Effects of dielectric permittivities on skin heating due to millimeter wave exposure

<p>Abstract</p> <p>Background</p> <p>Because the possibility of millimeter wave (MMW) exposure has increased, public concern about the health issues due to electromagnetic radiation has also increased. While many studies have been conducted for MMW exposure, the effect of dielectric permittivities on skin heating in multilayer/heterogeneous human-body models have not been adequately investigated. This is partly due to the fact that a detailed investigation of skin heating in a multilayer model by computational methods is difficult since many parameters are involved. In the present study, therefore, theoretical analyses were conducted to investigate the relationship between dielectric permittivities and MMW-induced skin heating in a one-dimensional three-layer model (skin, fat, and muscle).</p> <p>Methods</p> <p>Approximate expressions were derived for the temperature elevation and temperature difference in the skin due to MMW exposure from analytical solutions for the temperature distribution. First, the power absorption distribution was approximated from the analytical solution for a one-layer model (skin only). Then, the analytical expression of the temperature in the three-layer model was simplified on the basis of the proposal in our previous study. By examining the approximate expressions, the dominant term influencing skin heating was clarified to identify the effects of the dielectric permittivities. Finally, the effects of dielectric permittivities were clarified by applying partial differentiation to the derived dominant term.</p> <p>Results</p> <p>Skin heating can be characterized by the parameters associated with the dielectric permittivities, independently of morphological and thermal parameters. With the derived expressions, it was first clarified that skin heating correlates with the total power absorbed in the skin rather than the specific absorption rate (SAR) at the skin surface or the incident power density. Using Debye-type expression we next investigated the effect of frequency dispersion on the complex relative permittivity of tissue. The parametric study on the total power absorbed in the skin showed that skin heating increases as the static permittivity and static conductivity decrease. In addition, the maximum temperature elevation on the body surface was approximately 1.6 times that of the minimum case. This difference is smaller than the difference caused by the thermal and morphological parameters reported in our previous study.</p> <p>Conclusion</p> <p>This paper analytically clarified the effects of dielectric permittivities on the thermally steady state temperature elevation and the temperature difference in the skin of a one-dimensional three-layer model due to MMW exposure.</p

Identification of non-coding RNAs embracing microRNA-143/145 cluster

In a variety of cancers, altered patterns of microRNA (miRNA) expression are reported and may affect the cell cycle and cell survival. Recent studies suggest that the expression level of miRNAs that act as tumor suppressors is frequently reduced in cancers because of chromosome deletions, epigenetical changes, aberrant transcription and disturbances in miRNA processing. miR-143 and -145, which are located approximately 1.3 kb from each other at chromosome 5q33, are highly expressed in several tissues, but down-regulated in most cancers. However, the mechanism of this down-regulation has not been investigated in detail. Here, we show that both miRNAs were expressed well under the same control program in human tissues, but were down-regulated equally in the most of the cancer cell lines tested. Then we identified the host gene encoding both miRNAs. The transcripts of this gene were approximately 11, 7.5, and 5.5 kb long; and the expression of these transcripts was coordinated with that of its resident miRNAs and down-regulated in the cancer cell lines tested as well as in colorectal cancer tissue samples. These data demonstrate that the host gene can function as a primary miRNA transcript and suggest that the down-regulation of host gene expression caused the low-expression of its encoded microRNAs-143 and -145 in human cancer cell lines and in cancer tissues

Utility of Plain Chest Computed Tomography in Diagnosing Cardioembolic Stroke due to Paroxysmal Atrial Fibrillation

Background：Diagnosing cardioembolic stroke due to paroxysmal atrial fibrillation（PAF）is difficult, mainly due to low detection rate. We evaluated whether left atrial volume, which can be simply measured using non-contrast chest computed tomography（CT-LAV）, can contribute to the diagnosis of cardioembolic stroke due to PAF（PAF-CE）.Methods：Fifty-one consecutive patients with acute ischemic stroke within 24 h of onset were included in this study. Upon admission, we measured the left atrial diameter using transthoracic echocardiography（TTE-LAD）and CT-LAV. Patient background factors such as sex, age, and stroke risk factors were noted as well as brain natriuretic peptide（BNP）value and QTc interval were evaluated on admission. Utilities of BNP value, CT-ALV, and TTE-LAD in PAF-CE diagnosis were compared.Results：Patients were classified into three groups：cerebral thrombosis（CTB）group including large-artery atherosclerosis and small-vessel occlusion（n＝16）, cardioembolic stroke due to non-valvular atrial fibrillation（AF-CE）group（n＝20）, and cardioembolic stroke due to paroxysmal atrial fibrillation（PAF-CE）group（n＝15）. BNP value was highest in the AF-CE group（240.5 pg/mL）, followed by the PAF-CE（187.9 pg/mL）and CTB groups（35.0 pg/mL）（p＜0.001）. There was a significant difference in TTE-LAD among the groups（AF-CE group, 43.8 mm；PAF-CE group, 38.3 mm；CTB group, 34.1 mm）（p＜0.001）. CT-LAV was higher in the AF-CE group（142 mm3）than in the PAF-CE（95.8 mm3）and CTB groups（95.8 mm3）（p＜0.001）. In differentiating PAF-CE, the area under the receiver operating characteristic curve was 0.867, 0.742, and 0.845 for BNP value, TTE-LAD, and CT-LAV, respectively. A cut-off CT-LAV value of ≥ 69.6 mm3 had a high diagnostic rate（＞80％ of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy）.Conclusion：CT-LAV can be useful in diagnosing PAF-CE. Further studies with larger sample size are required to confirm our findings and determine better cut-off value for CT-LAV

KK-47膀胱癌移植ヌードマウスにおけるヘマトポルフィリン誘導体取り込みに関する研究

取得学位 : 博士（医学）, 学位授与番号 : 医博甲第960号, 学位授与年月日：平成2年8月31日,学位授与年：199

A comparison of the usefulness of nuclear beta‐catenin in the diagnosis of desmoid‐type fibromatosis among commonly used anti‐beta‐catenin antibodies

Desmoid-type fibromatosis (DF) is a locally aggressive but non-metastatic (myo)fibroblastic neoplasm. A hallmark of the tumor is nuclear positivity for beta-catenin in immunohistochemistry due mostly to CTNNB1 mutations. However, a recent study has reported that even beta-catenin ‘nuclear-negative’ DFs can harbor CTNNB1 mutations and that the positive ratio of nuclear beta-catenin in DF is different among antibodies. Here, we reviewed soft tissue lesions for which the possibility of DF was considered and compared the sensitivity and specificity of nuclear beta-catenin for the diagnosis of DF among commonly used anti-beta-catenin antibodies, i.e., clone beta-catenin 1, 17C2 and 14. We analyzed 26 cases of DF, 28 cases of benign fibroblastic lesions, and 27 cases of other soft tissue tumors. The sensitivity and specificity of nuclear beta-catenin for the diagnosis of DF were different among antibodies; 54% and 98% in clone beta-catenin 1, 85% and 84% in 17C2, and 96% and 62% in 14. IHC of LEF1 showed comparable results with IHC of beta-catenin, with a sensitivity of 88% and specificity of 76%. Additionally, when beta-catenin 1 was used, DFs showed characteristic dotted cytoplasmic staining, often appearing as rings. Our results might be helpful for making a correct diagnosis of DF

NASDA's Advanced On-Line System (ADOLIS)

Spacecraft operations including ground system operations are generally realized by various large or small scale group work which is done by operators, engineers, managers, users and so on, and their positions are geographically distributed in many cases. In face-to-face work environments, it is easy for them to understand each other. However, in distributed work environments which need communication media, if only using audio, they become estranged from each other and lose interest in and continuity of work. It is an obstacle to smooth operation of spacecraft. NASDA has developed an experimental model of a new real-time operation control system called 'ADOLIS' (ADvanced On-Line System) adopted to such a distributed environment using a multi-media system dealing with character, figure, image, handwriting, video and audio information which is accommodated to operation systems of a wide range including spacecraft and ground systems. This paper describes the results of the development of the experimental model

In-Stent Yellow Plaque at 1 Year After Implantation Is Associated With Future Event of Very Late Stent Failure The DESNOTE Study (Detect the Event of Very late Stent Failure From the Drug-Eluting Stent Not Well Covered by Neointima Determined by Angioscopy)

AbstractObjectivesThis study examined whether coronary angioscopy-verified in-stent yellow plaque at 1 year after drug-eluting stent (DES) implantation is associated with future event of very late stent failure (VLSF).BackgroundAtherosclerosis detected as yellow plaque by angioscopy has been associated with future events of acute coronary syndrome. Development of in-stent neoatherosclerosis is a probable mechanism of VLSF.MethodsThis study included 360 consecutive patients who received successful angioscopic examination at 1 year after implantation of a DES. They were clinically followed up for VLSF defined as cardiac death, acute myocardial infarction or unstable angina, or need for revascularization associated with the stent site.ResultsThe follow-up interval was 1,558 ± 890 days (4.3 ± 2.4 years). The incidence of VLSF was significantly higher in the patients with yellow plaque than in those without (8.1% vs. 1.6%; log rank p = 0.02). Multivariable analysis revealed the presence of yellow plaque (hazard ratio [HR]: 5.38; p = 0.02) and absence of statin therapy (HR: 3.25; p = 0.02) as risks of VLSF.ConclusionsIn-stent atherosclerosis evaluated by yellow plaque at 1 year after the implantation of DES and the absence of statin therapy were risks of VLSF. The underlying mechanism of VLSF appeared to be the progression of atherosclerosis as demonstrated by the yellow plaque

Recurrence of neovascular age-related macular degeneration after cessation of treat and extend regimen

The appropriate timing of treatment cessation after treat and extend (TAE) regimen for age-related macular degeneration has not been established. This study aimed to investigate the incidence and risk factors of recurrence after cessation of the TAE regimen. We included patients who received and discontinued the TAE regimen, after extension of the treatment interval to ≥ 12 weeks. Forty-nine patients were included in the study. The estimated recurrence rates were 33% at 1 year and 48% at 2 years after treatment cessation, respectively. Good visual acuity at cessation and a large number of injections in the 6 months before cessation were significant risk factors. Higher chances of recurrence were associated with < 0.1 logarithm of the minimum angle of resolution (logMAR) at cessation (P < 0.002). Meanwhile, five patients with visual acuity ≥ 1.0 logMAR at cessation did not show recurrence. Among the 25 recurrences, two lines of vision loss were noted in only two cases after resumed treatment. This study confirmed the importance of the number of injections in reducing recurrence and the association between visual acuity and recurrence. Recurrence is generally well-controlled with resumed treatment