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Wide-volume scanning with 320-row multidetector computed tomography coronary angiography (CTCA-WVS) enables the assessment of the aortic arch plaque (AAP) morphology and coronary arteries without requiring additional contrast volume. This study aimed to investigate the prevalence of AAPs and their association with coronary artery disease (CAD) and major adverse cardiovascular events (MACEs) in patients who underwent CTCA-WVS.This study included 204 patients without known CAD (mean age, 65 years; 53% men) who underwent CTCA-WVS. We evaluated the presence of aortic plaques in the ascending aorta, aortic arch, and thoracic descending aorta using CTCA-WVS. Large aortic plaques were defined as plaques of at least 4 mm in thickness. A complex aortic plaque was defined as a plaque with ulceration or protrusion. MACEs were defined as composite events of cardiovascular (CV) death, nonfatal myocardial infarction, and ischemic stroke.AAPs and large/complex AAPs were identified in 51% ( n = 105) and 18% ( n = 36) of the study patients, respectively. The prevalence of AAPs with large/complex morphology increased with CAD severity (2.1% in no CAD, 12% in nonobstructive CAD, and 39% in obstructive CAD). The univariate Cox hazard model demonstrated that the predictors associated with MACEs were diabetes, obstructive CAD, and large/complex AAPs. Independent factors associated with large/complex AAPs were male sex [odds ratio (OR), 2.90; P = 0.025], stroke history (OR, 3.48; P = 0.026), obstructive CAD (OR, 3.35; P = 0.011), and thoracic aortic calcification (OR, 1.77; P = 0.005).CTCA-WVS provides a comprehensive assessment of coronary atherosclerosis and thoracic aortic plaques in patients with CAD, which may improve the stratification of patients at risk for CV events.

Background A pulmonary hypertensive crisis (PHC) can be a life-threatening condition. We established a PHC model by exposing rats with monocrotaline (MCT)-induced pulmonary hypertension to acute hypoxia, and investigated the effects of vasopressin, phenylephrine, and norepinephrine on the PHC. Methods Four weeks after MCT 60 mg kg−1 administration i.v., right ventricular systolic pressure (RVSP), systolic BP (SBP), mean BP (MBP), cardiac index (CI), and pulmonary vascular resistance index (PVRI) were measured. PHC defined as an RVSP exceeding or equal to SBP was induced by changing the fraction of inspiratory oxygen to 0.1. Rats were subsequently treated by vasopressin, phenylephrine, or norepinephrine, followed by assessment of systemic haemodynamics, isometric tension of femoral and pulmonary arteries, cardiac function, blood gas composition, and survival. Results PHC was associated with increased RV dilatation and paradoxical septal motion. Vasopressin increased MBP [mean (standard error)] from 52.6 (3.8) to 125.0 (8.9) mm Hg and CI from 25.4 (2.3) to 40.6 (1.8) ml min−1 100 g−1 while decreasing PVRI. Vasopressin also improved RV dilatation, oxygenation, and survival in PHC. In contrast, phenylephrine increased MBP from 54.8 (2.3) to 96.8 (3.2) mm Hg without improving cardiac pump function. Norepinephrine did not alter MBP. Vasopressin contracted femoral but not pulmonary arteries, whereas phenylephrine contracted both arterial beds. Hence, improvements with vasopressin in PHC might be associated with decreased PVRI and selective systemic vasoconstriction. Conclusions In this rat model of a PHC, vasopressin, but not phenylephrine or norepinephrine, resulted in better haemodynamic and vascular recovery.

UNSTRUCTURED The authors estimated the true number of COVID-19 infected people in Japan using the LINE questionnaire data and the PCR test results. A statistically significant correlation was observed between the infection rate per prefecture with PCR test and the rate of high fever. Using this correlation, true number of COVID-19 infected people in Japan was estimated approximately twenty thousand (±ten thousand) as of April 1, 2020.

The authors estimated the true number of COVID-19 infected people in Japan using the LINE questionnaire data and the PCR test results. A statistically significant correlation was observed between the infection rate per prefecture with PCR test and the rate of high fever. Using this correlation, true number of COVID-19 infected people in Japan was estimated approximately twenty thousand (±ten thousand) as of April 1, 2020.

A long-term air-stable n-type organic semiconductor, 2,5-difluoro-1,4-phenylene-bis{2-[4-(trifluoromethyl)phenyl]acrylonitrile}, was synthesized by a high-yield simple procedure of Knoevenagel condensation with aldehyde and acetonitrile derivatives. A fabricated organic thin-film transistor (OTFT) using this compound exhibited good n-channel OTFT properties with a high electron mobility of 0.17 cm(2) V(-1) s(-1) and an on/off current ratio of 10(6) under both vacuum and ambient air operation. After storage in ambient air for 1 year, a stored n-channel OTFT still shows good n-channel OTFT performance with little degradation in ambient air operation.

An active matrix backplane based on solution-processed organic thin-film transistors (OTFTs) has been developed for flexible displays having multiphoton organic light-emitting diodes (OLEDs). The OTFT device has a bottom-gate/bottom-contact type structure consisting of a polyethylene naphthalate-based flexible substrate covered with patterned gate electrodes and a gate dielectric of UV-cured cardo-polymer. Teflon AF was used for a hydrophobic bank structure that defines active regions of the OTFTs, and the organic semiconductor was coated by solution shearing. The OTFT backplane fabricated here had $384 \times 128$ pixels at a resolution of 300 dpi; images and video were successfully displayed on the resulting flexible multiphoton-emission OLED display.

To realize printed manufacturing of electronic devices, including flexible displays, sensors, and integrated circuits that incorporate organic thin-film transistors (OTFT), developing and improving the materials and technologies used in this process is required. Solution processable organic semiconductors, insulating materials, and high-resolution patterning techniques of printed electrodes are all critical components of these electronic devices. The surface properties of insulators are particularly important because they contribute significantly to carrier transport at the interface of the organic semiconductors and affect the patterning of the printed electrode. Insulating materials that are solution-processable typically require high temperatures (∼150 °C) and long curing times during fabrication, which is undesirable because these conditions can cause significant distortion of common flexible substrates, such as polyethylene naphthalate. Thermal deformation of a flexible substrate prevents high-resolution patterning and the accurate alignment of the different layers within a device, and these problems become more significant as the size of the substrate increases. To overcome some of these challenges, we have recently developed a novel styrene-based polymer (PC200) for use as an insulating material that can be cured quickly via photo cross-linking. This material can be produced under atmospheric conditions, does not require heat treatment, is highly electrically insulating and has a low dielectric constant. Additionally, the surface of the PC200 insulating film can be transformed into a hydrophilic, wettable surface by selective irradiation using vacuum ultraviolet (VUV) radiation via a photomask. This allows the formation very fine printed electrodes using a metal nanoparticle ink. VUV exposure in air generates oxygen radicals and ozone molecules, which cause chemical bond dissociation on the polymer surface and render the region hydrophilic, resulting in patterned surfaces that are wettable. Compared with perfluoropolymers or parylene insulating films that have been reported recently, surface modification of the PC200 insulating film is relatively simple and requires less VUV irradiation. In this work, we have examined the electrical insulating properties of the PC200 insulator film and incorporated it into a short-channel OTFT with the recently developed soluble semiconductor (dithieno[2,3-d:2’,3’- d’]benzo[1,2-b:4,5-b’]dithiophene, DTBDT). The PC200 film was formed by spin-coating and subsequent UV exposure without heat treatment. The insulator film exhibited low surface roughness (RMS 0.5 nm), high electrical insulation (>3 MV/cm) and a low dielectric constant (εr=2.7). Additionally, we were able to form fine patterned electrodes on the polymer insulator with a minimum channel length of 5 μm using a VUV patterning technique. Importantly, these fine patterns (2/Vs and a very large I on/I off ratio above 107. These results demonstrated that the PC200 insulator shows great promise for realizing a variety of flexible and printable electrical circuits for use in displays and sensors.

Similar to the healthcare systems in other industrialized countries, the Japanese healthcare system is facing the problem of increasing medical expenditure. In Japan, this situation may be primarily attributed to advanced technological developments, an aging population, and increasing patient demand. Japan also faces the problem of a declining youth population due to a low birth rate. Taken together, these problems present the healthcare system with a very difficult financial situation. Several reforms have been undertaken to contain medical expenditure, such as increasing employee copayment for health insurance from 10% to 20% in 1997 and from 20% to 30% in 2003 in order to curb unnecessary visits to medical institutions. Since the aging of the Japanese population is inevitable, a suitable method to contain medical expenditure may be to screen individuals who are likely to develop lifestyle-related diseases and conduct early intervention programs for them to prevent the development of diseases such as myocardial infarction or stroke that are costly to treat. If this goal is attained, it may contribute to the containment of medical expenditure as well as to improving the quality of life of the elderly. Therefore, the Japanese Ministry of Health, Labor and Welfare has decided to introduce a nationwide health screening and intervention program specifically targeting the metabolic syndrome commencing April 2008. Here, we discuss (1) the background of the Japanese healthcare system and the problems facing it, (2) the underlying objective and details of the new screening program, and (3) the expected impact of the program.

After the Fukushima Nuclear Power Plant accident, one of the main issues at stake was the potential intake of contaminated foodstuff by residents of the affected areas. In this context, the importance of the management of the internal exposure by food intake has emerged. For this purpose, a system was developed for estimating the amount of the radioactivity ingested through the diet in order to manage the internal exposure evolution of exposed people. The ultimate goal of this system is to consider all the radiation exposure data including medical exposure in an integrated manner.

In order to predict the prognosis or complications of portal hypertension in patients with chronic liver disease, it is important to evaluate both hepatic functional reserve and portal circulation. On (99m)Tc-galactosyl human serum albumin ((99m)Tc-GSA) scintigraphy, the index of blood clearance (HH15) and receptor index (LHL15) have been widely used to evaluate the hepatic functional reserve. However, the relationship between these indices and portal circulation is unknown. The purpose of this study was to examine the relationship between HH15 and LHL15 and portosystemic shunts evaluated with arteriographic portography or esophagogastroduodenoscopy.A total of 82 patients with chronic liver disease (mean age, 66.7 years) who underwent (99m)Tc-GSA scintigraphy, arteriographic portography, and esophagogastroduodenoscopy were enrolled. HH15 and LHL15 were obtained from dynamic (99m)Tc-GSA scintigraphy. The patients were divided into three groups according to the arteriographic portography findings: group 1, no portal collateral circulation; group 2, mild collateral development; and group 3, moderate to severe collateral development. They were also divided into three groups based on the esophagogastroduodenoscopic findings: group A, no varices; group B, small-caliber varices; and group C, enlarged varices. The Kruskal-Wallis test was used to compare each index among these groups. Receiver operating characteristic (ROC) analysis was used to determine whether each index was an indicator for the presence of portosystemic shunts.Both HH15 and LHL15 differed significantly between groups 1 and 2 and between groups 1 and 3. However, only HH15 differed significantly between groups A and B and between groups A and C. On the basis of the ROC analysis, the HH15 threshold value of 0.62 yielded both excellent sensitivity (83.9%) and specificity (84.6%) for the presence of portosystemic shunts, as evaluated with arteriographic portography. The HH15 threshold value of 0.64 yielded both good sensitivity (66.1%) and specificity (69.2%) for the presence of portosystemic shunts, as evaluated with esophagogastroduodenoscopy, whereas no adequate threshold value of LHL15 was found for the presence of portosystemic shunts.HH15 is a potent indicator of the presence of portosystemic shunts in chronic liver disease.

We evaluated the cortical activations in postlingually deaf cochlear implant (CI) users in the early period (0–2 months) of CI usage. The subjects were 8 early CI users and 8 normal subjects. With tone burst stimuli (1 kHz) delivered to the right side, strong and broad activation of the ipsilateral (right) primary auditory cortex with 2 peaks and weaker activation of the contralateral (left) temporal lobe were observed in early CI users, in a clear contrast with the normal subjects in whom activation was observed in a small area of the contralateral (left) primary cortex. With word stimuli, activation of the superior frontomedian cortex presumably including the supplementary motor area and the neighboring cingulate gyri was observed in early CI users, which was absent in normal subjects. The activation in the immediate association cortices near the primary area was lower in early CI users, while the periphery of the association cortex seemed to be more mobilized.

We encountered a case of arteriovenous malformation (AVM) of the gallbladder in a patient with hepatocellular carcinoma (HCC). Contrast-enhanced computed tomography (CT) showed serpentine vessels around and within the gallbladder wall. Angiography showed dilated and tortuous cystic arteries, a racemose vascular network, and early-filling cystic veins. Transcatheter arterial embolization of two cystic arteries feeding the AVM was performed with platinum microcoils prior to transcatheter arterial chemoembolization for HCC to prevent embolic particles from flowing into these arteries. Follow-up contrast-enhanced CT showed blood flow in the gallbladder AVM, which appeared to be fed by the arterial collaterals.

Working group on JJ1017 nuclear medicine domain extension code in the Japanese Society of Nuclear Medicine has created nuclear medicine extension codes keeping the integrity with JJ1017. The objective of this study was to investigate the usefulness of nuclear medicine extension codes in real clinical settings.Nuclear medicine examinations of each institution were extracted from the examination master table and then the target subset of examinations to be coded with JJ1017 were identified. For this subset, working process was conducted, during which the followings compared conformity rate, application rate of representative frequently code set and compliance rate of nuclear medicine extension codes.Without using representative frequently code set, it was difficult to invent the same code for the same examination. By using the representative frequently code set, the same code expression could be invented for the same examination. Furthermore, using nuclear medicine extension codes additionally, these which could not be appropriately coded with representative frequently code set alone.Nuclear medicine extension codes keeping the integrity with JJ1017, was proved to be useful to improve the accuracy of coding.

We describe a 19-year-old man who developed muscle weakness due to hypokalemia. His blood pressure on admission was considered to be relatively high, and we performed captopril renography. His baseline renogram was normal, while the results of captopril renography showed delayed patterns similar to those of renovascular hypertension. However, his blood pressure level decreased and returned to the normal range without medication 2 weeks after admission. Our final diagnosis in this patient was Barter's syndrome. We speculate that the delayed pattern of captopril renography was due to an imbalance between the prostaglandin and the renin-angiotensin systems. The blockade of the renin-angiotensin system by captopril may cause dominant prostaglandins, produce systemic vasodilatory effects, and lead to hypoperfusion of the kidneys in patients with Bartter's syndrome.

The aim of this study was to estimate radiation exposure and evaluate the risks and benefits of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in cancer screening. A nationwide survey of FDG-PET cancer screening was conducted in 2006, and the results were analyzed with a common index, “extension/shortening of the average life expectancy.” The average estimated effective dose was 4.4 mSv (male 4.7 mSv; female 4.0 mSv) for dedicated PET and 13.5 mSv (male 14.2 mSv; female 12.8 mSv) for PET/computed tomography (CT). The risk–benefit break-even age from the viewpoint of radiation exposure was in the 40s for men and 30s for women for dedicated PET and in the 50s for men and 50s (variable injection dose) or 60s (constant injection dose) for women for PET/CT. FDG-PET cancer screening is beneficial for examinees above the break-even ages. The risks and benefits should be explained to examinees because of the larger radiation used in cancer FDG-PET screening compared with other X-ray tests.

Synthesis and electron transport characteristics of p-type organic semiconductor (III) are reported.

Conformational changes in hemoglobin (a “soft” protein) and catalase (a relatively “soft” protein) upon adsorption on ultrafine silica particles (average diameter 15 nm) have been studied by circular dichroism (CD). Because the light scattering intensity of the ultrafine silica particles is very low, the secondary structure of protein molecules on solid surfaces can be estimated from the CD spectra of the suspension of the ultrafine silica particles on which proteins are adsorbed. The extent of the changes in the secondary structure of both the protein molecules was found to increase with decreasing pH and adsorbed amount. Hemoglobin showed the changes in the secondary structure up to high pH and high adsorbed amount. Therefore, soft proteins are susceptible to conformational changes upon adsorption on solid surfaces. These CD spectrum data give us some quantitative information about the conformational changes in protein molecules upon adsorption on solid surfaces.

The most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan."FDG-PET cancer screening" was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.The detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.We analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.

PET (positron emission tomography) has been proved to be a powerful imaging tool in clinical oncology. The number of PET facilities in Japan has remarkably increased over the last decade. Furthermore, the approval of delivery FDG in 2005 resulted in a tremendous expansion of the PET institutions without a cyclotron facility. The aim of this study was to conduct a cost analysis of PET institutions that utilized delivery FDG.Three PET facilities using delivery FDG were investigated about the costs for PET service. Fixed costs included depreciation costs for construction and medical equipments such as positron camera. Variable costs consisted of costs for medical materials including delivery FDG. The break-even point was analyzed in each of three institutions.In the three hospitals (A, B and C), the annual number of PET scan was 1,591, 1,637 and 914, while cost per scan was accounted as yen 110,262, yen 111,091, and yen 134,192, respectively. The break-even point was calculated to be 2,583, 2,679 and 2,081, respectively.PET facilities utilizing delivery FDG seemed to have difficulty in business administration. Such a situation suggests the possibility that the current supply of PET facilities might exceed actual demand for the service. The efficiency of resource allocation should be taken into consideration in the future health service researches on PET.

The structural changes in horse cytochrome c, bovine ribonuclease A (RNase A), sperm whale myoglobin, ovalbumin, human hemoglobin, and bovine serum albumin (BSA) during adsorption on ultrafine silica particles have been studied. Since the intensity of light scattered by the ultrafine silica particles (average diameter 15 nm) is negligible, the structure of adsorbed protein molecules on the surface is directly estimated by measuring the circular dichroism (CD) spectra of the suspension of particles on which protein molecules were adsorbed. While the CD spectra of soft proteins such as hemoglobin and BSA were changed extensively by adsorption on ultrafine silica particles, those of rigid proteins such as cytochrome c and RNAse A were changed little. Changes in the CD spectrum of BSA during adsorption increased with decreasing pH. Thus, the magnitude of the structural changes is affected by both the flexibility of the protein molecules and the affinities of the particles for proteins. The BSA molecules desorbed from the ultrafine silica particles by addition of morpholine showed CD spectra similar to those of native BSA and hence were refolded. Thus, the conformational changes in BSA molecules produced by adsorption were highly reversible. The adsorption amounts of all these proteins on ultrafine silica particles were maximum at around their isoelectric points regardless of structural adaptability.

A patient with emphysema was evaluated before and after lung volume reduction surgery by pulmonary perfusion and ventilation imaging. Preoperative imaging showed marked nonhomogeneity of perfusion throughout both lung fields, with more segmental defects in the right lower field involving ventilation abnormalities. After resection of the right lower lobe, pulmonary imaging showed an improvement of matched perfusion and ventilation in the right lower field. This case illustrates perfusion and ventilation recovery after lung volume reduction surgery.

We report a case of esophageal carcinoma that showed extraosseous accumulation of 99mTc-MDP in lymph node metastases to the cervical and paracardial lymph nodes. There are few cases showing abnormal extraosseous accumulation of 99mTc-MDP in esophageal cancer lesion. The patient was a 53-year-old man with advanced esophageal cancer. Bone scintigraphy demonstrated extraosseous accumulations in left supraclavicular and paracardial lymph node metastases. The histopathological diagnosis was small cell carcinoma of the esophagus, which is a rare disease with aggressive behavior and poor prognosis. Our patient underwent 2 courses of systemic chemotherapy (CDDP + VP16), but died of rapidly growing systemic metastases 5 months after the initial treatment.

In the management of rectal cancer after the combined therapy of the radiation and surgical operation, the evaluation of the prognosis is important. Although fluoro-18-deoxy glucose positron emission tomography (FDG-PET) is considered as a useful tool for evaluation of therapeutic effect of this cancer as well as the other cancers, however, there are few articles that clearly describe the appropriate procedure of the FDG-PET in order to obtain the best prognostic value. The purpose of the present study is to compare several variations of a semi-quantification method, the Standardized Uptake Values (SUV) and to determine the most appropriate parameter for the prognostic prediction and to propose the quantitative guideline of the FDG-PET. Especially, the authors focused on the SUV after radiotherapy, which had not been considered as a key quantitative value, as it was rather taken as a mere indicator of the therapeutic (radiotherapeutic) effect, not a direct indicator of the prognosis for the cancer itself.Methods: Forty patients with rectal cancer in the lower rectal region underwent two series of FDG-PET study before and after pre-operative radiotherapy. Their SUVs were calculated from FDG-PET data and compared with the results of the long-term follow-up of the patients as well as with histopathological outcomes.Results: All 40 patients had high FDG uptake before radiotherapy. The mean value of SUV before radiotherapy (SUV1) was 7.6. After radiotherapy, the mean value of SUV (SUV2) decreased to 4.2. There was a significant difference in SUV2 between the groups with and without recurrence (p

A photolithographic patterning technique of perfluoropolymers was developed for the micropatterning of solution-processed organic semiconductors. We found that a small amount of fluorosurfactant additives in photoresist solutions enabled preparation of the spin-coated films even on the dewetting surfaces of perfluoropolymers. Subsequent photolithography and dry/wet etching achieved excellent patterning of perfluoropolymers, which provided a high contrast of wettability in microscale on the substrate. The dewetting patterns were applied for isolating solution-processed organic thin-film transistor arrays for a 100 ppi active-matrix display by selective dewetting. The isolation of the semiconducting layers achieved significant improvement in the current on/off ratio with a high mobility of >1 cm2 V−1 s−1.

The number of positron emission tomography (PET) machines has been increasing in regions of East-, Southeast-, and South-Asia as well as in Latin America including Mexico. This study was performed to assess the potential requirement of PET machines in 19 countries which already use PET in the aforementioned regions. Data on the number of PET machines and internationally available characteristics of the restrictive countries such as the land area, the total population, the gross national income (GNI), and the average life span of inhabitants were obtained from IAEA, UN, WB, and WHO. Correlation between the number of PET machines and the characteristics of each country was evaluated. The potentially required number of PET machines, which was obtained by adjusting the number of PET machines with statistically significant, correlative characteristics of each country, standardized on the state of Japan, were compared. The number of PET machines could be significantly correlated to the GNI of a country and the average life span of its inhabitants ( P < 0.05). Based on Japan, most of the countries in the regions would require considerably more PET machines. With installation of the potentially required number of PET machines in each of the countries, the number of PET machine per 10 6 population would increase by 1.1- to 12-fold, in comparison with the current situation. With regards to the potentially required number of PET machines, most of the countries in these regions may require a considerable increase of PET machines. Nevertheless, some countries in the Asia seem to require outside assistance such as international support in order to introduce PET and enhance the efficacy of their health services.

Ambipolar characteristics in an organic field-effect transistor (FET) with a bilayer structure consisting of poly(3-hexylthiophene) (P3HT) and a fullerene derivative (PCBM) are reported. P3HT was deposited by a floating film transfer method (FTM) with toluene solution on spin-coated PCBM. The FTM-deposited film was found to show relatively high hole mobility even when cast using toluene solution. Even after coating P3HT on PCBM by FTM, a relatively high n-type transport was obtained. This indicates that FTM employed in this study is a mild way to coat an organic thin film on an organic semiconductor layer in terms of minimizing the effect of carrier transport in the underlayer. The transport characteristics have been discussed in comparison with those of ambipolar FETs prepared by other methods previously reported.

Field-effect mobilities and threshold voltages in organic field-effect transistors (OFETs) were studied to elucidate the difference of the OFETs performance between Si/SiO2 and flexible polymer substrates. The polymer OFETs were built on poly(ethylene naphthalate) (PEN) film as the substrate with polyimide (PI) as the gate-insulators. Pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylicdiimide (PTCDI-C13) were employed as p- and n-type semiconductors. The n-type OFET on polymer substrates exhibited higher electron mobility and smaller threshold voltages compared with those on Si/SiO2. On the contrary, the p-type OFET on the Si/SiO2 substrate showed better transport performance than that on the polymer substrate. The results are discussed taking the difference of surface potential between SiO2 and PI gate-insulator, which possibly modifies OFET characteristics.

A new solution-processed technique of floating film transfer method (FTM) is proposed for depositing organic thin film semiconductor. Organic field-effect transistors (OFETs) have been fabricated to evaluate the transport characteristics in poly(3-hexylthiophene) (P3HT) films deposited with FTM and spin-coating methodology. An enhancement of hole mobility was found in the FTM film by one order of magnitude as compared to that in spin-coated films. Absorption spectra as well as X-ray diffraction profiles represent well-grown lamella structures of P3HT with FTM transverse to the substrate, representing the advantage of this method suitable for the carrier transport.

A novel n-type organic semiconductor, cyano-substituted distyrylbenzene derivative, 1,4-bis2-[4-(trifluoromethyl)phenyl]acrylonitorilebenzene, was synthesized by Knoevenagel condensation with aldehyde and acetonitrile derivatives. Fabricated thin-film transistors (TFTs) exhibited high electron field-effect mobility of 10-2–10-1 cm2 V-1 s-1, on/off current ratio of 6×105. Hysteresis-free n-type transport characteristics observed in this device promises a steady operation of organic logic circuit. Almost same TFT characteristic was observed even after 1 month storage in ambient condition. The findings indicate that the material has a good resistance to atmospheric oxidants.

The effect of surface properties on the adsorption of bovine gamma-globulin, a model protein for antibody, was studied. Polystyrene latex (PS), hydrophilic copolymer lattices of styrene/2-hydroxyethyl methacrylate [P(S/HEMA)], styrene/ methacrylic acid [P(S/MAA)] and methyl methacrylate/ 2-hydroxyethyl methacrylate [P(MMA/HEMA)], and colloidal silica were used. The adsorption isotherms of gamma-globulin on these colloidal particles were measured as a function of pH and ionic strength. The hydrophilic particles showed low affinities for gamma-globulin at alkaline pH, while PS showed high affinities for gamma-globulin over the whole range of pH and ionic strength. The gamma-globulin adsorption on hydrophilic particles was highly reversible with respect to the pH and ionic strength compared with that on PS. These differences indicate that the dominant driving forces of adsorption are related to the hydrophilicity of particles. The adsorption isotherms of all colloidal particles showed the plateau values, and the order of maximum values of plateau adsorption was P(S/MAA) > PS or P(S/HEMA), silica > P(MMA/HEMA). Thus, they were also affected by the charged groups and the hydrophilicity of the surfaces. On the other hand, the plateau values of all colloidal particles were more or less symmetrical with a maximum at around the isoelectric point of gamma-globulin at an ionic strength of 0.01. This behavior is attributed to the important role of the lateral interaction between the adsorbed molecules at low ionic strength.

π-conjugated low-molecules having the chemical structure of bis(alkyl-thiophene)thienothiophene, abbreviated as, C6-BTTT and C12-BTTT were synthesized and evaluated in their thermal, optical and electronic characteristics. Compounds were synthesized according with Suzuki reaction or Stille reaction. Thermal analysis represents both of C6- and C12-BTTTs did not possess liquid-crystalline phase. Comparison of hole transport characteristics shows a relative high hole transport in C6-BTTT and high air-stability in C12-BTTT, representing a contribution of alkyl-substituent.