The effect of potassium on aluminous phase stability in the lower mantle.

The aluminous calcium-ferrite type phase (CF) and new aluminous phase (NAL) are thought to hold the excess alumina produced by the decomposition of garnet in MORB compositions in the lower mantle. The respective stabilities of CF and NAL in the nepheline-spinel binary (NaAlSiO4-MgAl2O4) are well established. However with the addition of further components the phase relations at lower mantle conditions remain unclear. Here we investigate a range of compositions around the nepheline apex of the nepheline-kalsilite-spinel compositional join (NaAlSiO4-KAlSiO4-MgAl2O4) at 28-78 GPa and 2000 K. Our experiments indicate that even small amounts of a kalsilite (KAlSiO4) component dramatically impact phase relations. We find NAL to be stable up to at least 71 GPa in potassium-bearing compositions. This demonstrates the stabilizing effect of potassium on NAL, because NAL is not observed at pressures above 48 GPa on the nepheline-spinel binary. We also observe a broadening of the CF stability field to incorporate larger amounts of potassium with increasing pressure. For pressures below 50 GPa only minor amounts (<0.011(1)KK+Na+Mg) of potassium are soluble in CF, whereas at 68 GPa, we find a solubility in CF of at least 0.088(3)KK+Na+Mg. This indicates that CF and NAL are suitable hosts of the alkali content of MORB compositions at lower mantle conditions. For sedimentary compositions at lower mantle pressures, we expect K-Hollandite to be stable in addition to CF and NAL for pressures of 28-48 GPa, based on our simplified compositions. Supplementary Information: The online version contains supplementary material available at 10.1007/s00410-024-02129-w.

Experimental evidence for silica-enriched Earth's lower mantle with ferrous iron dominant bridgmanite.

Determination of the chemical composition of the Earth's mantle is of prime importance to understand the evolution, dynamics, and origin of the Earth. However, there is a lack of experimental data on sound velocity of iron-bearing Bridgmanite (Brd) under relevant high-pressure conditions of the whole mantle, which prevents constraints on the mineralogical model of the lower mantle. To uncover these issues, we have conducted sound-velocity measurement of iron-bearing Brd in a diamond-anvil cell (DAC) up to 124 GPa using Brillouin scattering spectroscopy. Here we show that the sound velocities of iron-bearing Brd throughout the whole pressure range of lower mantle exhibit an apparent linear reduction with the iron content. Our data fit remarkably with the seismic structure throughout the lower mantle with Fe2+-enriched Brd, indicating that the greater part of the lower mantle could be occupied by Fe2+-enriched Brd. Our lower-mantle model shows a distinctive Si-enriched composition with Mg/Si of 1.14 relative to the upper mantle (Mg/Si = 1.25), which implies that the mantle convection has been inefficient enough to chemically homogenize the Earth's whole mantle.

Synthesis of Ultra-Incompressible and Recoverable Carbon Nitrides Featuring CN4 Tetrahedra.

Carbon nitrides featuring three-dimensional frameworks of CN4 tetrahedra are one of the great aspirations of materials science, expected to have a hardness greater than or comparable to diamond. After more than three decades of efforts to synthesize them, no unambiguous evidence of their existence has been delivered. Here, the high-pressure high-temperature synthesis of three carbon-nitrogen compounds, tI14-C3 N4 , hP126-C3 N4 , and tI24-CN2 , in laser-heated diamond anvil cells, is reported. Their structures are solved and refined using synchrotron single-crystal X-ray diffraction. Physical properties investigations show that these strongly covalently bonded materials, ultra-incompressible and superhard, also possess high energy density, piezoelectric, and photoluminescence properties. The novel carbon nitrides are unique among high-pressure materials, as being produced above 100 GPa they are recoverable in air at ambient conditions.

New antiferromagnetic perovskite CaCo3V4O12 prepared at high-pressure and high-temperature conditions.

A new perovskite, CaCo(2+)3V(4+)4O12, has been synthesized at high-pressure and high-temperature (HP-HT) conditions. The properties of this perovskite were examined by a range of techniques. CaCo3V4O12 was found to adopt a double-perovskite cubic lattice [a = 7.3428(6) Å] with Im3 symmetry. We have established that this new perovskite is stable at ambient conditions, and its oxidation and/or decomposition at ambient pressure begins above 500 °C. It undergoes an abrupt antiferromagnetic transition around 98 K. Electrical resistivity data suggest semimetallic conductivity in the temperature range of 1.6-370 K. We have established that the Co(2+) ions in CaCo3V4O12 are in the high-spin state with a sizable orbital moment, even though their square-planar oxygen coordination could be more suitable for the low-spin state, which is prone to Jahn-Teller distortion. Electrical resistivity curves also exhibit a distinct steplike feature around 100 K. CaCo3V4O12 is a first example of perovskite in which the sites A' are fully occupied by Co(2+) ions, and hence its synthesis opens the door to a new class of double perovskites, ACo3B4O12, that may be derived by chemical substitution of the A sublattice by lanthanides, sodium, strontium, and bismuth and by other elements and/or of the B sublattice by some other transition metals.

A splenic volume increase due to preoperative chemotherapy may impair the long-term outcome after hepatectomy in patients with initially non-optimally resectable colorectal cancer liver metastases.

BACKGROUND/AIMS: In patients with colorectal cancer liver metastases (CRCLM), chemotherapy-associated hepatotoxicity (CAH) has been shown to be associated with splenomegaly. The aim of the present study was to investigate whether a higher splenic volume increase (SVI) after preoperative chemotherapy was associated with a worse long-term outcome after hepatectomy in patients with CRCLM. METHODOLOGY: Between 2007 and 2012, there were 36 patients who received preoperative chemotherapy based on a diagnosis of initially non-optimally resectable synchronous CRCLM. The splenic volume was measured by CT-volumetry before preoperative chemotherapy and 12 weeks after the start of the chemotherapy. Long-term outcome was analyzed in these patients. RESULTS: The overall survival was significantly shorter in the SVI ≥30% group than in the SVI <30% group (3-year survival = 52% vs. 28%, p <0.05). The disease-free survival was also significantly shorter in the SVI ≥30% group than in the SVI <30% group (Median = 11 vs. 6 months, p <0.05). The survival after recurrence was significantly shorter in the SVI ≥30% group than in the SVI <30% group (Median = 12.0 vs. 18 months, p<0.05). CONCLUSIONS: In patients with non-optimally resectable CRCLM, the SVI during the first 12 weeks of preoperative chemotherapy may be a significant predictor of the long-term survival after hepatectomy.

Extremely low thermal conductivity and high electrical conductivity of sustainable carbon-ceramic electrospun nonwoven materials.

Materials with an extremely low thermal and high electrical conductivity that are easy to process, foldable, and nonflammable are required for sustainable applications, notably in energy converters, miniaturized electronics, and high-temperature fuel cells. Given the inherent correlation between high thermal and high electrical conductivity, innovative design concepts that decouple phonon and electron transport are necessary. We achieved this unique combination of thermal conductivity 19.8 ± 7.8 mW/m/K (cross-plane) and 31.8 ± 11.8 mW/m/K (in-plane); electrical conductivity 4.2 S/cm in-plane in electrospun nonwovens comprising carbon as the matrix and silicon-based ceramics as nano-sized inclusions with a sea-island nanostructure. The carbon phase modulates electronic transport for high electrical conductivity, and the ceramic phase induces phonon scattering for low thermal conductivity by excessive boundary scattering. Our strategy can be used to fabricate the unique nonwoven materials for real-world applications and will inspire the design of materials made from carbon and ceramic.

A facile polymer templating route toward high-aspect-ratio crystalline titania nanostructures.

High-aspect-ratio rutile and anatase hybrid nanowires are produced via a template-directed process using a novel cylindrical polyelectrolyte brush template. Loading the highly negatively charged 1D templates with pre-synthesized TiO(2) nanocrystals, results in the fabrication of soluble crystalline TiO(2) hybrid nanowires.

Giant Room-Temperature Power Factor in p-Type Thermoelectric SnSe under High Pressure.

Materials that can efficiently convert heat into electricity are widely utilized in energy conversion technologies. The existing thermoelectrics demonstrate rather limited performance characteristics at room temperature, and hence, alternative materials and approaches are very much in demand. Here, it is experimentally shown that manipulating an applied stress can greatly improve a thermoelectric power factor of layered p-type SnSe single crystals up to ≈180 µW K-2 cm-1 at room temperature. This giant enhancement is explained by a synergetic effect of three factors, such as: band-gap narrowing, Lifshitz transition, and strong sample deformation. Under applied pressure above 1 GPa, the SnSe crystals become more ductile, which can be related to changes in the prevailing chemical bonding type inside the layers, from covalent toward metavalent. Thus, the SnSe single crystals transform into a highly unconventional crystalline state in which their layered crystal stacking is largely preserved, while the layers themselves are strongly deformed. This results in a dramatic narrowing in a band gap, from Eg = 0.83 to 0.50 eV (at ambient conditions). Thus, the work demonstrates a novel strategy of improving the performance parameters of chalcogenide thermoelectrics via tuning their chemical bonding type, stimulating a sample deformation and a band-structure reconstruction.

Characteristics of Fecal Incontinence in Male Patients in Japan.

Objectives: Although community studies have shown no difference between the sexes in the prevalence of fecal incontinence (FI), few direct comparisons of disease characteristics between male and female patients have been reported. The aim of this study was to determine whether characteristics of FI differ between male and female patients in Japan. Methods: Included in the study were 408 (149 men, 259 women) patients with FI who visited the Matsushima Hospital Coloproctology Center between October 2016 and September 2017. We retrospectively evaluated data on age, number of bowel movements, Bristol stool form scale, number of FI, incontinence scores, anorectal manometry, comorbidities, and history of anal surgery. Results: Maximum resting pressure and maximum squeeze pressure were found to be within normal range in significantly more male than female patients (34.9% vs. 12.4%, respectively; p < 0.0001). Irritable bowel syndrome (IBS, 20.1% vs. 9.3%; p = 0.003) and a history of anal surgery (29.5% vs. 17.5%; p = 0.02) were more prevalent among male patients than among female patients. Use of mepenzolate as treatment was significantly more common among male patients than among female patients (16.8% vs. 6.6%, respectively; p = 0.005). Responses to the various treatments were good, regardless of sex. Conclusions: FI appears to be more commonly accompanied by normal anal sphincter pressures in male patients than in female patients, and IBS and previous anal surgery appear to be more common among male patients than among female patients. FI appears to be controllable in most patients, regardless of sex.

Splenomegaly in FOLFOX-naïve stage IV or recurrent colorectal cancer patients due to chemotherapy-associated hepatotoxicity can be predicted by the aspartate aminotransferase to platelet ratio before chemotherapy.

BACKGROUND: Chemotherapy-associated hepatotoxicity is a common cause of postoperative complications after major hepatectomy. Splenomegaly may indicate portal hypertension due to chemotherapy. To identify chemotherapy-naïve patients with liver damage, the splenic volume (SV) and aspartate aminotransferase to platelet ratio (APR) were investigated. METHODS: Seventy-one patients receiving FOLFIRI, FOLFOX, or FOLFOX plus bevacizumab as first-line chemotherapy were included in this study. The SV measurement was performed by helical computed tomography volumetry, and the SV index (SVI) was calculated during 6 cycles of chemotherapy. The APR was used as an indicator of liver injury and the APR index (APRI) was calculated. RESULTS: The SVI and APRI were significantly higher in the FOLFOX group than in the FOLFIRI group. In the FOLFOX group, the maximum APR during FOLFOX administration was significantly higher in the subjects with SVI ≥ +30% than in those with SVI < +30% (p < 0.01). The incidences of grade 3 or 4 adverse events and grade 2 or greater histopathological sinusoidal injury were significantly higher in the SVI ≥ +30% than in the SVI < +30% group. Interestingly, the SVI was significantly higher in the group with APR ≥ 0.17 before FOLFOX than in the subjects with an APR < 0.17 before FOLFOX (p < 0.05). CONCLUSION: Splenomegaly due to FOLFOX-associated hepatotoxicity can be predicted if the APR before FOLFOX is 0.17 or higher.

Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids.

The dehydration and decarbonation in the subducting slab are intricately related and the knowledge of the physical properties of the resulting C-H-O fluid is crucial to interpret the petrological, geochemical, and geophysical processes associated with subduction zones. In this study, we investigate the C-H-O fluid released during the progressive devolatilization of carbonate-bearing serpentine-polymorph chrysotile, with in situ electrical conductivity measurements at high pressures and temperatures. The C-H-O fluid produced by carbonated chrysotile exhibits high electrical conductivity compared to carbon-free aqueous fluids and can be an excellent indicator of the migration of carbon in subduction zones. The crystallization of diamond and graphite indicates that the oxidized C-H-O fluids are responsible for the recycling of carbon in the wedge mantle. The carbonate and chrysotile bearing assemblages stabilize dolomite during the devolatilization process. This unique dolomite forming mechanism in chrysotile in subduction slabs may facilitate the transport of carbon into the deep mantle.

Usefulness of a Precursory Small Epigastric Midline Incision during Laparoscopic Right Hemicolectomy.

OBJECTIVES: During laparoscopic right hemicolectomy, many surgeons make a small incision near the umbilicus after the routine intraperitoneal operation. In this study, we created a precursory small epigastric incision at the center of a line connecting the xiphoid process and umbilicus (the M point, an empirically determined position) at the start of surgery prior to laparoscopic manipulation. This study aimed to determine whether the small incision at the center of the M point was a suitable position through which the right hemicolon is extracted. METHODS: The subjects included 148 patients who underwent laparoscopic right hemicolectomy at our hospital between January 2013 and December 2019. We measured the distance between the M point and the gastrocolic trunk (GCT) root at the base of the transverse mesocolon and the middle colic artery (MCA) root on preoperative contrast-enhanced computed tomography images. RESULTS: We found that the GCT and MCA roots are located within a radius of 1.5 cm from the M point, suggesting that the base of the transverse mesentery was located almost directly below the M point. Comparisons based on sex differences and body mass index (BMI) also revealed that the transverse mesocolon root is closer to the M point in men and overweight patients. CONCLUSIONS: From these results, the placement of a precursory small epigastric midline incision not only allows for a safe insertion of the first laparoscopic port in a short period of time but also facilitates safe transection and anastomosis due to the proximity of the M point to the transverse mesocolon root.

An extremely rare case of neuromuscular and vascular hamartoma of the appendix.

BACKGROUND: Neuromuscular and vascular hamartoma is a rare lesion of the small intestine, with only 26 cases reported since its initial description in 1982. No occurrence of hamartoma in the appendix has been reported until now. CASE PRESENTATION: A 60-year-old man had been suffering from longstanding right lower quadrant pain. Abdominal computed tomography showed a slight swelling of the appendix as the possible cause of his pain. Laparoscopic appendectomy with partial resection of the cecum was performed for diagnostic and therapeutic purposes. An 18 × 10-mm lesion located on the tip of the appendix was found in the resected specimen. Pathological examination showed that the lesion was covered with normal mucosa and consisted of adipose tissue, smooth muscle fibers, small vessels, and neural fibers. These findings were consistent with neuromuscular and vascular hamartoma of the appendix. CONCLUSION: This is the first report of neuromuscular and vascular hamartoma arising from the appendix.

In situ observation of nanolite growth in volcanic melt: A driving force for explosive eruptions.

Although gas exsolution is a major driving force behind explosive volcanic eruptions, viscosity is critical in controlling the escape of bubbles and switching between explosive and effusive behavior. Temperature and composition control melt viscosity, but crystallization above a critical volume (>30 volume %) can lock up the magma, triggering an explosion. Here, we present an alternative to this well-established paradigm by showing how an unexpectedly small volume of nano-sized crystals can cause a disproportionate increase in magma viscosity. Our in situ observations on a basaltic melt, rheological measurements in an analog system, and modeling demonstrate how just a few volume % of nanolites results in a marked increase in viscosity above the critical value needed for explosive fragmentation, even for a low-viscosity melt. Images of nanolites from low-viscosity explosive eruptions and an experimentally produced basaltic pumice show syn-eruptive growth, possibly nucleating a high bubble number density.

Shaping colloidal rutile into thermally stable and porous mesoscopic titania balls.

High crystallinity and controlled porosity are advantageous for many applications such as energy conversion and power generation. Despite many efforts in the last decades, the direct synthesis of organic-inorganic composite materials with crystalline transition metal oxides is still a major challenge. In general, molecules serve as inorganic precursors and heat treatment is required to convert as-synthesized amorphous composites to stable crystalline materials. Herein, an alternative approach to the direct synthesis of crystalline polymer-metal oxide composites by using a spherical polyelectrolyte brush as the template system is presented. Pre-synthesized electrostatically stabilized rutile nanocrystals that carry a positive surface charge are used as inorganic precursors. In this approach, the strong Coulomb interactions between anionic polyelectrolyte brush chains and cationic crystalline rutile colloids, whose surfaces are not capped and therefore reactive, are the key factors for the organic-inorganic crystalline composite formation. Stepwise calcination first under argon and followed with a second calcination in air lead to the complete removal of the polymer template without collapse and porous rutile balls are obtained. The results suggest that any colloids that carry a surface charge might serve as inorganic precursors when charged templates are used. It is expected that this hierarchical route for structuring oxides at the mesoscale is generally applicable.

Results of a multicenter study of 1,057 cases of rectal cancer treated by laparoscopic surgery.

BACKGROUND: The aim of this study was to clarify the feasibility of laparoscopic surgery for rectal cancer retrospectively in 28 centers throughout Japan. METHODS: Between May 1994 and February 2006, 1,057 selected patients with rectal cancer underwent laparoscopic surgery. All the data regarding the patient details, and operative and postoperative outcome were collected retrospectively. RESULTS: Mean follow-up was 30 months. Procedures included anterior resection in 938, abdominoperineal resection in 107, Hartmann's procedure in 10, and others in two patients. Conversion to open procedures occurred in 77 patients (7.3%). Postoperative surgical complications developed in 235 patients (22.2%), including anastomotic leakage in 84 (9.1%). Median length of postoperative hospital stay was 15 days (7-271 days). Patients with upper rectal cancer had shorter hospital stay than those with lower rectal cancer (14 versus 18 days, p < 0.01). Tumor-node-metastases (TNM) stage included 83(7.9%) stage 0, 495 (46.8%) stage I, 197 (18.6%) stage II, 230 (21.8%) stage III, and 52 (4.9%) stage IV. Recurrence was developed in 67 patients (6.6%) of the 1,011 curatively treated patients. Local recurrence occurred in 11 patients (1.0%). There was no port-site metastasis. Of the 1,011 curatively treated patients, the 3-year disease-free survival rate was 100% in stage 0, 94.6% in stage I, 82.1% in stage II, and 79.7% in stage III. CONCLUSIONS: Laparoscopic surgery is feasible and safe in selected patients with rectal cancer, with favorable short-term and mid-term outcome.

Burgers vector determination in deformed perovskite and post-perovskite of CaIrO(3) using thickness fringes in weak-beam dark-field images.

The thickness-fringe method [Ishida et al., Philosophical Magazine 42 (1980) 453] for complete determination of the character of a dislocation Burgers vector has been performed in CaIrO(3) perovskite and post-perovskite deformed at high pressures and high temperatures. By selecting several main zone axes and determining the number of terminating thickness fringes at the extremity of a dislocation from a wedge-shaped thin-foil specimen in weak-beam dark-field transmission electron microscope (TEM) images, the Burgers vectors were unambiguously determined. The results demonstrate that [100] screw and edge dislocations on the (010) slip plane are dominant in the post-perovskite phase. Curved [100] and [010] dislocations and straight 110 screw dislocations on a potential (001) slip plane were identified in the perovskite phase as well as a high density of {110} twins. Low-angle tilt boundaries consisting of different groups of parallel edge dislocations on the {110} and (001) planes indicate diffusion-assisted climb in perovskite at high temperatures. The differences in dislocation microstructures could be due to activations of limited numbers of slip systems for post-perovskite and of a large number of multiple slip systems for perovskite, which may result in the strong crystallographic preferred orientation (CPO) in post-perovskite and the lack of CPO in deformed perovskite.

[A case report of complete response to RPMI regimen for multiple lymph node metastases following rectal cancer surgery].

A 78-year old man underwent low anterior resection for Stage IIIb rectal cancer(Ra). After surgery, he underwent the Roswell Park Memorial Institute(RPMI)regimen for 6 months followed by oral UFT for 8 months. Since liver metastasis(S6)recurred 2 years and 2 months after surgery, he underwent S6 subsegmentectomy. Four years and 4 months later, he developed multiple lymph node metastases(the Virchow, paraaortic, and intrapelvic lymph nodes), for which FOLFIRI therapy was started, but converted to the RPMI regimen because of strong gastrointestinal side effects. After 3 courses of this regimen, tumor markers returned to normal, and imaging studies showed that the metastases had disappeared. This was interpreted as a complete response(CR). The patient has maintained the complete response for 1 year and 4 months since the start of the RPMI regimen.

Synthesis of an orthorhombic high pressure boron phase.

The densest boron phase (2.52 g cm-3) was produced as a result of the synthesis under pressures above 9 GPa and temperatures up to ∼1800 °C. The x-ray powder diffraction pattern and the Raman spectra of the new material do not correspond to those of any known boron phases. A new high-pressure high-temperature boron phase was defined to have an orthorhombic symmetry (Pnnm (No. 58)) and 28 atoms per unit cell.