Virtual Reality Computed Tomography Evaluation　- Anatomy and Clinical Implications for Valve-Sparing Aortic Root Replacement.

BACKGROUND: Three-dimensional aortic root evaluation using virtual reality (VR) techniques for valve-sparing aortic root replacement (VSARR) preparation has not yet been implemented, so we demonstrated VR computed tomography (VR-CT) and assessed its utility for VSARR.Methods and Results: We enrolled 72 patients who underwent multidetector CT before elective VSARR for annuloaortic ectasia with tricuspid aortic valve. The geometries of their aortic roots were measured with a VR-CT workstation. The mean values of geometric height (GH), free margin length (FML), and commissural height (CH) were 17.2±2.4 mm, 36.0±5.2 mm, and 24.0±4.3 mm, respectively. The right coronary/noncoronary CH was significantly greater than the left coronary/right coronary and left coronary/noncoronary CH. The left coronary cusp had the shortest FML, intercommissural distances (ICD), and smallest central angle. Although the right coronary cusp had the largest values for FML, ICD, and central angle, the right coronary cusp had the lowest GH and EH. The VR-CT measurements strongly correlated with intraoperative alternatives, especially with mean GH (R2=0.75) and left coronary/noncoronary CH (R2=0.79). Furthermore, mean GH was observed to be significantly different among the selected graft size groups; therefore, the preoperative mean GH could play a significant role in graft sizing. CONCLUSIONS: VR-CT evaluation allows a thorough understanding of aortic root anatomy, which could facilitate VSAAR.

Landau Quantization of a Narrow Doubly-Folded Wrinkle in Monolayer Graphene.

Folding can be an effective way to tailor the electronic properties of graphene and has attracted wide study interest in finding its novel properties. Here we present the experimental characterizations of the structural and electronic properties of a narrow graphene wrinkle on a SiO2/Si substrate using scanning tunneling microscopy/spectroscopy. Pronounced and nearly equally separated conductance peaks are observed in the d I/d V spectra of the wrinkle. We attribute these peaks to pseudo-Landau levels (PLLs) that are caused by a gradient-strain-induced pseudomagnetic field up to about 42 T in the narrow wrinkle. The introduction of the gradient strain and thus the pseudomagnetic field can be ascribed to the lattice deformation. A doubly-folded structure of the wrinkle is suggested. Our density functional theory calculations show that the band structure of the doubly folded graphene wrinkle has a parabolic dispersion, which can well explain the equally separated PLLs. The effective mass of carriers is obtained to be about 0.02 me ( me: the rest mass of electron), and interestingly, it is revealed that there exists valley polarization in the wrinkle. Such properties of the strained doubly folded wrinkle may provide a platform to explore some exciting phenomena in graphene, like zero-field quantum valley Hall effect.

[A Case of Meningeal Solitary Fibrous Tumour/Haemangiopericytoma WHO Grade III Metastasized to the Spleen Shortly After Tumor Resection].

Revision of WHO guidelines in 2016 led to the classification of solitary fibrous tumours(SFTs)and haemangiopericytomas(HPCs)as a single tumor entity characterized by NAB2-STAT6 fusion. Standard-of-care treatment involves surgery, but local recurrence and distant metastasis sometimes occur. The average latency to metastasis after surgery is 99 months. A 38-year-old female patient presented with a complaint of headache. An 8×5×2cm lesion showing Gd-T1 enhancement was detected near the superior sagittal sinus. Pathological assessment following resection revealed proliferating, polymorphic, atypical tumor cells with distinct nucleoli in a "patternless pattern." Cellularity was moderate to high, and mitotic figures were observed in 15/10 high power fields. Immunohistochemically, tumor cells tested positive for STAT6, and RT-PCR revealed a NAB2-STAT6 fusion gene(exons 6 and 17, respectively), supporting a diagnosis of SFT/HPC WHO grade III. Despite postoperative radiotherapy, multiple metastases to the spleen were detected 8 months after surgery, and distal pancreatectomy with splenectomy was performed. The pathology of the splenic tumor was similar to that of the intracranial tumor. Recurrent disease in a lymph node was detected 1 month later, and local radiation therapy was administered. The patient died of cancerous peritonitis 5 months later. In this case, exceedingly rapid metastasis to the spleen occurred, despite the administration of vigorous treatment. Here, we review SFT/HPC incidence, treatment, and outcomes to better understand this rare malignancy.

Spin correlation in O(2) chemisorption on Ni(111).

Molecular oxygen (O(2)) is a paramagnetic linear molecule, yet how its electron spin affects the chemisorption probability remains unclear. We here present the first spin- and alignment-resolved O(2) chemisorption experiment conducted with a single spin-rotational state-selected O(2) beam and a magnetized Ni(111) surface. The results show that the O(2) sticking probability is higher when its spin is oriented antiparallel to the majority spin direction of the Ni substrate. The spin dependence becomes more significant at low translational energy, and amounts to over 40% at thermal energy. This strong spin effect suggests that incident O(2) molecules keep high spin polarizations even at the position of the dissociation barrier.

Communication: fully alignment-specified O2 chemisorption on vicinal Si(100).

A fully alignment-resolved O2 sticking experiment on a single domain Si(100)-(2×1) surface is presented. This provides the first experimental evidence that the reactivity of O2 depends on both the polar and azimuthal angles of the molecular axis relative to a surface. It has been found that, in case of side-on collision, an O2 molecule perpendicular to the dimer on Si(100) is about 40% more reactive than that parallel to the dimer. Comparison of the O2 sticking on flat and vicinal Si(100) surfaces indicates that barrierless dissociation channels exist at the double layer step.

Steric effect in O2 sticking on Al(111): preference for parallel geometry.

We present experimental evidence that the sticking probability of O2 on Al(111) depends strongly on the alignment of an O2 molecule relative to the surface. The steric effect was measured with an aligned O2 beam prepared by a hexapole magnet. It has been found that, at translational energies <0.2 eV, O2 sticking occurs predominantly when the molecular axis is parallel to the surface, and that the dissociation barrier at the perpendicular geometry is ∼ 0.1 eV higher than at the parallel geometry. The present results indicate that the abstraction process, which would occur at the perpendicular geometry, is a minor event at low translational energies.

High-endurance micro-engineered LaB6 nanowire electron source for high-resolution electron microscopy.

The size tunability and chemical versatility of nanostructures enable electron sources of high brightness and temporal coherence, both of which are important characteristics for high-resolution electron microscopy1-3. Despite intensive research efforts in the field, so far, only conventional field emitters based on a bulk tungsten (W) needle have been able to yield atomic-resolution images. The absence of viable alternatives is in part caused by insufficient fabrication precision for nanostructured sources, which require an alignment precision of subdegree angular deviation of a nanometre-sized emission area with the macroscopic emitter axis4. To overcome this challenge, in this work we micro-engineered a LaB6 nanowire-based electron source that emitted a highly collimated electron beam with good lateral and angular alignment. We integrated a passive collimator structure into the support needle tip for the LaB6 nanowire emitter. The collimator formed an axially symmetric electric field around the emission tip of the nanowire. Furthermore, by means of micromanipulation, the support needle tip was bent to align the emitted electron beam with the emitter axis. After installation in an aberration-corrected transmission electron microscope, we characterized the performance of the electron source in a vacuum of 10-8 Pa and achieved atomic resolution in both broad-beam and probe-forming modes at 60 kV beam energy. The natural, unmonochromated 0.20 eV electron energy loss spectroscopy resolution, 20% probe-forming efficiency and 0.4% probe current peak-to-peak noise ratio paired with modest vacuum requirements make the LaB6 nanowire-based electron source an attractive alternative to the standard W-based sources for low-cost electron beam instruments.

Overexpression of IQGAP1 in advanced colorectal cancer correlates with poor prognosis-critical role in tumor invasion.

IQGAP1 is a multifunctional protein involved in actin cytoskeleton assembly and E-cadherin-mediated cell adhesion. We reported previously IQGAP1 overexpression in human colorectal carcinomas especially at the invasion front (IF) and that such overexpression tended to correlate with lymph node metastasis in advanced cases. Thus, in this study, we investigated the clinicopathological significance of IQGAP1 expression in 85 cases of pT2-3 colorectal carcinomas with special reference to its expression pattern and prognosis, followed by analysis of the role of IQGAP1 in cancer invasion in vitro. Quantitative reverse transcription-PCR showed significant upregulation of IQGAP1 in colorectal carcinomas compared with normal mucosa. Immunohistochemically, IQGAP1 expression pattern was classified into diffuse (20%), IF-associated (35.3%) and focal (44.7%). The diffuse pattern was associated with higher rates of distant metastasis. Patients with IQGAP1 overexpression and diffuse pattern had significantly shorter survival (p < 0.0001) than others, and the diffuse pattern was an independent predictor of poor survival by multivariate analysis. In vitro invasion assays using three human colon carcinoma cell lines showed that IQGAP1 siRNA significantly suppressed hepatocyte growth factor (HGF)-stimulated cell invasion. HGF reduced membranous localization of alpha-catenin, but did not alter localization of E-cadherin, beta-catenin and IQGAP1 in membranes. Suppression of IQGAP1 expression by siRNA did not alter membranous localization of alpha-catenin even in the presence of HGF. Our results indicate that IQGAP1 plays a critical role in colon cancer cell invasion, and therefore diffuse and high expression of IQGAP1 predicts poor prognosis in patients with colorectal carcinoma.

Single orifice vein reconstruction in left liver plus caudate lobe graft.

BACKGROUND/AIMS: We describe the innovative techniques with single orifice vein reconstruction for the complete venous drainage in the left liver plus caudate lobe graft. METHODOLOGY: Eight left liver plus caudate lobe grafts used for living donor adult liver transplantation were reviewed. A wide and single venous orifice was created by gathering the left, middle or its tributaries, and/or short hepatic vein using a patch vein graft or a conduit vein graft. This single, newly-created orifice was then anastomosed to the common trunk created in the recipient's hepatic veins. RESULTS: Of 8 liver grafts, six included the middle hepatic vein trunk. Another two included only the middle hepatic vein tributaries. Significantly-sized short hepatic veins were preserved in 4 grafts and were connected with the major hepatic veins or tributaries of the middle hepatic vein to make a single orifice using a conduit vein graft. For remaining 4 grafts without significantly-sized short hepatic veins, two adjacent hepatic vein trunks (left and middle hepatic veins) were simply connected together. To enlarge the common orifice of the hepatic veins, the patch vein grafts were further attached. Hepatic vein waveforms of all grafts showed the biphasic or triphasic pattern and the graft congestion was not observed immediately after venoplasty. No graft was lost due to hepatic venous outflow block with the mean follow-up of 15 months. CONCLUSIONS: The short-term results of our technique were satisfactory. The present technique can simplify graft-to-recipient hepatic vein reconstruction without unfavorable tension on the anastomosis.

Prospective randomized trial of a closed-suction drain versus a Penrose drain after a colectomy.

BACKGROUND/AIMS: Prospective studies in the gastroenterological surgery literature have shown fewer wound related complications with a closed-suction drainage than with an open passive drainage. This study compared the SSI and cost of closed-suction drainage and open passive drainage in a randomized trial. METHODOLOGY: This study involved 112 patients undergoing colectomy from December, 2003 through April, 2007. A closed-suction or an open (Penrose) drainage was used based on the surgeon's preference. The cost and the incidence of complications including SSI was compared in the two drain types. RESULTS: The SSI rate was 13/112 cases 11.6%, but there was no significant difference between the drain groups. In addition, 18 laparoscopic surgery cases did not show any wound infection or drain infections. The closed-suction drain was not expensive regarding personnel expenses and the cost of changing the dressings. CONCLUSIONS: No statistically significant postoperative differences were observed between a closed-suction drain or an open drain after a colectomy. However, a closed-suction drain management is useful for the reduction of a cost, labor saving, and the decrease of medical waste.

[Evaluation of bevacizumab for advanced colorectal cancer].

BACKGROUND: Recently, Bevacizumab became one of the major therapeutics in the care of advanced and recurrent colorectal cancer patients in Japan. The present study evaluated the efficacy and the adverse events in 23 patients who were treated with Bevacizumab. METHODS: From April, 2007 to February, 2009, 23 colorectal cancer patients were treated with Bevacizumab. We evaluated the adverse events and the time to progression (TTP). RESULTS: The median age of the patients was 60 years old. Advanced cases were 14 and recurrence cases were 9. The basic combination chemotherapy with Bevacizumab included FOLFOX (14 patients), FOLFIRI (8 patients), and IFL (1 patient). Although grade 3 of melena was recognized in one patient, the other mild adverse events were treated without accident. The median TTP was 108 days, and was not significantly different between combination with mFOLFOX6 or FOLFIRI. In combination therapy of Bevacizumab and mFOLFOX6, the TTP of Bevacizumab first-line treatment was significantly longer than that of second-line treatment (p<0. 05). In contrast, the TTP was no different in FOLFIRI therapy with or without Bevacizumab. CONCLUSION: Although one grade 3 side effect was observed, most patients were treated safely with Bevacizumab. mFOLFOX6 with Bevacizumab was recommended for first-line therapy of advanced or metastatic colorectal cancer.

Predictive factors of early recurrent death after a curative resection of gastric cancer.

Although several prognostic factors for gastric cancer have been shown, the predictive factors of early recurrent death remain to be elucidated. This study included 402 patients who underwent a curative resection for gastric cancer. Fifty-six patients died of recurrence. A multivariate analysis was performed to determine the independent factors correlated with survival time. The patients with an elevation of tumor markers, tumors in the upper one third of the stomach, deep wall invasion (T3, T4), extended lymph node metastases (N2, N3), an advanced stage (stages III and IV), and operation (total gastrectomy) showed a significantly different survival time. According to a multivariate analysis, the survival time was independently associated with tumor location, tumor markers, and lymph node metastases. The patients with tumors in the upper one third of the stomach, elevated tumor markers, and extended lymph node metastases can not be controlled by surgery alone.

Intermediate band solar cell materials through the doping of group-VA elements (N, P, As and Sb) in Cu2ZnSiSe4.

The electronic structure and optical properties of group-VA (N, P, As, and Sb)-doped Cu2ZnSiSe4 alloys have been studied using a hybrid functional through density functional theory calculations. The minor lattice distortion and small formation energy indicate that synthesis of these alloys is highly possible in experiment. For each doped alloy, an isolated and partially filled intermediate band (IB) appears in its band structure. The doping-induced IB is mainly contributed by the s states of the doped group-VA atom and the p states of four neighboring Se atoms, and slightly by the d states of eight Cu atoms. The existence of an IB obviously enhances the absorption coefficient with two additional absorption peaks in the visible light range. For P, As and Sb-doped Cu2ZnSiSe4 alloys, not only the bandgap between the valence band maximum and the conduction band minimum but also the sub bandgap between the valence band maximum and the IB are very close to the optimal values for visible light absorption. Therefore, these alloys are recommended as good candidates for IB solar cell materials.

Surface magnetization measurement with a spin-polarized metastable He beam under high magnetic fields of 0-5 T.

An apparatus for measuring the surface magnetization with a spin-polarized metastable helium atom (He(*)) beam under external magnetic fields of 0-5 T was developed. The He(*) beam, spin polarized by a sextupole magnet, was directed to the sample placed in the bore of 5 T superconducting magnet. A zero-field spin flipper was used for switching the polarity of beam polarization. A Stern-Gerlach analysis indicated the beam polarization of nearly 100% and the spin flipping efficiency of >90%. A surface magnetization curve was successfully measured from 0 to 5 T for an FeCu(100) surface.

Development of spin-polarized ion scattering spectroscopy.

Spin-polarized ion scattering spectroscopy using an electron-spin-polarized 4He+ ion beam was developed as a novel analytical method of the element selective spin state at outermost surfaces. Spin-polarized He+ ions were generated from the Penning ionization of metastable He 2(3)S1 atoms (He*), which were spin-polarized by optical pumping (OP). The spin polarization of He* (PHe*) was observed to be the highest with an OP radiation density of about 0.05 W cm(-2), and a further increase of the OP radiation density reduced P(He*). This decrease of PHe* is attributed to imperfect polarization of the OP radiation, hence optimization of the OP radiation density is essential to obtain He+ ions with high spin polarization. As a result of this optimization, we successfully observed the spin dependence of the scattered He+ ion yield on an Fe(100) surface exposed to an oxygen atmosphere.

Prospective evaluation of occlusive hydrocolloid dressing versus conventional gauze dressing regarding the healing effect after abdominal operations: randomized controlled trial.

OBJECTIVE: To compare occlusive hydrocolloid dressing (OHD; Karayahesive) and gauze dressing (GD) with regard to the cost and incidence of wound infection after abdominal surgery. METHODS: A total of 134 patients who underwent incisions were randomized to have their wounds dressed with either OHD or GD. OHD was left on until the sutures were removed, and GD was changed everyday postoperatively. The cost calculations represent the number of dressings required for each treatment group as determined by the frequency of required dressing changes and cost per dressing. RESULTS: There were no differences between the groups regarding the need for dressings to be changed or the incidence of infection. OHD was less expensive and complicated than GD, which needed to be changed everyday (p < 0.0001). CONCLUSION: The results suggest that OHD is less expensive to use than GD, and the risk of wound infection is not increased compared to GD.

Retransplantation of the liver in adults: long-term outcome and prognostic modeling.

BACKGROUND/AIMS: The purpose of this study was to assess the outcome of liver retransplantation in adults at our institution and identify the subset of patients in which the outcome was too poor to justify retransplantation. METHODOLOGY: Over a 12-year period, we performed 346 liver transplantations in 305 adult patients, and of these, 41 (11.8%) were retransplantations. Survival data were stratified and multivariate analysis was conducted to identify variables associated with poor outcome after retransplantation. RESULTS: The 90-day, 1-year, and 5-year survival rates after liver retransplantation were 65.9%, 62.6%, and 48.2%, respectively. These rates were significantly inferior compared to those following single liver transplantation. Major adverse events affecting patient survival after retransplantation occurred within the first 90 days after surgery. Three independent prognostic variables of patient survival after retransplantation were identified: preoperative coagulation factor, total bilirubin, and the need for preoperative dialysis. Using these variables, we defined a simplified mathematical model available at the time of decision of retransplantation. CONCLUSIONS: The present study indicated three important prognostic factors associated with a poor outcome after retransplantation. Based on our newly developed scoring-system estimating patient survival, we suggest that retransplantation must be indicated before the deterioration of more than two organs. These findings should assist in the decision process for liver retransplantation in adult patients.

Does a correlation exist between tumor occupation rate and Dukes classification in rectal cancer?

This study was undertaken to evaluate the correlation between tumor occupation rate and stage in rectal cancer patients. 210 patients with histologically confirmed adenocarcinoma of the rectum were evaluated. Retrospectively, we divided the subjects' pathological specimens into four groups: group A, tumor occupied less than one fourth of the colic lumen; group B, tumor occupied one fourth to one half of the colic lumen; group C, tumor occupied one half to three quarters of the colic lumen; group D, tumor occupied more than three quarters of the colic lumen. As the tumor occupation rate increased, more invasive cases were observed. Patients of group A had significantly longer survival than those of the other groups. Tumor occupation rates correlated significantly with the Dukes classification (r = 0.546, P < 0.0001). Tumor occupation rate is a primitive method but an easy and inexpensive technique for judging tumor stage. This method can assist in preoperative evaluation, thereby reducing the need for other redundant methods.