Particle filtration efficiency measured using sodium chloride and polystyrene latex sphere test methods.

Standards governing face masks differ in the test methods used to determine sub-micron particle filtration efficiency (PFE), such that the meaning of PFE is not universal. Unifying the meaning of PFE requires data using these different test methods to drive improvements in standards. This simple data set provides the equivalence between two major test methods used to assess PFE: (1) a test method using a neutralized, polydisperse sodium chloride (NaCl) and (2) a test method using an unneutralized, "monodisperse" polystyrene latex sphere (PSL) aerosols.

Comparison of measurement systems for assessing number- and mass-based particle filtration efficiency.

The particle filtration efficiency (PFE) of a respirator or face mask is one of its key properties. While the physics of particle filtration results in the PFE being size-dependent, measurement standards are specified using a single, integrated PFE, for simplicity. This integrated PFE is commonly defined concerning either the number (NPFE) or mass (MPFE) distribution of particles as a function of size.

Laser-induced incandescence for non-soot nanoparticles: recent trends and current challenges.

Laser-induced incandescence (LII) is a widely used combustion diagnostic for in situ measurements of soot primary particle sizes and volume fractions in flames, exhaust gases, and the atmosphere. Increasingly, however, it is applied to characterize engineered nanomaterials, driven by the increasing industrial relevance of these materials and the fundamental scientific insights that may be obtained from these measurements. This review describes the state of the art as well as open research challenges and new opportunities that arise from LII measurements on non-soot nanoparticles.

Effect of Drive Cycle and Gasoline Particulate Filter on the Size and Morphology of Soot Particles Emitted from a Gasoline-Direct-Injection Vehicle.

The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions.

Are emissions of black carbon from gasoline vehicles underestimated? Insights from near and on-road measurements.

Measurements of black carbon (BC) with a high-sensitivity laser-induced incandescence (HS-LII) instrument and a single particle soot photometer (SP2) were conducted upwind, downwind, and while driving on a highway dominated by gasoline vehicles. The results are used with concurrent CO(2) measurements to derive fuel-based BC emission factors for real-world average fleet and heavy-duty diesel vehicles separately. The derived emission factors from both instruments are compared, and a low SP2 bias (relative to the HS-LII) is found to be caused by a BC mass mode diameter less than 75 nm, that is most prominent with the gasoline fleet but is not present in the heavy-duty diesel vehicle exhaust on the highway.

Incidence, impact, and treatment of portal and hepatic venous complications following pediatric liver transplantation: a single-center 12 year experience.

PVT or PVS and HVOO are known causes of graft and patient loss after pediatric liver transplantation. Increased incidences of these complications have been reported in partial livers including DDSLT or LDLT. From 1997 to 2008, 241 consecutive pediatric patients received 271 hepatic grafts at a single center.

Liver retransplantation in children: the Atlanta experience.

Liver retransplantation is routinely offered at our institution. Previous reports document that patient and graft survival is significantly less after pediatric rLT compared to primary LT. This has engendered intense debate regarding optimal allocation of organs.

Pediatric liver transplantation for acute liver failure at a single center: a 10-yr experience.

Children transplanted for ALF urgently require an optimal graft and have lower post-transplant survival compared with children transplanted for chronic liver disease. Over 10 yr, 33 consecutive children transplanted for ALF were followed. Demographics, encephalopathy, intubation, dialysis, laboratory values, graft type ABOI, XL (GRWR > 5%), DDSLT, LDLT and WLT were evaluated.

Successful outcome after early combined liver and en bloc-kidney transplant in an infant with primary hyperoxaluria type 1: a case report.

PH1 is a metabolic disorder characterized by urolithiasis and the accumulation of oxalate crystals in the kidneys and other organs. Although patients often first present with renal failure, PH1 results from a deficiency of the hepatic peroxisomal enzyme AGT. Ultimately only liver transplantation will cure the underlying metabolic defect.

Does interferon use prior to liver transplant influence hepatitis C outcomes following transplantation?

Background: The most frequent reason for orthotopic liver transplantation (OLT) in the United States is due to complications of hepatitis C (HCV). Recent reports have shown decreased survival for HCV after OLT. Of note, the use of interferon (IFN) products has become wide spread with the majority of HCV patients being treated before transplant.

Diffuse-light two-dimensional line-of-sight attenuation for soot concentration measurements.

A technique of diffuse-light two-dimensional line-of-sight attenuation (diffuse 2D-LOSA) is described and demonstrated that achieves very high levels of sensitivity in transmissivity measurements (optical thicknesses down to 0.001) while effectively mitigating interferences due to beam steering. An optical system is described in which an arc lamp coupled with an integrating sphere is used as a source of diffuse light that is imaged to the center of the particulate laden medium.

Resistance to combined ganciclovir and foscarnet therapy in a liver transplant recipient with possible dual-strain cytomegalovirus coinfection.

We present a case report of a cytomegalovirus (CMV)-seronegative, 58-year-old male who received a CMV-seropositive donor liver transplant without CMV prophylaxis. On postoperative day 30, the patient developed primary CMV disease that responded to ganciclovir. On postoperative day 114, however, he was diagnosed with recurrent CMV infection.

Medical and surgical treatment of neonatal hemochromatosis: single center experience.

NH is a rare disorder of iron storage in newborns resulting in rapid liver failure. Outcomes are dismal with 20-30% survival. We report our experience in eight children with NH.

Successful ABO-incompatible pediatric liver transplantation utilizing standard immunosuppression with selective postoperative plasmapheresis.

Transplanting blood group A, B, or O (ABO)-incompatible (ABO-I) liver grafts has resulted in lower patient and graft survival with an increased incidence of vascular and biliary complications and rejection. We report that, without modification of our standard immunosuppression protocol, crossing blood groups is an acceptable option for children requiring liver transplantation. In our study, ABO-I liver grafts -- regardless of recipient age -- have comparable long-term survival (mean follow-up of 3.

A calibration-independent laser-induced incandescence technique for soot measurement by detecting absolute light intensity.

Laser-induced incandescence (LII) has proved to be a useful diagnostic tool for spatially and temporally resolved measurement of particulate (soot) volume fraction and primary particle size in a wide range of applications, such as steady flames, flickering flames, and Diesel engine exhausts. We present a novel LII technique for the determination of soot volume fraction by measuring the absolute incandescence intensity, avoiding the need for ex situ calibration that typically uses a source of particles with known soot volume fraction. The technique developed in this study further extends the capabilities of existing LII for making practical quantitative measurements of soot.

Low incidence of hepatic artery thrombosis after pediatric liver transplantation without the use of intraoperative microscope or parenteral anticoagulation.

The risk of hepatic artery thrombosis (HAT) after pediatric liver transplantation (PLT) has been reported to range from 0 to 25%. We report our experience focusing on the interrelationships between risk factors, surgical technique and the incidence of HAT after liver transplantation in the pediatric age group. From February 18, 1997 to December 31, 2003, 150 consecutive liver transplants were performed in 132 pediatric patients.

A refined long RT-PCR technique to amplify complete viral RNA genome sequences from clinical samples: application to a novel hepatitis C virus variant of genotype 6.

The goal of this study was to adapt a long RT-PCR technique to amplify large PCR fragments from the genome of hepatitis C virus (HCV) isolates using clinical samples. This was done by using a reverse transcriptase devoid of RNase H activity and a mixture of two antibody-bound thermostable polymerases to combine the high processivity of Taq and the high fidelity of Pwo with its 3'-->5' exonuclease activity. Other modifications included gentle handling during RNA extraction, the absence of tRNA and random primers, a two-step reverse transcription procedure to optimize cDNA synthesis, and increasing the annealing temperature for primers.

Peripheral eosinophilia and eosinophilic gastroenteritis after pediatric liver transplantation.

Reports indicate peripheral eosinophilia (PE) and gastrointestinal eosinophilic inflammation can occur after pediatric liver transplantation. The incidence of these conditions, potential risk factors, and the impact of PE and gastrointestinal eosinophilic inflammation on liver transplant outcome were determined in this pediatric liver transplant program. Medical records of liver transplant recipients from 1 to 97 and from 12 to 99 were reviewed.

Pediatric liver transplantation with daclizumab induction.

Background: A new class of monoclonal antibodies (non-T-cell depleting) has gained favor for induction therapy after transplantation. This study evaluated the non-T-cell depleting antibody to the CD25 cell, daclizumab, as a single-dose induction agent immediately after pediatric liver transplantation to spare the use of the calcineurin inhibitor, tacrolimus, for 7 days in respect to both efficacy and renal function.

Methods: From January 1998 to November 2001, 81 pediatric orthotopic liver transplant recipients receiving 89 liver grafts were evaluated.