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A novel tunable transmitter structure based on liquid crystal filter, to the best of our knowledge, is presented. The structure is designed for application to 5G fronthaul and supports 25 Gbps dense wavelength division multiplexing (WDM) transmission and tunable range of 35 nm. The design takes into account easy change of operation band over coarse WDM grid. Prototype samples are developed to test feasibility of the design.

BACKGROUND: Idiopathic guttate hypomelanosis (IGH) is a common hypopigmentary disorder occurring mainly on exposed areas in elderly individuals. Long-term sun exposure is thought to be a main cause of IGH but the pathogenesis is still unknown. OBJECTIVE: The aim of this study was to find out the pathogenesis of IGH through investigating the effect of senescent fibroblasts on melanogenesis and melanocyte survival. METHODS: Lesional and perilesional normal skins were obtained from patients with IGH (n=30). Skin tissues were stained with p16, a senescence marker as well as senescence-associated secretory phenotype (SASP) including MMP-1, MMP-2 and type IV collagen. In addition, the functional role of UVB-induced senescent fibroblasts in melanocytes was investigated in the aspect of melanogenesis and melanocyte survival. RESULTS: A significant higher number of p16-positive cells were observed in the dermis of IGH lesion than in perilesional normal skin. MMP-1 expression was significantly higher in the lesions of IGH and type IV collagen was significantly degraded in the basement membrane zone of IGH lesions. UVB-induced senescence of fibroblasts was established through in vitro experiment. When the culture media from UVB-induced senescent fibroblasts was incubated in melanocytes, the expression of p16 and p21 as well as SA-?-Gal-staining intensity were significantly increased in melanocytes. In addition, increased levels of cleaved caspase 3 and reduced number of Ki67-positive cells were observed in melanocytes treated with culture media from senescent fibroblast. CONCLUSIONS: Senescent fibroblasts might contribute to the development of IGH through induction of melanocyte senescence and apoptosis in melanocytes via SASP.

Erdosteine is widely used as a mucolytic agent and also has free radical scavenging and antioxidant activities. However, little is known about the mechanisms of the anti-inflammatory effect of erdosteine. We investigated the effect of erdosteine on the activation of the nuclear factor (NF)-kB/inhibitor of NFkB (IkB), and the mitogen-activated protein kinase (MAPK) and Akt pathways in the mouse macrophage cell line RAW 264.7. Cultured RAW 264.7 cells were pretreated with erdosteine and stimulated with lipopolysaccharide (LPS). In Western blotting, pretreatment with erdosteine inhibited the IkBα degradation induced in RAW 264.7 cells by LPS. LPS-induced IkB kinase (IKK) activity and NF-kB transcription were inhibited by pretreatment with erdosteine. Production of IL-6 and IL-1β was also inhibited by erdosteine pretreatment. However, erdosteine did not inhibit LPS-induced phosphorylation of Akt and MAPKs. These results suggest that the anti-inflammatory effect of erdosteine in mouse macrophages is mediated through inhibition of LPS-induced NF-kB activation.

Aim To investigate the role of nitric oxide (NO)-induced autophagy in human dental pulp cells (HDPCs) and the involvement of AMP-activated protein kinase (AMPK) pathway. Methodology The MTT assay was used to determine the cytotoxic effect of the NO donor sodium nitroprusside (SNP) in HDPCs. Apoptosis was detected by means of the terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay, and apoptosis- or autophagy-related signal molecules were observed by Western blot analysis. Acidic autophagolysosomal vacuoles were stained with acridine orange to detect autophagy in the presence of 3-methyladenine (3MA) used to inhibit autophagy. To explore the mechanism underlying autophagy and its protective role against apoptosis, compound C, the chemical AMPK inhibitor, was used. Statistical analysis was performed using Student's t-test or analysis of variance (anova) followed by the Student–Newman–Keuls test (P

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤ 1:50) and serum agglutination test (≤ 1:50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce-ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

ZnO buffer layer was prepared as electron selective layers (ESL) for photo-induced electron transport and hole blocking in inverted organic solar cells (IOSCs) by sol-gel process. The effects of thickness and surface roughness of ZnO ESL on the performance of IOSCs were investigated. Power Conversion Efficiency (PCE) of the IOSC strongly varied as a function of ZnO film thickness and surface roughness, in particular, when the film thickness was

Genetic immunotherapy is considered an ideal treatment modality for cancer because of its systemic nature. This study was designed to develop a potent novel genetic immunotherapy by combining conditionally replicating adenovirus (CRAd) and replication-defective adenovirus expressing interferon-beta (ad-IFN-beta). We investigated the efficacy of this therapy in an immunocompetent mouse tumor model. Transduction with CRAd (Delta24RGD) induced cytolysis in a mouse lung cancer cell line (Lewis lung carcinoma (LLC)). Combined transduction of ad-IFN-beta and Delta24RGD in the LLC cells induced a greater and more prolonged production of IFN-beta. Media transfer from the LLC-Delta24RGD-ad-IFN-beta to untransduced LLC cells induced the production of IFN-beta; these results confirmed the replication and release of ad-IFN-beta. LLC cells transduced with ad-IFN-beta and Delta24RGD had decreased tumorigenicity in syngeneic mice. Tumor vaccination with irradiated LLC-ad-IFN-beta-Delta24RGD showed a significant increase in the survival of tumor-bearing syngeneic mice compared with mice with a single transduced LLC vaccination; this was mediated by an enhanced cytotoxic T-lymphocyte response against the LLC cells. The results of this study showed that cotransduced Delta24RGD to ad-IFN-beta aided the replication of ad-IFN-beta in the LLC cells. A high local concentration of IFN-beta and local release of tumor antigen by CRAd induced strong antitumor immunity. This combination strategy might provide a powerful means by which ad-cytokines and CRAd can be combined and other adenoviruses expressing different cytokines might also be used.

This study characterised the population structure of Legionella pneumophila by comparing the rpoB (300-bp) and dotA (360-bp) sequences of 267 isolates (18 reference strains, 149 Korean isolates and 100 Japanese isolates). In addition to the six clonal subgroups established previously, four subgroups, P-V to P-VIII, were identified. Subgroupings based on rpoB and dotA sequences were found to correlate with the source of the isolates, and this data may be useful for future epidemiological studies. Fourteen (five Korean and nine Japanese) isolates showed incongruent subgroupings in the rpoB and dotA trees, suggesting that genetic exchange among subgroups, and even among subspecies, may occur frequently in nature.

A new antifuse device with a planar metal/dielectric/poly-Si1-x Ge x /dielectric/ metal structure has been proposed for use in FPGAs (field programmable gate arrays) as a voltage programmable link. The programming process is believed to proceed in four steps such as dielectric breakdown, double injection process, filament formation and filament enlargement. The maximum power of 38 mW is dissipated when a conductive filament is formed through the poly-Si1-x Ge x , and the velocity of filament formation is about 16 cm/s when 12.5 V is applied to the device. The device shows low leakage current (~ 0.01pA/antifuse) at the operating voltage of 5 V and low on-resistance (~ 13-15 Ω) at a 1ms-long 12.5 V pulse.

Endotracheal intubation is often necessary for positive pressure ventilation of rats during open thoracic surgery. Since endotracheal intubation in rats is technically difficult and is associated with numerous complications, many techniques using various devices have been described in the scientific literature. In this study, we compared the effectiveness of airway management of a home-made supraglottic airway device (SAD), which is cheap to fabricate and easy to place with that of an endotracheal intubation tube in enflurane-anaesthetized rats. Twenty male Sprague-Dawley rats (200–300 g) were randomly assigned to two equal groups for positive pressure mechanical ventilation using either the SAD or an endotracheal intubation tube. The carotid artery of each rat was cannulated for continuous blood pressure measurements and obtaining blood samples for determination of oxygen tension, carbon dioxide tension, and blood acidity before, during and after SAD placement or endotracheal intubation. Proper placement of the SAD was confirmed by observing chest wall movements that coincided with the operation of the mechanical ventilator. No complications and adverse events were encountered in the rats in which the SAD was placed, during SAD placement and immediate removal, during their mechanical ventilation through the SAD, and one week after SAD removal. From the results of blood gas analyses, we conclude that anaesthetized rats can be successfully ventilated using an SAD for open thoracic surgery.

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤ 1:50) and serum agglutination test (≤ 1:50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce-ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

Soluble TRAIL and adenovirus (ad)-TRAIL exhibit a strong antitumor effect by inducing apoptosis. Vorinostat is the histone deacetylase (HDAC) inhibitor that induces cell death in cancer cell lines and regulates the expression of epigenetically silenced genes, such as Coxackie adenoviral receptor (CAR), the receptor for adenoviral entry. We propose a new strategy in which vorinostat will induce high expression of ad-TRAIL and a strong antitumor response, and investigated the mechanism involved. The effect of vorinostat on transcription and expression of TRAIL from ad-TRAIL-transduced lung cancer cells were confirmed by reverse transciption-PCR (RT-PCR), quantitative real time-PCR and western blot assay. Anti-tumor effects were measured after cotreatment of vorinostat and ad-TRAIL, and the drug interactions were analyzed. After combined treatment of vorinostat and ad-TRAIL, apoptosis and western blot assays for Akt, Bcl-2 and caspase were performed. Vorinostat increased the expression of CAR in lung cancer cell lines and increased the expression of luciferase (luc) from ad-luc-transduced cells and TRAIL from ad-TRAIL-transduced cells. RT-PCR and quantitative real time-PCR, after sequential vorinostat treatment, revealed that vorinostat may enhance TRAIL expression from ad-TRAIL by increasing transduction through enhanced CAR expression and increasing adenoviral transgene transcription. Combined vorinostat and ad-TRAIL treatment showed the synergistic anti-tumor effect in lung cancer cell lines. Combined vorinostat and ad-TRAIL induced stronger apoptosis induction, suppression of NF-κB activation and breakdown of the anti-apoptotic molecule Bcl-2. In conclusion, the vorinostat synergistically enhanced the anti-tumor effect of ad-TRAIL by (1) increasing adenoviral transduction through the increased expression of CAR and (2) increasing adenoviral transgene (TRAIL) transcription in lung cancer cell lines.

The purpose of this study was to evaluate the efficacy of a low-dose cyclosporin therapy in psoriasis. In the multicentre study, carried out in Korea, 52 patients with moderate to severe psoriasis were treated with an initial dose of 2.5 mg/kg per day cyclosporin for 18 weeks. In 44 patients the dose was increased gradually up to 5 mg/kg per day according to the therapeutic response. Treatment success, defined as a reduction in PASI score by at least 66%, was achieved in 76.9% of patients. PASI scores reduced significantly from 20.0 to 5.4. Changes in systolic and diastolic blood pressure were not statistically significant. A 30% increase in serum creatinine in comparison with baseline was observed in five patients (9.6%) by the 18th week, but none of the patients showed an increase beyond the normal range. The overall assessments of efficacy and tolerability by both the investigators and the patients were mostly ‘good’ or ‘very good’. Our regimen of low-dose cyclosporin therapy (2.5 mg/kg per day initial...

Ceramic membranes made of titanium dioxide, magnesium titanate, calcium titanate or strontium titante sintered at high temperature have been studied for use as ion-selective electrode in aqueous solution. The selectrode of titanium dioxide sintered at 2614-2700 o C responded weakly to silver (I) and phosphate ions, and were unusable to determine the ions. Mg 1.00 Fe 0.10 Ti 0.90 O 3.00 selectrode sintered at 2614-2700 o C 'and cooled to room temperature responded selectively to silver (I) and phosphate ions

A case-control study was conducted involving 156 patients with scrub typhus and 130 controls. Three factors were associated significantly with the risk of developing scrub typhus: engaging in fruit farming (OR 2.44; 95% CI 1.04–5.69), gathering chestnuts (OR 2.05; 95% CI 1.09–3.87) and taking breaks in areas adjacent to agricultural operations (OR 3.06; 95% CI 1.50–6.22). In contrast, receiving information or educational materials concerning the prevention of scrub typhus had a protective effect (OR 0.45; 95% CI 0.24–0.83). These results suggest that a health education programme will lower the risk of developing scrub typhus when applied to high-risk groups.

To establish the design guide on coupling between inductor pairs, we measured the magnitude of the electromagnetic coupling between inductors with the variation of physical separation and substrate resistivity. We also found that the coupling effect degrades the reverse isolation of L-band CMOS LNAs, and analyzed several LNAs fabricated with different fabrication technology. Furthermore, we proposed inductors for preventing the coupling, and its coupling reduction effect on the LNA is demonstrated.

The goal of this study was to characterize three major excitation-contraction (E-C) coupling proteins: ryanodine receptor [RyR, the calcium release channel in the sarcoplasmic reticulum (SR)], dihydropyridine receptor (DHPR, the voltage-gated L-type calcium channel in the transverse tubule) and SR Ca2+-ATPase (SERCA, the calcium pump in the SR) in the differentiating primary cultures of rat skeletal and cardiac muscle cells. The expression levels of these proteins were determined by ligand binding assays and/ or immunoblottings along with an examination of the morphological changes in differentiating muscles by phase-contrast microscopy. In the skeletal cells, the expression levels of the E-C coupling proteins generally increased in the course of differentiation with the peak expression at the 9th day of culture. Simultaneous with the increased expression of the proteins, the myoblasts elongated, followed by alignment and fusion of the cells to form multinucleated myotubes. In the cardiac cells, on the contrary, the peak expression levels of DHPR, SERCA and RyR were reached within 2, 4, and 7 d of culture, respectively. Alignment of the cardiac muscle cells and spontaneous contraction occurred as early as several h after plating. These results suggest that expression patterns of E-C coupling proteins are different between skeletal and cardiac muscles, and that DHPR could play an important role in Ca2+ metabolism during the early stages of differentiation.

The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined.The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients.The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064).K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.

Twenty-two mutants between beta Glu-161 and beta Lys-201 of Escherichia coli H(+)-ATPase beta subunit could grow by oxidative phosphorylation, but 11 other such mutants, beta Glu-181--Gln, Asp, Asn, Thr, Ser, Ala, or Lys and beta Arg-182--Lys, Ala, Glu, or Gln, could not. The beta Asp-181, beta Lys-182, and other defective mutants had 1.4, 1, and0.1%, respectively, of the wild-type membrane ATPase activity. Partially purified F1-ATPases from all mutants at positions 181 and 182, except for the beta Asp-181 and beta Lys-182 mutants, showed very low unisite catalysis. Purified F1-ATPases of the beta Gln-181 and beta Ala-181 mutants showed no multisite (or steady state) catalysis and slow unisite catalysis (or = 1% of that of the wild type): their defects could be attributed to decreased catalytic rates (low k+2 and k-2). Changes of the k+2 and k-2 values in the beta Asp-181 enzyme, which showed detectable multi- and unisite catalysis, were less marked (27 and 21%, respectively, of wild-type rates). The beta Gln-182 enzyme showed defective catalysis (or = 0.1% of the multi- and approximately 1% of the unisite catalyses of the wild type), whereas the beta Lys-182 enzyme showed 1 and 85% of the wild-type multisite and unisite catalytic rates, respectively. beta Lys-182 had wild-type values of k+2 and k-2, but beta Gln-182 had k+2 about 10-fold lower than that of wild type.(ABSTRACT TRUNCATED AT 250 WORDS)

Salmonella typhi, the etiologic agent of typhoid fever, typically has only a phase-1 flagellar antigen, H1-d (fliC). While most strains of S. typhi have H1-d antigen, 10-20% of Indonesian isolates have been reported to possess H1-j antigen instead. To investigate the presence H1-j strains of S. typhi isolates in Korea, where typhoid fever is still a common infectious problem, we used the polymerase chain reaction (PCR) with a pair of oligonucleotides primers that specifically amplified the flagellin gene of S. typhi. Of 375 isolates of S. typhi tested, only one was shown to possess the H1-j antigen, which was shown by the presence of a 1,269-basepair fragment on agarose gel electrophoresis after the PCR. The isolate with the H1-j antigen was cultured from a Korean-Indonesian man who was already symptomatic in Indonesia and was thought to be an Indonesian strain. Because 375 strains tested in this study were collected from cases with typhoid fever in different regions of Korea during the period from 1986 to 1991, it could be concluded that the mutation rate to j antigen is negligible among S. typhi endemic in Korea.

The Ser-beta 174 residue of the Escherichia coli H(+)-ATPase beta subunit has been shown to be near the catalytic site together with Gly-beta 149, Gly-beta 172, Glu-beta 192, and Val-beta 198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-beta 174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-beta 174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (approximately 10% of the wild type). The defective energy coupling of the Phe-beta 174 mutant was suppressed by the second mutation (Arg-alpha 296--Cys) in the alpha subunit. The Cys-alpha 296/Phe-beta 174 mutant had essentially the same membrane ATPase activity as the Phe-beta 174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the alpha/beta interaction, especially that between the regions near Arg-alpha 296 and Ser-beta 174, for energy coupling in the H(+)-ATPase. The 2 residues (Ser-beta 174 and Arg-alpha 296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the alpha subunit of Cys-alpha 296/Phe-beta 174 or Cys-alpha 296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.

Purpose: The recent introduction of targeted therapy for non-small cell lung cancer (NSCLC) has changed the paradigm of lung cancer chemotherapy. However, only a small portion of NSCLC patients received the benefit of these new drugs. A proteasome inhibitor (bortezomib) and a histone deacetylase inhibitor (SAHA) were approved for clinical use for treating some hematologic malignancies. In this study, we investigated the combination treatment of bortezomib and SAHA in NSCLC cell lines. Materials and Methods: The combined effects of bortezomib and SAHA on lung cancer cell lines were measured by Calcusyn software. Induction of apoptosis was examined by performing an Annexin V assay. Generation of reactive oxygen species (ROS) and protection by N-acetylcysteine were measured by flow cytometry after staining with DCFH-DA. The effect of the combination of drugs on apoptosis and autophagy was investigated by Western blot assay. Results: Strong synergism was found for the combination of bortezomib and SAHA. The synergistic interaction was mediated by strong apoptosis. Increased ROS generation was partly responsible for the induction of apoptosis, and this was suppressed by the ROS scavenger N-acetylcysteine. Combined treatment induced the strong activation of caspase-3 and the breakdown of the antiapoptotic molecule Bcl-2. Furthermore, increased breakdown of beclin-1, which is known to be an autophagic molecule, was also found. Conclusion: Combination therapy with bortezomib and SAHA showed a strong synergistic antitumor effect on human lung cancer cell lines. Enhanced induction of apoptosis was a responsible mechanism, and this was partly mediated by ROS generation. Further studies are warranted for determining the role of apoptosis and autophagy for this combination therapy. (J Lung Cancer

Background: TRAIL is a cytokine that selectively induces apoptosis in various cancer cell lines. Gefitinib is new targeted drug applied in lung cancer that selectively inhibits EGFR tyrosine kinase. However, lung cancers have shown an initial or acquired resistance to these drugs. This study examined the effect of IGF-1R and its blockade on enhancing the sensitivity of lung cancer cell lines to TRAIL and gefitinib. Methods: Two lung cancer cell lines were used in this study. NCI H460 is very sensitive to TRAIL and gefitinib. On the other hand, A549 shows moderate resistance to TRAIL and gefitinib. The IGF-1R blockade was performed using adenoviruses expressing the dominant negative IGF-1R and shRNA to IGF-1R and AG1024 (IGF-1R tyrosine kinase inhibitor). Results: The adenovirus expressing dominant negative IGF-1R(950st) induced the increased expression of defective IGF-1R on the lung cancer cell surface, and the adenovirus-shIGF-1R effectively decreased the level of IGF-1R expression on cell surface. The genetic blockade of IGF-1R by the adenovirus-dnIGF-1R and AG1024 increased the sensitivity of A549 cells to TRAIL. The reduction of IGF-1R by transduction with ad-shIGF-1R also increased the sensitivity of the A549 cells to gefitinib. Conclusion: The blockade of IGF-1R through various mechanisms increased the sensitivity of the lung cancer cell line that was resistant to TRAIL and gefitinib. However, further studies using other cell lines showing acquired resistance as well as in vivo animal experiments will be needed.

Four hearing protectors—a foam‐cushion earmuff, foam and triple‐flanged polymer earplugs, and an earmuff over foam earplug combination—were evaluated to determine the effects of wearing time, movement activity, and fitting procedure on spectral attenuation. Using a psychophysical real‐ear‐attenuation‐at‐threshold measurement procedure (as per ANSI S12.6‐1984), attenuation data were collected from 40 naive subjects before, during, and after the activity movement tasks, which induced highly kinematic subject movements. Loss in attenuation over the 2‐h wearing period was up to 6 dB for all devices except the foam earplug, and all protectors except the earmuff significantly improved protection (from 4 to 14 dB) at 1000 Hz and below due to trained fitting. The foam plug benefited more than other devices from the training for proper fitting but was resilient to subject movement. [Work supported by NIOSH‐NIH.]

Overestimation of hearing protector noise attenuation, as based on laboratory-obtained data, combined with several in-field factors which often degrade protector performance, poses the threat of underprotection for the user. This research investigated the effects of several work-related factors, including wearing time, movement activity, and fitting procedure, on the frequency-specific attenuation achieved with a foam cushion earmuff, two types of earplugs, (slow-recovery foam and flanged polymer), and an earmuff over foam earplug combination. Using a real-ear-attenuation-at-threshold testing procedure, attenuation data were collected from 40 subjects at nine test frequencies. Occluded thresholds were obtained before, during, and after the movement activity task, so that the effects of wearing time and task activity could be determined. The tasks were designed to elicit movements akin to those performed in the typical industrial workplace. The results indicated that achieved attenuation was significantly decreased as a function of time, and that trained-fit provided noticeably greater attenuation than subject-fit without training, though these changes were device-specific. Overall, the study illuminated the strong influence of in-field factors on hearing protector effectiveness, and demonstrated the need for laboratory attenuation tests which yield more realistic results.

Many countries where scrub typhus is endemic use their own cutoff values for antibody titres to differentiate between cured cases and current infections. To establish an antibody titre cutoff value, one needs to investigate the seroprevalence in endemic areas, and the duration of the increase in titre after complete cure. We conducted a follow-up study of anti- Orientia tsutsugamushi antibody titres using indirect immunofluorescence assays (IFA) and passive haemagglutination assays (PHA) in patients with scrub typhus. After the onset of symptoms, IgM antibody titres increased gradually over 2–3 weeks, peaked at about 4 weeks, and started to decrease rapidly between 4 and 5 weeks. At 1-year follow-up, the median IgM value was 1:10. Out of 77 patients who were tested at that time, 36 (47%) had IgM titres ≥1:20, and none had titres exceeding 1:80. Over the first 2 weeks, IgG antibody titres increased sharply, peaked at about 4 weeks and decreased rather gradually thereafter, with a median titre of 1:128 maintained up to the 18th month. At 1-year follow-up, five out of 77 patients (6.5%) had titres ≥1:1,024 and 57% had titres ≥1:128. Based on these results, a cutoff value of ≥1:160 for IgM antibody should differentiate between previous and current infections in endemic areas such as Korea and Japan, where scrub typhus occurs mainly in the autumn.

Orientia tsutsugamushi is a causative agent of scrub typhus, and a Gram-negative obligate intracellular bacterium that is transmitted to humans by the bite of infected Leptotrombidium mites. In Korea, the incidence of scrub typhus has increased remarkably in recent years. A total of 6022 cases of scrub typhus were reported in 2007, and the incidence of scrub typhus infection was 13.2 cases per 100 000 persons. To develop a national strategy for the control and prevention of this disease that is based upon scientific data, we surveyed the infection rate and analysed the distribution of O. tsutsugamushi genotypes among wild rodents and engorged chigger mites in Korea. The specimens used in the present study were obtained from rodents because rodents have been recognised as a natural reservoir of O. tsutsugamushi and a host of chigger mites. At monthly intervals between August 2005 and July 2007, Sherman live traps were used to capture wild rodents living in four regions of Korea. Specimens were obtained from two areas in southern Korea, Chogye in Chollanam province and Ganjeon in Gyeongsangnam province, and from two areas in the middle region of Korea, Jangan and Songsan in Gyeonggi province. Chigger mites were collected from the wild rodents that had been captured. The 56-kDa genes of O. tsutsugamushi were collected from the blood or spleens of the wild rodents, and were detected from the pools of 30 chigger mites by nested PCR amplification, which was carried out as described by Furuya et al. [1]. In the present study, genotypes were determined by PCR-RFLP using DdeI. Analysis of the nucleotide sequence homology among the nested PCR products was performed using the CLUSTALX (http://clustal.org) and Tree Explorer (Tamura; http://evolgen.biol.metrou.ac.jp/TE/TE_man.html) programs in order to confirm the genotype in cases that could not be determined by RFLP. The rates of positivity among wild rodents from Chogye, Ganjeon, Jangan and Songsan, were 4.5% (12 ⁄266), 5.0% (10 ⁄201), 12.4% (25 ⁄202) and 5.0% (13 ⁄258), respectively, as shown in Table 1. To monitor the infection rate in mites, we calculated the MPR (minimum positive rate) using the equation: number of positive mites ⁄total number of mites examined. The MPRs were 0.6% (6 ⁄1071), 0.3% (12 ⁄4215), 0.9% (26 ⁄2893) and 1.3% (85 ⁄6752) in Chogye, Ganjeon, Jangan and Songsan respectively. The rates of positivity for O. tsutsugamushi were 6.5% (60 ⁄927) and 0.9% (129 ⁄14 931) in the wild rodents and chigger mites, respectively. In a previous study, Ree et al. [2] analysed the incidence of O. tsutsugamushi by IFA and PCR using 4315 individual mites collected from eight localities in Korea and reported that the infection rate was 1.5%, which was slightly higher than the result reported in the present study. From these results, we were able to determine that there is a high risk of scrub typhus infection in the natural environment of Korea. The Boryong genotype was the most common, at a rate of 76.7% in wild rodents and 82.9% in chigger mites, followed by the Gilliam (10%), Pajoo (8.3%) and Karp (5%) genotypes in the wild rodents and the Karp (11.6%), Pajoo (3.1%), Yoncheon (1.6%) and Kawasaki (0.8%) genotypes in the chigger mites. The Kato genotype was not detected in any of the specimens. The geographical distribution of the Boryong genotype was slightly higher in southern Korea than in mid-Korea, while the Gilliam, Karp and