Quantized Grain Boundary States Promote Nanoparticle Alignment During Imperfect Oriented Attachment.

Oriented attachment (OA) has become a well-recognized mechanism for the growth of metal, ceramic, and biomineral crystals. While many computational and experimental studies of OA have shown that particles can attach with some misorientation then rotate to remove adjoining grain boundaries, the underlying atomistic pathways for this "imperfect OA" process remain the subject of debate. In this study, molecular dynamics and in situ transmission electron microscopy (TEM) are used to probe the crystallographic evolution of up to 30 gold nanoparticles during aggregation. It is found that Imperfect OA occurs because 1) grain boundaries become quantized when their size is comparable to the separation between constituent dislocations and 2) kinetic barriers associated with the glide of grain boundary dislocations are small. In support of these findings, TEM experiments show the formation of a single crystal aggregate after annealing nine initially misoriented, agglomerated particles with evidence of dislocation activity and twin formation during particle/grain alignment. These observations motivate future work on assembled nanocrystals with tailored defects and call for a revision of Read-Shockley models for grain boundary energies in nanocrystalline materials.

Five-Year Mortality After Transient Ischemic Attack: Focus on Cardiometabolic Comorbidity and Hospital Readmission.

BACKGROUND AND PURPOSE: We aimed at providing estimates of mortality associated with cardiometabolic comorbidity and incident readmission from cardiometabolic as compared with noncardiometabolic conditions after a first transient ischemic attack. METHODS: Between 2000 and 2015, patients hospitalized for a first transient ischemic attack were examined for cardiometabolic comorbidities (diabetes mellitus, coronary artery disease, heart failure, and atrial fibrillation), 5-year incident hospitalization, and time to death. RESULTS: Of 251 patients with transient ischemic attack, 134 (53%) had at least 1 and 55 (22%) had at least 2 cardiometabolic conditions. By 5 years, 491 readmissions (134 [27%] cardiometabolic and 357 [73%] noncardiometabolic) and 75 deaths (27 [36%] cardiometabolic and 47 [64%] noncardiometabolic) were observed. Mortality was increased with any concurrent cardiometabolic comorbidity (hazard ratio, 1.89; 95% confidence interval, 1.17-3.03; P=0.0089) with multiplicative mortality risk from a combination of coronary artery disease and heart failure. Each hospitalization was associated with a 1.5-fold risk of death (95% confidence interval, 1.37-1.64; P<0.0001). Risk of cardiometabolic and noncardiometabolic mortality was correlated with the corresponding category-specific readmission. CONCLUSIONS: Among patients hospitalized for first transient ischemic attack, 5-year mortality is associated with concurrent cardiometabolic comorbidity and rates of subsequent hospitalization.

Ultralight Conductive Silver Nanowire Aerogels.

Low-density metal foams have many potential applications in electronics, energy storage, catalytic supports, fuel cells, sensors, and medical devices. Here, we report a new method for fabricating ultralight, conductive silver aerogel monoliths with predictable densities using silver nanowires. Silver nanowire building blocks were prepared by polyol synthesis and purified by selective precipitation. Silver aerogels were produced by freeze-casting nanowire aqueous suspensions followed by thermal sintering to weld the nanowire junctions. As-prepared silver aerogels have unique anisotropic microporous structures, with density precisely controlled by the nanowire concentration, down to 4.8 mg/cm3 and an electrical conductivity up to 51 000 S/m. Mechanical studies show that silver nanowire aerogels exhibit "elastic stiffening" behavior with a Young's modulus up to 16 800 Pa.

Laser damage mechanisms in conductive widegap semiconductor films.

Laser damage mechanisms of two conductive wide-bandgap semiconductor films - indium tin oxide (ITO) and silicon doped GaN (Si:GaN) were studied via microscopy, spectroscopy, photoluminescence (PL), and elemental analysis. Nanosecond laser pulse exposures with a laser photon energy (1.03 eV, 1064 nm) smaller than the conductive films bandgaps were applied and radically different film damage morphologies were produced. The laser damaged ITO film exhibited deterministic features of thermal degradation. In contrast, laser damage in the Si:GaN film resulted in highly localized eruptions originating at interfaces. For ITO, thermally driven damage was related to free carrier absorption and, for GaN, carbon complexes were proposed as potential damage precursors or markers.

On-demand and location selective particle assembly via electrophoretic deposition for fabricating structures with particle-to-particle precision.

Programmable positioning of 2 µm polystyrene (PS) beads with single particle precision and location selective, "on-demand", particle deposition was demonstrated by utilizing patterned electrodes and electrophoretic deposition (EPD). An electrode with differently sized hole patterns, from 0.5 to 5 µm, was used to illustrate the discriminatory particle deposition events based on the voltage and particle-to-hole size ratio. With decreasing patterned hole size, a larger electric field was required for a particle deposition event to occur in that hole. For the 5 µm hole, particle deposition began to occur at 10 V/cm where as an electric field of 15 V/cm was required for particles to begin depositing in the 2 µm holes. The likelihood of particle depositions continued to increase for smaller sized holes as the electric field increased. Eventually, a monolayer of particles began to form at approximately 20 V/cm. In essence, a voltage threshold was found for each hole pattern of different sizes, allowing fine adjustments in pattern hole size and voltage to control when a particle deposition event took place, even with the patterns on the same electrode. This phenomenon opens a route toward controlled, multimaterial deposition and assembly onto substrates without repatterning of the electrode or complicated surface modification of the particles. An analytical approach using the theories for electrophoresis and dielectrophoresis found the former to be the dominating force for depositing a particle into a patterned hole. Ebeam lithography was used to pattern spherical holes in precise configurations onto electrode surfaces, where each hole accompanied a polystyrene (PS) particle placement and attachment during EPD. The versatility of e-beam lithography was utilized to create arbitrary pattern configurations to fabricate particle assemblies of limitless configurations, enabling fabrication of unique materials assemblies and interfaces.

Prospective Randomized Trial of Continuous Passive Motion Versus Physical Therapy After Arthroscopic Release of Elbow Contracture.

BACKGROUND: Continuous passive motion (CPM) has been used for decades, but we are not aware of any randomized controlled trials (RCTs) in which CPM has been compared with physical therapy (PT) for rehabilitation following release of elbow contracture. METHODS: In this single-blinded, single-center RCT, we randomly assigned patients undergoing arthroscopic release of elbow contracture to a rehabilitation protocol involving either CPM or PT. The primary outcomes were the rate of recovery and the arc of elbow motion (range of motion) at 1 year. The rate of recovery was evaluated by measuring range of motion at 6 weeks and 3 months. The secondary outcomes included other range-of-motion-related outcomes, patient-reported outcome measures (PROMs), flexion strength and endurance, grip strength, and forearm circumference at multiple time points. RESULTS: A total of 24 patients were assigned to receive CPM, and 27 were assigned to receive PT. At 1 year, CPM was superior to PT with regard to the range of motion, with an estimated treatment difference of 9° (95% confidence interval [CI], 3° to 16°; p = 0.007). Similarly, the use of CPM led to a greater range of motion at 6 weeks and 3 months than PT. The percentage of lost motion recovered at 1 year was higher in the CPM group (51%) than in the PT group (36%) (p = 0.01). The probability of restoring a functional range of motion at 1 year was 62% higher in the CPM group than in the PT group (risk ratio for functional range of motion, 1.62; 95% CI, 1.01 to 2.61; p = 0.04). PROM scores were similar in the 2 groups at all time points, except for a difference in the American Shoulder and Elbow Surgeons (ASES) elbow function subscale, in favor of CPM, at 6 weeks. The use of CPM decreased swelling and reduced the loss of flexion strength, flexion endurance, and grip strength on day 3, with no between-group differences thereafter. CONCLUSIONS: Among patients undergoing arthroscopic release of elbow contracture, those who received CPM obtained a faster recovery and a greater range of motion at 1 year, with a higher chance of restoration of functional elbow motion than those who underwent routine PT. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Patients Use Fewer Opioids Than Prescribed After Arthroscopic Release of Elbow Contracture: An Evidence-Based Opioid Prescribing Guideline to Reduce Excess.

PURPOSE: To generate an evidence-based opioid-prescribing guideline by assessing the pattern of total opioid consumption and the factors that may predict opioid consumption following arthroscopic release of elbow contracture and to investigate whether the use of continuous passive motion (CPM), as compared to physical therapy (PT), was associated with a decrease in pain and opioid consumption after arthroscopic release of elbow contracture. METHODS: Data collected from a randomized controlled trial that compared continuous passive motion (CPM) (n = 24) to physical therapy (PT) (n = 27) following arthroscopic release of elbow contracture was analyzed for opioid use. Fifty-one participants recorded their daily opioid consumption in a postoperative diary for 90 days. Multivariate analysis was performed to identify factors associated with opioid use. Recommended quantities for postoperative prescription were generated using the 50th percentile for patients without and the 75th percentile for patients with factors associated with higher opioid use. RESULTS: The median total opioid prescription was 437.5-mg morphine milligram equivalents (MMEs) (58 pills of 5 mg oxycodone) and the median total opioid consumption was 75 MMEs (10 pills of 5-mg oxycodone). Twenty-two percent of patients took no opioid medication, 53% took ≤10 pills, 69% took ≤20 pills and 75% took ≤30 pills. Predictors of higher opioid use were preoperative opioid use, age <60 years and inflammatory arthritis. The total opioid consumption appeared similar between the CPM and the PT group. Seventy-five percent of patient's home opioid requirements would be satisfied using the following guideline: Patients undergoing contracture release for osteoarthritis or post-traumatic contracture should be given a prescription for 10 pills of 5 mg oxycodone or its equivalent at discharge. Patients with inflammatory conditions or those taking preoperative opioids should be prescribed 30 pills of 5 mg oxycodone or its equivalent. CONCLUSION: This study suggests that most patients undergoing arthroscopic release of elbow contracture use relatively few opioid pills after surgery. Use of an evidence-based guideline could decrease opioid prescriptions substantially, while still effectively treating patients' pain.

Synthesis of graphene aerogel with high electrical conductivity.

We report the synthesis of ultra-low-density three-dimensional macroassemblies of graphene sheets that exhibit high electrical conductivities and large internal surface areas. These materials are prepared as monolithic solids from suspensions of single-layer graphene oxide in which organic sol-gel chemistry is used to cross-link the individual sheets. The resulting gels are supercritically dried and then thermally reduced to yield graphene aerogels with densities approaching 10 mg/cm(3). In contrast to methods that utilize physical cross-links between GO, this approach provides covalent carbon bonding between the graphene sheets. These graphene aerogels exhibit an improvement in bulk electrical conductivity of more than 2 orders of magnitude (∼1 × 10(2) S/m) compared to graphene assemblies with physical cross-links alone (∼5 × 10(-1) S/m). The graphene aerogels also possess large surface areas (584 m(2)/g) and pore volumes (2.96 cm(3)/g), making these materials viable candidates for use in energy storage, catalysis, and sensing applications.

Molecular fiber sensors based on surface enhanced Raman scattering (SERS).

Molecular sensors based on surface enhanced Raman scattering (SERS) and optical fibers have been widely used in biological, environmental and chemical detection procedures due to their unique advantages, such as molecular specificity, high sensitivity and flexibility. In this paper, we review the development and highlight some of the important milestones of SERS fiber sensor development with emphasis on recent work to improve the sensitivity of the fiber sensors. In particular in the area to increase the sensitivity, we've reviewed various methods of sample preparation as well as different fiber SERS sensors. One way is to strengthen the field enhancement around the surface of the probe tip and the other is to increase the number of the interacting particles during the SERS process. These techniques are known as the double substrate "sandwich" structure (DSSS) and the liquid core photonic crystal fiber (LCPCF), and in both cases the sensitivities are significantly improved. These fiber sensors were tested with Rhodamine 6G, human insulin and tryptophan and showed excellent performance.

In vitro and in vivo targeting of hollow gold nanoshells directed at epidermal growth factor receptor for photothermal ablation therapy.

Laser-induced phototherapy is a new therapeutic use of electromagnetic radiation for cancer treatment. The use of targeted plasmonic gold nanoparticles can reduce the laser energy necessary for selective tumor cell destruction. However, the ability for targeted delivery of the currently used gold nanoparticles to tumor cells is limited. Here, we describe a new class of molecular specific photothermal coupling agents based on hollow gold nanoshells (HAuNS; average diameter, approximately 30 nm) covalently attached to monoclonal antibody directed at epidermal growth factor receptor (EGFR). The resulting anti-EGFR-HAuNS exhibited excellent colloidal stability and efficient photothermal effect in the near-infrared region. EGFR-mediated selective uptake of anti-EGFR-HAuNS in EGFR-positive A431 tumor cells but not IgG-HAuNS control was shown in vitro by imaging scattered light from the nanoshells. Irradiation of A431 cells treated with anti-EGFR-HAuNS with near-infrared laser resulted in selective destruction of these cells. In contrast, cells treated with anti-EGFR-HAuNS alone, laser alone, or IgG-HAuNS plus laser did not show observable effect on cell viability. Using 111In-labeled HAuNS, we showed that anti-EGFR-HAuNS could be delivered to EGFR-positive tumors at 6.8% ID/g, and the microscopic image of excised tumor with scattering signal from nanoshells confirmed preferential delivery to A431 tumor of anti-EGFR-HAuNS compared with IgG-HAuNS. The absence of silica core, the relatively small particle size and high tumor uptake, and the absence of cytotoxic surfactant required to stabilize other gold nanoparticles suggest that immuno-HAuNS have the potential to extend to in vivo molecular therapy.

Effect of early hospital readmission and comorbid conditions on subsequent long-term mortality after transient ischemic attack.

Background: The implications of early readmission on long-term mortality after transient ischemic attack (TIA) are not known. We aimed at examining the effect of 180-day readmission on subsequent long-term mortality after index hospitalization for TIA. Methods: A retrospective study of patients hospitalized for first-ever TIA at Mayo Clinic from 2000 through 2017. Patients readmitted within 180 days postdischarge were compared with those not readmitted in long-term risk of death. Results: Of 251 TIA patients aged 73 ± 15 years with 1509 person-years of follow-up, 65 (26%) were readmitted within 180 days of discharge and 125 died during a median follow-up of 5.7 years. The mortality was 10 vs. 7 deaths per 100 person-years in patients who were readmitted compared to those who were not readmitted with hazard ratio (HR) 1.73 (95% confidence interval [CI] 1.13-2.66). Other competing predictors of mortality were age ≥65 years (HR 5.70, 95% CI 2.72-11.96), cancer (HR 1.65, 95% CI 1.03-3.38), chronic obstructive pulmonary disease (HR 1.90, 95% CI 1.07-3.38), heart failure (HR 3.03, 95% CI 1.82-5.06), dementia (HR 5.87, 95% CI 3.27-10.52), creatinine ≥1.4 mg/dl (HR 1.89, 95% CI 1.17-3.06), and hemoglobin level <10 g/dl (HR 2.80, 95% CI 1.20-6.66). Conclusions: Hospital readmission within 180 days of discharge from index TIA was associated with increased risk of death several years after initial readmission. Older age and several comorbidities identified during index hospitalization also confer increased risk for long-term mortality.

Synthesis, characterization, and tunable optical properties of hollow gold nanospheres.

Nearly monodisperse hollow gold nanospheres (HGNs) with tunable interior and exterior diameters have been synthesized by sacrificial galvanic replacement of cobalt nanoparticles. It is possible to tune the peak of the surface plasmon band absorption between 550 and 820 nm by carefully controlling particle size and wall thickness. Cobalt particle size is tunable by simultaneously changing the concentration of sodium borohydride and sodium citrate, the reducing and capping agent, respectively. The thickness of the gold shell can be varied by carefully controlling the addition of gold salt. With successful demonstration of ensemble as well as single HGN surface-enhanced Raman scattering, these HGNs have shown great potential for chemical and biological sensing applications, especially those requiring nanostructures with near-IR absorption.

Interobserver agreement in the trial of org 10172 in acute stroke treatment classification of stroke based on retrospective medical record review.

BACKGROUND: The reliability of the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system of stroke in siblings of stroke-affected probands has not been tested. Similarly, the reliability of using clinical medical records to classify ischemic stroke has not been assessed. The purpose of this study was to establish the interrater reliability of sibling stroke subtyping by applying the TOAST criteria to retrospectively obtained medical records. METHODS: Thirty medical records were randomly sampled from among the records of all siblings previously classified as stroke affected by the Siblings with Ischemic Stroke Study (SWISS) Stroke Verification Committee. Blinded medical records for these individuals were sent to 6 physician reviewers who independently classified TOAST stroke subtype on the basis of record review. RESULTS: Using the kappa statistic to assess interrater reliability, the overall reliability (SE) for assigning a TOAST subtype of stroke was 0.54 (0.03). Pair-wise comparisons between the original SWISS Stroke Verification Committee diagnoses and the diagnoses made by other reviewers exhibited moderate reliability (kappa range 0.41-0.56). The kappa statistics for common stroke subtypes were large vessel, 0.80 (0.06); cardioembolic, 0.80 (0.06); small vessel, 0.53 (0.06); and unknown cause, 0.40 (0.06). CONCLUSION: We conclude that TOAST subtyping had moderate interrater reliability. Large-artery and cardioembolic subtype diagnoses seemed most reliable.

Multiphase separation of copper nanowires.

This communication reports a new method to purify copper nanowires with nearly 100% yield from undesired copper nanoparticle side-products formed during batch processes of copper nanowire synthesis. This simple separation method can yield large quantities of long, uniform, high-purity copper nanowires to meet the requirements of nanoelectronics applications as well as provide an avenue for purifying copper nanowires in the industrial scale synthesis of copper nanowires, a key step for commercialization and application of nanowires.

Bollgard II cotton: compositional analysis and feeding studies of cottonseed from insect-protected cotton (Gossypium hirsutum L.) producing the Cry1Ac and Cry2Ab2 proteins.

Bollgard II cotton event 15985 producing the Cry1Ac and Cry2Ab2 proteins has been developed by genetic modification to broaden the spectrum of insects to which the plant is tolerant and to provide an insect resistance management tool to impede the onset of resistance. The purpose of this study was to evaluate the composition and nutrition of Bollgard II cotton, relative to the use for food and animal feed, compared to that of conventional cotton varieties. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, gossypol, and mineral contents of cottonseed from a total of 14 U.S. field sites over two years. Compositional analysis results showed that the cottonseed and cottonseed oil from Bollgard II cotton were comparable in their composition to those of the conventional control cotton line and other commercial varieties. The composition data are supported by nutritional safety studies conducted with dairy cows, catfish, and quail. Results from these studies showed that Bollgard II performed similarly to the conventional control cotton varieties. These data demonstrate that Bollgard II cotton is compositionally and nutritionally equivalent to conventional cotton varieties. These data support the conclusion that Bollgard II cotton is as safe and nutritious as conventional cotton for food and feed use.

High Surface Area, sp(2)-Cross-Linked Three-Dimensional Graphene Monoliths.

Developing three-dimensional (3D) graphene assemblies with properties similar to those individual graphene sheets is a promising strategy for graphene-based electrodes. Typically, the synthesis of 3D graphene assemblies relies on van der Waals forces for holding the graphene sheets together, resulting in bulk properties that do not reflect those reported for individual graphene sheets. Here, we report the use of sol-gel chemistry to introduce chemical bonding between the graphene sheets and control the bulk properties of graphene-based aerogels. Adjusting synthetic parameters allows a wide range of control over surface area, pore volume, and pore size, as well as the nature of the chemical cross-links (sp(2) vs sp(3)). The bulk properties of the graphene-based aerogels represent a significant step toward realizing the properties of individual graphene sheets in a 3D assembly with surface areas approaching the theoretical value of an individual sheet.

Effects of chromophore orientation and molecule conformation on surface-enhanced Raman scattering studied with alkanoic acids and colloidal silver nanoparticles.

Experimental studies have been carried out to gain a better understanding of the effects of chromophore orientation and molecular conformation on surface-enhanced Raman scattering (SERS) based on metal nanostructures. A series of alkanoic acids that contain a phenyl ring separated by methylene groups from the carboxylic acid, including phenylacetic acid, 3-phenylpropionic acid, 4-phenylbutyric acid, 5-phenylvaleric acid, and 6-phenylhexanoic acid, was investigated as model molecules with colloidal silver nanoparticles as SERS substrates. As the number of methylene groups increases, the molecules display an interesting zigzag intensity pattern of the phenyl ring bending mode around 1000 cm(-1) as well as a trend of appearance and disappearance of either the degenerate ring breathing mode or C[Double Bond]O vibrational mode near 1585 and 1630 cm(-1), respectively. Molecules containing an odd number of methylene units display a higher ring bending intensity and degenerate ring breathing mode and are suggested to have a trans conformation on the particle surface. Molecules with an even number of methylene units show a C[Double Bond]O vibrational mode and weaker ring bending in their SERS spectra and are suggested to have a gauche conformation on the silver nanoparticle surface. The different conformation is attributed to the varying interactions of the carboxylic group or the phenyl ring pi electrons with the silver surface. The SERS intensity was found to change little as the length between the phenyl ring and the carboxylic group was increased by adding CH(2) spacers. This is possibly because the effective distance between the phenyl ring and the silver surface does not change much with increasing number of CH(2) spacers as a result of changes in molecular conformation and variations in the phenyl ring orientation with CH(2) addition. The insight gained from this study is important for understanding SERS of complex molecules for which chromophore orientation and molecular conformation must be taken into careful consideration.