval 0.80-0.99; p = 0.039, area under the curve 0.867). Additionally, SAR patients had AMW with persistent muscle mass loss at 3 months that was associated with decreased health-related quality of life and SF-36 physical function domains (P < 0.05). Persistent AMW at 3 months was not predictive of mortality or poor functional status, with return to near-baseline muscle mass among sepsis survivors by 6 months. CONCLUSIONS: Critically ill patients have an acute and persistent loss of muscle mass after intra-abdominal sepsis, which is associated with decreased health-related quality of life and physical function at 3 months. However, pre-existing sarcopenia, rather than persistent acute muscle mass loss at 3 months after sepsis, is independently associated with poor long-term functional status and increased 1 year mortality.

The shortage of veterinarians in emergency practice: A survey and analysis.

OBJECTIVE: To examine factors that impact veterinarians' decisions to pursue a career in, or remain working in emergency medicine. DESIGN: Survey. SETTING: General practitioner and student members of Veterinary Information Network. ANIMALS: None. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Veterinarians working in (or having worked in), and students hoping to work in emergency medicine mostly enjoy this type of medicine but find the scheduling and stress of the job create impediments to remaining in the field. Fear of being left without support, especially early in their career, also hinder veterinarians from pursuing a career in or remaining in emergency medicine. CONCLUSIONS: Programs that increase flexibility of work hours or schedules, and provide either a formal or informal mentoring environment, might help increase retention of veterinarians within the field and encourage students to consider a career in emergency medicine.

Two-incision Approach for the Open Reduction Internal Fixation of Intra-articular Hamate Body Fractures Using a Cannulated Headless Compression Screw.

Fractures of the hamate are relatively rare and there is a paucity of literature describing their natural history, indications for operative fixation, surgical techniques, and outcomes. Most authors recommend operative fixation of displaced intra-articular coronal hamate body fractures, and a dorsal approach with Kirschner wires has most commonly been recommended to achieve this. In this report, a 2-incision approach to the hamate is presented that facilitates rigid internal fixation of coronal hamate body fractures with a cannulated headless compression screw and minimizes the possibility of iatrogenic injury to critical branches of the ulnar nerve. The authors summarize a series of 2 patients with displaced, intra-articular coronal hamate body fractures of differing severity treated successfully with the proposed approach.

Novel collection method for volatile organic compounds (VOCs) from dogs.

Host derived chemical cues are an important aspect of arthropod attraction to potential hosts. Host cues that act over longer distances include CO2, heat, and water vapor, while cues such as volatile organic compounds (VOCs) act over closer distances. Domestic dogs are important hosts for disease cycles that include dog heartworm disease vectored by mosquitoes, however the host VOCs utilized by vectors are not well known. Herein we present a novel method that sampled VOCs from a dog host. A Tenax TD stainless steel tube was held near a dog's fur and skin, which collected VOCs that were later desorbed and tentatively identified using a gas chromatograph-mass spectrospectrometer (GC-MS). Background air chemicals were subtracted from the dog sample, resulting in 182 differentiated compounds, a majority of which were identified by ionization fragmentation patterns. Four dogs were sampled and shared 41 of the identified chemicals. VOCs were representative of aliphatics, aromatics, aldehydes, alcohols and carboxylic acids. This chemical characterization method has the potential to identify both individuals and breeds of dogs in addition to other potential uses such as disease diagnosis.

Observation of compositional domains within individual copper indium sulfide quantum dots.

The origin of photoluminescence in copper indium sulfide (CIS) quantum dots (Qdots) has previously been ascribed to a donor-acceptor pair (DAP) recombination, with a crystal lattice defect implicated as the origin of the donor state. In this study, electron energy-loss spectroscopy (EELS) was used to observe defect-rich compositional domains within individual CIS Qdots, supporting a model of defect-state-mediated photoluminescence for these particles, and identifying them as an ideal model system for future study of lattice defects on Qdot properties.

Stable knockdown of hCGß mRNA expression in bladder cancer cells results in significant growth inhibition.

BACKGROUND: Expression of human chorionic gonadotropin beta subunit (hCGß) by epithelial carcinomas is associated with a poor prognosis and has a proposed autocrine growth effect on cancer cells by inhibition of apoptosis. MATERIAL AND METHODS: We transduced the hCGß-expressing bladder cancer cell line SCaBER with short hairpin (sh) RNA lentiviral gene-specific (CGB) constructs and determined its impact on the synthesis of hCGß and the resultant effect on cancer cell growth. RESULTS: Stable CGB gene-silenced clones exhibited a 60%-80% reduction in the level of hCGß expressed and a reduced growth rate of more than 40% compared to wild-type SCaBER cells. CONCLUSIONS: shRNA Lentiviral particles achieve stable knockdown of hCGß translation in the bladder cancer cell line SCaBER. This transforms the phenotype by reducing hCGß expression and cell growth rate. This is consistent with the proposed autocrine/paracrine function of ectopic hCGß expression during oncogenesis.

Feasibility of a breath test for monitoring adherence to vaginal administration of antiretroviral microbicide gels.

Adherence to microbicide gel use is critical to optimizing effectiveness in preventing human immunodeficiency virus transmission. The authors hypothesized that ester taggants added to vaginal gels would generate exhaled alcohol and ketone metabolites and provide a "breath test" for vaginal gel use. This 2-arm (vaginal and dermal), randomized, participant-blinded, pilot study tested this hypothesis. On 8 visits, healthy women (n = 8) received intravaginal taggant (2-butyl acetate, 2-pentyl acetate, isopropyl butyrate, or 2-pentyl butyrate; 30 mg) formulated in hydroxyethylcellulose or tenofovir placebo gel. A second group (n = 4) of women received the same formulations administered dermally on the forearm to determine if skin administration might confound the system. Breath samples were collected using bags before and after taggant administration for 1 hour. Samples were measured using a miniature gas chromatograph and/or gas chromatography-mass spectroscopy for ester taggant, alcohol, and ketone concentrations. After vaginal administration, 2-butyl acetate, 2-pentyl acetate, and metabolites were observed in breath, whereas isopropyl butyrate, 2-pentyl butyrate, and metabolites were not. Some women reported self-resolving, mild burning (24/64 visits) with vaginal administration or a "bubblegum" taste (7/64 visits). No taggants or metabolites were detected following dermal application. A "breath test" for adherence to antiretroviral vaginal gel application appears physiologically and technically feasible.

A novel breath test to directly measure use of vaginal gel and condoms.

We assessed the feasibility of a breath test to detect women's single or concurrent use of vaginal products by adding ester taggants to vaginal gel and condom lubricant. Healthy non-pregnant women were enrolled into a two-day cohort (N = 13) and a single-day cohort (N = 12) in San Francisco. Within each cohort, women were randomized (5:1) to tagged or untagged products, and inserted in a clinical setting: 4 mL of tenofovir placebo gel (ten tagged with 15 mg 2-pentyl acetate; three untagged), and an artificial phallus with a lubricated condom (11 tagged with 15 mg 2-butyl acetate; two untagged), on two separate days (two-day cohort) or concurrently (single-day cohort). Using a portable mini-gas chromatograph, the presence/absence of taggants was determined in breath specimens collected prior to, and at timed intervals following product exposure. Demographic, clinical and product use experience data were collected by structured interview. All participants completed all visits and inserted their assigned products. At 5 min post-insertion, the breath test was 100% accurate in identifying insertion of the tagged (or untagged) gel and/or condom. The half-life in breath of the two esters tested was <1 h with large variability between individuals, taggants and cohorts. Overall, among those receiving tagged product, six mild and two moderate product-related AEs were reported. All were transient and resolved spontaneously. Additional sensations included taste in mouth (N = 4) and scent (N = 5). The tagged products were well tolerated. This breath test has the potential to accurately and objectively monitor adherence to vaginal gel and condom used separately or concurrently.

Oral adherence monitoring using a breath test to supplement highly active antiretroviral therapy.

A breath-based adherence system to document ingestion of oral medications (e.g., HAART) was investigated. Specifically, the food additive 2-butanol, which can be easily packaged with a drug, is converted via alcohol dehydrogenase to the volatile metabolite 2-butanone that rapidly appears in breath, indicating adherence. In healthy adults using a portable sensor and GC-MS, the following experiments were performed: yield of 2-butanone in breath following ingestion of 2-butanol, adherence system accuracy, and potential interference of the adherence system by food or misplacement of 2-butanol on the tongue. During feasibility testing, every subject exhaled 2-butanone with 6.6 ± 1.5 min to peak concentrations of 548 ± 235 ppb following ingestion of 2-butanol (40 mg). ROC areas at 5 and 10 min were 0.95 (0.86-1.00) and 1.00 (1.00-1.00). Food did not interfere. Tongue application resulted in large concentrations of 2-butanol, but not 2-butanone. A breath test to provide definitive evidence of oral medication adherence appears technically feasible.

Measurement of ethanol in gaseous breath using a miniature gas chromatograph.

We designed and built a novel, miniature gas chromatograph (mGC) to use exhaled breath to estimate blood ethanol concentrations that may offer GC quality sensitivity and specificity, but with portability, reduced size, and decreased cost. We hypothesized that the mGC would accurately estimate the serum ethanol concentration using exhaled breath. Human subjects (n = 8) were dosed with ethanol employing the Widmark criteria, targeting a blood concentration of 0.08 g/dL. Serum and breath samples were collected concurrently over an hour. Ethanol concentrations in serum were measured using a CLIA-approved laboratory. Ethanol concentrations in conventional breath were assayed using a calibrated mGC or Intoxilyzer 400PA. Data were analyzed using Bland-Altman analysis using serum concentrations as a "gold standard". For the mGC, the regression line (correlation coefficient), bias, and 95% limits of agreement were y = 1.013x - 0.009 (r = 0.91), -0.008 g/dL, and -0.031 to 0.016 g/dL, respectively, for 30 specimens. For the Intoxilyzer 400PA, the regression line (correlation coefficient), bias, and 95% limits of agreement were y = 0.599x + 0.008 (r = 0.86), -0.024 g/dL, and -0.049 to 0.002 g/dL, respectively, for 71 specimens with a large magnitude effect. We concluded that the mGC, using exhaled breath, performed well to estimate the serum ethanol concentrations.

Identification of compounds from Etonia rosemary (Conradina etonia).

Mosquitoes transmit pathogens that result in diseases harmful to human, livestock, and wildlife hosts. Numerous measures can be used to reduce insect-borne disease risk to humans, and one approach is the use of topical repellents to prevent host-seeking arthropods from taking a blood meal. A current emphasis in the development of new repellents is that they be safe. Therefore, natural products sources are increasingly being explored. Compounds from plants of the mint family (Lamiaceae) have been demonstrated to be insect repellents. This study examines compounds from Etonia rosemary (Conradina etonia) to identify compounds for examination as insect repellents. Samples of Etonia rosemary were passively extracted with hexane, dichloromethane, and methanol and analyzed by GC/MS. This extraction method was chosen to eliminate thermal degradation of plant components that can occur during the distillation procedure. Additional headspace volatile compounds from this plant were identified using microscale purge-and-trap GC/MS. A variety of terpenes, terpenic alcohols, ketones, and aldehydes were identified in the extracts with terpenes and short-chained aldehydes detected in greatest abundance.

The effects of buprenorphine on fentanyl withdrawal in rats.

RATIONALE: Fentanyl is a potent mu-opioid receptor agonist that is widely used for the treatment of severe chronic pain. Discontinuation of fentanyl administration has been shown to induce a negative emotional state. OBJECTIVES: The aim of the present studies was to investigate the effects of the partial mu-opioid receptor agonist buprenorphine on the negative emotional state associated with precipitated and spontaneous fentanyl withdrawal in rats. MATERIALS AND METHODS: Fentanyl and saline were chronically administered via osmotic minipumps. A discrete-trial intracranial self-stimulation procedure was used to provide a measure of brain reward function. Somatic signs were recorded from a checklist of opioid abstinence signs. RESULTS: Naloxone induced a deficit in brain reward function in rats chronically treated with fentanyl. Buprenorphine dose-dependently prevented the naloxone-induced deficit in brain reward function. Discontinuation of fentanyl administration was also associated with a deficit in brain reward function. After explantation of the minipumps, the administration of buprenorphine induced a potentiation of brain reward function in the fentanyl-withdrawing rats, but did not affect brain reward function of saline-treated control rats. Buprenorphine prevented the somatic withdrawal signs associated with spontaneous fentanyl withdrawal and attenuated the somatic signs associated with precipitated fentanyl withdrawal. CONCLUSIONS: Buprenorphine prevents affective and somatic fentanyl withdrawal signs. Moreover, buprenorphine is rewarding in rats previously exposed to fentanyl, but not in opioid-naïve rats. This pattern of results suggests that buprenorphine may be an effective treatment for the anhedonic-state associated with fentanyl withdrawal, but further study of buprenorphine's abuse potential is warranted.

Evaluation of alternative landfill cover soils for attenuating hydrogen sulfide from construction and demolition (C&D) debris landfills.

Hydrogen sulfide (H(2)S) generated from C&D debris landfills has emerged as a major environmental concern due to odor problems and possible health impacts to landfill employees and surrounding residents. Research was performed to evaluate the performance of various cover materials as control measures for H(2)S emissions from C&D debris landfills. Twelve laboratory-scale simulated landfill columns containing gypsum drywall were operated under anaerobic conditions to promote H(2)S production. Five different cover materials were placed on top of the waste inside duplicate columns: (1) sandy soil, (2) sandy soil amended with lime, (3) clayey soil, (4) fine concrete (particle size less than 2.5 cm), and (5) coarse concrete (particle size greater than 2.5 cm). No cover was placed on two of the columns, which were used as controls. H(2)S concentrations measured from the middle of the waste layer ranged from 50,000 to 150,000 ppm. The different cover materials demonstrated varying H(2)S removal efficiencies. The sandy soil amended with lime and the fine concrete were the most effective for the control of H(2)S emissions. Both materials exhibited reduction efficiencies greater than 99%. The clayey and sandy soils exhibited lower reduction efficiencies, with average removal efficiencies of 65% and 30%, respectively. The coarse concrete was found to be the least efficient material as a result of its large particle size.

A novel HSV-1 virus, JS1/34.5-/47-, purges contaminating breast cancer cells from bone marrow.

PURPOSE: Oncolytic herpes simplex virus type 1 (HSV-1) vectors show considerable promise as agents for cancer therapy. We have developed a novel recombinant HSV-1 virus (JS1/34.5-/47-) for purging of occult breast cancer cells from bone marrow of patients. Here, we evaluate the therapeutic efficacy of this oncolytic virus. EXPERIMENTAL DESIGN: Electron microscopy was used to determine whether human breast cancer and bone marrow cells are permissive for JS1/34.5-/47- infection. Subsequently, the biological effects of JS1/34.5-/47- infection on human breast cancer cells and bone marrow were established using cell proliferation and colony formation assays, and the efficiency of cell kill was evaluated. Finally, the efficiency of JS1/34.5-/47- purging of breast cancer cells was examined in cocultures of breast cancer cells with bone marrow as well as bone marrow samples from high-risk breast cancer patients. RESULTS: We show effective killing of human breast cancer cell lines with the JS1/34.5-/47- virus. Furthermore, we show that treatment with JS1/34.5-/47- can significantly inhibit the growth of breast cancer cell lines without affecting cocultured mononuclear hematopoietic cells. Finally, we have found that the virus is effective in destroying disseminated tumors cells in bone marrow taken from breast cancer patients, without affecting the hematopoietic contents in these samples. CONCLUSION: Collectively, our data show that the JS1/34.5-/47- virus can selectively target breast cancer cells while sparing hematopoietic cells, suggesting that JS1/34.5-/47- can be used to purge contaminating breast cancer cells from human bone marrow in the setting of autologous hematopoietic cell transplantation.

Anesthetic properties of a propofol microemulsion in dogs.

Microemulsions of propofol with nanometer droplet diameter are alternatives to soybean macroemulsions for inducing anesthesia, and may have important advantages. We used a propofol (10 mg/mL) microemulsion (particle diameter 24.5 +/- 0.5 nm) and a commercial macroemulsion to induce anesthesia in dogs (n = 10) using a randomized, crossover design separated by a 7-day rest interval. The end points were loss of leg withdrawal after a toe pinch and changes in vital signs. Venous blood samples were acquired at multiple times to measure plasma propofol concentrations and indices of erythrocytes, leukocytes, and coagulation. All dogs were rendered insensitive to pain followed by successful recovery without noticeable complications. Comparing indices between microemulsion and macroemulsion formulations, no differences were noted with respect to dose (10.3 +/- 1.2 and 9.7 +/- 1.6 mg/kg, respectively, P = 0.39), time to induction (1.0 +/- 0.1 and 1.0 +/- 0.2 min, P = 0.39), time to recovery (17.4 +/- 4.6 and 18.2 +/- 3.8 min, P = 0.70), heart rate (P = 0.62), arterial blood pressure (P = 0.81), respiratory rate (P = 0.60), hemogram variables, prothrombin time (P = 0.89), activated partial thromboplastin time (P = 0.76), fibrinogen concentration (P = 0.52), platelet concentration (P = 0.55), or plasma propofol concentrations (P = 0.20). Induction with a propofol microemulsion or macroemulsion did not significantly vary with respect to vital signs, the hemogram, clotting variables, and plasma propofol concentrations.

Hydrogen sulfide generation in simulated construction and demolition debris landfills: impact of waste composition.

Hydrogen sulfide (H2S) generation in construction and demolition (C&D) debris landfills has been associated with the biodegradation of gypsum drywall. Laboratory research was conducted to observe H2S generation when drywall was codisposed with different C&D debris constituents. Two experiments were conducted using simulated landfill columns. Experiment 1 consisted of various combinations of drywall, wood, and concrete to determine the impact of different waste constituents and combinations on H2S generation. Experiment 2 was designed to examine the effect of concrete on H2S generation and migration. The results indicate that decaying drywall, even alone, leached enough sulfate ions and organic matter for sulfate-reducing bacteria (SRB) to generate large H2S concentrations as high as 63,000 ppmv. The codisposed wastes show some effect on H2S generation. At the end of experiment 1, the wood/drywall and drywall alone columns possessed H2S concentrations > 40,000 ppmv. Conversely, H2S concentrations were < 1 ppmv in those columns containing concrete. Concrete plays a role in decreasing H2S by increasing pH out of the range for SRB growth and by reacting with H2S. This study also showed that wood lowered H2S concentrations initially by decreasing leachate pH values. Based on the results, two possible control mechanisms to mitigate H2S generation in C&D debris landfills are suggested.