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Experimental study.In this study, the ambient temperature of a radiofrequency (RF) electrode tip was compared and analyzed in terms of products, mode, flow quantity, and flow rate.Endoscopic spine surgery is a widely used operation for degenerative lumbar stenosis and herniated lumbar disc. To perform endoscopic spine surgery, dedicated instruments like a RF generator and electrode are essential.An evaluation system capable of measuring temperature under equal conditions at a certain distance from the electrode tip was manufactured. The distance between the electrode tip and the temperature sensor was set to 1, 5, and 10 mm. The flow quantities of 0, 50, 100, and 150 mL/min and the flow rates of 0, 0.20, 0.53, and 0.80 m/s were compared and statistically analyzed.The temperatures measured in the experiments conducted on the four combinations of RF device showed similar values, and showed differences according to the characteristics of each mode of the RF. As the distance between the electrode tip and the temperature sensor increased, the temperature decreased, and as flow quantity or flow rate increased, the temperature decreased. The maximum temperatures differed significantly according to flow quantity, between flow quantities of 0 and 100 mL/min (P = 0.03) and between 0 and 150 mL/min (P ≤ 0.01). The maximum temperatures also differed significantly between the flow rate of 0 m/s, and the flow rates of 0.20, 0.53, and 0.80 m/s, with P ≤ 0.01 in all three comparisons.This is the first study in which we made a customized RF temperature evaluation system and verified the temperature changes in various environments. When irrigation was performed, we could confirm that the maximum temperature was less than 60°C. Irrigation is considered essential in endoscopic spine surgery.3.

Socioeconomic disparities have been reported as the main risk factors contributing to the spread of coronavirus disease 2019 (COVID-19) at the community level. We conducted an epidemiological study on the risk of COVID-19 incidence using area deprivation indices (DIs) depending on the characteristics of the susceptible population.The database of the confirmed COVID-19 cases in eight metropolitan cities, the Republic of Korea, from January 20, 2020 to December 31, 2021, was combined with the area DIs and standardized prevalence of diabetes and hypertension from the community health survey. The relative risk (RR) was estimated using a generalized linear model with Poisson distribution by age group.The risk of COVID-19 incidence increased with the increasing age group, especially in patients aged ≥75 years. The RR per interquartile range increment of total social deprivation index (total SDI) was 1.54 (95% confidence interval [CI]: 1.34-1.70) in the COVID-19 incidence. Especially, the risk of COVID-19 incidence in the first wave was about three times higher in the region belonging to the lowest socioeconomic status than in the region with the highest socioeconomic status. The risk was 3.08 (95% CI: 2.42 to 3.78) based on the total SDI and 3.13 (95% CI: 2.53 to 3.83) based on the social deprivation index.This study provides scientific evidence that socioeconomic inequity is an important risk factor for the spread of COVID-19. This finding suggests that a mid-to-long-term strategy is needed for the susceptible population to reduce the burden of COVID-19 in the community.

This study aims to investigate the trends of avoidable mortality and regional inequality from 1995 to 2019 and to provide evidence for policy effectiveness to address regional health disparities in Korea. Mortality and population data were obtained from the Statistics Korea database. Age-standardized all-cause, avoidable, preventable, and treatable mortality was calculated for each year by sex and region. Changes in mortality trends between metropolitan and non-metropolitan areas were compared with absolute and relative differences. Avoidable mortality decreased by 65.7% (350.5 to 120.2/100,000 persons) in Korea, 64.5% in metropolitan areas, and 65.8% in non-metropolitan areas. The reduction in avoidable mortality was greater in males than in females in both areas. The main causes of death that contribute to the reduction of avoidable mortality are cardiovascular diseases, cancer, and injuries. In preventable mortality, the decrease in non-metropolitan areas (−192.4/100,000 persons) was greater than that in metropolitan areas (−142.7/100,000 persons). However, in treatable mortality, there was no significant difference between the two areas. While inequalities in preventable mortality improved, inequalities in treatable mortality worsened, especially in females. Our findings suggest that regional health disparities can be resolved through a balanced regional development strategy with an ultimate goal of reducing health disparities.

This study has been conducted to utilize the open source code in analyzing the performance of a gas turbine engine. The turbine nozzle vanes, which are relatively simple to analyze among the gas turbine engine components, were selected for analysis, and the analysis was carried out by OpenFOAM which is the most well-known tool as an open source CFD code. Among the solvers provided by OpenFOAM, rhoSimpleFoam and rhoPimpleFoam were used to analyze the compressible flow, and the JANAF option enabled to apply the function of temperature to the thermal properties. rhoSimpleFoam was able to calculate quickly and correctly in the region below the Ma = 1, but not affordable for the transonic region with shock wave, which was compensated with rhoPimpleFoam with the transonic option resulting in converged solution. The calculated results by OpenFOAM were compared to those by ANSYS – CFX and showed good agreement.

Activated carbon monoliths of kenaf (ACMKs) were prepared by moulding kenaf fibers into a column-shape monolith and then carrying out pyrolysis at 500, 600, 700 or 800 °C, followed by activation with KOH at 700 °C. Then, the sample was characterized using thermogravimetric analyzer (TGA), field-emission scanning electron microscopy (FE-SEM), field-emission transmission electron microscopy (FE-TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD) and N

A well-ordered polymer nanocomposite was prepared as a supercapacitor electrode based on sulfonated graphene oxide (SGO) and a two-monomer-connected precursor (TMCP). Biphenyldisulfonic acid (BPDSA...

Objectives In this study the relationship between neighborhood deprivation and the unmet health care needs of elderly individuals (≥ 65 years) was examined. Some previous studies suggested that neighborhood characteristics affect access to health care, yet research on the unmet needs of older individuals is limited. Methods Multilevel logistic regression analysis was used to assess the relationship of neighborhood-level factors with unmet health care needs due to costs, adjusting for individual-level factors, in individuals ≥ 65 years in the 2017 Korean Community Health Survey (n = 63,388). Results There were 2.6% of elderly individuals who experienced unmet health care needs due to costs. Following adjustment for individual and neighborhood characteristics, the neighborhood deprivation in urban areas was found to have an inverse association with unmet needs (odds ratio = 0.50; 95% confidence interval = 0.24-1.06) for the most deprived quartile versus the least deprived quartile). However, in rural areas neighborhood deprivation was not a significant variable. Among the individual-level variables, household income was one of the strongest correlates with unmet needs in both urban and rural areas. Conclusion The present findings suggest that targeted policy interventions reflecting both neighborhood and individual characteristics, should be implemented to reduce the unmet health care needs of elderly individuals.

Activated carbon xerogel monoliths were prepared from resorcinol and formaldehyde via a catalyst-free and template-free hydrothermal polycondensation reaction, followed by pyrolysis and activation. The ratio of resorcinol (R) to distilled water (W) was varied to afford an interconnected pore structure with controlled pore size, while the pyrolysis temperature was optimized to give high specific surface area. Activation was carried out at 700 °C after soaking the samples in 6 M KOH aqueous solution. The same process, called “heat treatment”, was also carried out without soaking in KOH for comparison. The weight loss upon pyrolysis, activation and heat treatment and the weight gain via KOH soaking were measured. Field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and an N2 sorption instrument were utilized for characterization. Additionally, electrochemical properties were evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) with a 3-electrode system, while a 2-electrode system was also employed for selected samples. The highest specific capacitance of 323 F g−1 via GCD at 1 A g−1 was obtained at the R/W ratio of 45 and with 500 °C pyrolysis. In addition, this sample also exhibited 89.4% retention at 20 A g−1 in the current density variation and 100% retention in 5000 cycling tests.

Spatiotemporal distribution of the fish larvae and eggs is one of the most important information for their reproduction and recruitment in an aquatic ecosystem. We here employed the metabarcoding strategy as an alternative method for the conventional ichthyoplankton survey, which requires considerable amount of times, labors, and cost. First, a piscine-specific universal primer set (FishU) was designed to amplify the region flanking the highly conserved mitochondrial 12S and 16S ribosomal sequences, which was optimized for MiSeq platform. Based on both in-silico and in-vitro analyses, the newly designed FishU primers outperformed the two previously reported fish-specific universal primer sets (ecoPrimer and MiFish) in taxon coverage and specificity and accuracy in species identification. The metabarcoding results by FishU primers successfully presented the diversity of ichthyoplankton directly from the zooplankton net samples in the East/Japan presenting more accurate and more species numbers compared with those by MiFish primers. Despite several limitations, the metabarcoding analysis of ichtyoplankton using the newly designed FishU primers would be one of the promising tools providing many useful data to understand the reproduction of fish such as spawning sites, reproductive periods, population structures with relatively low cost and labors.

We determined the complete mitochondrial genome of Metapenaeopsis dalei (Rathbun, 1902), which is collected from East China Sea (124°E and 33.5°N). Total mitochondrial genome length of M. dalei was 15 939 bp, in which 13 proteins, two ribosomal RNAs, 22 transfer RNAs and a putative control region were encoded. The gene arrangement of M. dalei was well conserved with nine known Penaeidae mitochondrial genomes from COX1 to tRNATyr. The protein-coding genes started with ATN except for COX1 in which ACG is used. Four genes (COX2, COX3, ND3 and ND5) exhibited an incomplete stop codon. Nucleotide sequence identity of M. dalei mitochondrial genome to those of nine Penaeidae species ranged from 78% to 80%. Based on the COI region, M. dalei is most closely related to Penaeus notialis.

Self‐emulsion polymerization (SEP), a green route developed by us for the polymerization of amphiphilic monomers, does not require any emulsifier or an organic solvent except that the water‐soluble initiators such as 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane]dihydrochloride (VA‐044) and potassium persulfate (KPS) are only used. We report here the polymer nanoscaffolds from a number of amphiphilic monomers, which can be used for in situ encapsulation of a variety of nanoparticles. As a demonstration of the efficacy of these nanoscaffolds, the synthesis of a biocompatible hybrid nanoparticle (nanohybrid), prepared by encapsulating Fe₃O₄ magnetic nanoparticle (Fe₃O₄ MNPs) in poly(2‐hydroxyethyl methacrylate) in water, for MRI application is presented. The nanohybrid prepared following the SEP in the form of an emulsion does not involve the use of any stabilizing agent, crosslinker, polymeric emulsifier, or surfactant. This water‐soluble, spherical, and stable nanohybrid containing Fe₃O₄ MNPs of average size 10 ± 2 nm has a zeta potential value of −41.89 mV under physiological conditions. Magnetic measurement confirmed that the nanohybrid shows typical magnetic behavior having a saturation magnetization (Ms) value of 32.3 emu/g and a transverse relaxivity (r2) value of 29.97 mM⁻¹ s⁻¹, which signifies that it can be used as a T2 contrast agent in MRI. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019

Monolithic carbon xerogel (MCX) with co-continuous hierarchical porosity was prepared via a one-step, template- and catalyst-free hydrothermal polycondensation reaction with resorcinol (R), formaldehyde (F) and distilled water (W), followed by pyrolysis and CO2 activation. The reaction was carried out in a pressurized Teflon mold at 100 °C for 6 h, while F/R (2.2, 2.4, 2.6, and 2.8) and R/W ratios (40 and 45) were varied to obtain a co-continuous pore structure with interconnected particles. Next, the gels were dried at 60 °C for 36 h and then at 100 °C for 12 h to produce xerogels, which were then subjected to pyrolysis at 900 °C for 2 h and CO2 activation at 1000 °C for 2, 4 or 6 h. A co-continuous pore structure with interconnected particles was observed in gels with F/R = 2.4 and 2.6 at R/W = 40 and with F/R = 2.2 at R/W = 45, but the gel with F/R = 2.4 at R/W = 40 was the only one that showed no crack generation upon 6 h CO2 activation. Thus, this gel was subjected to a N2 sorption study, which resulted in a specific surface area (SSA) of 1418, 2489 and 3418 m2 g−1 at 2, 4 and 6 h activation, respectively. This was attributed to the introduction of micro-pores via activation, which also generated meso- and macro-pores to form hierarchical porosity.

Introduction The purpose of this study was to investigate if machined springs in nickel-titanium (NiTi) rotary instruments can improve their mechanical properties. The bending and torsion properties were assessed using finite element (FE) model analysis. Methods A basic 3-dimensional file model without a spring was created with apical size #25, 25-mm full length, and 16-mm cutting flutes. Three other models were created with a spring machined into their shaft portion with different numbers of spring coils: standard (STspr), 10% more (INspr), and 10% less (DEspr). To compare the mechanical responses among the 4 FE models, file bending and torsion were simulated using FE analysis. Results Spring machined NiTi rotary instruments showed higher torsional resistance and less bending stiffness than the same instrument without. The spring machined models required more torque to bend or rotate the DEspr model than was required for the STspr and INspr models; however, the STSpr and INSpr models were similar. Conclusions Within the limitations of this study, the FE analysis indicated that machining a spring into the shaft of NiTi rotary instruments improved torsional resistance and bending flexibility. Therefore, spring machining has the potential to increase the durability of the NiTi rotary instruments.

Background Korea has seen a rapid increase in the use of percutaneous coronary intervention (PCI) with the ratio of PCI to coronary artery bypass graft (CABG) the highest in the world. This study was performed to examine the factors associated with the rates of CABG and PCI. Methods The data were acquired from the National Health Insurance database in Korea in 2013. We calculated the age-sex standardized rates of CABG and PCI. We examined the factors associated with the CABG and PCI rates by performing a regression analysis. Results The rate of CABG showed a negative association with the deprivation index score, and other factors, such as the number of providers or hospital beds, did not show any significant association with the CABG rate. The rate of PCI had a strong negative association with the number of cardiothoracic surgeons and a strong positive association with the number of hospital beds. Conclusions The positive association between the PCI rate and the number of hospital beds suggests that the use of PCI may be driven by the supply of beds, and the inverse association between the PCI rate and the number of cardiothoracic surgeons indicates the overuse of PCI due to lack of the providers of CABG. Policy measures should be taken to optimize the use of revascularization procedures, the choice of which should primarily be based on the patient’s need.

Background The recent increase in knee arthroplasty (KA) use in Korea is among the highest in the world. The rapid increase in KA use suggests that the KA use in Korea could have been affected by medically unjustifiable factors. This study aimed to examine the geographic variation in the rate of KA and its associated factors in Korea. Methods We used the data from the National Health Insurance in Korea in 2013, from which a total of 67,086 claims for KA were obtained. We calculated the age-sex-standardized KA rates of the entire population and the crude rates of the age groups 0–64 and 65 and over in 251 districts. We assessed the geographic variation of the KA rates and examined the associated factors with a multivariate linear regression with the KA rate as a dependent variable. Results The overall rate of KA in Korea was 132.7 per 100,000 persons. The rates of KA showed a four-fold variation. The deprivation index score and the number of beds in the small to medium sized hospitals showed a positive association with the rates of KA while the number of orthopedic surgeons showed a negative association. Conclusions Korea has been experiencing a rapid increase in the use of KA for the last decade or so, which was most prominent among the elderly population aged 65 and older. Our results suggest that the higher rate of KA is strongly related to a higher supply of beds and the socioeconomically deprived conditions. Considering that the decision concerning KA has room for discretion and also affects a considerable portion of health care expenditures, the use of KA should be thoroughly monitored with more emphasis on standardization in the decision making process and preventive measures that can lessen the need for KA. Electronic supplementary material The online version of this article (10.1186/s12891-019-2766-y) contains supplementary material, which is available to authorized users.

Monolithic carbon xerogels with hierarchical porosity were prepared from resorcinol (R) and formaldehyde (F) via a base-catalysed hydrothermal polycondensation reaction, without a template and supercritical drying. First, an aqueous solution of resorcinol, formaldehyde and sodium carbonate was prepared by varying R/W (25–45) and R/C (1–10k) ratios to produce monolithic RF gels. The reaction was carried out in a pressurized Teflon mould at 100 °C for 6 h to give a co-continuous pore structure via spinodal decomposition and a tenacious gel to avoid supercritical drying. Next, the RF gels were dried for 42 h at 60 °C and another 6 h at 100 °C to produce RF xerogels without cracks, followed by pyrolysis in a tube furnace at 900 °C for 2 h under N2 flow, and then activation at 1000 °C for 2, 4 or 6 h under CO2 flow. Finally, the carbon xerogels were characterized by SEM and N2 adsorption–desorption measurements. Monolithic RF gels were obtained from all combinations of R/W and R/C, but the gels from R/W = 45 exhibited a co-continuous large-pore structure, providing a specific surface area (SSA) of ∼650 m2 g−1, which increased to 3311 m2 g−1 (for R/C = 10k) at 6 h of CO2 activation without exhibiting cracks. N2 isotherms demonstrated that micro- and meso-pores were introduced via activation, forming hierarchical porosity in combination with large pores from spinodal decomposition without using a template.

Although eyestalk ablation (ESA) is currently considered the most effective method to facilitate molting and maturation, its physiological responses are still not clearly explained in decapod crustaceans. In this study, we analyzed the hepatopancreatic transcriptomes of Litopenaeus vannamei after ESA using the Illumina Miseq platform. After screening 53,029 contigs with high cutoff values (fold change|10|; P-value0.05; RPKM1), we were able to identify 105 differentially expressed genes (DEGs), of which 100 were up-regulated and five were down-regulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that many DEGs were involved in the synthetic pathways for glycerol and trehalose, which are known to function as the major protectants under conditions of low temperature and osmotic stress in arthropods. Additional analysis of the other DEGs enabled us to classify them in four categories: immunity; cellular trafficking; transcriptional regulation; molting and maturation. Many DEGs were involved in immunity and stress responses, in particular the proPO activation system, which is the major immune and wound-healing system in arthropods. In addition to immunity and stress responses, we were also able to identify DEGs involved in molting and maturation processes (e.g., group I chitinase), as well as those involved in hormone metabolism and trafficking. Collectively, based on the transcriptomic analysis, ESA causes not only stress and immune responses, but also molting and maturation in L. vannamei. The DEGs identified in this study could be useful markers to understand the physiological responses that ESA induces in shrimp, such as molting, maturation, and immunity.

Reconstruction of fully edentulous arches with implant-retained dentures requires thorough planning and precise registration of the interocclusal relationship, to achieve a successful treatment outcome.

Objectives The aim of this study was to measure income differences in smoking prevalence at the district level and to investigate correlations among area deprivation, smoking prevalence, and income differences in smoking prevalence, stratified by urbanity. Methods Data were pooled from the Community Health Survey data of South Korea between 2008 and 2014. The age-standardized prevalence of smoking and its interquintile income differences were calculated. We conducted correlation analyses to investigate the association of the deprivation index with smoking prevalence and interquintile differences in smoking prevalence. Results Across 245 districts, the median prevalence of smoking in men was 45.9% (95% confidence interval [CI], 43.4 to 48.5%), with an interquartile range (IQR) of 4.6% points. In women, the median prevalence was 3.0% (95% CI, 2.4 to 3.6%) and IQR was 1.6% points. The median interquintile difference in smoking prevalence was 7.4% points (95% CI, 1.6 to 13.2% points) in men and 2.7% points (95% CI, 0.5 to 4.9% points) in women. The correlation coefficients for the association between the deprivation index and smoking prevalence was 0.58, 0.15, -0.22 in metropolitan, urban, and rural areas, respectively, among men, and 0.54, -0.33, -0.43 among women. No meaningful correlation was found between area deprivation and interquintile difference in smoking prevalence. The correlation between smoking prevalence and interquintile difference in smoking prevalence was more evident in women than in men. Conclusions This study provides evidence of geographical variations in smoking prevalence and interquintile difference in smoking prevalence. Neither smoking prevalence nor the deprivation index was closely correlated with interquintile income difference in smoking prevalence. Measuring inequalities in smoking prevalence is crucial to developing policies aimed at reducing inequalities in smoking.

Graphene and graphene derivatives, such as graphene oxide (GO) and reduced GO (rGO), have been extensively employed as novel components of biomaterials because of their unique electrical and mechanical properties. These materials have also been used to fabricate electrically conductive biomaterials that can effectively deliver electrical signals to biological systems. Recently, increasing attention has been paid to electrically conductive hydrogels that have both electrical activity and a tissue-like softness. In this study, we synthesized conductive graphene hydrogels by mild chemical reduction of graphene oxide/polyacrylamide (GO/PAAm) composite hydrogels to obtain conductive hydrogels. The reduced hydrogel, r(GO/PAAm), exhibited muscle tissue-like stiffness with a Young’s modulus of approximately 50 kPa. The electrochemical impedance of r(GO/PAAm) could be decreased by more than ten times compared to that of PAAm and unreduced GO/PAAm. In vitro studies with C2C12 myoblasts revealed that r(GO/PAAm) significantly enhanced proliferation and myogenic differentiation compared with unreduced GO/PAAm and PAAm. Moreover, electrical stimulation of myoblasts growing on r(GO/PAAm) graphene hydrogels for 7 days significantly enhanced the myogenic gene expression compared to unstimulated controls. As results, our graphene-based conductive and soft hydrogels will be useful as skeletal muscle tissue scaffolds and can serve as a multifunctional platform that can simultaneously deliver electrical and mechanical cues to biological systems. Statement of Significance Graphene-based conductive hydrogels presenting electrical conductance and a soft tissue-like modulus were successfully fabricated via mild reduction of graphene oxide/polyacrylamide composite hydrogels to study their potential to skeletal tissue scaffold applications. Significantly promoted myoblast proliferation and differentiation were obtained on our hydrogels. Additionally, electrical stimulation of myoblasts via the graphene hydrogels could further upregulate myogenic gene expressions. Our graphene-incorporated conductive hydrogels will impact on the development of new materials for skeletal muscle tissue engineering scaffolds and bioelectronics devices, and also serve as novel platforms to study cellular interactions with electrical and mechanical signals.

Objectives The objective of this study is to investigate associations between contextual characteristics and unmet healthcare needs in South Korea after accounting for individual factors. Methods The present study used data from the 2012 Korean Community Health Survey (KCHS) of 228 902 adults residing within 253 municipal districts in South Korea. A multilevel analysis was conducted to investigate how contextual characteristics, defined by variables that describe the regional deprivation, degree of urbanity, and healthcare supply, are associated with unmet needs after controlling for individual-level variables. Results Of the surveyed Korean adults, 12.1% reported experiencing unmet healthcare needs in the past. This figure varied with the 253 districts surveyed, ranging from 2.6% to 26.2%. A multilevel analysis found that the association between contextual characteristics and unmet needs varied according to the factors that caused the unmet needs. The degree of urbanity was associated with unmet need due to "financial burden" (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.42 to 0.66 for rural vs. metropolitan), but not unmet need due to "service not available when needed." There were no significant associations between these unmet need measures and regional deprivation. Among individual-level variables, income level showed the highest association with unmet need due to "financial burden" (OR, 5.63; 95% CI, 4.76 to 6.66), while employment status showed a strong association with unmet need due to "service not available when needed." Conclusions Our finding suggests that different policy interventions should be considered for each at-risk population group to address the root cause of unmet healthcare needs.

Background The incidence of pneumonia in Korea started to increase in the 1990’s after a period of decrease and stabilization, and the mortality and hospitalization rates for pneumonia in Korea are alarmingly high. This study was performed to examine geographic variation and factors associated with hospitalization for bacterial pneumonia in Korea. Methods Data were acquired from the inpatient claims of the 2015 period of the National Health Insurance Service. The age- and sex-standardized hospitalization rates for bacterial pneumonia were calculated for three age groups. Geographic variation was measured with the coefficient of variation, the ratio of the 90th to the 10th percentile of the distribution of rates, and the systematic component of variation. Considering the results of Moran’s I statistic which suggested spatial autocorrelation, we estimated spatial regression models using spatial error models. Results The hospitalization rate for bacterial pneumonia was 79.1 per 10,000 population, and the rate was the highest in the age group 0–14 at 325.3, and it was 161.5 among the elderly. The geographic variation statistics showed high variation with the coefficient variation at 0.6. The deprivation score showed positive associations, and the number of primary care physicians had a negative association with the hospitalization rates across all age groups but the age group 0–14. The number of beds in hospitals with less than 300 beds had a positive association with the hospitalization rates for bacterial pneumonia, and the impact was the strongest in the age group 0–14. Conclusions The present study shows that pneumonia can be a major public health issue even in a developed country. Socioeconomic conditions can still be a concern for pneumonia in developed countries, and the role of primary care physicians in preventing hospitalization for bacterial pneumonia needs to be recognized. Most of all, the strong impact of hospital beds on the hospitalization rates for pneumonia, especially for the children, should be addressed. High disease burden of pneumonia in Korea can partly be attributable to oversupply of hospital beds. These factors should be taken into consideration in establishing policy measures for the rise in pneumonia. Electronic supplementary material The online version of this article (10.1186/s12890-019-0798-6) contains supplementary material, which is available to authorized users.

Monolithic carbon xerogel (MCX) with co-continuous hierarchical porosity was prepared

Three different morphologies of ZnO nanostructures, such as nanospheres, nanorods, and nanoribbons, were controlled by tuning the ratio of the Zn2+ precursor to the 4VP monomer when polymerized in aqueous medium utilizing self-emulsion polymerization. The amphiphilic homopolymer (P4VP) acts as a template to form the ZnO/P4VP nanocomposite. The aspect ratio of the nanostructures is strongly dependent on the molar concentration of the Zn2+ precursor and becomes higher as its concentration increases. This results in different morphologies that are consistently repeatable. Pure ZnO was obtained from the ZnO/P4VP nanocomposites by calcination at 400 °C or by solvent washing. The calcination of the nanocomposties resulted in different morphologies, such as spherical, corolla shaped, and nanosheets. In addition, hexagonal nanoblocks, nanorods, and nanoribbons were observed when the polymer was removed from the nanocomposites by washing with chloroform. Removing polymer by solvent washing is a very easy, cost-eff...