Differences in time-to-fusion based on "absence of peri-graft radiolucency" and "trabecular bone bridging" criteria after transforaminal lumbar interbody fusion in patients with low and normal bone density.

OBJECTIVE: To investigate the difference in time-to-fusion between two sets of interbody fusion criteria (absence of peri-graft radiolucency vs. trabecular bone bridging), and to determine the effect of osteoporosis on time-to-fusion. MATERIALS AND METHODS: This retrospective study enrolled 79 patients treated for degenerative disease with one-level transforaminal lumbar interbody fusion from February 2012 to December 2018, and who had both pre- and post-operative CTs. Patients were divided into osteoporosis, osteopenia, and normal groups based on L1 vertebral body attenuation values in pre-operative CT with cutoff of 90 Hounsfield units (HU) and 120 HU. The osteoporosis, osteopenia, and normal groups included 36 patients (mean age: 69.9 years; 8 men and 28 women), 18 patients (mean age: 62.6 years; 7 men and 11 women), and 25 patients (mean age: 56.6 years; 15 men and 10 women), respectively. Fusion was assessed annually on post-operative CT images using absence of peri-graft radiolucency and trabecular bone bridging criteria. Time-to-fusion was estimated using the Kaplan-Meier method, and differences between the groups were examined using the log-rank test. Cox proportional hazards regression was performed. RESULTS: Time-to-fusion took significantly longer in the osteoporosis group in both fusion criteria (0.5 years in normal vs. 2 years in osteopenia vs. 3 years in osteoporosis for absence of peri-graft radiolucency; p = 0.003, and 3 years vs. 4 years vs. 5 years for trabecular bone bridging; p = 0.001). Only osteoporosis grouping was independent risk factor for slow trabecular bone fusion (hazard ratio:0.339; p = 0.003). CONCLUSION: The median time to fusion was significantly longer when using trabecular bone bridging criteria than absence of peri-graft radiolucency criteria.

Noninvasive evaluation of liver fibrosis: comparison of the stretched exponential diffusion-weighted model to other diffusion-weighted MRI models and transient elastography.

OBJECTIVES: To compare the diagnostic performance of the stretched exponential model to those of other DWI models and transient elastography (TE) and to evaluate the influence of confounding factors on the staging of liver fibrosis. METHODS: This retrospective study included 78 consecutive patients who underwent both DWI and TE. The distributed diffusion coefficient (DDC) and intravoxel heterogeneity index (α) from the stretched exponential model, apparent diffusion coefficient (ADC), perfusion fraction (f), pseudodiffusion coefficient (Dp), true diffusion coefficient (Dt), and TE were obtained. Associations between imaging parameters and pathological fibrosis, inflammation, and steatosis were evaluated using Spearman's correlation and multiple regression analysis. Diagnostic accuracy of parameters for fibrosis staging was assessed via the Obuchowski measures. RESULTS: DDC was the only parameter to differ between F0-1 and F2-3 (p < 0.001) and between F2-3 and F4 (p = 0.013). DDC showed significant correlation with fibrosis (p < 0.001) and inflammation (p = 0.001), but not with steatosis (p = 0.619), and was independently associated with only fibrosis in multiple regression analysis (ß = - 0.114, p < 0.001). ADC, Dp, and Dt showed a significant correlation with steatosis (ps ≤ 0.038). DDC showed the highest diagnostic performance for liver fibrosis (0.717; 95% confidence interval, 0.653-0.765) followed by TE (0.681, 0.623-0.733) without a significant difference between DDC and TE (p > 0.999). CONCLUSIONS: DDC from the stretched exponential model is the most accurate DWI parameter with no confounding effect from steatosis and with overall similar diagnostic performance to TE. KEY POINTS: • The distributed diffusion coefficient (DDC) from the stretched exponential model is the most accurate DWI parameter for staging liver fibrosis. • DDC and transient elastography have similar good diagnostic performance for evaluating liver fibrosis. • The stretched exponential DWI model has no confounding effect by steatosis, unlike other DWI models.

Which Factors Affect the Stress of Intraoperative Orthopedic Surgeons by Using Electroencephalography Signals and Heart Rate Variability?

Can we recognize intraoperative real-time stress of orthopedic surgeons and which factors affect the stress of intraoperative orthopedic surgeons with EEG and HRV? From June 2018 to November 2018, 265 consecutive records of intraoperative stress measures for orthopedic surgeons were compared. Intraoperative EEG waves and HRV, comprising beats per minute (BPM) and low frequency (LF)/high frequency (HF) ratio were gathered for stress-associated parameters. Differences in stress parameters according to the experience of surgeons, intraoperative blood loss, and operation time depending on whether or not a tourniquet were investigated. Stress-associated EEG signals including beta 3 waves were significantly higher compared to EEG at rest for novice surgeons as the procedure progressed. Among senior surgeons, the LF/HF ratio reflecting the physical demands of stress was higher than that of novice surgeons at all stages. In surgeries including tourniquets, operation time was positively correlated with stress parameters including beta 1, beta 2, beta 3 waves and BPM. In non-tourniquet orthopedic surgeries, intraoperative blood loss was positively correlated with beta 1, beta 2, and beta 3 waves. Among orthopedic surgeons, those with less experience demonstrated relatively higher levels of stress during surgery. Prolonged operation time or excessive intraoperative blood loss appear to be contributing factors that increase stress.

Predicting Bone Marrow Edema and Fracture Age in Vertebral Fragility Fractures Using MDCT.

OBJECTIVE. The purpose of this study was to evaluate whether CT features can predict bone marrow edema (BME) on MRI and fracture age in vertebral fragility fractures. MATERIALS AND METHODS. A total of 189 thoracolumbar compression fractures in 103 patients (14 men, 89 women; mean age, 76 years) imaged with both spine CT and MRI were retrospectively included. The presence and extent of BME were assessed on MRI to divide fractures into those with and without BME. The group with BME was then classified for subgroup analysis into fractures with extensive BME (comprising 50% or more of the vertebral body) and those with BME comprising less than 50% of the vertebral body. On CT, five features (presence of cortical or endplate fracture line, presence of trabecular fracture line, presence of condensation band, change in trabecular attenuation, and width of paravertebral soft-tissue change) were analyzed. RESULTS. All five CT findings were predominantly seen in fractures with BME (p < 0.001). Elevated trabecular attenuation, presence of a cortical or endplate fracture line, and paravertebral soft-tissue width showed excellent diagnostic indication for fractures with BME (ROC AUCs: 0.990, 0.976, and 0.950, respectively). In the subgroup with extensive BME, paravertebral soft-tissue width was significantly higher, whereas the change in trabecular attenuation was lower compared with those with BME comprising less than 50% of the vertebral body (p < 0.001). When BME was present, fracture age was not significantly different between the two subgroups, and only greater trabecular attenuation elevation was predictive of older fracture age on linear mixed model analyses (p < 0.001). Interobserver agreement was good for the trabecular fracture line factor and excellent for all other factors. CONCLUSION. CT features accurately correlate with the presence and extent of BME in vertebral fragility fractures. Elevation of trabecular attenuation was the only significant image predictor of fracture age.

Paraspinal Lean Muscle Mass Measurement Using Spine MRI as a Predictor of Adjacent Segment Disease After Lumbar Fusion: A Propensity Score-Matched Case-Control Analysis.

OBJECTIVE. The purpose of this study was to compare paraspinal muscle mass between patients with and without adjacent segment disease (ASD) after lumbar fusion. MATERIALS AND METHODS. Fifty patients with ASD (mean age, 61.4 years; ratio of male to female patients: 13:37; mean body mass index [BMI; weight in kilograms divided by the square of height in meters], 25.1) were matched to 50 control patients on the basis of age, sex, BMI, and fusion segment. The total cross-sectional area (CSA) and functional CSA (FCSA; i.e., the area containing lean muscle tissue only) of the paraspinal muscle group (the multifidus and erector spinae muscles) and the psoas muscles were measured on preoperative MRI. The ratio of the FCSA to the total CSA and the skeletal muscle index (SMI; calculated as muscle area [expressed as centimeters squared] divided by the square of the patient's height in meters]) were calculated and compared between the two groups with use of the independent-sample t test. RESULTS. The mean FCSA (2178.6 mm2 vs 2594.0 mm2; p = 0.004), the ratio of the FCSA to the total CSA (45.4% vs 52.2%; p = 0.001), and the SMI of the FCSA (8.8 vs 10.6; p = 0.001) of the paraspinal muscle group were significantly smaller in patients with ASD compared to the control group. When the paraspinal and psoas muscle groups were combined, the mean FCSA (3680.8 mm2 vs 4268.2 mm2; p = 0.013), the ratio of FCSA to total CSA (53.3% vs 58.6%; p = 0.004), the SMI of the total CSA (27.7 vs 29.3; p = 0.049), and the SMI of the FCSA (14.9 vs 17.3; p = 0.002) were significantly lower in patients with ASD than in control patients. CONCLUSION. Patients with ASD had smaller lean muscle mass (FCSA), a lower ratio of FCSA to total CSA, and a lower SMI of the FCSA of the paraspinal muscle group on pre-operative MRI, compared with control patients.

Tuning the electronic structure of single-walled carbon nanotube by high-pressure H2 exposure.

We report on an electronic structure change of single-walled carbon nanotube (SWNT) on hexagonal boron nitride due to electron doping via high-pressure H2 exposure. The fractional coverage of hydrogenated carbon atom is estimated to be at least θ = 0.163 from the in situ I ds-V g measurements of the release process. Raman spectroscopy and x-ray photoelectron spectroscopy were carried out to support the in situ electrical measurements. In particular, we used the dissociative Langmuir-type model to yield the desorption coefficient k des by fitting it to the in situ electrical data. Finally, we applied this hydrogenation method to the SWNT network on the commercial Si/SiO2 substrate to open the possibility of the scalable n-type semiconducting SWNT FETs.

Degradation of dimethyl phthalate using a liquid phase plasma process with TiO2 photocatalysts.

The liquid phase plasma (LPP) method with a TiO2 photocatalyst and hydrogen peroxide was used to decompose dimethyl phthalate (DMP). As the applied voltage, pulse width, and frequency were increased, the rate of decomposition was increased and the decomposition rate was 63% for 180 min under plasma optimum conditions. The addition of TiO2 photocatalyst and hydrogen peroxide increased the DMP decomposition reaction rate, but an excess cause a decrease in decomposition rate due to a decrease in conductivity, blocking of ultraviolet light, and scavenger effect. When the TiO2 photocatalyst and hydrogen peroxide were used together, the decomposition reaction rate of DMP was greatly improved by using LPP single process alone. Also, when all the processes were used at the same time, the decomposition reaction rate was improved to about 2.8 times. DMP undergoes bond cleavage and ultimately decomposes into CO2 and H2O via dimethyl 4-hydroxyphthalate and methyl salicylates due to hydroxyl radicals and various active species generated by the LPP reaction.

Risk factors for recurrence and retreatment after endovascular treatment of intracranial saccular aneurysm larger than 8 mm.

BACKGROUND: Large intracranial aneurysm is challenging for both surgical and endovascular treatment. High recurrence and retreatment rates are still limitations for endovascular treatment. Analysing risk factors of recurrence after endovascular treatment can be useful for planning future treatment strategies. METHOD: We retrospectively reviewed patients with intracranial saccular aneurysm (≥ 8 mm) who underwent endovascular treatment from 2008 to 2017 at our institution. The demographic features, clinical information and angiographic results were analysed to reveal the risk factors for recurrence and retreatment. Subgroup analysis was performed according to packing density (PD) and stent insertion status. RESULTS: The total recurrence and retreatment rates were 25.7% (44/171) and 10.5% (18/171), respectively. Independent risk factors for recurrence after endovascular treatment were larger aneurysm size (OR 1.32; 95% CI 1.17-1.51; p < 0.001), ruptured status (OR 3.91; 95%CI 1.44-10.90; p = 0.008), initial incomplete occlusion (OR 2.72; 95%CI 1.18-6.41; p = 0.020), and low dome-to-neck ratio (OR 0.61; 95%CI 0.36-0.97; p = 0.047). The recurrence rate for the no-stent with low PD (< 17.5%) group was 50% (14/28); 37.5% (6/16) for stent-assisted coil (SAC) with low PD group, 22.0% (20/91) for no-stent with high PD group and 11.1% (4/36) for SAC with high PD group. CONCLUSION: The independent risk factors for recurrence after endovascular treatment in large (≥ 8 mm) intracranial saccular aneurysm were larger aneurysm size, ruptured status, low dome-to-neck ratio and initial incomplete occlusion state. SAC is a useful method for lowering recurrence after endovascular treatment for relatively large (≥ 8 mm) cerebral aneurysm.

Liver fibrosis: stretched exponential model outperforms mono-exponential and bi-exponential models of diffusion-weighted MRI.

OBJECTIVES: To compare the ability of diffusion-weighted imaging (DWI) parameters acquired from three different models for the diagnosis of hepatic fibrosis (HF). METHODS: Ninety-five patients underwent DWI using nine b values at 3 T magnetic resonance. The hepatic apparent diffusion coefficient (ADC) from a mono-exponential model, the true diffusion coefficient (D t ), pseudo-diffusion coefficient (D p ) and perfusion fraction (f) from a biexponential model, and the distributed diffusion coefficient (DDC) and intravoxel heterogeneity index (α) from a stretched exponential model were compared with the pathological HF stage. For the stretched exponential model, parameters were also obtained using a dataset of six b values (DDC#, α#). The diagnostic performances of the parameters for HF staging were evaluated with Obuchowski measures and receiver operating characteristics (ROC) analysis. The measurement variability of DWI parameters was evaluated using the coefficient of variation (CoV). RESULTS: Diagnostic accuracy for HF staging was highest for DDC# (Obuchowski measures, 0.770 ± 0.03), and it was significantly higher than that of ADC (0.597 ± 0.05, p < 0.001), D t (0.575 ± 0.05, p < 0.001) and f (0.669 ± 0.04, p = 0.035). The parameters from stretched exponential DWI and D p showed higher areas under the ROC curve (AUCs) for determining significant fibrosis (≥F2) and cirrhosis (F = 4) than other parameters. However, D p showed significantly higher measurement variability (CoV, 74.6%) than DDC# (16.1%, p < 0.001) and α# (15.1%, p < 0.001). CONCLUSIONS: Stretched exponential DWI is a promising method for HF staging with good diagnostic performance and fewer b-value acquisitions, allowing shorter acquisition time. KEY POINTS: • Stretched exponential DWI provides a precise and accurate model for HF staging. • Stretched exponential DWI parameters are more reliable than D p from bi-exponential DWI model • Acquisition of six b values is sufficient to obtain accurate DDC and α.

Predicting factors for shunt-dependent hydrocephalus in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND: Chronic hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH) is a major complication that leads to a medical burden and poor clinical outcomes. The aim of this study was to evaluate the predictive factors of shunt-dependent hydrocephalus focusing on postoperative fever and infection. METHOD: A total of 418 patients were included in this study and the patient demographic features, radiologic findings, days of fever burden, and infection were compared between the shunt (n = 72) and no shunt group (n = 346). Days of fever burden was defined as the total number of days with the highest body temperature ≥ 38.0 °C each day from day 1 to day 14. Pneumonia, urinary tract infection (UTI), meningitis, and bacteremia were recorded in all patients. RESULTS: The independent predictive factors for shunt-dependent hydrocephalus were older age ≥ 65, microsurgical clipping, placement of extraventricular drainage (EVD), days of fever burden, and infection. The incidence of shunt dependency was 2.4% in the no fever burden patients (n = 123), 14.9% in the 1-3 days of fever burden patients (n = 161), 27.0% in the 4-6 days of fever burden patients (n = 74), and 41.7% in the ≥ 7 days of fever burden patients with statistical significance among groups (p < 0.001). CONCLUSION: The rate of shunt dependency increased proportionally as the days of fever burden increased. Older age (≥ 65), microsurgical clipping, placement of EVD, days of fever burden, and infection were independent predictive factors for shunt dependency. Proper postoperative care for maintaining normal body temperature and preventing infectious disease can help reduce the rate of shunt dependency and improve clinical outcomes.

Infections of Intestinal Helminth at Two Species of Field Mice, Apodemus agrarius and A. Peninsulae, in Gangwondo and Chungcheongnam-do, Korea.

Rodents are important reservoirs of diseases affecting people and livestock, and are major sources of parasite contamination of agricultural products. We surveyed the infection status of intestinal helminths in 2 species of field mice, Apodemus agrarius and A. peninsulae, captured in the agricultural fields of Gangwon-do and Chungcheongnam-do, Korea. Total 83 mice (57 A. agrarius and 26 A. peninsulae) were collected in 2 surveyed areas, and the intestines of each mouse were opened with scissors, and then intestinal contents were examined with microscope. Total 6 species of intestinal helminth were detected in 61 (73.5%) out of 83 mice examined. Four species of nematode, i.e., Nippostrongylus brasiliensis, Aspiculuris tetraptera, Heterakis spp. and ascarid, were found in 40 (48.2%), 14 (16.9%), 11 (13.3%) and 13 (15.7%) mice respectively. One species of cestode, Hymenolepis diminuta and 1 unidentified egg were also detected in the intestines of 14 (16.9%) and 1 (1.2%) mice, respectively. Conclusively, this study identified 5 helminth species in the gastrointestinal tracts of wild rodents captured in some areas in central and northern Korea, and N. brasiliensis was the most prevalent (dominant) species rather than zoonotic ones.

The effect of disability awareness educational program of university students in the department of physical therapy on reducing prejudices against people with disabilities and increasing positive attitudes toward people with disabilities.

[Purpose] The purpose of this study is to investigate the effects of disability awareness educational program of university students in the department of physical therapy on reducing prejudice against people with disabilities and increasing positive attitudes toward people with disabilities. [Participants and Methods] Students who participated in the disability awareness educational program were selected as experiment group and 15 students who did not take program were selected as control group. [Results] First, in the comparisons between the control and experimental group, there was no difference in the overall prejudice on people with disabilities and positive attitudes toward people with disabilities before the disability awareness educational program. However, there was a significant difference in the overall prejudice and positive attitudes between two groups after the disability awareness educational program. Second, in the comparisons between pretest and posttest, there was no significant difference in the overall prejudice on people with disabilities in control group. However, in the comparisons between pretest and posttest, there was a significant difference in the overall prejudice in experimental group. [Conclusion] It is necessary to provide disability awareness educational program for the university students in the department of physical therapy to reduce the overall prejudices against people with disabilities and increase positive toward people with disabilities.

Anti-inflammatory effect of torilidis fructus ethanol extract through inhibition of Src.

CONTEXT: Torilidis fructus, fruits of Torilis japonica Decadolle (Umbelliferae), is a medicinal herb traditionally used as a pesticide, an astrictive, or a medicine for various inflammatory diseases. OBJECTIVES: Due to the lack of pharmacological studies on this herbal medicine, we explored the inhibitory activity of torilidis fructus on the macrophage-mediated inflammatory response using its ethanol extract (Tf-EE). MATERIAL AND METHODS: The Griess assay and prostaglandin (PGE2) ELISA assay were conducted with Tf-EE (0-75 µg/mL) and LPS (1 µg/mL) treated RAW264.7 cells in cultured media. Tf-EE pretreated RAW264.7 cells were incubated with LPS for 6 h and semi-quantitative PCR was performed. Reporter gene assays, overexpression of target enzymes and immunoblotting were performed on macrophages to determine the molecular targets of Tf-EE. RESULTS: Tf-EE markedly suppressed the inflammatory response of macrophages, such as lipopolysaccharide (LPS)-induced nitric oxide (NO) and PGE2 production with IC50 values of 35.66 and 62.47 µg/mL, respectively. It was also found that Tf-EE reduced the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 by 80%. Nuclear translocation and activation of nuclear factor (NF)-κB (p65 and p50) were declined by 60% and 30% respectively, and their regulatory events including the phosphorylation of AKT, IκBα, Src, and the formation of complexes between Src and p-p85 were also recognized to be diminished. CONCLUSIONS: The signalling events managed by Src and p85 complex seemed to be critically involved in Tf-EE-mediated anti-inflammatory response. This might suggest that Tf-EE exhibited anti-inflammatory effects through Src-targeted inhibition of NF-κB.

Analysis of prejudices and attitudes of students in the department of physical therapy against people with disabilities.

[Purpose] The purpose of this study is to examine prejudices and attitudes of students in the department of physical therapy, in order to suggest basic data for constructing an effective program to develop a positive attitude toward people with disabilities and lower social distance from them. [Subjects and Methods] For this study, students in the department of physical therapy participate in the survey examining prejudices and attitude towards people with disabilities. [Results] First, there were statistically significant differences in the prejudice against people with disabilities among student groups divided by whether they had contact on a frequent basis currently with those who have disabilities. Second, there were statistically significant differences in the prejudice against people with disabilities among student groups divided by whether they had an experience of being harmed by people with disabilities. Third, there was a correlation among prejudices against people with disabilities with each other that is articulated in the eighth domain. Finally, as a result of regression analysis, the students' attitudes towards people with disabilities were explained appropriately by the prejudices about performance of daily tasks and NIMBY (Not In My Back Yard) syndrome. [Conclusion] It is crucial to create an environment where University students in the department of physical therapy can have positive interactions with people with disabilities, to reduce the overall prejudices, and specifically, the prejudices about performance of daily tasks and about NIMBY syndrome.

Novel chimeric peptide with enhanced cell specificity and anti-inflammatory activity.

An antimicrobial peptide (AMP), Hn-Mc, was designed by combining the N-terminus of HPA3NT3 and the C-terminus of melittin. This chimeric AMP exhibited potent antibacterial activity with low minimal inhibitory concentrations (MICs), ranging from 1 to 2 µM against four drug-susceptible bacteria and ten drug-resistant bacteria. Moreover, the hemolysis and cytotoxicity was reduced significantly compared to those of the parent peptides, highlighting its high cell selectivity. The morphological changes in the giant unilamellar vesicles and bacterial cell surfaces caused by the Hn-Mc peptide suggested that it killed the microbial cells by damaging the membrane envelope. An in vivo study also demonstrated the antibacterial activity of the Hn-Mc peptide in a mouse model infected with drug-resistant bacteria. In addition, the chimeric peptide inhibited the expression of lipopolysaccharide (LPS)-induced cytokines in RAW 264.7 cells by preventing the interaction between LPS and Toll-like receptors. These results suggest that this chimeric peptide is an antimicrobial and anti-inflammatory candidate as a pharmaceutic agent.

Electronic transport in heterostructures of chemical vapor deposited graphene and hexagonal boron nitride.

CVD graphene devices on stacked CVD hexagonal boron nitride (hBN) are demonstrated using a novel low-contamination transfer method, and their electrical performance is systematically compared to devices on SiO(2). An order of magnitude improvement in mobility, sheet resistivity, current density, and sustained power is reported when the oxide substrate is covered with five-layer CVD hBN.

Ultralong Ordered Nanowires from the Concerted Self-Assembly of Discotic Liquid Crystal and Solvent Molecules.

The realization of long, aligned molecular wires is a great challenge, and a variety of approaches have been proposed. Interestingly, hexapentyloxytriphenylene (HAT5) discotic liquid crystal molecules, a model system of molecules with flat and aromatic cores, can spontaneously form well-aligned, micrometer long, yet only tens of nanometers thick, nanowires on solid surfaces. We have investigated the formation mechanism of these wires using different solvents with selected characteristics, including chemical structure, boiling point, vapor pressure, and surface tension. When casting from toluene and benzene solutions, atomic force microscopy reveals that the discotics spontaneously form very long and thin wires, self-aligning along a common orientation. If instead dodecane or heptane are used, different and in general thicker structures are obtained. The chemical structure of the solvent appears to have a key role, coupling to the liquid crystal self-assembly by allowing solvent molecules to enter the ordered structure if their design matches the core of HAT5 molecules, thereby guiding the assembly. However, other aspects are also relevant in the assembly, including the nature of the substrate and the rate of solvent evaporation, and these can favor or interfere with the self-assembly into long structures. The use of solvents with aromatic structure is advantageous not only because it affects the geometry of the assembly, promoting long wire formation, but it is also compatible with good quality of the intermolecular order, as suggested by a high anisotropy of the Raman spectra of the nanowires formed from these solvents. Finally, the electrical properties of ordered systems show a clearly higher electrical conductivity compared to the disorganized aggregates.

Scalable production of highly sensitive nanosensors based on graphene functionalized with a designed G protein-coupled receptor.

We have developed a novel, all-electronic biosensor for opioids that consists of an engineered µ-opioid receptor protein, with high binding affinity for opioids, chemically bonded to a graphene field-effect transistor to read out ligand binding. A variant of the receptor protein that provided chemical recognition was computationally redesigned to enhance its solubility and stability in an aqueous environment. A shadow mask process was developed to fabricate arrays of hundreds of graphene transistors with average mobility of ∼1500 cm(2) V(-1) s(-1) and yield exceeding 98%. The biosensor exhibits high sensitivity and selectivity for the target naltrexone, an opioid receptor antagonist, with a detection limit of 10 pg/mL.

Correlating atomic structure and transport in suspended graphene nanoribbons.

Graphene nanoribbons (GNRs) are promising candidates for next generation integrated circuit (IC) components; this fact motivates exploration of the relationship between crystallographic structure and transport of graphene patterned at IC-relevant length scales (<10 nm). We report on the controlled fabrication of pristine, freestanding GNRs with widths as small as 0.7 nm, paired with simultaneous lattice-resolution imaging and electrical transport characterization, all conducted within an aberration-corrected transmission electron microscope. Few-layer GNRs very frequently formed bonded-bilayers and were remarkably robust, sustaining currents in excess of 1.5 µA per carbon bond across a 5 atom-wide ribbon. We found that the intrinsic conductance of a sub-10 nm bonded bilayer GNR scaled with width as GBL(w) ≈ 3/4(e(2)/h)w, where w is the width in nanometers, while a monolayer GNR was roughly five times less conductive. Nanosculpted, crystalline monolayer GNRs exhibited armchair-terminated edges after current annealing, presenting a pathway for the controlled fabrication of semiconducting GNRs with known edge geometry. Finally, we report on simulations of quantum transport in GNRs that are in qualitative agreement with the observations.

Minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis and degenerative spondylosis: 5-year results.

BACKGROUND: Multiple studies have reported favorable short-term results after treatment of spondylolisthesis and other degenerative lumbar diseases with minimally invasive transforaminal lumbar interbody fusion. However, to our knowledge, results at a minimum of 5 years have not been reported. QUESTIONS/PURPOSES: We determined (1) changes to the Oswestry Disability Index, (2) frequency of radiographic fusion, (3) complications and reoperations, and (4) the learning curve associated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup. METHODS: We reviewed our first 124 patients who underwent minimally invasive transforaminal lumbar interbody fusion to treat low-grade spondylolisthesis and degenerative lumbar diseases and did not need a major deformity correction. This represented 63% (124 of 198) of the transforaminal lumbar interbody fusion procedures we performed for those indications during the study period (2003-2007). Eighty-three (67%) patients had complete 5-year followup. Plain radiographs and CT scans were evaluated by two reviewers. Trends of surgical time, blood loss, and hospital stay over time were examined by logarithmic curve fit-regression analysis to evaluate the learning curve. RESULTS: At 5 years, mean Oswestry Disability Index improved from 60 points preoperatively to 24 points and 79 of 83 patients (95%) had improvement of greater than 10 points. At 5 years, 67 of 83 (81%) achieved radiographic fusion, including 64 of 72 patients (89%) who had single-level surgery. Perioperative complications occurred in 11 of 124 patients (9%), and another surgical procedure was performed in eight of 124 patients (6.5%) involving the index level and seven of 124 patients (5.6%) at adjacent levels. There were slowly decreasing trends of surgical time and hospital stay only in single-level surgery and almost no change in intraoperative blood loss over time, suggesting a challenging learning curve. CONCLUSIONS: Oswestry Disability Index scores improved for patients with spondylolisthesis and degenerative lumbar diseases treated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup. We suggest this procedure is reasonable for properly selected patients with these indications; however, traditional approaches should still be performed for patients with high-grade spondylolisthesis, patients with a severely collapsed disc space and no motion seen on the dynamic radiographs, patients who need multilevel decompression and arthrodesis, and patients with kyphoscoliosis needing correction. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.