Room temperature thermal rectification in suspended asymmetric graphene ribbon.

Thermal rectifiers are essential in optimizing heat dissipation in solid-state devices to enhance energy efficiency, reliability, and overall performance. In this study, we experimentally investigate the thermal rectification phenomenon in suspended asymmetric graphene ribbons (GRs). The asymmetry within the graphene is introduced by incorporating periodic parallel nanoribbons on one side of the GR while maintaining the other side in a pristine form. Our findings reveal a substantial thermal rectification effect in these asymmetric graphene devices, reaching up to 45% at room temperature and increasing further at lower environmental temperatures. This effect is attributed to a significant thermal conductivity contrast between pristine graphene and nanoribbon graphene within the asymmetric structure. We observe that the incorporation of nanoribbons leads to a notable reduction in thermal conductivity, primarily due to phonon scattering and bottleneck effects near the nanoribbon edges. These findings suggest that graphene structures exhibiting asymmetry, facilitated by parallel nanoribbons, hold promise for effective heat management at the nanoscale level and the development of practical phononic devices.

In-situ electrical conductance measurement of suspended ultra-narrow graphene nanoribbons observed via transmission electron microscopy.

Graphene nanoribbon is an attractive material for nano-electronic devices, as their electrical transport performance can be controlled by their edge structures. However, in most cases, the electrical transport has been investigated only for graphene nanoribbons fabricated on a substrate, which hinders the appearance of intrinsic electrical transport due to screening effects. In this study, we developed special devices based on silicon chips for transmission electron microscopy to observe a monolayer graphene nanoribbon suspended between two gold electrodes. Moreover, with the development of an in-situ transmission electron microscopy holder, the current-voltage characteristics were achieved simultaneously with observing and modifying the structure. We found that the current-voltage characteristics differed between 1.5 nm-wide graphene nanoribbons with armchair and zigzag edge structures. The energy gap of the zigzag edge was more than two-fold larger than that of the armchair edge and exhibited an abrupt jump above a critical bias voltage in the differential conductance curve. Thus, our in-situ transmission electron microscopy method is promising for elucidating the structural dependence of electrical conduction in two-dimensional materials.

Novel endoscopic marking clip equipped with resin-conjugated fluorescent indocyanine green during laparoscopic surgery for gastrointestinal cancer.

PURPOSE: Intraoperative identification of the cancer location is often difficult to conduct during laparoscopic surgery, especially in early-stage cancers. This study aimed to investigate the feasibility and accuracy of a novel endoscopic clip resin-conjugated fluorescent indocyanine green during laparoscopic surgery for gastrointestinal cancer. METHODS: Preoperative placement of endoscopic marking clips equipped with resin-conjugated fluorescent indocyanine green was performed to determine the resection margin in eight patients with gastrointestinal cancer. During laparoscopic surgery, a dedicated laparoscopic system with a xenon light source was used to detect fluorescence. The evaluation determined whether the fluorescent from the clips was visualized during laparoscopic surgery. RESULTS: Fluorescent signal emitted from ICG in the resin of the clips was detected in six patients from the outer layer of the serosal surfaces of the gastrointestinal tract, and the clips aided in accurate resection line of the organ. There were no significant differences of age, gender, and BMI between the patients in whom we could and could not detect ICG fluorescence. CONCLUSIONS: The results demonstrated the usefulness of a novel clip-equipped fluorescent resin, which is a promising diagnostic tool to detect accurate tumor location during laparoscopic surgery.

Reference values for the locomotive syndrome risk test quantifying mobility of 8681 adults aged 20-89 years: A cross-sectional nationwide study in Japan.

BACKGROUND: The locomotive syndrome risk test was developed to quantify the decrease in mobility among adults, which could eventually lead to disability. The purpose of this study was to establish reference values for the locomotive syndrome risk test for adults and investigate the influence of age and sex. METHODS: We analyzed 8681 independent community dwellers (3607 men, 5074 women). Data pertaining to locomotive syndrome risk test (the two-step test, the stand-up test, and the 25-question geriatric locomotive function scale [GLFS-25]) scores were collected from seven administrative areas of Japan. RESULTS: The reference values of the three test scores were generated and all three test scores gradually decreased among young-to-middle-aged individuals and rapidly decreased in individuals aged over 60 years. The stand-up test score began decreasing significantly from the age of 30 years. The trajectories of decrease in the two-step test score with age was slightly different between men and women especially among the middle-aged individuals. The two physical test scores were more sensitive to aging than the self-reported test score. CONCLUSION: The reference values generated in this study could be employed to determine whether an individual has mobility comparable to independent community dwellers of the same age and sex.

Dielectric-Screening Reduction-Induced Large Transport Gap in Suspended Sub-10 nm Graphene Nanoribbon Functional Devices.

The predicted quasiparticle energy gap of more than 1 eV in sub-6 nm graphene nanoribbons (GNRs) is elusive, as it is strongly suppressed by the substrate dielectric screening. The number of techniques that can produce suspended high-quality and electrically contacted GNRs is small. The helium ion beam milling technique is capable of achieving sub-5 nm patterning; however, the functional device fabrication and the electrical characteristics are not yet reported. Here, the electrical transport measurement of suspended ≈6 nm wide mono- and bilayer GNR functional devices is reported, which are obtained through sub-nanometer resolution helium ion beam milling with controlled total helium ion budget. The transport gap opening of 0.16-0.8 eV is observed at room temperature. The measured transport gap of the different edge orientated GNRs is in good agreement with first-principles simulation results. The enhanced electron-electron interaction and reduced dielectric screening in the suspended quasi-1D GNRs and anti-ferromagnetic coupling between opposite edges in the zigzag GNRs substantiate the observed large transport gap.

Enhanced Sodium Ion Storage in Interlayer Expanded Multiwall Carbon Nanotubes.

We report an effective approach of utilizing multiwalled carbon nanotubes (MWCNTs) as an active anode material in sodium ion batteries by expanding the interlayer distance in a few outer layers of multiwalled carbon nanotubes. The performance enhancement was investigated using a density functional tight binding (DFTB) molecular dynamics simulation. It is found that a sodium atom forms a stable bonding with the partially expanded MWCNT (PECNT) with the binding energy of -1.50 eV based on the density functional theory calculation with van der Waals correction, where a sodium atom is caged between the two carbon hexagons in the two consecutive MWCNTs. Wave function and charge density analyses show that this binding is physisorption in nature. This larger exothermic nature of binding energy favors the stable bonding between the PECNT and a sodium atom, and thereby, it helps to enhance the electrochemical performance. In the experimental works, partial opening of the MWCNT with the expanded interlayer has been designed by the well-known Hummer's method. It has been found that the introduction of functional groups causes a partial opening of the outer few layers of a MWCNT, with the inner core remaining undisturbed. The enhanced performance is due to an expanded interlayer of carbon nanotubes, which provide sufficient active sites for the sodium ions to adsorb as well as to intercalate into the carbon structure. The PECNT shows a high specific capacity of 510 mAh g-1 at a current density of 20 mA g-1, which is about 2.3 times the specific capacity obtained for a pristine MWCNT at the same current density. This specific capacity is higher when compared to other carbon-based materials. The PECNT also shows a satisfactory cyclic stability at a current density of 200 mA g-1 for 100 cycles. Based on our experimental and theoretical results, an alternative perspective for the storage of sodium ions in MWCNTs is proposed.

SIRT7 is an important regulator of cartilage homeostasis and osteoarthritis development.

Sirtuins (SIRT1-7) are NAD+-dependent deacetylase/deacylases that regulate a wide variety of biological functions. Although the roles of sirtuins in cartilage homeostasis and cartilage diseases have been well studied, there is no information on the contribution of SIRT7 to cartilage homeostasis and osteoarthritis (OA) pathologies. Here, we demonstrate that Sirt7 knockout mice are resistant to the development of aging-associated OA and forced exercise-induced OA. Attenuation of Sirt7 in the murine chondrogenic cell line ATDC5 increased the deposition of a glycosaminoglycan-rich extracellular matrix and the mRNA expression of extracellular matrix components such as Col2a1 and Acan. Mechanistically, we found that SIRT7 suppressed the transcriptional activity of SOX9, which is an important transcription factor in chondrocytes, and that the enzymatic activity of SIRT7 was required for its function. Our results indicate that SIRT7 is a novel important regulator of cartilage homeostasis and OA development.

Controlled fabrication of electrically contacted carbon nanoscrolls.

Carbon nanoscrolls (CNS) with their open ended morphology have recently attracted interest due to the potential application in gas capture, biosensors and interconnects. However, CNS currently suffer from the same issue that have hindered widespread integration of CNTs in sensors and devices: formation is done ex situ, and the tubes have to be placed with precision and reliability-a difficult task with low yield. Here, we demonstrate controlled in situ formation of electrically contacted CNS from suspended graphene nanoribbons with slight tensile stress. Formation probability depends on the length to width aspect ratio. Van der Waals interaction between the overlapping layers fixes the nanoscroll once formed. The stability of these CNSs is investigated by helium nano ion beam assisted in situ cutting. The loose stubs remain rolled and mostly suspended unless subject to a moderate helium dose corresponding to a damage rate of 4%-20%. One CNS stub remaining perfectly straight even after touching the SiO2 substrate allows estimation of the bending moment due to van der Waals force between the CNS and the substrate. The bending moment of 5400 eV is comparable to previous theoretical studies. The cut CNSs show long-term stability when not touching the substrate.

Edoxaban Enhances Thromboprophylaxis by Physiotherapy After Total Knee Arthroplasty　- The Randomized Controlled ESCORT-TKA Trial.

BACKGROUND: The pharmacological advantage of combining physiotherapy with anticoagulants for the prevention of venous thromboembolism (VTE) after total knee arthroplasty (TKA) is not fully known. Herein we investigated the potential benefit of this combination therapy in patients undergoing TKA.Methods and Results:The 38 patients were randomly assigned to a physiotherapy group (n=19) or a physiotherapy plus 30 mg/day edoxaban group (n=19). The occurrence of VTE was evaluated, as were serial changes in parameters measured by the Total Thrombus-formation Analysis System, a novel system for quantitatively analyzing thrombus formation using microchips with thrombogenic surfaces (collagen plus tissue factor, atheroma [AR]-chip). Combination therapy significantly reduced the incidence of VTE after TKA compared with monotherapy (P=0.038). The area under the curve (AUC) of thrombus formation for the AR-chip (AR10-AUC30) was significantly lower in the combination group (P=0.001) on Day 7 after TKA than before TKA, but no significant change was observed with monotherapy (P=0.809). In 13 VTE-positive patients, AR10-AUC30was significantly lower in the combination group (n=3) than in the monotherapy group (n=10) on Day 7 (P=0.045). CONCLUSIONS: The combination of physiotherapy and edoxaban significantly reduced the incidence of VTE after TKA compared with physiotherapy alone. However, it is possible that VTE occurrence after TKA is not only associated with thrombogenicity, but also rheological factors.

[Homeostasis and Disorder of Musculoskeletal System.Enthesis formation and repair:Current understanding and perspectives for the future regenerative therapy.]

Tendons and ligaments are dense fibrous connective tissues mainly composed of type I collagen, aligned in highly ordered arrays along the axis of the tendon and ligament. The enthesis is defined as the attachment site of a tendon, ligament, joint capsule, or fascia to bone. During morphogenesis, the cell population co-expressing Scleraxis(Scx)and the SRY-box containing gene 9(Sox9)contributes to the formation of fibrocartilaginous entheses. Scx regulates tendon and ligament maturation, while Sox9 is a key regulatory factor for cartilage formation. The considerable mechanical forces transmitted through the enthesis and avascular properties of the tissue make it more prone to injuries and degenerative changes. Thus, integration of tendons or ligaments with bone following surgical repair remains a clinical challenge. In this review, we summarize the current knowledge regarding the formation, maintenance, damage, and repair of fibrocartilaginous entheses, focusing on the rotator cuff tendon-to-bone attachment sites.

Mice Deficient in Angiopoietin-like Protein 2 (Angptl2) Gene Show Increased Susceptibility to Bacterial Infection Due to Attenuated Macrophage Activity.

Macrophages play crucial roles in combatting infectious disease by promoting inflammation and phagocytosis. Angiopoietin-like protein 2 (ANGPTL2) is a secreted factor that induces tissue inflammation by attracting and activating macrophages to produce inflammatory cytokines in chronic inflammation-associated diseases such as obesity-associated metabolic syndrome, atherosclerosis, and rheumatoid arthritis. Here, we asked whether and how ANGPTL2 activates macrophages in the innate immune response. ANGPTL2 was predominantly expressed in proinflammatory mouse bone marrow-derived differentiated macrophages (GM-BMMs) following GM-CSF treatment relative to anti-inflammatory cells (M-BMMs) established by M-CSF treatment. Expression of the proinflammatory markers IL-1ß, IL-12p35, and IL-12p40 significantly decreased in GM-BMMs from Angptl2-deficient compared with wild-type (WT) mice, suggestive of attenuated proinflammatory activity. We also report that ANGPTL2 inflammatory signaling is transduced through integrin α5ß1 rather than through paired immunoglobulin-like receptor B. Interestingly, Angptl2-deficient mice were more susceptible to infection with Salmonella enterica serovar Typhimurium than were WT mice. Moreover, nitric oxide (NO) production by Angptl2-deficient GM-BMMs was significantly lower than in WT GM-BMMs. Collectively, our findings suggest that macrophage-derived ANGPTL2 promotes an innate immune response in those cells by enhancing proinflammatory activity and NO production required to fight infection.

Nitrogen Gas Field Ion Source (GFIS) Focused Ion Beam (FIB) Secondary Electron Imaging: A First Look.

The recent technological advance of the gas field ion source (GFIS) and its successful integration into systems has renewed the interest in the focused ion beam (FIB) technology. Due to the atomically small source size and the use of light ions, the limitations of the liquid metal ion source are solved as device dimensions are pushed further towards the single-digit nanometer size. Helium and neon ions are the most widely used, but a large portfolio of available ion species is desirable, to allow a wide range of applications. Among argon and hydrogen, $${\rm N}_{2}^{{\plus}} $$ ions offer unique characteristics due to their covalent bond and their use as dopant for various carbon-based materials including diamond. Here, we provide a first look at the $${\rm N}_{2}^{{\plus}} $$ GFIS-FIB enabled imaging of a large selection of microscopic structures, including gold on carbon test specimen, thin metal films on insulator and nanostructured carbon-based devices, which are among the most actively researched materials in the field of nanoelectronics. The results are compared with images acquired by He+ ions, and we show that $${\rm N}_{2}^{{\plus}} $$ GFIS-FIB can offer improved material contrast even at very low imaging dose and is more sensitive to the surface roughness.

Enhancement of rotator cuff tendon-bone healing with fibroblast growth factor 2 impregnated in gelatin hydrogel sheets in a rabbit model.

BACKGROUND: Application of fibroblast growth factor 2 (FGF-2) may improve the healing response after rotator cuff (RC) surgical repair. This study aimed to determine whether FGF-2-impregnated gelatin hydrogel sheet (GHS) incorporation into the bony trough on the greater tuberosity facilitates healing after RC surgical repair in rabbits. METHODS: We assigned 120 adult male Japanese white rabbits treated with unilateral surgery for supraspinatus tendon repair into the following groups: suture-only group (suture); suture and GHS with phosphate-buffered saline (carrier); suture and GHS with 3 µg of FGF-2 (F3); and suture and GHS with 30 µg of FGF-2 (F30). The effect of FGF-2 was assessed using histologic, biomechanical, and microcomputed tomography evaluations at 2, 6, and 12 weeks. RESULTS: At 12 weeks, loose fibrovascular tissues emerged at the repair site in the suture and carrier groups and dense tendon-like tissues in the F3 and F30 groups, which demonstrated significantly higher ultimate load-to-failure and stress-to-failure at 12 weeks than that in the suture and carrier groups. Microcomputed tomography imaging showed ectopic calcification formation in some specimens from each group. Appearances or frequencies were similar among groups. The histologic and biomechanical effects of FGF-2 on RC healing were obvious at ≥6 weeks postoperatively. CONCLUSION: FGF-2-impregnated GHS incorporation into the bony trough on the greater tuberosity before RC surgical repair is feasible and results in histologic and biomechanical improvements during RC healing in rabbits. No detrimental effect on ectopic calcification was observed.

Precise milling of nano-gap chains in graphene with a focused helium ion beam.

A focused helium ion beam was used to introduce nano-sized gap chains in graphene. The effect of beam scanning strategies in the fabrication of the nano-gap chains was investigated. The tuning of graphene conductivity has been achieved by modulating the magnitude and uniformity of the ion dose and hence the morphology of the nano-gap chains. A model based on the site-specific and dose-dependent conductivity was built to understand the tuning of the conductivity, taking into account the nanoscale non-uniformity of irradiation.

Neuropathic pain in patients with rotator cuff tears.

BACKGROUND: Recent studies have confirmed the existence of neuropathic pain (NeP) components in patients with musculoskeletal disorders. However, the presence of NeP in patients with rotator cuff tears has not been investigated thus far. Therefore, we studied the prevalence of NeP and the prognostic factors for NeP in patients with rotator cuff tears. METHODS: Data were collected from 110 patients with rotator cuff tears, diagnosed by physical examination and magnetic resonance imaging, who attended an outpatient clinic between August 2013 and August 2014. The measured parameters included visual analog scale (VAS) pain scores, painDETECT questionnaire (PDQ) responses, a physical examination, and magnetic resonance imaging. To evaluate the factors associated with NeP, we performed a two-stage analysis. For univariate analysis, we used the Mann-Whitney U test. For multivariate analysis, forward stepwise regression was performed using factors that demonstrated statistical significance in the univariate analysis. RESULTS: Patients were classified into three groups according to their PDQ score: an NeP group (n = 12; 10.9 %), possible NeP group (n = 33; 30.0 %), and a nociceptive pain (NoP) group (n = 65; 59.1 %). In the univariate analysis between the NeP group and NoP group, NeP was affected by sex (p = 0.034), VAS score (average pain during the past 4 weeks; p = 0.013), and positive Neer and Hawkins impingement signs (p = 0.039). In the multivariate analysis, VAS score (p = 0.031) was an independent prognostic factor for NeP. CONCLUSIONS: Using the PDQ, we found that 10.9 % of patients with rotator cuff tears may have NeP. The VAS score (average pain during the past 4 weeks) was a prognostic factor for NeP. Clinicians should remain vigilant for heterogeneous etiologies of pain in patients with rotator cuff tears.

Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice.

Danforth's short tail (Sd) is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.

Hypertrophic teres minor restores shoulder strength and range of external rotation in posterosuperior rotator cuff tears.

BACKGROUND: In posterosuperior rotator cuff tears (PS-RCT), the progression of infraspinatus (ISP) muscle atrophy seems to induce compensatory hypertrophy of the teres minor (TM) muscles. However, the effect of these changes on shoulder strength and range of external rotation (ER) remains unclear. This study determined the strength and range of ER in patients with PS-RCT with atrophic ISP and hypertrophic TM and compared this with patients with PS-RCT and normal or deficient TM. METHODS: We investigated 35 patients with PS-RCT and atrophic ISP. TM muscles were classified as hypertrophic (type A) in 17, normal (type B) in 10, or deficient (type C) in 8. The strength ratio of the affected shoulder to the healthy contralateral shoulder was calculated, and the active range of motion was measured for both shoulders. RESULTS: The strength ratios of ER in types A, B, and C were 60%, 33%, and 7% (P < .01) with the patient's arm at the side and were 60%, 35%, and 5% (P < .001) at 90° abduction, respectively. The average ranges of ER in types A, B, and C were 22.6°, 15.0°, and -12.5° (P < .001) with the patient's arm at the side and were 71.6°, 44.5°, and 21.9° at 90° abduction (P < .01), respectively. The differences between shoulder types in other measures of strength or ER range were not significant. CONCLUSIONS: In patients with PS-RCT and atrophic ISP, shoulders with compensatory hypertrophy of the TM had greater strength and range of ER than shoulders with normal or atrophic TM.

Electrically Tunable van der Waals Interaction in Graphene-Molecule Complex.

van der Waals (vdW) interactions play a central role in the surface-related physics and chemistry. Tuning of the correlated charge fluctuation in a vdW complex is a plausible way of modulating the molecules interaction at the atomic surface. Here, we report the vdW interaction tunability of the graphene-CO2 complex by combining the first-principles calculations with the vdW density functionals and the time evaluation measurements of CO2 molecules adsorption/desorption on graphene under an external electric field. The field-dependent charge transfer within the complex unveils the controllable tuning of CO2 from acceptor to donor. Meanwhile, the configuration of the adsorbed molecule, the equilibrium distance from graphene and O-C-O bonding angle, is modified accordingly. The range of electrical tunability is a unique feature for each type of molecule.

Amyloid deposits derived from transthyretin in the ligamentum flavum as related to lumbar spinal canal stenosis.

Amyloidosis is a protein conformational disorder with the distinctive feature of extracellular accumulation of amyloid fibrils that come from different proteins. In the ligamentum flavum of the lumbar spine, amyloid deposits were frequently found in elderly patients with lumbar spinal canal stenosis and were at least partially formed by wild-type transthyretin. However, how amyloid deposits in the ligamentum flavum affect lumbar spinal canal stenosis has remained unclear. In this study, we analyzed clinical, pathologic, and radiologic findings of patients with lumbar spinal canal stenosis who had amyloid deposits in the ligamentum flavum. We studied 95 ligamentum flavum specimens obtained from 56 patients with lumbar spinal canal stenosis and 21 ligamentum flavum specimens obtained from 19 patients with lumbar disk herniation. We evaluated histopathologic findings and clinicoradiologic manifestations, such as thickness of the ligamentum flavum and lumbar spinal segmental instability. We found that all 95 ligamentum flavum specimens resected from patients with lumbar spinal canal stenosis had amyloid deposits, which we classified into two types, transthyretin-positive and transthyretin-negative, and that transthyretin amyloid formation in the ligamentum flavum of patients with lumbar spinal canal stenosis was an age-associated phenomenon. The amount of amyloid in the ligamentum flavum was related to clinical manifestations of lumbar spinal canal stenosis, such as thickness of the ligamentum flavum and lumbar spinal segmental instability, in the patients with lumbar spinal canal stenosis with transthyretin-positive amyloid deposits. To our knowledge, this report is the first to show clinicopathologic correlations in transthyretin amyloid deposits of the ligamentum flavum. In conclusion, transthyretin amyloid deposits in the ligamentum flavum may be related to the pathogenesis of lumbar spinal canal stenosis in elderly patients.

Position detection and observation of a conducting filament hidden under a top electrode in a Ta2O5-based atomic switch.

Resistive random access memories (ReRAMs) are promising next-generation memory devices. Observation of the conductive filaments formed in ReRAMs is essential in understanding their operating mechanisms and their expected ultimate performance. Finding the position of the conductive filament is the key process in the preparation of samples for cross-sectional transmission electron microscopy (TEM) imaging. Here, we propose a method for locating the position of conductive filaments hidden under top electrodes. Atomic force microscopy imaging with a conductive tip detects the current flowing through a conductive filament from the bottom electrode, which reaches its maximum at a position that is above the conductive filament. This is achieved by properly biasing a top electrode, a bottom electrode and the conductive tip. This technique was applied to Cu/Ta2O5/Pt atomic switches, revealing the formation of a single Cu filament in a device, although the device had a large area of 5 × 5 µm(2). Change in filament size was clearly observed depending on the compliance current used in the set process. It was also found from the TEM observation that the cross-sectional shape of the formed filament varies considerably, which is attributable to different Cu nuclei growth mechanisms.