Gas Sensing Based on a Nonlinear Response: Discrimination between Hydrocarbons and Quantification of Individual Components in a Gas Mixture

A novel sensing system is proposed based on the multidimensional information contained in a dynamic nonlinear response. A sinusoidal temperature change was applied to a SnO(2) semiconductor gas sensor, and the resulting output conductance of the sensor was analyzed by fast Fourier transformation (FFT). The higher harmonics of the FFT characterized the nonlinear properties of the response. The amplitudes of the higher harmonics of the FFT exhibit characteristic changes which depend on the chemical structure, concentration, and the kinetics of adsorption and the reaction of hydrocarbon gases and aromatic vapors on the sensor surface. In addition, it is possible to distinguish between gases in a gaseous mixture with a single detector using this dynamic nonlinear response. Nonlinear responses are discussed in relation to the kinetics of the reaction at the sensor surface and the temperature-dependent barrier potential of the semiconductor.

Ablation of demineralized dentin using a mid-infrared tunable nanosecond pulsed laser at 6 μm wavelength range for selective excavation of carious dentin

In dental clinic, some lasers have already realized the optical drilling of dental hard tissue. However, conventional lasers lack the ability to discriminate and excavate carious tissue only, and still depend on the dentist's ability. The objective of this study is to develop a selective excavation of carious dentin by using the laser ablation with 6 μm wavelength range. Bovine dentin demineralized with lactic acid solution was used as a carious dentin model. A mid-infrared tunable pulsed laser was obtained by difference-frequency generation technique. The wavelength was tuned around the absorption bands called amide 1 and amide 2. In the wavelength range from 5.75 to 6.60 μm, the difference of ablation depth between demineralized and normal dentin was observed. The wavelength at 6.02 μm and the average power density of 15 W/cm(2), demineralized dentin was removed selectively with less-invasive effect on normal dentin. The wavelength at 6.42 μm required the increase of average power density, but also showed the possibility of selective ablation. In the near future, development of compact laser device will open the minimal invasive laser treatment to the dental clinic.

Transient expression of Xpn, an XLMR protein related to neurite extension, during brain development and participation in neurite outgrowth

KIAA2022 has been implicated as a gene responsible for expressing X-linked mental retardation (XLMR) proteins in humans. However, the functional role of KIAA2022 in the human brain remains unclear. Here, we revealed that depletion of Kiaa2022 inhibits neurite outgrowth of PC12 cells, indicating that the gene participates in neurite extension. Thus, we termed Kiaa2022 as an XLMR protein related to neurite extension (Xpn). Using the mouse brain as a model and ontogenetic analysis of Xpn by real-time PCR, we clearly demonstrated that Xpn is expressed transiently during the late embryonic and perinatal stages. In situ hybridization histochemistry further revealed that Xpn-expressing neurons could be categorized ontogenetically into three types. The first type showed transient expression of Xpn during development. The second type maximally expressed Xpn during the late embryonic or perinatal stage. Thereafter, Xpn expression in this type of neuron decreased gradually throughout development. Nevertheless, a significant level of Xpn expression was detected even into adulthood. The third type of neurons initiated expression of Xpn during the embryonic stage, and continued to express the gene throughout the remaining developmental stages. Subsequent immunohistochemical analysis revealed that Xpn was localized to the nucleus and cytoplasm throughout brain development. Our findings indicate that Xpn may participate in neural circuit formation during developmental stages via nuclear and cytoplasmic Xpn. Moreover, disturbances of this neuronal circuit formation may play a role in the pathogenesis of mental retardation.

Inhibition of 5-lipoxygenase activity in mice during cuprizone-induced demyelination attenuates neuroinflammation, motor dysfunction and axonal damage

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Increased expression of 5-lipoxygenase (5-LO), a key enzyme in the biosynthesis of leukotrienes (LTs), has been reported in MS lesions and LT levels are elevated in the cerebrospinal fluid of MS patients. To determine whether pharmacological inhibition of 5-LO attenuates demyelination, MK886, a 5-LO inhibitor, was given to mice fed with cuprizone. Gene and protein expression of 5-LO were increased at the peak of cuprizone-induced demyelination. Although MK886 did not attenuate cuprizone-induced demyelination in the corpus callosum or in the cortex, it attenuated cuprizone-induced axonal damage and motor deficits and reduced microglial activation and IL-6 production. These data suggest that during cuprizone-induced demyelination, the 5-LO pathway contributes to microglial activation and neuroinflammation and to axonal damage resulting in motor dysfunction. Thus, 5-LO inhibition may be a useful therapeutic treatment in demyelinating diseases of the CNS.

Interface dynamics under nonequilibrium conditions: from a self-propelled droplet to dynamic pattern evolution

In this article, we describe the instability of a contact line under nonequilibrium conditions mainly based on the results of our recent studies. Two experimental examples are presented: the self-propelled motion of a liquid droplet and spontaneous dynamic pattern formation. For the self-propelled motion of a droplet, we introduce an experiment in which a droplet of aniline sitting on an aqueous layer moves spontaneously at an air-water interface. The spontaneous symmetry breaking of Marangoni-driven spreading causes regular motion. In a circular Petri dish, the droplet exhibits either beeline motion or circular motion. On the other hand, we show the emergence of a dynamic labyrinthine pattern caused by dewetting of a metastable thin film from the air-water interface. The contact line between the organic phase and the aqueous phase forms a unique spatio-temporal pattern characterized as a dynamic labyrinth. Motion of the contact line is controlled by diffusion processes. We propose a theoretical model to interpret essential aspects of the observed dynamic behavior.

Effect of Kampo medicine Juzen-taiho-to on adverse events induced by cetuximab

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Background: Cetuximab is now considered a standard treatment for advanced or unresectable colorectal cancer, unfortunately patients suffer a skin reaction as the main indication of the toxicity of cetuximab. It is recently reported that Kampo medicine (Goshajinkigan) is considered to be an effective agent for the neuropathy of oxaliplatin. Kampo medicine “Juzen-taiho-to” (TJ-48, Tsumura CO. Ltd.), which consists of 10 component herbs, is known as a tonic agent which improves the general systemic condition of cancer patients by reducing the adverse effects of chemotherapy, radiation therapy, and surgical treatment and to inhibit metastases. The aim of this study was to clarify the efficacy of TJ-48 for adverse events associated with cetuximab therapy.

Methods: From 2009, cetuximab was administered initially at a dose of 400 mg/m2 followed by weekly infusions at 250 mg/m2 to 20 patients with non-resectable or recurrent colorectal cancer. Eighteen patients received oral administration of 7.5 g/day of TJ-48 (TJ-48 group) every day in the first course and 7 patients did not receive TJ-48 (Control group). Adverse events were evaluated for every course according to CTCAE version 3.0.

Results: There was no statistically significant difference between the two groups based on any of patient characteristics. No patients complained of persistent Grade 3 infusion reaction. The percentage of Grade 2 or more skin reactions in each course tended to be lower in the TJ-48 group compared with the Control group (TJ-48 group 34% vs control group 57%). Incidence of Grade 2 anorexia in the TJ-48 group was significantly lower than in the Control group (TJ-48 group 34% vs control group 71%, p=0.03). There were no differences regarding tumor response between the two groups.

Conclusions: TJ-48 is useful to prevent anorexia in non-resectable or recurrent colorectal cancer patients treated with cetuximab regimen.

[Table: see text]

The role of UGT1A1 polymorphisms (*28 and *6) in Japanese cancer patients

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Background: Combination protocol using FU-LV with irinotecan (FOLFIRI) is currently regarded as standard first-line therapy in advanced colorectal cancer (CRC). Although irinotecan prolongs survival, it causes severe diarrhea and neutropenia. Recent pharmacogenetic studies on irinotecan have revealed significant associations of UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms *28 and *6, the latter being specifically detected in East Asians resulting in severe toxicity. It is necessary that the dose-finding trial that decided the optimal dose according to the gene polymorphism to draw out the maximum therapeutic effect while evading the side effect. Here we present the result of prospective trial of the safety about FOLFIRI therapy according to each gene type of UGT1A1 for Japanese patients with advanced CRC.

Methods: From 2008, 250 Japanese patients in TOKUSHIMA University were enrolled in this study. Homo group (*6/*6 and *28/*28 or a both hetero types), hetero group (It was *28 and either *6 was hetero type), and wild group (*28 and *6 were wild types) were defined. On the 23 patients with advanced CRC treated with FOLFIRI after standard chemotherapy, wild and homo groups were administered 150mg/m2 irinotecan, and homo group was 100mg/m2.

Results: On the 23 patients, the genotypes of UGT1A1 *28 were homozygous in 1 (0.5%) and heterozygous in 5 (28%), *6 were homozygous in 0 and heterozygous in 6 (26%). In *6 heterozygous patients, severe toxicities (grade 3 or more) were found (33%), but in *28 heterozygous patients were not (0%). There was no decrease of irinotecan doses in each group. In Japanese people, UGT1A1 *6 polymorphisms were higher than *28 (*6 homo 3%, hetero 27% vs *28 homo 0.5%, hetero 13%).

Conclusions: When the dosage of irinotecan is decided, it is necessary to consider the UGT1A1 *6 heterozygous in Japanese cancer patients.

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A randomized phase II trial of chemoradiotherapy with oral fluoropyrimidine inhibitory for dihydropyrimidine dehydrogenase for low rectal cancer: An interim report

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Background: Preoperative chemoradiotherapy (CRT) has been widely used to improve local control of disease and to preserve anal sphincter in the treatment of rectal cancer. However, the response to CRT differs among individual tumors. In ASCO 2008 Gastrointestinal Cancers Symposium, we reported that the patients with up-regulation of 17 genes were suggested to be good responder of CRT. Our purpose of this study was to evaluate the toxicity and efficacy of CRT using UFT versus S-1 and explore biomarkers for response in patients with locally advanced rectal cancer.

Methods: Fifty patients who received preoperative CRT (40Gy radiotherapy) were randomly assigned to either UFT or S-1. UFT and S-1 were administered during the radiotherapy course. S-1 was a novel oral fluoropyrimidine inhibitory for dihydropyrimidine dehydrogenase and had potent radiosensitizing property. Biopsy specimens were obtained from rectal cancer before preoperative CRT and were analyzed by focused DNA microarray (132 genes). To pick up the predictive factors, the 132 genes were selected in the view of sensitivity of 5FU. Response to CRT was determined by RECIST and histopathologic examination of surgically resected specimens and classified as responders (CR, PR and grade 2, 3) or nonresponders (SD, PD and grade 0, 1).

Results: UFT group (n=25) and S-1 group (n=25) were enrolled. Response rate (grade 2 or 3) to CRT determined by histopathologic examination of surgically resected specimens was 58% in the UFT group and was 75% in the S-1 group. Response rate evaluated by RECIST criteria was 62% in the UFT group and was 77% in the S-1 group. National Cancer Institute Common Toxicity Criteria grade 2 or 3 toxicity was observed in 8% of the patients in the UFT group and 23% of patients in the S-1 group. Grade 2 or 3 toxicity in the UFT group was neutropenia and was diarrhea, neutropenia and dermatitis in the S-1 group. In ASCO 2010, we will report each candidate biomarker genes for response to CRT in the UFT and S-1 group.

Conclusions: The results have suggested that CRT using UFT or S-1 is feasible and effective for patients with locally advanced rectal cancer.

[Table: see text]

Role of thrombospondin 1 (THBS1) expression in peritoneal metastasis of gastric cancer treated with taxanes

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Background: To clarify the utility of taxanes and to pick up the prognostic factors in the treatment with 5FU- based chemotherapy for peritoneal metastasis of gastric cancer.

Methods: Responder analysis: 18 patients with peritoneal metastasis of gastric cancer were enrolled in phase I study. The regimen consists of S-1 (80-120 mg) for 14 days and intraperitoneal infusion of PTX (dose escalation: 40 - 100 mg/m2) at day 1 and 14, which was repeated 2 cycles. To pick up the predictive factors, the 137 genes, which were selected in the viewpoint of sensitivity of 5FU, CPT11 and taxanes, were analyzed using focused DNA microarray for the 12 patients. Role of THBS1 expression: THBS1 expressions were evaluated in immunohistochemical (IHC) staining of surgical specimens of 59 patients with peritoneal metastasis of gastric cancer who were administered 5FU-based chemotherapy. THBS1 positive was defined > 30% of the population stained moderate to strong.

Results: Responder analysis: Expressions of THBS1 gene of the 6 patients who had clinical benefits (2: partial response, 2: positive adenocarcinoma cells in peritoneal cytology became negative, 2: remarkable decrease of ascites) were more than 2 folds higher than those of no responders. THBS1 expression was confirmed in 5 (83.3%) using IHC staining, who had significantly higher survival rate compared with that of the negative. Role of THBS1 expression: 17 patients (28.8%) was THBS1 positive and had significantly better prognosis compared with negative patients (1year survival: 64.7% vs 34.7%). 38 patients treated with regimes including taxanes revealed a tendency of improved overall survival rates (p=0.05). Overall survival of 15 patients with THBS1 positive administered taxanes was significantly higher than that of the negative patients. (1 year survival: 66.7% vs 42.4%)

Conclusions: PTX could improve the survival of peritoneal metastasis of gastric cancer. THBS1 is a prognostic factor especially in the patients treated with taxanes, which leads to tailor-made therapy.

[Table: see text]

DNA compaction in a crowded environment with negatively charged proteins

We studied the conformational properties of DNA in a salt solution of the strongly charged protein bovine serum albumin. DNA is compacted when a suitable amount of bovine serum albumin is added to the solution due to a crowding effect and strong electrostatic repulsion between DNA and bovine serum albumin, both of which carry negative charges. However, DNA undergoes an unfolding transition with an increase in the salt concentration. This observation contradicts the current understanding of polymer- and salt-induced condensation, ψ condensation. We propose a simple theoretical model by taking into account the competition between the translational entropy of ions and electrostatic interaction.

Mass-yield distribution of the fission products in fallout from the 14 may 1965 nuclear explosion

Twenty single particles separated from a 20-liter sample of rain collected in Osaka, Japan, shortly after the 14 May 1965 test explosion of the Chinese nuclear device, were analyzed radiochemically. The abundance pattern of the fission products in these particles resembled the shape of the mass-yield curve for the thermal neutron-induced fission of uranium-235, except for the facts that cesium-hl37 and strontium-90 were markedly depleted and the yields near the symmetric fission region appeared to be somewhat enhanced.

Navigation-guided fence-post tube technique for resection of a brain tumor: technical note

INTRODUCTION

A new technique using a navigation system to minimize the influence of brain shift and to perform precise resection of brain tumors is demonstrated. To determine the resection plane, one to six tubes were inserted around the tumor under the guidance of a navigation system before dural incision.

RESULTS

This technique termed the "navigation-guided fence-post tube" (NGFP) procedure was used to treat 34 patients with intraaxial brain tumors including gliomas (23 cases), malignant lymphomas (4 cases) and metastatic tumors (7 cases). Tumors were removed totally in 23 cases (67.6%), subtotally (95% or more removal) in 6 cases (17.6%) and partially (less than 95% removal) in 5 cases (14.7%). The cases with subtotal or partial resection contained tumors that were close to or involved the eloquent area, or disseminated lesions. No complications due to tube insertion occurred.

CONCLUSION

NGFP is a useful and safe technique for brain tumor surgery with no influence of brain shift during tumor resection.