Inhalation exposure to nanosized aerosols of disinfectants for the application of continuous releasing sprayers and fogger.

This study aimed to investigate the airborne exposure to aerosols according to the particle size distribution of three different spray types (nano-nozzled spray gun, low-temperature steam spray, and fogger) and compare the concentrations of inhaled aerosols between children and adults. Airborne aerosols released from three products were observed using size-segregated particle measurements, and particle concentrations deposited in the respiratory tracts of adults and children were estimated using multi-path particle dosimetry lung deposition models. All types of sprayers generated the most nanoparticles (~100 nm). Due to their higher respiratory rate than adults, a larger number of particles <1.0 µm deposited in the children's respiratory tracts was higher. The sequences of the total number of particles in the respiratory regions after spraying nano-nozzled spray gun and fogger were alveolar (AL)>tracheobronchial (TB)>head airway (HA) in adults and AL>HA>TB in children. Meanwhile, the trend of low-temperature steam spray was AL>TB>HA in adults and AL>TB>HA in children.

Electron-Transport-Chain-Mediated Selective Growth of Gold Nanocrystals in the Intermembrane Space of Live Microbial Cells.

Hybridization of microbial cells with inorganic nanoparticles that could dramatically improve cellular functions such as electron transfer has been realized by the random attachment or stochastic entry of the nanoparticles. Clearly, the selective growth of inorganic nanoparticles on target functional organelles is ideal for such hybridization. Here, we report the selective growth of gold nanocrystals in the intermembrane space (IMS) of Escherichia coli by exploiting the electron transport chain (ETC). We systematically show that gold ions are permeated through porins in the outer membrane of E. coli and further reduced to gold nanocrystals by the ETC in live E. coli. We directly observe that the resulting gold nanocrystals exist only in the IMS by transmission electron microscopy measurements of cross-sectioned E. coli. Molecular dynamics simulations suggest that once gold ions are reduced to small nuclei by the ETC, the nuclei can be stably physisorbed onto ETC complexes, further supporting the ETC-mediated growth. Finally, we show that the ATP synthesis of E. coli where gold nanocrystals are formed in the IMS is up to 9 times higher than that of E. coli alone. We believe that our work can significantly contribute to not only improving microbial metabolic functions for biological energy conversion but also restoring physiological dysfunctions of microbial cells for biomedicine.

Prevalence of Venous Thromboembolism after Immediate Screening in Hip Fracture Patients.

Purpose: Venous thromboembolism (VTE) is a major complication for hip fracture patients, and may exist preoperatively. This study aimed to examine the prevalence of VTE after immediate screening in hip fracture patients. Materials and Methods: Hip fracture patients with an elevated level of D-dimer underwent screening for VTE using computed tomography (CT) angiography. Anticoagulation treatments were administered preoperatively to patients diagnosed with VTE, followed by administration of additional anticoagulation postoperatively. Medical records were reviewed to identify risk factors for preoperative VTE and determine the prognosis of the patients. Results: Among 524 hip fracture patients, 66 patients (12.6%) were diagnosed with VTE, including 42 patients with deep vein thrombosis (DVT), 17 patients with pulmonary thromboembolism (PTE), and 7 patients with both DVT and PTE. Of the patients with VTE, 68.2% were diagnosed within 24 hours of injury, and 33.3% of these patients had PTE. VTE patients showed a tendency toward being overweight (P<0.01) and not on anticoagulant medication (P=0.02) compared to patients without VTE. The risk of VTE was higher for femur shaft fractures (odds ratio [OR] 4.83, 95% confidence interval [CI] 2.18-10.69) and overweight patients (OR 2.12, 95% CI 1.17-3.85), and lower for patients who were previously on anticoagulants (OR 0.36, 95% CI 0.18-0.74). Patients with preoperatively diagnosed VTE were asymptomatic before and after surgery. Conclusion: Clinicians should be aware that VTE may be present within 24 hours of injury, and screening for VTE or prophylactic measures should be considered for high-risk patients.

Incidence and outcomes of intraoperative periprosthetic acetabular fractures during cementless total hip arthroplasty: a prospective three-dimensional computer tomography-based study.

PURPOSE: Unlike periprosthetic femoral fractures, periprosthetic acetabular fractures during total hip arthroplasty (THA) have not been evaluated in detail. We prospectively evaluated the incidence, patterns, risk factors, and clinical outcomes of intraoperative periprosthetic acetabular fractures using pre- and postoperative computer tomography (CT). METHODS: In this prospective single-centre study, we evaluated 234 consecutive patients (250 hips) who underwent THA and three-dimensional CT before and after the surgery. We assessed the incidence, pattern of fractures, outcomes for each fracture pattern, reoperation and revision rates, Harris hip score, and visual analog scale (VAS) for pain. Multivariate regression models were used to identify risk factors for periprosthetic acetabular fractures. RESULTS: In total, 43 periprosthetic acetabular fractures (17.2%) were identified via CT. Fractures occurred most frequently at the superolateral wall. Early cup migration occurred in three hips. None of the patients underwent revision surgery for acetabular loosening. Regression modeling showed that rheumatoid arthritis was a significant predictor of periprosthetic acetabular fractures. CONCLUSIONS: Periprosthetic acetabular fractures are not infrequent during cementless THA and are more common in patients with rheumatoid arthritis.

Non-thermal atmospheric pressure plasma treatment increases hydrophilicity and promotes cell growth on titanium alloys in vitro.

Most medical implants are made of titanium. When titanium is exposed to air for a long time, hydrocarbons are deposited and the surface becomes hydrophobic. Cell attachment is important for bone ingrowth to occur on the implant surface, and hydrophilicity can enhance this. We examined whether non-thermal atmospheric pressure plasma treatment could increase the hydrophilicity of the titanium surface. Samples coated with four widely used coating types [grit blasting, micro arc oxidation (MAO), titanium plasma spray (TPS), and direct metal fabrication (DMF)] were treated with plasma. Each of the four surface-treated samples was divided into groups with and without plasma treatment. We analysed wettability by surface analysis and evaluation of contact angles, cell proliferation, and adhesion using scanning electron microscopy (SEM), confocal laser scanning microscopy, absorbance tests, and alkaline phosphatase (ALP) activity assay; four different Ti6Al4V surface types were compared. After plasma treatment, the contact angle was reduced on all surfaces, and the carbon content was reduced on all surfaces based on X-ray photoelectron spectroscopy (XPS) surface analysis. Under confocal laser scanning, the cell layer was thicker on the plasma-treated samples, especially in groups TPS and DMF. Cell proliferation was 41.8%, 17.7%, 54.9%, and 83.8% greater for the plasma- than non-plasma-treated grit blasting, MAO, TPS, and DMF samples, respectively. Hydrophilicity increased significantly under plasma treatment, and biological responsivity was also improved.

Simple Minimally Invasive Method to Reduce Valgus-Impacted and Tilted Femoral Neck Fractures without Soft Tissue or Cartilage Injury: Radiological and Clinical Results.

OBJECTIVE: This is a rare study comparing the radiological and functional outcomes of fixation after reduction with in situ fixation group using Femoral Neck System (FNS). The aim of this study was to introduce a simple, innovative, minimally invasive method to reduce valgus-impacted and tilted femoral neck fractures without soft tissue or cartilage injury. METHODS: A retrospective comparative analysis of 46 patients between May 2020 and February 2022 was performed. In the control group, 23 patients underwent in situ fixation without reduction. In the study group, another 23 patients were managed by fixation after reduction using a percutaneous pull-out technique with a full threaded Steinmann pin. Caput-collum-diaphysis (CCD) angle, tilt, and femoral neck shortenings were compared between the two groups. In addition, Harris Hip Score (HHS) was evaluated and compared at 1 year after surgery. Basically, independent samples t-test was used to compare radiological and functional results. RESULTS: Patients' initial valgus and tilt angles were not significantly different between the groups (n.s.). However, the CCD and tilt angles measured immediately and at one year postoperatively were significantly different between the groups (p < 0.05). Regarding femoral neck shortening, shortening in the three directions, the x, y, and z vectors, was significantly less in the reduction group immediately postoperatively and at 1 year post-surgery (p < 0.05). The mean HHS at 1 year postoperatively was 79.7 ± 8.4 in the in situ fixation group and 87.9 ± 6.6 in the reduction groups, and there was a significant difference (p < 0.05). CONCLUSION: The pull-out method with a threaded Steinmann pin to reduce valgus-impacted and tilted femoral neck fracture is safe and effective for accomplishing anatomical restoration. This may achieve successful bone union and maintain the femoral neck length and original tilt without nearby soft tissue or cartilage injury.

Bubble-free diatoms polymerase chain reaction.

Polymerase chain reaction (PCR) in small fluidic systems not only improves speed and sensitivity of deoxyribonucleic acid (DNA) amplification but also achieves high-throughput quantitative analyses. However, air bubble trapping and growth during PCR has been considered as a critical problem since it causes the failure of DNA amplification. Here we report bubble-free diatom PCR by exploiting a hierarchically porous silica structure of single-celled algae. We show that femtoliters of PCR solution can be spontaneously loaded into the diatom interior without air bubble trapping due to the surface hydrophilicity and pore structure of the diatom. We discover that a large pressure gradient between air bubbles and nanopores rapidly removes residual air bubbles through the periodically arrayed nanopores during thermal cycling. We demonstrate the DNA amplification by diatom PCR without air bubble trapping and growth. Finally, we successfully detect DNA fragments of SARS-CoV-2 with as low as 10 copies/µl by devising a microfluidic device integrated with diatoms assembly. We believe that our work can be applied to many PCR applications for innovative molecular diagnostics and provides new opportunities for naturally abundant diatoms to create innovative biomaterials in real-world applications.

Is the construct stability of the acetabular cup affected by the acetabular screw configuration in bone defect models?

BACKGROUND: In revision surgery with significant segmental acetabular defects, adequate implant selection and fixation methods are critical in determining successful bony ingrowth. Commercially available total hip prosthesis manufacturers generally offer additional multi-hole options of acetabular shells with identical designs for use in revision THAs where screw holes configurations vary from product to product. This study aims to compare the mechanical stability of the two types of acetabular screw constructs for the fixation of acetabular components: spread-out and pelvic brim-focused configurations. METHODS: We prepared 40 synthetic bone models of the male pelvis. In half of the samples with acetabular defects, identical curvilinear bone defects were manually created using an oscillating electrical saw. On the right side, multi-hole-cups in which the direction of the screw holes are centered on the pelvic brim (brim-focused) and, on the left side, multi-hole-cups with the direction of the screw hole spread throughout the acetabulum (spread-out) were implanted into the pelvic synthetic bones. Coronal lever-out and axial torsion tests were performed with a testing machine, measuring load versus displacement. RESULTS: The average torsional strengths were significantly higher in the spread-out group over the brim-focused group regardless of the presence of the segmental defect of the acetabulum (p < 0.001). But for the lever-out strength, the spread-out group exhibited significantly higher average strength over the brim-focused group for the intact acetabulum (p = 0.004), whereas the results were reversed in the brim-focused group when the defects were generated (p < 0.001). The presence of acetabular defects reduced the average torsional strengths of the two groups by 68.66% versus 70.86%. In comparison, the decrease in the average lever-out strength was less significant for the brim-focused group than the spread-out group (19.87% vs. 34.25%) (p < 0.001). CONCLUSION: Constructs of multi-hole acetabular cups with the spread-out screw holes configuration exhibited statistically better axial torsional strength and coronal lever-out strength. With the presence of posterior segmental bone defects, the spread-out constructs demonstrated significantly better tolerance to axial torsional strength. Still, they exhibited inverted results of higher lever-out strength in the pelvic brim-focused constructs.

The incidence of focal osteonecrosis of the femoral head and its impact on conversion hip arthroplasty after screw fixation of femoral neck fractures: a multicenter retrospective study based on postoperative magnetic resonance imaging.

PURPOSE: Osteonecrosis of the femoral head (ONFH) and subsequent head collapse is a major concern after internal fixation of femoral neck fracture (FNF). Previous studies focused on ONFH incidence using plain radiography; postoperative magnetic resonance imaging (MRI) was rarely performed. We performed a multicenter retrospective study to investigate the incidence of ONFH and the need for conversion hip arthroplasty after FNF screw fixation. METHODS: We reviewed 195 patients who underwent screw fixation during closed FNF reduction between 2012 and 2017 at three institutions. Except for patients who did not consent to MRI, all patients underwent postoperative MRI either 1-3 years after screw fixation. The occurrence of ONFH was investigated through plain radiography and MRI. RESULTS: Thirty patients were diagnosed with ONFH through plain radiography, and an additional 33 patients were diagnosed with MRI, resulting in a total of 63 patients (32.3%) diagnosed with ONFH. The mean time to ONFH diagnosis was 18.9 months and the conversion rate to hip arthroplasty was 10.2%. Of the 33 patients who were normal on hip radiography but exhibited ONFH on MRI, all had small focal lesions not associated with head collapse at the last follow-up. The ONFH group diagnosed through plain radiography had more unstable FNFs than the group diagnosed through MRI. CONCLUSION: Although postoperative MRI revealed a higher incidence of ONFH after FNF screw fixation than reported previously, the small focal MRI lesions were not associated with increased risks of femoral head collapse or conversion to arthroplasty.

Outcomes of total hip arthroplasty after failed free vascularized fibular grafting for osteonecrosis of the femoral head.

PURPOSE: Total hip arthroplasty (THA) after vascularized fibular grafting (VFG) is technically demanding with poorer outcomes compared to primary THA in patients with osteonecrosis of the femoral head (ONFH). The purpose of this study was to compare the outcomes of THA after VFG after removal of the graft with that of primary THA. METHODS: ONFH patients treated by VFG at a single institution were studied retrospectively. THAs after VFG performed by single arthroplasty surgeon with a single type of THA prosthesis were enrolled in the study. A control cohort of patients was created by 1:1 matching with the THA after VFG cohort according to age, gender, and American Society of Anesthesiology (ASA) score from ONFH patients treated by primary THA. Early and long-term outcomes were compared between the two groups. RESULTS: A total of 24 hips were included in the THA after VFG group and compared with 24 primary THA hips. No significant difference was noted in stem position. The THA after VFG group had increased blood loss and longer duration of operation time. There were two cases of intraoperative femur fractures in the THA after VFG group. The femoral stem of both groups were stable, with no cases of revision, and similar HHS scores at the last follow-up. CONCLUSION: THA after VFG may have similar short to midterm outcomes with primary THA after removal of the residual abutting bone graft and correct positioning of the femoral stem.

Utilizing Three-Dimensional Head-Lesser Trochanter Distance Could Further Reduce Leg Length Inequality in Primary Bipolar Hemiarthroplasty.

Background: The aim of this study was to investigate whether the use of three-dimensional (3-D) computed tomography (CT)-based head-lesser trochanter distance (HLD) could reduce leg length discrepancy (LLD) more than the use of a two-dimensional (2-D) plain film method in primary bipolar hemiarthroplasty. Methods: Propensity score matching (PSM) analysis was used to adjust the confounding factors. A retrospective comparative analysis of 128 patients was performed. In the control group, the leg length was equalized using the 2-D, plain film-based HLD. In the study group, primary bipolar hemiarthroplasty was performed using the 3-D CT-based HLD method. Postoperative LLDs were compared between the two groups using the method of Ranawat. In addition, the Harris hip score (HHS) was evaluated and compared at one year after surgery. Results: A significant difference was observed in mean postoperative LLD between the 2-D HLD group and the 3-D CT HLD group: 1.6 ± 1.2 mm (range, 0.1−6.0 mm) and 1.1 ± 1.2 mm (range, 0.1−5.1 mm), respectively (p < 0.05). Additionally, a higher percentage of patients in the 3-D CT HLD group had an LLD of less than 2 mm. The mean HHS at one year after surgery showed no significant difference between the two groups. Conclusions: To minimize the occurrence of LLD, HLD measurement from a CT scanner may be more accurate than an X-ray. The 2-D and 3-D HLD differences in the 3-D CT HLD group were statistically significant. Using a 3-D, CT-based HLD method might decrease the possibility of an LLD over 2 mm.

Comparison between self-reported smoking habits and daily ad-libitum smoking topography in a group of Korean smokers.

Tobacco smoking is associated with a high global mortality rate since it is known to cause cancers and lung and heart diseases. To control and reduce annual mortality attributed to smoking, it is essential to design applicable smoke cessation programs based on realistic tobacco exposure risk assessment. In this regard, understanding the smoking habits of the smoker is crucial. Using self-report smoking habit surveys is a common approach in measuring basic variables of smoking habits. However, smoking topography measurement devices have recently become available for investigating smoking habit variables accurately. In this study, we conducted a self-report survey to investigate a group of Korean smokers' smoking habit variables such as the number of smoked cigarettes per day, puff counts, and total smoking time. The survey also included items from the Fagerström Test for Nicotine Dependence (FTND). The results were compared with the corresponding variables from machine-determined data to investigate their correlation and reliability. Results indicate that Korean smokers have a reliable understanding of the average number of cigarettes they smoke daily (ρ = 0.517, Cronbach's α = 0.754) and the time to first cigarette (TTFC) after waking up (ρ = -0.587, Cronbach's α = 0.623), as fundamental items of the FTND score. Nevertheless, these smokers significantly under-reported the puff number and total smoking time, which can cause significant underestimation in the tobacco exposure risk assessment. Consequently, we suggest the application of self-report surveys that are based on the amount of daily smoked cigarettes (e.g. FTND) for clinical or risk assessment purposes. Using smoking topography measurement devices is recommended overusing self-report surveys in measuring smoking habit variables such as puff count and smoking time more accurately.

The Association between Blood Concentrations of PCDD/DFs, DL-PCBs and the Risk of Type 2 Diabetes Mellitus and Thyroid Cancer in South Korea.

BACKGROUND AND OBJECTIVES: Epidemiological studies have inconsistently shown an association between dioxin and risk of type 2 diabetes mellitus (T2DM) and cancer. This study aims to examine the effects of blood concentration of dioxin-like polychlorinated biphenyls (DL-PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) on T2DM and thyroid cancer. METHODS: We conducted a nested case-control study within the Korean cancer prevention study-II (KCPS-II) consisting of 15 thyroid cancer cases, 30 T2DM cases, and 55 controls. A total of 500 samples were used in 100 pooling samples. An average value of a pooled sample was calculated weighted by the blood volume of each sample. RESULTS: The study population included 100 participants from the KCPS-II (median (IQR) baseline age, 54.06 [21.04] years; 48 women). The toxic equivalents of PCDD/DFs showed a significant positive association with T2DM and thyroid cancer, after adjustments for potential confounders (T2DM ORs = 1.23; 95% CI = 1.05-1.43; thyroid cancer ORs = 1.34; 95% CI = 1.12-1.61). CONCLUSION: In this study, both T2DM and thyroid cancer were associated with the blood concentrations of PCDD/DFs. The association between PCDD/DFs and T2D was found among women but not among men. Our findings suggest that further biochemical in vivo research and epidemiologic studies are needed to clarify the association between dioxins concentrations and diseases.

Evaluation of transdermal exposure of phthalates in children's products.

In this study, 16 children's products with the highest detection potential of phthalates were selected, and a phthalate assay and transdermal delivery analysis (NIER, US EPA Wipe [stress condition], US EPA Wipe [physiological condition], and US EPA Hand Wipe) were conducted with these products. The content of 6 controlled phthalates (DBP, BBP, DEHP, DNOP, DINP, and DIDP) was measured and most products contained more phthalates than the regulated guidelines (a total content of 6 phthalates to be ≤0.1%). For transdermal delivery, all items were found to be lower in the NIER transdermal delivery test method compared to the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method. For the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method, a similar result was observed, except for DINP. The average daily dose (ADD) estimated by determining the exposure algorithm for each transdermal delivery test method was highest in mats with a large contacting surface area and a long exposure time in the respective test methods. Conclusively, there was a difference between the NIER transdermal delivery test method and the US EPA Wipe transdermal delivery test method.

Exposure and Risk Assessment of Second- and Third-Hand Tobacco Smoke Using Urinary Cotinine Levels in South Korea.

Exposure to environmental tobacco smoke (ETS) is the reason for approximately 1% of global mortality. ETS exposure can happen either as inhalation of direct cigarette smoke (second-hand smoke) or its associated residue particles (third-hand smoke), especially when living with a smoker in the same family. This study investigated the association between the urinary cotinine levels, as biomarkers of exposure to tobacco smoke, of smokers and those exposed to second-hand and third-hand smoke while living in the same family, through a Korean nationwide survey. Direct assessment of ETS exposure and its lifetime effect on human health is practically difficult. Therefore, this study evaluated the internal estimated daily intake (I-EDI) of nicotine and equivalent smoked cigarette per day (CPD). The carcinogenic and non-carcinogenic inhalation risks of ETS exposure were assessed by considering the calculated equivalent CPD and composition of cigarette smoke of high-selling cigarette brands in South Korea. The results show that there is a statistically significant positive correlation between the cotinine levels of smokers and those of the non-smokers living in the same family. The risk assessment results yielded that hazard index (HI) and total excess lifetime cancer risk (ECR) for both second-hand and third-hand smoke exposure can exceed 1 and 1 × 10-6, respectively, especially in women and children. In the composition of the cigarette smoke, 1,3-butadiene and acrolein substances had the highest contribution to HI and ECR. Consequently, the provision of appropriate plans for smoking cessation as a strategy for the prevention of ETS exposure to women and children is deemed necessary.

Minimum 10-year follow-up of micro-arc oxidation coating on a cementless grit-blasted tapered-wedge stem of total hip arthroplasty: a multicentre study.

BACKGROUND: Recently, a femoral stem treated with grit-blasting and micro-arc oxidation (MAO) coating has commercialised but medium-term follow-up studies are lacking. The aim of this study was to report the outcome of a grit-blasted and MAO-coated femoral component designed as a straight, double-wedged, tapered stem with a rectangular cross-section with minimum 10 years follow-up. METHODS: Between March 2006 and December 2008, 309 primary total hip arthroplasties using a grit-blasted and MAO-coated femoral component were performed by 3 experienced hip surgeons in 3 hospitals. At minimum 10 years after index THA, 299 hips were living, 10 hips were deceased, and 65 hips were lost to follow-up or had a follow-up period <10 years. Finally, 234 hips were enrolled in this study. RESULTS: Mean duration of clinical follow-up was 129.6 months. The mean Harris Hip Score was improved from 46.9 to 88.4 at the final follow-up. 4 hips were revised for 2 aseptic femoral loosening, 1 aseptic acetabular cup loosening and 1 late infection. 3 hips were revised for a periprosthetic femoral fracture requiring a femoral component revision. The average time to revision was 51.6 (range 0-148) months. Kaplan-Meier survivorship analysis with an end point of revision for any reason demonstrated a survival rate of 97.4% at 10 years. Survival was 98.7% with revision for aseptic loosening as the endpoint. CONCLUSIONS: The outcomes of a cementless grit-blasted and MAO-coated tapered-wedge stem of THA were excellent to satisfactory after a follow-up of at least 10 years.

Usefulness of intraoperative C-arm image intensifier in reducing errors of acetabular component during primary total hip arthroplasty: an application of Widmer's method.

BACKGROUND: Acetabular prosthesis positioning in total hip arthroplasty (THA) is crucial in reducing the risk of dislocation. There has been minimal research on the proper way to put the acetabular components into the safe zone intraoperatively. Assessment of version by intraoperative imaging intensifier is very valuable. The value of Widmer's method, using the intraoperative C-arm available to determine cup anteversion was assessed. METHODS: One hundred one hips in 91 patients who underwent primary THA were eligible for inclusion. Utilizing intraoperative C-arm images, measurement was performed using the technique described by Widmer. The values obtained using 3D computed tomography postoperatively, which determined the anteversion of the acetabular component, were regarded as the reference standard. RESULTS: The method of Widmer obtained values similar to those obtained using 3D computed tomography and was considered accurate (n.s.). All 101 hips were positioned in the set target zone. Among the 101 hips, the cup position in nine hips (8.9%) was changed. The dislocation rate in our study was 1.0% with all dislocations occurring in hips placed in the target zone. The mean Harris hip score after THA in 1 year was 94.2 (82-98). CONCLUSIONS: The method of Widmer was accurate using intraoperative imaging intensifier for the measurement of the anteversion of the acetabular component during THA, with reference to the anteversion obtained from the 3D computed tomography. Also, utilizing intraoperative C-arm imaging was very useful because it allowed for correction of the position of the acetabular cup.

Study on the daily Ad Libitum smoking habits of active Korean smokers and their effect on urinary smoking exposure and impact biomarkers.

INTRODUCTION: Understanding interactions of smoking topography with biomarkers of exposure to tobacco is essential for accurate smoking risk assessments. METHODS: In this study, the smoking topography and the levels of tobacco smoke exposure urinary biomarkers of a sample of active Korean smokers were quantified and measured. The results were used to investigate the effect of daily activities and smoking time on the smoking topography. Moreover, correlations between the smoking topography parameters and biomarkers were assessed. RESULTS: No significant effect of either the daily activities or time on the smoking topography of the subjects were observed. Synchronic correlations of the cigarette consumption per day (CPD) and the average flow per puff with both urinary cotinine and trans-3'-hydroxycotinine were significant. For the urinary nicotine metabolites, the peak levels appeared when the CPD was over 19 cigarettes per day and the average puff velocity was between 35 and 45 ml/s. Nevertheless, when the average flow was over 60 ml/s, the levels of cotinine and trans-3'-hydroxycotinine significantly dropped. CONCLUSIONS: The findings of this study may be beneficial for further smoking risk assessments with contributions of both the smoking topography and biomarkers to provide current smokers with applicable cession programs.Clinical significanceSmoking habits and levels of urinary biomarkers of Korean smokers are investigated.People with a higher dependency on nicotine smoke cigarettes with slower puffs.Effects of daily activities or time on smoking topography were not significant.Correlations between smoking topography and urinary biomarkers were significant.Peak biomarker levels were observed under certain smoking topography conditions.

Improved Biological Responses of Titanium Coating Using Laser-Aided Direct Metal Fabrication on SUS316L Stainless Steel.

Direct metal fabrication (DMF) coatings have the advantage of a more uniform porous structure and superior mechanical properties compared to coatings provided by other methods. We applied pure titanium metal powders to SUS316L stainless steel using laser-aided DMF coating technology with 3D printing. The purpose of this study was to determine the efficacy of this surface modification of stainless steel. The capacity of cells to adhere to DMF-coated SUS316L stainless steel was compared with machined SUS316L stainless steel in vitro and in vivo. Morphological in vitro response to human osteoblast cell lines was evaluated using scanning electron microscopy. Separate specimens were inserted into the medulla of distal femurs of rabbits for in vivo study. The distal femurs were harvested after 3 months, and were then subjected to push-out test and histomorphometrical analyses. The DMF group exhibited a distinct surface chemical composition, showing higher peaks of titanium compared to the machined stainless steel. The surface of the DMF group had a more distinct porous structure, which showed more extensive coverage with lamellipodia from osteoblasts than the machined surface. In the in vivo test, the DMF group showed better results than the machined group in the push-out test (3.39 vs. 1.35 MPa, respectively, p = 0.001). In the histomorphometric analyses, the mean bone-to-implant contact percentage of the DMF group was about 1.5 times greater than that of the machined group (65.4 ± 7.1% vs. 41.9 ± 5.6%, respectively; p < 0.001). The porous titanium coating on SUS316L stainless steel produced using DMF with 3D printing showed better surface characteristics and biomechanical properties than the machined SUS316L.

Economic damage cost of premature death due to fine particulate matter in Seoul, Korea.

Analyzing the economic value of the damage to human health caused by environmental risks has become an essential research focus, given the increasing necessity for effective decision-making. Since logical and rational analyses such as cost-benefit and cost-utility analyses will likely gain importance in future policymaking, the evaluation of economic costs becomes necessary. Among the various types of air pollutants, fine particulate matter (PM) is reported as closely related to mortality. To reduce result uncertainty by improving the methodology of risk assessment or the economic evaluation of fine PM, risk control measures are required for high-priority areas. This study addresses this issue by estimating the relative risk of PM2.5 while calculating the economic loss cost arising from acute death due to fine PM exposure in Seoul, Korea. The value of statistical life of one person's willingness to pay for mortality risk reduction is calculated to estimate the economic loss cost at each current level of exposure. The estimated economic loss cost due to all-cause mortality during 2016-2018 totaled approximately USD 1307.9 million per year; the costs of loss from respiratory and cardiovascular mortalities were USD 128.1 million per year and USD 426.9 million, respectively. Based on these results, this study concludes that the standards for PM2.5 are more effective than the ones established for PM10 in terms of economic value.