Effects of Ponderal Index on Neonatal Mortality and Morbidities in Extremely Premature Infants.

BACKGROUND: To evaluate how intrauterine stress affects extremely premature infants in terms of intrauterine growth restriction. We hypothesized that extremely premature infants with mildly-low ponderal index (MPI) would have better neonatal outcomes. METHODS: We selected 2,721 subjects of 23 to 28 weeks of gestation between 2013 and 2015 from Korean Neonatal Network database. They were divided into 4 groups based on ponderal index (PI) percentile; PI ≤ 3rd as severely-low PI (SPI, n = 82), 3rd < PI ≤ 10th as MPI (n = 190), 10th < PI ≤ 90th as adequate PI (API, n = 2,179), and PI > 90th as high PI (HPI, n = 270). RESULTS: The mortality in MPI and API groups was comparable (16.3% vs. 16.9%). It was significantly lower than that in the SPI and HPI groups (30.5% and 24.9%, respectively; P = 0.001). The MPI and API groups had better neonatal morbidities compared with the SPI and/or HPI groups, while the MPI group (8.2%) showed a lower incidence of severe intraventricular hemorrhage (IVH) than the other groups (SPI, 21.3%; API, 15.0%; HPI, 19.7%, respectively; P = 0.004). The MPI group had a trend of a bottom in neonatal mortality and morbidities in extremely premature infants. CONCLUSION: The MPI and API groups had lower mortality, massive pulmonary hemorrhage, severe bronchopulmonary dysplasia or death, pulmonary hypertension and neonatal seizure rates than the SPI and/or HPI groups, while the MPI group showed a lower incidence of severe IVH than the other groups. We speculate that the lower incidence of neonatal morbidities and mortality in the MPI group indicating mild intrauterine stress might accelerate fetal maturation resulting in better outcomes in extremely premature infants.

Differences in cytokine levels between the nasal polyps of adolescents with local allergic and adolescents with allergic or nonallergic rhinitis.

BACKGROUND: Local allergic rhinitis (LAR) is rhinitis with a localized nasal allergic response in the absence of systemic allergy. This study aimed to evaluate the pathogenesis specific to LAR compared with allergic rhinitis (AR) and nonallergic rhinitis (NAR) by using cytokines from polypous tissues. METHODS: We recruited 43 patients with AR (n = 15; mean age, 17.4 years), LAR (n = 12; mean age, 15.9 years), and NAR (n = 16; mean age, 15.6 years) who underwent polypectomy. Atopic status was defined as presenting a sufficiently high total immunoglobulin E (IgE) serum concentration and skin-prick test or serum allergen test. Immunoassays were performed by using polyp tissue homogenates to quantify the levels of regulated on activation of normal T cell expressed and secreted (RANTES), tumor necrosis factor (TNF) alpha, interleukin (IL) 5, and sera to assess total IgE and eosinophil cationic protein. RESULTS: RANTES levels were higher in patients with LAR than in patients with AR and NAR. There was a significant correlation in the concentration of RANTES between polyp tissue homogenates and serum (R2 = 0.51, p < 0.05). The levels of IL-5, TNF alpha, and interferon gamma also demonstrated positive correlations between polyp tissue homogenates and serum; however, they were not significantly different. CONCLUSION: Results of our study indicated that RANTES may play an important role and contribute to allergic reaction in LAR, and RANTES may be related to the pathogenesis of LAR.

Rotavirus infection as a frequent cause of neonatal fever.

BACKGROUND: Fever rather than diarrhea or vomiting was the most common symptom of neonatal rotavirus (RV) infection in our previous study. We investigated whether RV infection is a major cause of neonatal fever and compared the clinical characteristics of bacterial infection, viral infection and unknown causes of neonatal fever. METHOD: We reviewed the electronic medical records of 48 newborns aged ≤28 days who were admitted to the Special Care Nursery of Hanyang University Guri Hospital for fever (≥38°C) from 2005 to 2009. All the newborns underwent complete blood count, urinalysis, C-reactive protein, cultures of blood, urine, and cerebrospinal fluid as well as stool RV enzyme-linked immunosorbent assay. Respiratory virus polymerase chain reaction for cough or rhinorrhea, and stool culture for diarrhea were also done. RESULTS: All the babies were term, with mean age 13 ± 8 days and peak body temperature 38.5 ± 0.5°C. The causes of neonatal fever were viral (44%), bacterial (10%) and unknown (46%). The viral infections included RV (n = 12), enterovirus (n = 6), respiratory syncytial virus (n = 2), and rhinovirus (n = 1). All the rotavirus genotypes were G4P[6]. Only three of 12 RV-infected febrile newborns had diarrhea. The bacterial infections included three cases of urinary tract infection (Escherichia coli, n = 2; Klebsiella pneumoniae, n = 1), and two cases of sepsis complicated with meningitis (all Streptococcus agalactiae). CONCLUSIONS: RV infection is the most common single cause of neonatal fever. It may be necessary to include stool RV tests for febrile newborns.

The effect of hydrophilic photoacid generator on acid diffusion in chemical amplification resists.

A photoacid generator (PAG) is a component of chemical amplification photoresists (CAR). The most widely used PAG in CAR system is triphenyl onium salt which is well known to one of the best leaving groups from various radiation. Acid diffusion influences resist characteristics in area such as resolution and linewidth control. The structure of the hydrophilic PAG was designed to restrict acid diffusion within the photoresist. Acid amplification was suppressed by the hydroxyl group-acid interaction. Novel PAGs with functional groups were synthesized and characterized. Poly(GMA-co-MMA) was synthesized with a combination of crosslinkable glycidyl methacrylate (GMA) and highly refractive methyl methacrylate (MMA). The synthesized polymers were confirmed by NMR and FT-IR, and their thermal properties were studied using TGA and DSC. The resists were evaluated as a positive type resist for ArF lithography. PAGs exhibited good acid generation efficiency with controlled acid diffusion. We found that the energy latitude property of the photoresist was improved with hydroxyl-PAG.

Synthesis of triphenylsulfonium triflate bound copolymer for electron beam lithography.

Photoacid generator (PAG) has been widely used as a key component in photoresist for high-resolution patterning with high sensitivity. A novel acrylic monomer, triphenylsulfonium salt methyl methacrylate (TPSMA), was synthesized and includes triphenylsulfonium triflate as a PAG. The poly(MMA-co-TPSMA) (PMT) as a polymer-bound PAG was synthesized with methyl methacrylate (MMA) and TPSMA for electron beam lithography. Characterization of PMT was carried out by NMR and FTIR. The molecular weight was analyzed by GPC. Thermal properties were studied using TGA and DSC. Thecharacterization results were in good agreement with corresponding chemical compositions and thermal stability. PMT was subsequently employed in electron beam lithography and its lithographic performance was confirmed by FE-SEM. This PMT was accomplished to improve the lithographic performance including sensitivity, line width roughness (LWR) and resolution. We found that PMT was capable of 20 nm negative tone patterns with better sensitivity than hydrogensilsesquioxane (HSQ) which is a conventional negative tone resist.

Enhanced Acid Diffusion Control by Using Photoacid Generator Bound Polymer Resist.

Photoacid generators (PAGs) have been widely used as a key component for improving photoresist performance. The acid diffusion influences on the photoresist characteristics of resolution and line edge roughness (LER). The PAG bound polymer resist has been a key component for solving the problems of PAG aggregation and acid diffusion control. A triphenyl sulfonium salt methacrylate as PAG was synthesized and copolymerized with crosslinkable glycidyl methacrylate and methyl methacrylate by radical reaction for a new PAG bound polymer resist. The characterization of resist polymers was carried out by 1H NMR. The lithographic performance of photoresists was investigated by ArF lithography. Both PAG bound resist and the PAG blended resist were employed to demonstrate the effect of PAG unit in a resist system. The polymer bound PAG resist improved the LER and showed a higher resolution than the PAG blend resist.