Role of five-fold twin boundary on the enhanced mechanical properties of fcc Fe nanowires

The role of 5-fold twin boundary on the structural and mechanical properties of fcc Fe nanowire under tension is explored by classical molecular dynamics. Twin-stabilized fcc nanowire with various diameters (6-24 nm) are examined by tension tests at several temperatures ranging from 0.01 to 1100 K. Significant increase in the Young's modulus of the smaller nanowires is revealed to originate from the central area of quinquefoliolate-like stress-distribution over the 5-fold twin, rather than from the surface tension that is often considered as the main source of such size-effects found in nanostructures. Because of the excess compressive stress caused by crossing twin-boundaries, the atoms in the center behave stiffer than those in bulk and even expand laterally under axial tension, providing locally negative Poisson's ratio. The yield strength of nanowire is also enhanced by the twin boundary that suppresses dislocation nucleation within a fcc twin-domain; therefore, the plasticity of nanowire is initiated by strain-induced fcc→bcc phase transformation that destroys the twin structure. After the yield, the nucleated bcc phase immediately spreads to the entire area, and forms a multigrain structure to realize ductile deformation followed by necking. As temperature elevated close to the critical temperature between bcc and fcc phases, the increased stability of fcc phase competes with the phase transformation under tension, and hence dislocation nucleations in fcc phase are observed exclusively at the highest temperature in our study.

A water soluble prodrug of a novel camptothecin analog is efficacious against breast cancer resistance protein-expressing tumor xenografts

PURPOSE

Identification of a novel topoisomerase I inhibitor which shows superior efficacy and less individual variation than irinotecan hydrochloride (CPT-11).

METHODS

A novel camptothecin analog that is effective against breast cancer resistance protein (BCRP)-positive cells was screened, and a water soluble prodrug was generated. Antitumor activity of the prodrug was examined in BCRP-positive and -negative xenografts both as a single agent and in combination with other anti-cancer drugs.

RESULTS

A novel camptothecin analog, CH0793076, was discovered. Because CH0793076 was found to be highly lipophilic, a water soluble prodrug (TP300) was generated. TP300 is stable in an acidic solution but is rapidly converted to CH0793076 under physiological pH conditions such as in sera. This efficient prodrug activation would minimize interpatient differences in pharmacokinetic and toxicity profiles. Unlike CPT-11, TP300 does not exhibit cholinergic interaction or cause acute diarrhea at effective doses. In mouse xenograft models, TP300 showed antitumor activity against both BCRP-positive and -negative xenografts, whereas CPT-11 was less active against BCRP-positive xenografts. In addition, the effective dose range (MTD/ED(50)) for TP300 was wider than for CPT-11 and TP300 showed additive or synergistic antitumor effects in combination with other anti-cancer drugs such as capecitabine, oxaliplatin, cisplatin, bevacizumab and cetuximab.

CONCLUSION

It is therefore expected that TP300 will provide an additional treatment option for patients who will undergo chemotherapy with camptothecins.

Influence of Humic Acid on Sorption of Neptunium(V) onto Soil

The pH dependence of the stability constant of Np(V)-humate and the sorption of Np(V) onto soil was studied to clarify the influence of dissolved organic carbon on the migration behavior of Np(V) in soil layer. The stability constant of Np(V)-humate was expressed by logβ1=(0.35 ±0.03)pH+0.04±0.01 in the pH region from 5.3 to 8.7, and the intrinsic stability constant by logβ*1=3.66±0.05.

The sorption of Np(V) increased with pH up to pH 7, and tended to reach maximum, about 95%, at pH 9 in the absence of humic acid. In the presence of humic acid more than 140mg/l, the sorption of Np(V) was lower than that in the absence of humic acid above pH 7, while any influence of humic acid on the sorption of Np(V) onto soil was not observed below pH 7. The sorption behavior of Np(V) onto soil was explained by reversible sorption of NpO2+ and sorption of NpO2CO3- and/or NpO2OH. Further, the influence of the size distribution of Np(V) on the sorption onto soil was examined and discussed.

Coarse-grained molecular dynamics simulations on size effect of glassy polyethylene particles

The size effect on mechanical properties of glassy polyethylene (PE) nanoscale particles has been investigated by extensive coarse-grained molecular dynamics simulations. The diameter of the PE particles varies in the range of 5-40 nm, we confirm that the particle's behaviour under compressive stress strongly depends on its size-the smaller the particle diameter is, the stiffer the particle behaves. The present mechanical responses of compressed particles are in good agreement with our previous experimental phenomena of micron-sized polymer particles measured by a nanoindentation-based flat punch method. Possible reasons for the size effect are discussed.

Interferon-α increases monocyte migration via platelet-monocyte interaction in murine intestinal microvessels

The aim of this study was to investigate the effect of interferon (IFN)-α on recruitment of platelets and monocytes within the murine small intestinal venular endothelium. Monocytes were isolated from bone marrow of C57B6 mice. Platelets were collected from murine blood. Rolling and adhesion to submucosal microvessels in the small intestine were examined under an intravital fluorescence microscope after injection of fluorescein-labelled monocytes or platelets. In some mice, IFN-α (5×10(5) U/kg) was administered intraperitoneally. After treatment with an antibody against P-selectin, changes in monocyte and platelet migration were also investigated. Changes in monocyte migration under the condition of thrombocytopenia were also investigated. Platelets and monocytes interacted with murine intestinal microvessels, although only few platelets and monocytes showed migration behaviour. Intraperitoneal injection of IFN-α enhanced the migration of both platelets and monocytes in the intestinal microvessels. Pretreatment with anti-P-selectin attenuated the increase in migration of platelets and monocytes induced by administration of IFN-α. Thrombocytopenia decreased the rolling ratio of monocytes, suggesting that the effect of IFN-α on migration was P-selectin-dependent, derived from both the endothelium of microvessels and platelets. The results of this study suggest that IFN-α acts as a potent proinflammatory agent via its stimulatory effect on the endothelium-platelet-monocyte interaction in intestinal microvessels by a P-selectin-dependent mechanism.

Omega-3 polyunsaturated fatty acids ameliorate the severity of ileitis in the senescence accelerated mice (SAM)P1/Yit mice model

Clinical studies using omega-3 polyunsaturated fatty acids (omega3-PUFA) to Crohn's disease (CD) are conflicting. Beneficial effects of dietary omega3-PUFA intake in various experimental inflammatory bowel disease (IBD) models have been reported. However, animal models of large intestinal inflammation have been used in all previous studies, and the effect of omega3 fat in an animal model of small intestinal inflammation has not been reported. We hypothesized that the effects of omega3 fat are different between large and small intestine. The aim of this study was to determine whether the direct effect of omega3 fat is beneficial for small intestinal inflammation. Senescence accelerated mice (SAM)P1/Yit mice showed remarkable inflammation of the terminal ileum spontaneously. The numbers of F4/80-positive monocyte-macrophage cells as well as beta7-integrin-positive lymphocytes in the intestinal mucosa were increased significantly compared with those in the control mice (AKR-J mice). The area of mucosal addressin cell adhesion molecule-1 (MAdCAM-1)-positive vessels was also increased. The degree of expression levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6 and interferon (IFN)-gamma mRNA were increased significantly compared with those in the control mice. The feeding of two different kinds of omega3 fat (fish-oil-rich and perilla-oil-rich diets) for 16 weeks to SAMP1/Yit mice ameliorated inflammation of the terminal ileum significantly. In both the omega3-fat-rich diet groups, enhanced infiltration of F4/80-positive monocytes/macrophages in intestinal mucosa of SAMP1/Yit mice cells and the increased levels of MCP-1, IL-6 and IFN-gamma mRNA expression were ameliorated significantly compared with those in the control diet group. The results suggest that omega3 fat is beneficial for small intestinal inflammation by inhibition of monocyte recruitment to inflamed intestinal mucosa.

Diffusive transport of neptunium and plutonium through compacted sand-bentonite mixtures under anaerobic conditions

Diffusive transport of neptunium, plutonium, tritiated water (HTO), Cs+and I-in compacted sand-bentonite mixtures was studied by a through-diffusion method. Experiments for Np were performed in the presence of carbonate where Np is stable as NpIV(CO3)2(OH)22-and those for Pu in the presence of fulvic acid where the Pu is stable as fulvic complexes. These experiments were performed under Ar (pO2< 10-6atm). Effective diffusivity (De) values of (1.81 ± 0.03) × 10-10, (1.8 ± 0.8) × 10-10, (5.1 ± 0.8) × 10-11and (9.0 ± 4.1) × 10-11m2s-1were obtained for HTO, Cs+, I-and Np(CO3)2(OH)22-, respectively. The ratio of theDeto the diffusivity in bulk of the water was around 0.1 for Np(CO3)2(OH)22-, HTO and Cs+, which is consistent with the pore diffusion model. Observed diffusive transport of Pu was much smaller than those of HTO, Cs+, I-and Np(CO3)2(OH)22-probably because Pu was present as colloidal forms and that confined pore space in the compacted sand-bentonite mixtures does not allow diffusive transport of colloidal plutonium.

A feasibility study of intravenous (IV) paclitaxel, intraperitoneal (IP) carboplatin, and IP paclitaxel in patients with epithelial ovarian carcinoma, fallopian tube carcinoma, or peritoneal carcinoma

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Background: This is a feasibility study for a future trial to assess the feasibility of intravenous (IV) paclitaxel, intraperitoneal (IP) carboplatin and IP paclitaxel (TCipTip therapy) in patients with epithelial ovarian carcinoma, fallopian tube carcinoma or peritoneal carcinoma. Methods: The patients eligible for this study had histologically confirmed, stage IC-IV epithelial ovarian carcinoma, fallopian tube carcinoma or peritoneal carcinoma. IV paclitaxel was administered at 135 mg/m2 followed by IP carboplatin administration based on the area under the curve =6 on day1, and IP paclitaxel was administered at 60 mg/m2 on day 8. To ensure the safety, the three initial patients received 45 mg/m2 of IP paclitaxel on day 8. The toxicity grade was determined by CTCAE version 3. This study has been approved by the institutional review committee. Results: During November 2007 and December 2008, 10 patients were entered in this study. The patients included 7 epithelial ovarian carcinoma (stage IC, 2; stage IIIC, 5), 2 stage IIIC primary peritoneal carcinoma, and 1 stage IIA fallopian tube carcinoma. There were 7 serous adenocarcinoma, 2 endometrioid adenocarcinoma, 1 clear cell adenocarcinoma. The incidences of grade 3/4 hematological toxicities were 48% for neutropenia, 28% for thrombocytopenia, and 48% for anemia. Grade 3/4 neurotoxicity, abdominal pain nor IP catheter related toxicity was not observed. IP paclitaxel at 2nd or 3rd cycle was skipped in 4 patients by grade 3/4 neutropenia (grade 3, 3; grade 4, 1 ). Conclusions: TCipTip therapy is feasible for patients with epithelial ovarian carcinoma, fallopian tube carcinoma or peritoneal carcinoma.

No significant financial relationships to disclose.

Patch technique for repair of a dural tear in microendoscopic spinal surgery

A dural tear is a common but troublesome complication of endoscopic spinal surgery. The limitations of space make repair difficult, and it is often necessary to proceed to an open operation to suture the dura in order to prevent leakage of cerebrospinal fluid. We describe a new patch technique in which a small piece of polyglactin 910 is fixed to the injured dura with fibrin glue. Three pieces are generally required to obtain a watertight closure after lavage with saline. We have applied this technique in seven cases. All recovered well with no adverse effects. MRI showed no sign of leakage of cerebrospinal fluid.

Combination chemotherapy of intraperitoneal carboplatin and intravenous paclitaxel in suboptimally debulked epithelial ovarian cancer

The objective of this study was to retrospectively assess the efficacy and safety of combination chemotherapy of intraperitoneal (IP) carboplatin and intravenous (IV) paclitaxel in suboptimally debulked ovarian cancer. Between March 1998 and March 2006, 44 patients with histologically confirmed epithelial ovarian carcinoma or peritoneal carcinoma with a residual mass greater than 1 cm received combination chemotherapy of IV paclitaxel and IP carboplatin. Administration of IV paclitaxel at 175 mg/m2 immediately followed by IP carboplatin at an area under the curve of 6 was scheduled every 3 weeks for at least six cycles. The diagnosis and stage were ovarian carcinoma stage II in 8, III in 25, and IV in 6 cases, and peritoneal carcinoma stage III in 5 cases. Eighty-three percent of patients completed more than six cycles of chemotherapy. The incidences of grade 3/4 hematologic toxicities were 41 (93%) for neutrocytopenia, 10 (41%) for thrombocytopenia, and 18 (23%) for anemia. Observed grade 3/4 nonhematologic toxicities were 1 (2%) for allergy, 1 (2%) for fatigue, 1 (2%) for vomiting, 1 (2%) for liver dysfunction, and 4 (9%) for peripheral neuropathy. Two patients (5%) encountered catheter problems (one obstruction and one infection). Overall response rate was 80% (16 complete response, 19 partial response, 3 stable disease, and 6 progressive disease). Median progression-free survival and overall survival were 24 and 31 months, respectively. Combination chemotherapy of IP carboplatin and IV paclitaxel is effective and safe in suboptimally debulked ovarian cancer, and further evaluation is warranted.

Regional cerebral blood flow and oxygen metabolism in aneurysmal subarachnoid hemorrhage: positron emission tomography evaluation of clipping versus coiling

OBJECTIVE

We investigated early postoperative hemodynamic and metabolic values using positron emission tomography (PET) scanning in subarachnoid hemorrhage (SAH) patients treated with clipping or coiling, and evaluated usefulness of PET studies in predicting late ischemic events and neurological outcome in SAH patients.

METHODS

We examined 14 SAH patients treated with neurosurgical clipping (CLIP group) and 16 patients treated with endovascular coiling (COIL group). Cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), and oxygen extraction fraction (OEF) were determined using 15O-PET scanning about 8.5 days after SAH.

RESULTS

1) Mean regional CBF (rCBF) in the middle cerebral artery (MCA) territory was significantly higher in CLIP group compared with COIL group; regional CMRO2 (rCMRO2) and regional OEF (rOEF) were also higher. Four clipped patients showed true hyperemia in the MCA territory; none of the coiled patients showed hyperemia. 2) Surgical intervention significantly decreased mean rCMRO2 and rOEF in the operated frontal lobe compared with the unoperated side. 3) Nine of 30 patients (40%) developed subsequent clinical vasospasm after SAH. Significant differences between the spasm group and non-spasm group were not observed in the MCA territory before vasospasm.

CONCLUSION

A wide range of cerebral perfusion patterns including hyperemia were found in the CLIP group. Surgical manipulation of the brain significantly reduced oxygen metabolism in the operated frontal lobe. PET data alone may not have independent prognostic value for detecting delayed cerebral ischemia or in predicting neurological outcome.