Mohs surgeon workforce survey: a spectrum of clinical, academic, and leadership activities.

Workforce adequacy for Mohs micrographic surgery (MMS) is not fully understood. The purpose of this study was to describe the current spectrum of clinical, academic, advocacy and leadership activities through a survey of members of the American College of Mohs Surgery (ACMS). The ACMS membership was electronically sent a 43-question anonymous survey between January and May 2023 and there was a 10.7% response rate representing 184 members across 37 states. Nearly 90% are board certified in micrographic dermatologic surgery and 10.3% indicate that they practice in a rural setting (57.1% suburban and 32.6% urban). The median number of half-day surgeons performed Mohs surgery is 6 and nearly half of Mohs surgeons work in a dermatology-only medical group (48.4%), do no use immunohistochemical stains (60.3%), and do not participate in a multidisciplinary tumor board (58.7%). Many respondents indicate they have capacity in their clinical schedules to accommodate more cases and the reasons are multifactorial.

A Potential Approach to Compensate the Gas Interference for the Analysis of NO by a Non-dispersive Infrared Technique.

Interference is a pivotal issue of a non-dispersive infrared (NDIR) sensor and analyzer. Therefore, the main contribution of this study is to introduce a potential method to compensate for the interference of the NDIR analysis. A potential method to compensate for the interference of a nitric oxide (NO) NDIR analyzer was developed. Double bandpass filters (BPFs) with HITRAN (high-resolution transmission molecular absorption database)-based wavelengths were used to create an ultranarrow bandwidth, where there were least-interfering effects with respect to the coal-fired power plant emission gas compositions. Key emission gases from a coal-fired power plant, comprising carbon monoxide (CO), NO, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon dioxide (CO2), and water (H2O) (in the form of vapor), were used to investigate the gas interference. The mixtures of those gases were also used to investigate the performance of the double BPFs. We found that CO, CO2, SO2, and H2O significantly affected the detection of NO when a commercial, single narrow BPF was used. In contrast, the double BPFs could remove the interference of CO, NO2, SO2, and CO2 in terms of their concentrations. In the case of H2O, the filter performed well until a level of 50% relative humidity at 25 °C. Moreover, the signal-to-noise ratio of the analyzer was approximately 10 when the double BPFs were applied. In addition, the limit of detection of the analyzer with the double BPFs was approximately 4 ppm, whereas that with the commercial one was 1.3 ppm. Therefore, double BPFs could be used for an NO NDIR analyzer instead of a gas filter correlation to improve the selectivity of the analyzer under the condition of a known gas composition, such as a coal-fired power plant. However, the sensitivity of the analyzer would be decreased.

Are rare, long waiting times between rearrangement events responsible for the slowdown of the dynamics at the glass transition?

The dramatic slowdown of the structural relaxation at the glass transition is one of the most puzzling features of glass dynamics. Single molecule orientational correlation times show this strong Vogel-Fulcher-Tammann temperature dependence typical for glasses. Through statistical analysis of single molecule trajectories, we can identify individual glass rearrangement events in the vicinity of a probe molecule in the glass former poly(vinyl acetate) from 8 K below to 6 K above the glass transition temperature. We find that changes in the distribution of waiting times between individual glass rearrangement events are much less dramatic with temperature, the main difference being a small, but decisive number of increasingly long waiting times at lower temperatures. We notice similar individual, local relaxation events in molecular dynamics trajectories for a variety of glassy systems further from the glass transition, leading to waiting time distributions with similar features as those observed in the single molecule experiments. We show that these rare long waiting times are responsible for the dramatic increase in correlation time upon cooling.

Risk factors for delayed post-polypectomy hemorrhage: a case-control study.

BACKGROUND AND AIM: Delayed post-polypectomy hemorrhage is a rare but serious complication. The aim of this study was to identify risk factors for the development of delayed post-polypectomy hemorrhage. METHODS: This was a retrospective case-control study of patients who developed delayed hematochezia after receiving colonoscopic polypectomy. The control patients underwent uneventful polypectomy and were selected at a 4:1 ratio. RESULTS: Of the 7447 lesions examined from the 3253 patients who received colonoscopic polypectomy, 53 lesions (0.7%) of 42 patients (1.3%) developed delayed hemorrhage, and 168 patients were selected as controls. According to multivariate logistic regression analysis, a polyp larger than 10 mm (odds ratio [OR] 2.355, 95% confidence interval [CI] 1.225-4.528, P = 0.010), a pedunculated polyp (OR 3.473, 95% CI 1.576-7.657, P = 0.002), and a polyp located in the right hemi-colon (OR 2.690, 95% CI 1.465-4.940, P = 0.001) were significant risk factors for delayed post-polypectomy hemorrhage. The presence of comorbidities did not increase the risk of delayed hemorrhage. CONCLUSION: Polyp size (large), shape (pedunculated), and location (right hemi-colon) represented substantial risk factors for the development of delayed hemorrhage after colonoscopic polypectomy.

[Spontaneous regression of sclerosing mesenteritis presenting as a huge mass].

Sclerosing mesenteritis is a rare benign disease originated from the mesenteries. It can be related to autoimmune disease, vasculitis, ischemia, infection, trauma and operation, but most of cases are idiopathic. The overall prognosis of sclerosing mesenteritis is usually good with benign, course. However, no consensus of treatment has yet been established. We report a case of spontaneous partial regression of sclerosing mesenteritis presented as a huge mass and diagnosed by finding of contrast enhanced abdominal computed tomography and percutaneous ultrasonography guided needle biopsy.

Emission rates of volatile organic compounds released from newly produced household furniture products using a large-scale chamber testing method.

The emission rates of volatile organic compounds (VOCs) were measured to investigate the emission characteristics of five types of common furniture products using a 5 m(3) size chamber at 25°C and 50% humidity. The results indicated that toluene and α-pinene are the most dominant components. The emission rates of individual components decreased constantly through time, approaching the equilibrium emission level. The relative ordering of their emission rates, if assessed in terms of total VOC (TVOC), can be arranged as follows: dining table > sofa > desk chair > bedside table > cabinet. If the emission rates of VOCs are examined between different chemical groups, they can also be arranged in the following order: aromatic (AR) > terpenes (TER) > carbonyl (CBN) > others > paraffin (PR) > olefin (HOL) > halogenated paraffin (HPR). In addition, if emission strengths are compared between coated and uncoated furniture, there is no significant difference in terms of emission magnitude. Our results indicate that the emission characteristics of VOC are greatly distinguished between different furniture products in terms of relative dominance between different chemicals.

Offensive odorants released from stormwater catch basins (SCB) in an urban area.

The potent role of stormwater catch basins (SCB) as a source of malodor in urban areas has been recognized because of its active involvement in the production and release of diverse odorants. Here, the status of odor pollution was investigated from two types of SCBs (i.e., wet and dry systems) by measuring a list of offensive odorants (i.e., reduced sulfur compounds (RSC), carbonyl compounds, nitrogenous, volatile organic compounds (VOCs), and fatty acids). Samples from those SCB systems were collected three times a day for five non-consecutive days. According to our study, H(2)S recorded consistently the highest mean values of 2554 ppb (wet) and 699 ppb (dry system) among all major offensive odorants. In contrast, the most prevalent VOCs were distinguished between methyl ethyl ketone (250 ppb in dry SCB) and toluene (32.8 ppb in wet SCB). In general, most odorants tend to exhibit relative enhancement in the afternoon, regardless of SCB types. If the concentration values of each odorant are converted into odor intensity (OI), the RSC group was identified as the key components of odor formation in SCB. If the OI values of each individual component are bound to yield sum of odor intensity (SOI), their values for wet and dry system were 4.99 and 4.25, respectively. In light of the fact that SCBs can serve as a potential odor source in urban areas, it should be managed and maintained properly to suppress the propagation of odor into the surrounding environments.

Barbecue charcoal combustion as a potential source of aromatic volatile organic compounds and carbonyls.

The emission concentrations of a number of aromatic volatile organic compounds (VOCs) and carbonyl compounds were quantified during the combustion of commonly used barbecue charcoal. The concentrations of VOC and carbonyls were determined by gas chromatography coupled with thermal desorption and HPLC method, respectively. The analysis of VOC emission concentrations showed that toluene (116+/-444 ppb) was the most abundant. On the other hand, the carbonyls were dominated by formaldehyde (275+/-477 ppb) and acetaldehyde (126+/-229 ppb). A line of evidence indicates that the emission patterns of these pollutants are associated with the diverse nature of raw materials and the processes involved in their production. Although emission concentrations of target compounds were in most cases below the permissible exposure limits (PEL), a proper regulation against the use of BBQ charcoal is needed to reduce potential health risks associated with its use.

BBQ charcoal combustion as an important source of trace metal exposure to humans.

To provide information about charcoal combustion as an important source of atmospheric trace metal pollution, 11 charcoal products were combusted and PM(10) filter samples were collected. The PM-bound metal elements were extracted by microwave acid digestion and analyzed by ICP-AES. The concentrations of trace metal elements ranged from a few to 10(5)ng m(-3) in the following order of magnitude: Zn>Pb>Mg>Ba>Cu>V>Cr>Co>Cd>Ni>Mn>Se>As. Emissions of most elements from charcoal combustion were high compared to other sources. In case of Cd, Co, and Ni, their concentrations exceeded the inhalation minimum risk levels (MRLs) of the United States Agency for Toxic Substances and Disease Registry (US-ATSDR) for chronic duration exposure by a factor of 30, 3.9, and 2.2, respectively. Likewise, Cd levels exceeded the US-ATSDR MRLs for acute-duration exposure by a factor of 10, while those of Pb and Cd exceeded air quality guideline (AQG) of the World Health Organization (WHO) by a factor of 29 and 59, respectively. Mn levels also exceeded the United States Environmental Protection Agency (US EPA) Reference Air Concentrations (RfCs) by a factor of 2.7. This study shows that barbecue charcoal combustion can be an important source of trace metal emissions to the atmosphere with potential health risks.

Food decay and offensive odorants: a comparative analysis among three types of food.

In this study, a list of offensive odorants including reduced sulfur, carbonyls, nitrogenous, and volatile organic compounds was measured by the indirect (instrumental) method during the decay processes of three food types (snipe egg, mackerel, and squid). The strengths of the odor release were also quantified in terms of dilution-to-threshold (D/T) ratio based on the air dilution sensory test. To collect odor samples for each food type, decaying experiments were conducted in 100mL throwaway syringes for 1 month. The results showed that ammonia had the largest mean ranging from 385 ppm (fish) to 554 ppm (egg). However, most odorants generally fell in the range of 0.01-10 ppm, regardless of food type. The odor strengths measured with the suprathreshold method in terms of average D/T values increased on the order of 33,520 (egg), 202,330 (fish), and 766,330 (squid). These results were highly comparable to the patterns of odor indices derived by empirical conversion of odorant concentration data. The overall results of this study thus suggest that a unique pattern of odor release develops among different odorants as well as food type.

The loss patterns of reduced sulfur compounds in contact with different tubing materials.

To collect or transfer samples of airborne pollutants, tubings made of various materials are used. To analyze the reactive loss patterns of reduced sulfur compounds (RSC) in the use of tubing fittings, a series of laboratory experiments were conducted so that the concentration changes were induced by the physical contact between gas samples and tubing walls. For the purpose of this study, a total of five tubing materials were investigated in reference to silcosteel (S1) tubing: stainless steel (S2), silicone (S3), PTFE Teflon (T1), tygon (T2), and copper (C). This comparative experiment was made using gaseous standards containing equimolar concentrations of four RSCs (H(2)S, CH(3)SH, DMS, and DMDS). The loss patterns of RSC were then evaluated and compared in terms of their calibration slope values across different tubing materials. The results of this comparative analysis indicated that except for a few cases, a fairly good compatibility was seen consistently among different tubing types and different RSCs. The results generally showed that the magnitude of calibration slope values obtained from different tubing materials tend to increase with an increase in RSC molecular weights. If the results are compared between different tubing materials, a highly contrasting pattern was evident. For instance, C tubing shows significant losses of light RSCs (H(2)S and CH(3)SH), while S3 tubing experiences the large losses of DMS and DMDS. A line of evidence found in this study thus suggests that most tubing types have their unique loss mechanism for RSCs, when they contact RSCs in sample gas stream passing through the tubing walls.