Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments.

Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

OH-Initiated Oxidation of m-Xylene on Black Carbon Aging.

Laboratory experiments are conducted to investigate aging of size-classified black carbon (BC) particles from OH-initiated oxidation of m-xylene. The variations in the particle size, mass, effective density, morphology, optical properties, hygroscopicity, and activation as cloud condensation nuclei (CCN) are simultaneously measured by a suite of aerosol instruments, when BC particles are exposed to the oxidation products of the OH-m-xylene reactions. The BC aging is governed by the coating thickness (Δrve), which is correlated to the reaction time and initial concentrations of m-xylene and NOx. For an initial diameter of 100 nm and Δrve = 44 nm, the particle size and mass increase by a factor of 1.5 and 10.4, respectively, and the effective density increases from 0.43 to 1.45 g cm(-3) due to organic coating and collapsing of the BC core. The BC particles are fully converted from a highly fractal to nearly spherical morphology for Δrve = 30 nm. The scattering, absorption, and single scattering albedo of BC particles are enhanced accordingly with organic coating. The critical supersaturation for CCN activation is reduced to 0.1% with Δrve = 44 nm. The results imply that the oxidation of m-xylene exhibits larger impacts in modifying the BC particle properties than those for the OH-initiated oxidation of isoprene and toluene.

Observations of aminium salts in atmospheric nanoparticles and possible climatic implications.

We present laboratory studies and field observations that explore the role of aminium salt formation in atmospheric nanoparticle growth. These measurements were performed using the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) and Ultrafine Hygroscopicity Tandem Differential Mobility Analyzers. Laboratory measurements of alkylammonium-carboxylate salt nanoparticles show that these particles exhibit lower volatilities and only slightly lower hygroscopicities than ammonium sulfate nanoparticles. TDCIMS measurements of these aminium salts showed that the protonated amines underwent minimal decomposition during analysis, with detection sensitivities comparable to those of organic and inorganic deprotonated acids. TDCIMS observations made of a new particle formation event in an urban site in Tecamac, Mexico, clearly indicate the presence of protonated amines in 8-10 nm diameter particles accounting for about 47% of detected positive ions; 13 nm particles were hygroscopic with an average 90% RH growth factor of 1.42. Observations of a new particle formation event in a remote forested site in Hyytiälä, Finland, show the presence of aminium ions with deprotonated organic acids; 23% of the detected positive ions during this event are attributed to aminium salts while 10 nm particles had an average 90% RH growth factor of 1.27. Similar TDCIMS observations during events in Atlanta and in the vicinity of Boulder, Colorado, show that aminium salts accounted for 10-35% of detected positive ions. We conclude that aminium salts contribute significantly to nanoparticle growth and must be accounted for in models to accurately predict the impact of new particle formation on climate.

Nipple-areola reconstruction: satisfaction and clinical determinants.

After performing a chart review, the authors identified 120 patients who underwent breast cancer-related reconstruction. All charts were evaluated with regard to breast mound reconstruction type, nipple-areola reconstruction type, the interval between breast mound and nipple-areola reconstruction, the number of procedures needed to achieve nipple-areola reconstruction, patient history of radiation therapy, and complications. A questionnaire was then developed and mailed to all of the patients who underwent both breast mound and nipple/areola reconstruction (n = 105) to evaluate their level of satisfaction. Of the 43 patients who returned the questionnaire, 41 completed all portions correctly. The questionnaire evaluated patient satisfaction with breast mound reconstruction; patient satisfaction with nipple-areola reconstruction; what the patient disliked most about the nipple-areola reconstruction; and whether or not the patient would choose to have breast reconstruction again. Several parameters were then tested statistically against the reported patient satisfaction.A review of all patients who underwent breast reconstruction revealed that their breast mound reconstructions were done using either a TRAM flap (59 percent), a latissimus dorsi flap and an implant (19 percent), an expander followed by an implant (9 percent), an implant only (4 percent), or other means (9 percent). The nipple-areola was reconstructed in these patients with either a star flap (36 percent), nipple sharing (10 percent), a keyhole flap (9 percent), a skate flap (9 percent), an S-flap (8 percent), a full-thickness skin graft (6 percent), or by another means (22 percent). The number of procedures needed to achieve nipple-areola reconstruction was either one (in 66 percent of the patients), two (in 32 percent of the patients), or three or more (2 percent of the patients). Eleven percent of the patients experienced the complication of nipple necrosis. Satisfaction with breast mound reconstruction was reported by 81 percent of patients to be excellent/good, by 14 percent of patients to be fair, and by 5 percent of patients to be poor. Reported satisfaction with nipple-areola reconstruction was excellent/good for 64 percent of patients, fair for 22 percent of patients, and poor for 14 percent of patients. The factors patients disliked most about their nipple-areola reconstruction were, in descending order, lack of projection, color match, shape, size, texture, and position. Statistical analysis of the data revealed inferior patient satisfaction when there was a longer interval between breast mound and nipple areola reconstruction (p = 0.003). No significant difference was observed in nipple/areola reconstruction satisfaction ratings when compared with breast mound reconstruction type (p = 0.46), nipple-areola reconstruction type (p = 0.98), and history of radiation therapy (p = 0.23). There was also no significant difference when breast mound reconstruction was compared with technique (p = 0.51) and history of radiation therapy (p = 0.079). Overall, there was a greater satisfaction with breast mound reconstruction than with nipple-areola reconstruction (p = 0.0001).

Patient satisfaction after blepharoplasty performed as office surgery using oral medication with the patient under local anesthesia.

BACKGROUND: Blepharoplasty can be performed in the office setting using oral medication with the patient under local anesthesia. This article reviews the authors' experience with this approach, evaluating patient satisfaction and demonstrating why this technique has become their procedure of choice for selected healthy patients. METHODS: The authors conducted a retrospective review of the 86 patients who underwent office-based blepharoplasty and mailed surveys to assess patient satisfaction with the procedure. RESULTS: Upper and lower blepharoplasties were performed with no major complications. The surveys were completed and returned by 83% of the patients. The survey results indicated that this procedure is well accepted and highly rated by patients. Many patients unwilling to undergo blepharoplasty outside the office were willing to have the procedure using this approach. A strong majority indicated that they would be referring friends and family for the procedure. CONCLUSIONS: The fact that blepharoplasty can be performed in the office using oral medication with the patient under local anesthesia proves to be a strong determinant toward the final decision of patients to undergo surgery. This procedure meets the safety requirements outlined by the American Society of Plastic Surgeons (ASPS) and is desired by our patients for its many obvious advantages. Recommendations are provided to assist others who desire to use this safe and cost-effective method.

Efficacy of a local anesthetic pain pump in abdominoplasty.

BACKGROUND: Recently, pain infusion pumps for postoperative pain control have gained popularity in many surgical specialties. This investigation was designed to evaluate the efficacy of a local anesthetic pain infusion pump in management of postoperative pain in abdominoplasty patients. METHODS: A retrospective study of 38 abdominoplasty patients with local anesthetic pain pumps and 35 abdominoplasty patients without pain pumps was performed. Pain pumps were loaded with 0.25% or 0.5% bupivacaine and infused at a constant rate of 4 ml/hour. All patients were admitted postoperatively and started on a narcotic patient-controlled analgesia. Postoperative patient-controlled analgesia narcotic use and pain scores were recorded every 2 hours by the nursing staff. For the first 24 hours of postoperative hospital stay, pain medication, pain scores, and antiemetic use were determined from the patients' charts. Hospital stay was also reviewed. RESULTS: In the pain pump group, there was a small but not statistically significant reduction in pain medication use (2.65 versus 3.04 pain units) (p = 0.34). Interestingly, pain scores were higher in the pain pump group but not significantly (2.73 versus 2.31) (p = 0.17). There was no statistically significant difference in the use of antiemetics (0.8 versus 0.6) (p = 0.60). Hospital length of stay averaged 2.2 days in the pain pump group and 2.5 days in the group without pain pumps (p = 0.09). CONCLUSIONS: The postoperative use of pain pumps in abdominoplasty patients does not significantly improve pain management. Further investigation into this application of the pain pump is necessary before recommending their routine use in abdominoplasty patients.

Continuous collection of soluble atmospheric particles with a wetted hydrophilic filter.

Approximately one-third of the area (14-mm diameter of a 25-mm diameter) of a 5-microm uniform pore size polycarbonate filter is continuously wetted by a 0.25 mL/min water mist. The water forms a continuous thin film on the filter and percolates through it. The flowing water substantially reduces the effective pore size of the filter. At the operational air sampling flow rate of 1.5 standard liters per minute, such a particle collector (PC) efficiently captures particles down to very small size. As determined by fluorescein-tagged NaCl aerosol generated by a vibrating orifice aerosol generator, the capture efficiency was 97.7+% for particle aerodynamic diameters ranging from 0.28 to 3.88 microm. Further, 55.3 and 80.3% of 25- and 100-nm (NH4)2SO4 particles generated by size classification with a differential mobility analyzer were respectively collected by the device. The PC is integrally coupled with a liquid collection reservoir. The liquid effluent from the wetted filter collector, bearing the soluble components of the aerosol, can be continuously collected or periodically withdrawn. The latter strategy permits the use of a robust syringe pump for the purpose. Coupled with a PM2.5 cyclone inlet and a membrane-based parallel plate denuder at the front end and an ion chromatograph at the back end, the PC readily operated for at least 4-week periods without filter replacement or any other maintenance.

Postoperative nausea and vomiting in the plastic surgery patient.

Despite great advances in modern medicine, postoperative nausea and vomiting (PONV) continue to be a significant problem without a definitive cure. This article describes a prospective study conducted with 143 plastic surgery patients at a single institution between 1998 and 2000 to identify preoperative risk factors for PONV that may be specific to plastic surgery patients. In addition, a prophylactic regimen was identified that demonstrated a decrease in the incidence of PONV from the published incidence of 22% to 3%. The regimen includes the use of multiple antiemetic agents including ondansetron (Zofran) promethazine (Phenergan), and metoclopramide (Reglan), with the addition of dexamethasone (Decadron) in selected cases

Preventing seroma in the latissimus dorsi flap donor site with fibrin sealant.

Donor site seroma continues to be the most common complication of latissimus dorsi flap reconstruction. Numerous preventive methods and treatments have been described. The use of fibrin sealant in the donor site before closure may be an effective means of seroma prevention. The authors evaluated the efficacy of fibrin sealant in conjunction with closed suction drainage in a series of 17 latissimus flap donor sites. They also determined their approximate institutional seroma rate with a retrospective chart review of 20 donor sites. The fibrin sealant patients had a seroma rate of 11.8% compared with a rate of 35% among the untreated patients (P = 0.047). This compares favorably with seroma rates as high as 79% described in the literature. In conclusion, the use of fibrin sealant in the latissimus flap donor site appears to be effective in preventing seroma.