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A 59-year-old woman who had been diagnosed with cirrhotic primary biliary cholangitis (PBC) 5 years earlier was admitted for severe jaundice (total bilirubin: 30.1 mg/dL). We suspected that her cirrhotic PBC had deteriorated acutely for some reason. Her general condition deteriorated quickly, and she passed away on day 18 of admission. Hepatitis E virus (HEV)-IgA antibodies were positive, and Genotype 3b HEV involvement was confirmed from a blood sample taken on admission. Histopathological findings revealed cirrhosis and submassive loss and necrosis of hepatocytes. Clinicians should consider the possibility of acute HEV infection as a trigger for acute PBC exacerbation.

Background. Recently, chronic hepatitis E has been reported in solid organ transplant (SOT) recipients in European countries. Previously, we clarified the prevalence of hepatitis E virus (HEV) infection in Japanese liver transplant recipients and identified 2 chronic hepatitis E patients infected by blood transfusion. However, the rate of HEV infection in recipients of SOTs other than liver in Japan remains unclear, so we conducted a nationwide survey to clarify the prevalence of chronic HEV infection in Japanese heart and kidney transplant recipients. Methods. A total of 99 heart and 2526 kidney transplant recipients in 17 hospitals in Japan were examined for the presence of the IgG class of anti-HEV antibodies as well as for serum HEV RNA. Results. The prevalence of anti-HEV IgG among heart and kidney transplant recipients was 7.07% (7/99) and 4.08% (103/2526), respectively. One heart transplant patient (1.01%) and 11 kidney transplant patients (0.44%) were found to be positive for HEV RNA. The HEV isolates from all viremic patients were typed as genotype 3. Four patients developed chronic hepatitis E after transplantation. Three patients were treated with ribavirin; their liver enzymes normalized, and HEV RNA became negative immediately. Sustained virologic response was achieved in all cases. Conclusions. This is the first nationwide survey of HEV infection in Japanese heart and kidney transplant recipients. The prevalence of anti-HEV IgG and HEV RNA in heart and kidney transplant recipients in Japan was lower than that in European countries. Of note, 42% of viremic transplant patients developed chronic hepatitis.

A 76-year-old woman with spontaneous reactivation of hepatitis B virus (HBV) without any immunosuppressants who had been successfully treated with tenofovir alafenamide fumarate (TAF) was reported. The patient was admitted to our hospital because of acute exacerbation of the liver function and jaundice. She had been found to have chronic HBV infection with a normal liver function and had been treated for lifestyle-related diseases, such as diabetes mellitus, dyslipidemia and hypertension, for over 10 years at a local clinic. At admission, her serum HBV DNA was high (7.3 log IU/mL), and anti-hepatitis B core protein immunoglobulin M was slightly elevated (1.47 S/CO). Due to the absence of known risk factors for HBV reactivation, the reactivation was regarded as "spontaneous". After the initiation of the nucleotide analog TAF, her liver function gradually improved with a decrease in the HBV DNA load. Her HBV genome was typed as subgenotype B1 and possessed a frameshift mutation due to an insertion of T after nucleotide (nt) 1817 and G to A mutations at nt 1896 and nt 1899 (G1896A/G1899A) in the precore region as well as serine to glutamine substitution of amino acid 21 in the core protein. In addition to these viral mutations, aging and complications of lifestyle-related diseases in the present case may have been responsible for the spontaneous HBV reactivation. Careful observation and management of aged HBV carriers with underlying diseases are needed even when persistent HBV infection is free from symptoms and liver dysfunction and no immunosuppressive conditions are involved.

A 65-year-old man presented with acute liver failure and grade IV coma caused by hepatitis B virus (HBV) infection in 2017. The patient died on day 12 from the disease onset. The HBV isolated from the patient was genotype/subgenotype B/B1 and had multiple genomic mutations. The patient's wife was hepatitis B surface antigen (HBsAg)-positive when she delivered her first daughter in 1979. The HBV isolates of the patient and the wife shared 100% similarity over the entire genome. Because the patient's HBsAg value had been negative one year earlier, we considered the source of HBV transmission to be his wife.

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2018-05-07, 資料番号: PA1910018000

Aim Studies regarding changes in antibodies to hepatitis E virus (HEV) after HEV infection in organ transplant patients are limited. This study aimed to clarify HEV infection trends in organ transplant patients who contracted HEV using data from a previous Japanese nationwide survey. Methods This study was conducted from 2012 to 2019. Among 4518 liver, heart, and kidney transplant patients, anti-HEV IgG antibodies were positive in 164 of which data were collected from 106 patients who consented to participate in the study. In total, 32 liver transplant patients, 7 heart transplant patients, and 67 kidney transplant patients from 16 institutions in Japan were examined for IgG, IgM, and IgA antibodies to HEV and the presence of HEV RNA in the serum. Chi-square test was used to determine the relationship between the early and late post-infection groups in patients with anti-HEV IgG positive-to-negative conversion rates. The Mann-Whitney U test was used to compare clinical factors. Results Anti-HEV IgG positive-to-negative conversion occurred in 25 (23.6%) of 106 organ transplant patients. Of eight patients with hepatitis E who tested positive for HEV RNA, one (14.0%) had anti-HEV IgG positive-to-negative conversion. Meanwhile, 24 (24.5%) of 98 patients negative for HEV RNA had anti-HEV IgG positive-to-negative conversion. Conclusions This study demonstrated, for the first time, the changes in HEV antibodies in organ transplant patients. Loss of anti-HEV IgG may often occur unexpectedly in organ transplant patients with previous HEV infection. This article is protected by copyright. All rights reserved.

In recent years, wireless power transmission (WPT) to an electric vehicle (EV) has attracted increasing attention. More than several kW is assumed for WPT, so that electromagnetic interference (EMI) is required to be considered. The WPT can also affect the control system and the automotive networks of the EV. Therefore, the noise current induced on the wire harness due to WPT cannot be ignored. The purpose of this paper is to investigate the noise current on the wire harness. As a result of the investigation, we confirmed up to several hundred μA on the wire harness.

The clinical and virologic features of hepatitis E virus (HEV) infection seem to vary among regions even in developed countries. However, we have little information on the diversity of HEV infection. Here, we investigated the characteristics of 26 patients in our hospital located in Tochigi prefecture, 90 km north of Tokyo, between 2000 and 2019. The reported number of patients with acute hepatitis E is increasing in Japan because measurement of IgA-class anti-HEV antibody was commercially available from 2011. In contrast, the numbers at our hospital were 1.5/y and 1.0/y in 2000 to 2011 and 2012 to 2019, respectively. This is attributed to the fact that we have been investigating HEV as a cause of unknown hepatitis before 2011. Among isolated HEV subgenotypes, including 3a, 3b, 4b, 4c, and 4d, all three patients with subgenotype 4c infection presented acute liver failure. Four HEV strains shared more than or equal to 99% identity within the 412-nucleotide partial sequence, in which the time and place of HEV infection varied, except for one intrafamilial infection. In addition, some strains were similar to HEV strains isolated far from Tochigi prefecture. In conclusion, the number of patients with acute hepatitis E was not increasing at Jichi Medical University Hospital and some strains were found to circulate in Japan.

Background: To date, no reports exist regarding changes in anti-hepatitis E virus (HEV) antibodies after HEV infection in organ transplant patients. We followed up participants in a previously reported “Japanese national survey of Hepatitis E in liver, heart, and kidney transplant patients” from 2012 to 2017, to clarify HEV infection trends. Methods: Data on 106 transplant patients that were included in the current study; 32 liver, seven heart, and 67 kidney transplant recipients in 16 institutes in Japan were examined for immunoglobulin G (IgG), IgM, IgA classes of anti-HEV antibodies, and HEV RNA in the serum. Two, one, and five liver, heart, and kidney transplant patients, respectively, in whose serum HEV RNA was identified were examined. Furthermore, 30, six, and 62 liver, heart, and kidney transplant patients, respectively, positive for anti-IgG-HEV antibody were also examined. In each patient, HEV RNA, anti-HEV IgA antibody, anti-HEV IgM antibody, and anti-HEV IgG antibody titres were measured. Findings: Of eight patients with hepatitis E who were positive for HEV RNA, one (14·0%) had anti-IgG-HEV antibody negative conversion. Contrariwise, of 98 patients that were negative for HEV RNA, 24 (24·5%) had anti-HEV IgG antibody negative conversion. Of 24 patients, eight, 12, and four were liver, kidney, and heart transplant patients, respectively. Interpretation: Anti-HEV IgG antibody loss may occur unexpectedly with high frequency in transplanted patients with past HEV infection. Therefore, the possibility of HEV re-infection in transplanted patients exists, and care should be taken to prevent this. Funding: This research was supported by AMED (Grant Number JP19fk0210043). Declaration of Interests: None declared. Ethical Approval Statement: The date of birth, sex, date of transplantation, and number of immunosuppressant were extracted from the medical records. This research was approved by the Ethics Committee at our centre and at each patient's institution (IB1811). All the recipients gave written informed consent to participate in this study.

Background Several studies have reported that viral infections are related to lung cancer. We previously reported the involvement of Torque teno virus (TTV) in patients with lung cancer and idiopathic pulmonary fibrosis. However, the role of TTV in lung cancer growth, and its influence on changes in TTV DNA titers due to idiopathic pulmonary fibrosis (IPF) in lung cancer patients are poorly understood. Methods Serum TTV DNA titers were measured in serum samples obtained from patients with lung cancer. Forty-eight patients with primary lung cancer, including 8 patients with IPF, were enrolled. Serum TTV DNA titers were quantitated before and after chemotherapy. In addition, patients were classified into two groups according to the presence or absence of IPF, and clinical characteristics were compared between these two groups. Results Among the 33 patients with partial response to treatment or stable disease in the lung cancer, the mean TTV DNA titer in 28 patients without IPF had significantly decreased after chemotherapy. In contrast, the mean TTV DNA titer in the 5 patients with IPF tended to increase after chemotherapy. In the 15 patients with progressive lung cancer, TTV DNA titers were significantly elevated in those with and without IPF. Conclusion In lung cancer patients without IPF, changes in TTV titers may be correlated with tumor growth. However, in lung cancer patients with IPF, TTV titers were not consistently associated with chemotherapy responses. Therefore, IPF may have an influence on changes in TTV DNA titers.

In January 2012, Mongolia started a hepatitis A vaccination program, which has not yet been evaluated. The first occurrence of autochthonous acute hepatitis E in 2013, caused by genotype 4 hepatitis E virus (HEV), suggests the need for a routine study to monitor its prevalence. One hundred fifty-four consecutive patients who were clinically diagnosed with acute hepatitis between 2014 and 2015 in Ulaanbaatar, Mongolia were studied. By serological and molecular testing followed by sequencing and phylogenetic analysis, only one patient (0.6%) was diagnosed with acute hepatitis A, caused by genotype IA hepatitis A virus (HAV), and 32 (20.8%) patients were diagnosed with acute hepatitis E, caused by genotype 1 HEV. The 32 HEV isolates obtained in this study shared 99.5-100% nucleotide identity and were grouped into a cluster separated from those of subtypes 1a to 1f. Upon comparison of p-distances over the entire genome, the distances between one representative HEV isolate (MNE15-072) and 1a-1f strains were 0.071-0.137, while those between 1b and 1c were 0.062-0.070. In conclusion, the prevalence of acute hepatitis A has decreased in Mongolia since the start of the vaccination program, while the monophyletic genotype 1 HEV strain of a probably novel subtype has been prevalent.

Background The prevalence of occult hepatitis B virus (HBV) infection (OBI) in children who develop the infection via mother-to-child transmission (MTCT) despite immunoprophylaxis remains controversial and is still unknown in Japan. The aim of this study was to determine the OBI prevalence among such children in Japan and identify the genomic mutations that might be associated with the pathogenesis of OBI in children. Methods The data on 158 children born to HBV carrier mothers and who received complete passive-active immunoprophylaxis after birth 2002-2014 were reviewed. HBV markers were detected using commercial enzyme-linked immunosorbent assay kits. HBV DNA was detected using real-time and nested polymerase chain reaction. Complete genomic sequences were determined. Results Among the 158 children studied, 3 experienced HBV-MTCT: 2 had OBI, and 1 had resolved HBV infection (RBI). The prevalence of OBI and RBI was estimated to be 1.3% and 0.6%, respectively. The HBV genomes of the 2 OBI children were wild type and 100% identical to those of their mothers. Of these two children, one received repeated administration of HB immunoglobulin (HBIG) and developed overt HBV infection. Her HBV genome had a G145R mutation in the S gene that might have been induced by HBIG administration. One RBI child was persistently positive for antibody to HBV core antigen (anti-HBc; 10-12 S/CO). Conclusions A low prevalence of OBI was observed in children who received immunoprophylaxis for preventing MTCT in Japan. The development of overt HBV infection in infants with OBI indicates the necessity of close and long-term monitoring. This article is protected by copyright. All rights reserved.

Along with the spread of novel types of mobile phones such as smartphones, there has been increasing public interest in the health hazards associated with exposure to electromagnetic waves from these devices. Therefore, we estimated the specific absorption rate (SAR) of electromagnetic radiation by numerical simulation using a realistic computational smartphone model with an antenna for a third generation communication (3G) system (operating frequencies: 900 MHz and 2 GHz) and computational human models with the anatomical structures of Japanese male and female adults. We also assessed the relative variability of SAR based on holding a smartphone at various positions for data communications. The 10-g-averaged SAR (SAR 10g ) when the smartphone was operating at 2 GHz was generally higher than that at 900 MHz independent of the placement of the smartphone. Moreover, we found that SAR 10g had a tendency to increase when the smartphone was placed vertically in relation to the torso. In addition, it is possible that SAR 10g variability depends mainly not on placement height but on tilt angle.

A 64-year-old woman was infected with hepatitis E virus (HEV) during chemotherapy for leukemia. By retrospective analyses of stored serum from the blood products and the patient, the source of the infection was determined to be platelet concentration (PC) transfused during chemotherapy. The partial nucleotide sequence of the HEV strain isolated from the donated PC and that from the patient’s sera was identical and was subgenotype 3b. Clinical indicators such as alanine aminotransferase, HEV RNA titer, and anti-HEV antibodies in the serum were investigated from the beginning of the infection until 1 year after the termination of HEV infection. HEV RNA had propagated over 6 months and then cleared spontaneously after the completion of chemotherapy. Anti-HEV antibodies appeared in the serum just before the clearance of HEV RNA. Interestingly, HEV RNA was detected in the patient’s urine, spinal fluid, and saliva. The HEV RNA titers in those samples were much lower than in the serum and feces. No renal, neurological, or salivary gland disorders appeared during the follow-up. We observed virological and biochemical progress and cure of transfusion-transmitted chronic hepatitis E in the patient despite an immunosuppressive status during and after chemotherapy against hematological malignancy.

In recent years, in a hospital, a biological information monitoring system that constantly monitors biological information such as blood pressure and heart rate to grasp a patient's condition is generally used. However, in the current system, 420 to 450 MHz band are mainly used, and it is difficult to manage such as channel switching and device addition/deletion to wireless communication experts. Also, there is a problem that a transmitter having a size as large as a small terminal must be carried around. Therefore, we proposed the textile antenna using the 5.2 GHz band as a transmitting antenna of the system. In this paper, we report on the antenna characteristics when a transmitting antenna designed by the authors is placed on the human body and the result of received power transmitted by the textile antenna analysis in an imitated actual environment model.

Along with the remarkable informationization in recent years, the spread of wireless communication devices has progressed, and opportunities to expose the human body from electromagnetic waves have become increasing. The biological effects of electromagnetic waves on wireless terminals have been evaluated by various research organizations around the world. In Japan, it is known from the survey conducted by Ministry of Internal Affairs and Communications [1], the penetration rate of wireless LAN (Local Area Network) routers in households have become rising. Wireless LAN routers are often installed in the vicinity of the celling, however in the home it is installed at a height of 1 - 2 m from the floor as on the shelf, and in this case, it is assumed that they are close to the human head or chest. Nevertheless, few examples of evaluating biological effects due to electromagnetic wave exposure from wireless LAN routers have been reported.

Aim To evaluate the clinical and virological features of acute hepatitis E (AH-E) in Gunma prefecture and focus on the hepatitis E virus (HEV) infection in immunocompromised patients. Methods A total of 30 patients with AH-E diagnosed at our Gunma University Hospital, and located in 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan, and its affiliated hospitals from 2004 to 2015, were studied. We evaluated the detailed medical histories, laboratory examinations and virological features of these participants. Results Of the 30 patients, 21 patients were men, with a median age of 61 years. Three of these patients had a history of recent oversea travel. A total of 14 patients had eaten raw or undercooked meat/viscera from animals, and two patients had contracted transfusion-transmitted AH-E. Eight patients were immunocompromised, including those with hematological disease, cancer receiving systemic chemotherapy and kidney transplant or connective tissue disease undergoing immunosuppressive medications. The alanine aminotransferase and total bilirubin levels were more significantly reduced in these immunocompromised patients than in the non-immunocompromised patients. Severe thrombocytopenia, an extra-hepatic manifestation of AH-E, occurred in one case. Among the 22 HEV strains whose subgenotype was determined, two were imported strains (1a and 1f), and 11 strains formed four distinct phylogenetic clusters within subgenotype 3b. The remaining nine strains differed from each other by 9.8–22.4%, and were classified into four subgenotypes (3a, 3b, 3e and 3f). Conclusion Markedly divergent HEV strains (3a, 3b, 3e and 3f) were found to circulate in Gunma. Although immunosuppression appears to play a crucial role in establishing chronic sequels, AH-E in eight immunocompromised patients, including transfusion-transmitted HEV infection in two patients, did not become chronic.

Electromagnetic interference (EMI) from mobile phones affecting implanted cardiac pacemakers has become a recent concern. In previous numerical computations of the EMI, a half-wavelength dipole antenna has been employed as a radiator of electromagnetic waves. However, current mobile phones are generally equipped with an internal antenna. Furthermore, recent mobile phone systems are operated at higher frequencies, i.e., 2 GHz, whereas lower frequencies around 900 MHz have been assumed in the previous studies. In this study, a mobile phone with an internal antenna was modeled with a planar inverted-F antenna (PIFA) mounted on a metallic case, in order to calculate the interference voltage induced at the pacemaker due to the internal antenna. The PIFA was then scanned in a plane parallel to the torso surface, in order to calculate the interference voltage at each position and to clarify the detailed relationship between the interference voltage and the position of the antenna. Moreover, the interference voltage was experimentally evaluated to validate the numerical calculations. It is shown that the PIFA has interference voltage characteristics, which differ from those of the half-wavelength dipole antenna. Comparing the calculation with the measurement, both results show the same tendency, especially around the position of maximum interference. Therefore, the measured results indicate the validity of the numerical results.

Recently, wearable wireless devices or terminals have become hot a topic not only in research but also in business. Implantable wireless devices can temporarily be utilized to monitor a patient’s condition in an emergency situation or to identify people in highly secured places. Unlike conventional wireless devices, wearable or implantable devices are used on or in the human body. In this sense, body-centric wireless communications (BCWCs) have become a very active area of research. Radiofrequency or microwave medical devices used for cancer treatment systems and surgical operation have completely different functions, but they are used on or in the human body. In terms of research techniques, such medical devices have a lot of similarities to BCWCs. The antennas to be used in the vicinity of the human body should be safe, small and robust. Also, their interaction with the human body should be well considered. This review paper describes some of the wearable antennas as well as implantable antennas that have been studied in our laboratory. key words: wearable antenna, implantable antenna, body-centric wireless communications, RFID, hyperthermia, medical device, human body, phantom

Recently, the capsular endoscope that has extra function has been investigated. Although the power consumption tends to increase as the ability increases, it is difficult to increase the capacity of the battery due to the volumetric problem. In this study, we proposed an antenna for both wireless power transmission and image transmission to be mounted on a capsule endoscope. In this paper, we proposed antennas to be mounted in a capsular endoscope and external on the body.

Wireless capsule endoscopy is a medical device that examines the human gastrointestinal (GI) tract without burdening patients. Wireless power transmission technology of the capsule endoscope has been researched, and getting the capsule location is important to improve the power transmission efficiency. In this report, we try to develop a localization method for wireless power transmission. An algorithm corresponding to both horizontally and vertically polarized waves is developed, and the performance is evaluated by three-dimensional localization with eight receiving antennas.

The characteristics of a cultured pearl are influenced by two kinds of pearl oysters. One is the donor pearl oyster, which provides a small piece of mantle to be transplanted, and the other is the recipient pearl oyster, in which the pearl nucleus and a small piece of mantle are transplanted. Generally, the brightness, luster, and color of pearls are affected by the donor oyster, while the thickness of nacre is affected by the recipient oyster. Previously, we have indicated that the sex of recipient pearl oyster directly affects the quality of pearl, and the optical characteristics measured by FT-IR (Fourier transform infrared spectroscopy) of pearl produced from male and female pearl oysters significantly differ (Iwai et al. Aquaculture 437:333–338, 2015). Moreover, using the various strains of Akoya pearl oyster as recipient and the same donor oyster, the produced Akoya pearl had different spectra for each strain. Also, besides the culture of the Akoya pearl oyster, the transplantation also produced different optically characterized pearls by breeding them in various environments. These results suggested that the optical characteristics underlying pearl quality are not only the influence by donor oyster but also the sex, the strain, and the breeding conditions of recipient oyster.

Despite the high endemicity of hepatitis A virus (HAV) in Mongolia, the genetic information on those HAV strains is limited. Serum samples obtained from 935 patients with acute hepatitis in Ulaanbaatar, Mongolia during 2004-2013 were tested for the presence of HAV RNA using reverse transcription-PCR with primers targeting the VP1-2B region (481 nucleotides, primer sequences at both ends excluded). Overall, 180 patients (19.3%) had detectable HAV RNA. These 180 isolates shared 94.6-100% identity and formed four phylogenetic clusters within subgenotype IA. One or three representative HAV isolates from each cluster exhibited 2.6-3.9% difference between clusters over the entire genome. Cluster 1 accounted for 65.0% of the total, followed by Cluster 2 (30.6%), Cluster 3 (3.3%), and Cluster 4 (1.1%). Clusters 1 and 2 were predominant throughout the observation period, whereas Cluster 3 was undetectable in 2009 and 2013 and Cluster 4 became undetectable after 2009. The Mongolian HAV isolates were closest to those of Chinese or Japanese origin (97.7-98.5% identities over the entire genome), suggesting the evolution from a common ancestor with those circulating in China and Japan. Further molecular epidemiological analyses of HAV infection are necessary to investigate the factors underlying the spread of HAV and to implement appropriate prevention measures in Mongolia.

Reactivation of a former hepatitis B virus (HBV) infection can be triggered by immunosuppressive therapy, diseases associated with an immunocompromised state, organ transplantation or the withdrawal of antiviral drugs. Despite the absence of such risk factors, a spontaneous reactivation of HBV replication occurred in two elderly patients with resolved or occult HBV infection. A 73-year-old male underwent coronary artery bypass grafting in October 2008, and was negative for HBsAg but positive for anti-HBs. In July 2009, his serum became positive for HBsAg, HBeAg and HBV DNA (6.4 log copies/ml; genotype C), but negative for anti-HBc IgM, with abrupt elevation of the liver enzymes. The entire genomic sequence of HBV recovered from this patient revealed no mutations in the core promoter and precore regions that interfere with HBeAg production. A 76-year-old male with a history of endoscopic mucosal resection for esophageal cancer in 2002 and an initial diagnosis of diabetes mellitus in 2009, at which time he was negative for HBsAg. He was found to be positive for HBsAg in September 2012 during a laboratory examination performed prior to the resection of recurrent esophageal cancer, despite a low HBV load (2.1 log copies/ml). Three months later, without the administration of any anticancer drugs, the HBV DNA (genotype B) level increased to 5.1 log copies/ml. A precore G1896A variant with high quasispecies diversity was recovered from the patient. Aging, surgical stress and complication of disease(s) associated with compromised immunity, such as cancer, arteriosclerosis and diabetes mellitus may trigger spontaneous HBV reactivation. J. Med. Virol. 87:589–600, 2015. © 2015 Wiley Periodicals, Inc.

In recent years, capsule endoscopy has attracted attention as a medical device that examines the internal digestive tract without burdening the patient. Wireless power transmission of the capsule endoscope is researching now, and the power transmission efficiency can be improved by knowing the capsule location. In this report, we try to use the three-dimensional localization method with five antennas.

Recently, various studies of capsular endoscope have been investigated. It has some disadvantage such as limited driving time and inconvenience of taking pictures cause of batteries that has limited capacity. If capsular endoscope operates by wireless transmission instead of cell batteries, we do not have to consider how improve the driving time and number of pictures. This paper presents a film antenna made by flexible printed circuit (FPC) for capsular endoscope. The antenna works with microwave wireless power transmission By this method, it is unnecessary to install a coil which is indispensable for the induction method in a capsule. Furthermore the antenna can be used by not only wireless power transmission but also captured images transmission. We confirmed that the designed antenna has good performance at the 433.92 MHz.

In 1998, JAMSTEC started the development project of the first prototype of a long-range cruising AUV (LCAUV) to evaluate fundamental technologies needed to travel through under the ice covered area of the Arctic. In 2005, The LCAUV, Urashima, achieved 317 km continuous cruising powered by a deep sea fuel cell developed in JAMSTEC [1]. We then moved to next stage and have conducted to design the second prototype LCAUV with target range of over 3,000 km. It included improvement of power source, communication system, and positioning system. In 2010 a small high efficiency multi-less (HEML) fuel cell was completed [2] and a long range acoustic communication system achieved 1,000 km communication using time-reversal waves. But we had not developed practical positioning system for under the ice by 2010. In past years the dramatic melting of Arctic ice would be driving extreme weather. This is very serious problem, but it is still poorly understood. Scientists need more research to understand it. We have thus a plan to develop an Arctic research platform that especially performs observations under the ice. Now we are conducting a research of a new positioning method with communication availability before developing the platform or an AUV. The proposed method is based on low frequency electromagnetic waves which can propagate inside of ice and sea water. A prototype to evaluate the method is like GPS repeater. The repeater to be set on the ice receives GPS signal, transmitting radio waves into the sea water via the ice up to several tens meters deep. To realize the system feasibility we started developing underwater antennas and measuring wave propagation in the sea ice and the sea water in 2016.

Aim To examine the prevalence and characteristics of hepatitis A virus (HAV) and hepatitis E virus (HEV) infections in the northern part of Honshu, Japan, during the last decade. Methods Using the registration system of a prospective cohort study for acute liver injury (ALI) in Iwate and three neighboring prefectures, we examined the prevalence of sporadic acute hepatitis (AH) with HAV (AH-A) and HEV (AH-E) and the distribution of viral genotypes in 487 patients diagnosed with ALI between 2004 and 2013. Results Among all 487 patients, 135 (28%) had ALI with viral infection. In the cases with viral ALI, the prevalence of hepatitis B virus-related AH was highest (55.6%). AH-E was seen in 23 patients (17.0%) and its prevalence was higher than that of AH-A (10 patients, 7.4%). There were no appreciable differences in the prevalence of AH-A and AH-E between 2004–2008 and 2009–2013. However, subgenotype IIIA HAV homologous to Korean strains has recently emerged, and the number of AH-E cases seems to be increasing. HEV genotype 3 was predominant throughout the observation period, but HEV genotype 4 was found in three patients after 2010. The transmission routes of HAV and HEV infections were unknown in approximately 60% of the patients. Conclusion In the northern part of Honshu, Japan, HEV has been more frequently implicated in the development of AH than HAV, and HEV genotype 4 has been recently increasing. To provide an effective prophylactic management for HAV and HEV infections, further clarification of the transmission routes is needed.

SUMMARY In recent years, there has been rapid developments in radio-frequency identification (RFID) systems, and their industrial applications include logistics management, automatic object identification, access and parking management, etc. Moreover, RFID systems have also been introduced for the management of medical instruments in medical applications to improve the quality of medical services. In recent years, the combination of such a system with a biological monitoring system through permanent implantation in the human body has been suggested to reduce malpractice events and ameliorate the patient suffering. This paper presents an implantable RFID tag antenna design that can match the conjugate impedance of most integrated circuit (IC) chips (9.3 − j55.2 Ω at 2.45 GHz. The proposed antenna can be injected into the human body through a biological syringe, owing to its compact size of 9.3 mm × 1.0 mm × 1.0 mm. The input impedance, transmission coefficient, and received power are simulated by a finite element method (FEM). A three-layered

An in-body wireless communication system has attracted increasing attention because it can replace the connectivity of biological telemetry monitoring. However, the human body is a very complex environment (lossy, dispersive, and inhomogeneous) and affects the electromagnetic (EM) wave in the near field. Moreover, the entire human geometry affects the radiation pattern in the far field. This communication presents the behavior of the EM wave in the near and far fields at 2.45 GHz when a dipole antenna (used as an implantable antenna) is embedded in the vicinity of the clavicle, upper arm, lower arm, and hand of a human body. The effect on the electric field and radiation performance is simulated by the finite-difference time-domain method. By introducing a three-layered phantom, the antenna performance is confirmed. Moreover, the measured and simulated results are in good agreement with each other. The information derived from this study can be used in the evaluation of the link budget of in-body wireless communication.

The physical channels establishing intrabody communications were first treated as capacitive circuits by Zimmerman. In Zimmerman's model, the human body is approximated as a perfect conductor. The equivalent-circuit parameters of the perfect conductor models can be strictly obtained based on electrostatic analyses; however, the perfect conductor models cannot be applied if conduction currents inside the human body are not negligible. In the present paper, a theory of the equivalent circuit for lossy conductors is described, and the physical mechanism of the communication channels inducing conduction currents inside the human body is addressed.

Implantable devices have been continually anticipated as a future tool for in-body wireless communication because of their potential to replace cable connectivity with biological telemetry monitoring. This paper presents an implanted compact folded antenna of 20.3 mm × 0.8 mm × 0.8 mm that is designed to operate at one of the UHF bands (0.951-0.956 GHz). The measurement is implemented with an equivalent human phantom such as layered phantom representing the human arm. When the proposed antenna is implanted into a human arm, it has a maximum antenna gain of -23.5 dBi and wireless communication is viable because the margin exceeds 20 dB, according to link budget calculations.