A retrospective characterization of pediatric facemasks marketed in the United States and implications for future designs.

BACKGROUND: Device manufacturers who seek to market their pediatric facemasks in the United States (U.S.), as part of anthropometric data requirement, need to demonstrate their mask designs are expected to fit the intended user population. However, currently there are no well accepted test methodologies for pediatric facemasks. In addition, unlike N95 respirators, the expected maximum flow rate, and the pressure drop at that expected maximum flow rate for pediatric facemasks have not been established. METHOD: The objective of this article is three-fold; use a literature survey to determine the worst-case flow rate, and an acceptable breathing resistance; and come up with a bench-test based protocol for assessing fit of pediatric facemasks. RESULTS & DISCUSSION: The worst-case breathing flow rate for mask testing in the pediatric population is 45-60 Liters/minute (LPM), and the acceptable pressure drop at the worst-case flow rate is 2.0 mmH2O. A retrospective assessment of all the four brands of legally marketed facemasks in the U.S. that could be purchased, revealed that majority of the brands have high filtration efficiency (>95%) at low flow rate 5 LPM which reduces to ~ 80% at 45 LPM. At 5 LPM, the pressure drop ranges from 0.3-0.6 mmH2O, remaining below the 2.0 mmH2O. However, at higher flow rates, (representing strenuous activities, or older children (> 12 years)), most masks exhibited a pressure drop within the range of 2.9 to 6.0 mmH2O. Furthermore, opening the pleats of the facemasks completely results in a notable reduction in pressure drop (a 6.6-fold decrease, p = 0.03). To assess fit of these same brands of facemasks, we then updated our previous validated adult manikin fit-test method and used it in manikins in the age group of 2 to 14 years. Either poor nose-clip adherence to the manikin, low filtration efficiency of the pediatric facemasks, or off-label use (i.e. when donned on manikins representing 2 years to 14 years) contributed to low fit. CONCLUSIONS: A new bench-top tool to evaluate quantitative fit of pediatric facemasks was developed. In addition, based on the research reported here, we provide practical implications for the members of the community: users, academia and medical device manufacturers.

Impact of dispersion media and carrier type on spray-dried proliposome powder formulations loaded with beclomethasone dipropionate for their pulmonary drug delivery via a next generation impactor.

Drug delivery via aerosolization for localized and systemic effect is a non-invasive approach to achieving pulmonary targeting. The aim of this study was to prepare spray-dried proliposome (SDP) powder formulations to produce carrier particles for superior aerosolization performance, assessed via a next generation impactor (NGI) in combination with a dry powder inhaler. SDP powder formulations (F1-F10) were prepared using a spray dryer, employing five different types of lactose carriers (Lactose monohydrate (LMH), lactose microfine (LMF), lactose 003, lactose 220 and lactose 300) and two different dispersion media. The first dispersion medium was comprised of water and ethanol (50:50% v/v ratio), and the second dispersion medium comprised wholly of ethanol (100%). In the first dispersion medium, the lipid phase (consisting of Soya phosphatidylcholine (SPC as phospholipid) and Beclomethasone dipropionate (BDP; model drug) were dissolved in ethanol and the lactose carrier in water, followed by spray drying. Whereas in second dispersion medium, the lipid phase and lactose carrier were dispersed in ethanol only, post spray drying. SDP powder formulations (F1-F5) possessed significantly smaller particles (2.89 ± 1.24-4.48 ± 1.20 µm), when compared to SDP F6-F10 formulations (10.63 ± 3.71-19.27 ± 4.98 µm), irrespective of lactose carrier type via SEM (scanning electron microscopy). Crystallinity of the F6-F10 and amorphicity of F1-F15 formulations were confirmed by XRD (X-ray diffraction). Differences in size and crystallinity were further reflected in production yield, where significantly higher production yield was obtained for F1-F5 (74.87 ± 4.28-87.32 ± 2.42%) then F6-F10 formulations (40.08 ± 5.714-54.98 ± 5.82%), irrespective of carrier type. Negligible differences were noted in terms of entrapment efficiency, when comparing F1-F5 SDP formulations (94.67 ± 8.41-96.35 ± 7.93) to F6-F10 formulations (78.16 ± 9.35-82.95 ± 9.62). Moreover, formulations F1-F5 demonstrated significantly higher fine particle fraction (FPF), fine particle dose (FPD) and respirable fraction (RF) (on average of 30.35%, 890.12 µg and 85.90%) when compared to counterpart SDP powder formulations (F6-F10). This study has demonstrated that when a combination of water and ethanol was employed as dispersion medium (formulations F1-F5), superior formulation properties for pulmonary drug delivery were observed, irrespective of carrier type employed.

Effect of Beta-Alanine Supplementation on Exercise-Induced Cell Damage and Lactate Accumulation in Female Basketball Players: A Randomized, Double-Blind Study.

Beta-alanine (BA) is a supplement that has received attention for its buffering potential among athletes. The aim of this study was to investigate the effects of BA supplementation on exercise performance and exercise-induced cell damage in female basketball players. Twenty-two female basketball players participated in a randomized, double-blind study. They ingested 6.4 g·day-1 of BA or an isocaloric placebo (dextrose) over 4 weeks. Exercise performance including aerobic (Bruce test), anaerobic (Wingate test), intermittent (Yo-Yo test) and basketball performance (countermovement jump and free throw shots) was measured before and following the intervention. Exercise measures were performed at the lab and free throw shots were undertaken on a wooden indoor basketball court. Blood samples were also collected before and after the exhaustive exercise to assess lactate concentration, creatine kinase (CK), lactate dehydrogenase (LDH) and malondialdehyde (MDA) activity. The exhaustive exercise test induced an increase in lactate concentration and MDA, CK and LDH activity (all p < 0.05). BA supplementation significantly reduced the lactate response to exhaustive exercise (p = 0.001); however, it had no significant effect on exercise-induced MDA, CK and LDH activity (all p > 0.05). Furthermore, exercise performance measures improved from pre- to post-test regardless of supplement/placebo ingestion (all p < 0.05). BA consumption over 4 weeks significantly reduced lactate accumulation following exhaustive exercise, but had no ergogenic effect in female basketball players. Usual dosing of BA does not seem to exhibit protective effect against oxidative damage.

Vapor Condensation and Coating Evaporation Are Both Responsible for Soot Aggregate Restructuring.

Fresh soot is made of fractal aggregates, which often appear collapsed in atmospheric samples. A body of work has concluded that the collapse is caused by liquid shells when they form by vapor condensation around soot aggregates. However, some recent studies argue that soot remains fractal even when engulfed by the shells, collapsing only when the shells evaporate. To reconcile this disagreement, we investigated soot restructuring under conditions ranging from capillary condensation to full encapsulation, also including condensate evaporation. In these experiments, airborne fractal aggregates were exposed to vapors of wetting liquids, and particle size was measured before and after coating loss, allowing us to isolate the contribution from condensation toward restructuring. We show the existence of three distinct regions along the path connecting the initial fractal and final collapsed aggregates, where minor restructuring occurs already at zero vapor supersaturation due to capillary condensation. Increasing supersaturation increases the amount of condensate, producing a more notable aggregate shrinkage. At even higher supersaturations, the aggregates become encapsulated, and subsequent condensate evaporation leaves behind fully compacted aggregates. Hence, for wetting liquids, minor restructuring begins already during capillary condensation and significant restructuring occurs as the coating volume increases. However, at this time, we cannot precisely quantify the contribution of condensate evaporation to the full aggregate compaction.

Novelty in limbal stem cell culture and cell senescence.

Limbal stem cell deficiency is a pathological state. Recently, limbal stem cell (LSC) transplantation has attracted great interest as a therapeutic method which mainly involves in-vitro expansion of LSCs. It is believed that ex-vivo cultivation conditions could affect the outcome of surgery and the rate of successful transplantation. Thus, we aimed to define a suitable culture condition by conducting a research on ex-vivo expanded LSCs to maintain an optimized graft of amniotic membrane with cultivated-limbal stem cells, regarding the quantity and quality, with the hope of improving the clinical outcome.

Seroprevalence of Anti-Toxoplasma Gondii Antibodies in Healthy Voluntary Blood Donors from Mashhad City, Iran.

OBJECTIVE: The present investigation aims to evaluate the prevalence of IgM and IgG anti-T. gondii antibodies and the associated risk factors among healthy blood donors in Mashhad city, Razavi Khorasan province, Iran. METHODS: We screened a total of 500 serum samples by census method from apparently healthy blood donors of the Mashhad Blood Transfusion Organization (MBTO) for IgG and IgM anti-T. gondii antibodies by enzyme linked immunosorbent assay (ELISA). RESULTS: We found that 29.6%, 25%, 1.4%, and 3.2% of tested donors were positive for anti-T. gondii antibodies, only IgG antibody, both IgM and IgG, and IgM antibody alone, respectively. Several risk factors which were significantly related to T. gondii seropositivity in the univariate analysis at P < 0.05 included female gender (OR = 3.222, P < 0.001), age more than 40 years (P = 0.026), and sausage/hot dog consumption (OR = 4.472, P < 0.001). CONCLUSIONS: The results of this study can be a warning for blood transfusion organizations to pay special attention to toxoplasmosis among blood donors and also design screening programs for prevention of transfusion-transmitted toxoplasmosis.

Frontal-view nasolabial soft tissue alterations after bimaxillary orthognathic surgery in Class III patients.

INTRODUCTION: The aim of this before-after clinical trial was to evaluate nasolabial soft tissue changes in the frontal plane after bimaxillary surgery. METHODS: A total of 20 skeletal Class III Iranian patients needing bimaxillary Le Fort I osteotomy plus mandibular setback surgery were enrolled in this trial. Patients underwent 4.02 ± 1.02 mm of maxillary advancement (Le Fort I osteotomy, 4.33 ± 1.21 mm in men, 3.81 ± 0.86 mm in women) and 7.13 ± 1.74 mm of mandibular setback (intraoral vertical ramus osteotomy, 7.71 ± 2.33 mm in men, and 6.74 ± 1.16 mm in women). Data were acquired via 2D frontal photographs. We compared pretreatment baseline (T 1), preoperative postorthodontic treatment (T 2), and postoperative (T 3) anthropometric measurements using repeated-measures ANOVA and Bonferroni tests (α = 0.05). RESULT: The 20 patients (12 men, 8 women) were aged 21.85 ± 1.75 years. Between T 1 and T 2, nasal width, cutaneous upper labial heights increased overall; cutaneous lower labial height decreased (P < 0.05). Between T 2 and T 3, nasal width, widths of the philtrum and mouth, cutaneous upper-lip height, vermilion height of the lower lip, lateral upper-lip height increased; the upper-lip vermilion height and cutaneous lower lip height decreased (P < 0.05). The changes ranged between 0.5 and 5 mm. CONCLUSION: The applied orthognathic surgery procedures might widen the alar base and mouth width. It might increase the lateral upper-lip height, vermilion height of the lower lip, and cutaneous and overall upper-lip heights while reducing upper-lip vermilion height and shortening the overall lower-lip height.

The Impact of Emotional Solidarity on Residents' Attitude and Tourism Development.

In many countries, especially one such as Malaysia, tourism has become a key factor in economic development, and the industry heavily relies on feedback from local residents. It is essential to observe and examine the perceptions of residents towards tourists and tourism development for better planning in realizing successful and sustainable tourism development. Therefore, this research measured the relationship between residents' welcoming nature, emotional closeness, and sympathetic understanding (emotional solidarity) towards tourists and their respective attitudes towards supporting tourism development. To test the proposed research model, we collected data using a questionnaire survey from 333 residents in rural areas in Malaysia. We used the structural equation modelling technique (Amos) to evaluate the research model, and the results revealed that the residents' willingness (welcoming nature) to accept tourists is the strongest factor that effects the residents' attitudes towards supporting tourism development. However, there was no significant relationship between residents' emotional closeness and their sympathetic understanding towards tourists with their attitude and support towards tourism development. Welcoming nature, emotional closeness, and sympathetic understanding are able to predict 48% of residents' attitudes towards tourism development and 62% of their support towards tourism development.

Efficacy of Antimicrobial Photodynamic Therapy as an Adjunctive to Mechanical Debridement in the Treatment of Peri-implant Diseases: A Randomized Controlled Clinical Trial.

Introduction: The purpose of the present study was to assess the clinical effects of anti-microbial photodynamic therapy (PDT) after closed surface scaling in the treatment of peri-implant diseases. Methods: Ten patients with a total of 15 pairs of dental implants, showing clinical and radiographic signs of peri-implant diseases, were included in this study. In each patient, one implant randomly served as control implant and the other served as test implant. The control implants were treated with closed surface scaling only and the test implants received additionally PDT, using light with a wavelength of 630 nm and intensity of 2000 mw/cm2 for 120 seconds after application of photosensitizer in peri-implant sulcus. Clinical parameters were evaluated before and 1.5 and 3 months after treatment. Results: Statistical analysis showed significant differences in probing pocket depth (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), and gingival index (GI) at each time point between the two groups. There were no statistically significant changes with respect to any of the parameters in the control group. Complete resolution of BOP at 3 months was achieved in 100% of test implants. At 1.5 and 3 months, there were significant differences in the mean probing depth and CAL gain measurements at implants in the test group. Conclusion: The present study revealed that adjunctive use of PDT following closed surface scaling could lead to clinical improvement of peri-implant diseases. Further studies are necessary to confirm our results.

Differences in viral and host genetic risk factors for development of human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis between Iranian and Japanese HTLV-1-infected individuals.

Human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurological disease observed only in 1-2 % of infected individuals. HTLV-1 provirus load, certain HLA alleles and HTLV-1 tax subgroups are reported to be associated with different levels of risk for HAM/TSP in Kagoshima, Japan. Here, it was determined whether these risk factors were also valid for HTLV-1-infected individuals in Mashhad in northeastern Iran, another region of endemic HTLV-1 infection. In Iranian HTLV-1-infected individuals (n=132, 58 HAM/TSP patients and 74 seropositive asymptomatic carriers), although HLA-DRB1*0101 was associated with disease susceptibility in the absence of HLA-A*02 (P=0.038; odds ratio=2.71) as observed in Kagoshima, HLA-A*02 and HLA-Cw*08 had no effect on either the risk of developing HAM/TSP or HTLV-1 provirus load. All Iranian subjects possessed tax subgroup A sequences, and the protective effects of HLA-A*02 were observed only in Kagoshima subjects with tax subgroup B but not in those with tax subgroup A. Both the prevalence of HTLV-1 subgroups and the host genetic background may explain the different risks levels for HAM/TSP development in these two populations.