Automated registration of optical coherence tomography and dermoscopy in the assessment of sub-clinical spread in basal cell carcinoma

Optical coherence tomography (OCT) has been shown to be of clinical value in imaging basal cell carcinoma (BCC). A novel dual OCT-video imaging system, providing automated registration of OCT and dermoscopy, has been developed to assess the potential of OCT in measuring the degree of sub-clinical spread of BCC. Seventeen patients selected for Mohs micrographic surgery (MMS) for BCC were recruited to the study. The extent of BCC infiltration beyond a segment of the clinically assessed pre-surgical border was evaluated using OCT. Sufficiently accurate (<0.5 mm) registration of OCT and dermoscopy images was achieved in 9 patients. The location of the OCT-assessed BCC border was also compared with that of the final surgical defect. Infiltration of BCC across the clinical border ranged from 0 mm to >2.5 mm. In addition, the OCT border lay between 0.5 mm and 2.0 mm inside the final MMS defect in those cases where this could be assessed. In one case, where the final MMS defect was over 17 mm from the clinical border, OCT showed >2.5 mm infiltration across the clinical border at the FOV limit. These results provide evidence that OCT allows more accurate assessment of sub-clinical spread of BCC than clinical observation alone. Such a capability may have clinical value in reducing the number of surgical stages in MMS for BCC. There may also be a role for OCT in aiding the selection of patients most suitable for MMS.

Characterization of electrode materials for lithium ion and sodium ion batteries using synchrotron radiation techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g. changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g. on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

Mesoscale phase distribution in single particles of LiFePO4 following lithium deintercalation

The chemical phase distribution in hydrothermally grown micrometric single crystals LiFePO4 following partial chemical delithiation was investigated. Full field and scanning X-ray microscopy were combined with X-ray absorption spectroscopy at the Fe K- and O K-edges, respectively, to produce maps with high chemical and spatial resolution. The resulting information was compared to morphological insight into the mechanics of the transformation by scanning transmission electron microscopy. This study revealed the interplay at the mesocale between microstructure and phase distribution during the redox process, as morphological defects were found to kinetically determine the progress of the reaction. Lithium deintercalation was also found to induce severe mechanical damage in the crystals, presumably due to the lattice mismatch between LiFePO4 and FePO4. Our results lead to the conclusion that rational design of intercalation-based electrode materials, such as LiFePO4, with optimized utilization and life requires the tailoring of particles that minimize kinetic barriers and mechanical strain. Coupling TXM-XANES with TEM can provide unique insight into the behavior of electrode materials during operation, at scales spanning from nanoparticles to ensembles and complex architectures.

Assembly of ligand-stripped nanocrystals into precisely controlled mesoporous architectures

The properties of mesoporous materials hinge on control of their composition, pore dimensions, wall thickness, and the size and shape of the crystallite building units. We create ordered mesoporous materials in which all of these parameters are independently controlled. Different sizes (from 4.5 to 8 nm) and shapes (spheres and rods) of ligand-stripped nanocrystals are assembled using the same structure-directing block copolymers, which contain a tethering domain designed to adsorb to their naked surfaces. Material compositions range from metal oxides (Sn-doped In(2)O(3) or ITO, CeO(2), TiO(2)) to metal fluorides (Yb,Er-doped NaYF(4)) and metals (FePt). The incorporation of new types of nanocrystals into mesoporous architectures can lead to enhanced performance. For example, TiO(2) nanorod-based materials withstand >1000 electrochemical cycles without significant degradation.

Dynamically modulating the surface plasmon resonance of doped semiconductor nanocrystals

Localized surface plasmon absorption features arise at high doping levels in semiconductor nanocrystals, appearing in the near-infrared range. Here we show that the surface plasmons of tin-doped indium oxide nanocrystal films can be dynamically and reversibly tuned by postsynthetic electrochemical modulation of the electron concentration. Without ion intercalation and the associated material degradation, we induce a > 1200 nm shift in the plasmon wavelength and a factor of nearly three change in the carrier density.

Fluorographene: a wide bandgap semiconductor with ultraviolet luminescence

The manipulation of the bandgap of graphene by various means has stirred great interest for potential applications. Here we show that treatment of graphene with xenon difluoride produces a partially fluorinated graphene (fluorographene) with covalent C-F bonding and local sp(3)-carbon hybridization. The material was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, electron energy loss spectroscopy, photoluminescence spectroscopy, and near edge X-ray absorption spectroscopy. These results confirm the structural features of the fluorographane with a bandgap of 3.8 eV, close to that calculated for fluorinated single layer graphene, (CF)(n). The material luminesces broadly in the UV and visible light regions, and has optical properties resembling diamond, with both excitonic and direct optical absorption and emission features. These results suggest the use of fluorographane as a new, readily prepared material for electronic, optoelectronic applications, and energy harvesting applications.

The interaction of Li+ with single-layer and few-layer graphene

The interaction of Li(+) with single and few layer graphene is reported. In situ Raman spectra were collected during the electrochemical lithiation of the single- and few-layer graphene. While the interaction of lithium with few layer graphene seems to resemble that of graphite, single layer graphene behaves very differently. The amount of lithium absorbed on single layer graphene seems to be greatly reduced due to repulsion forces between Li(+) at both sides of the graphene layer.

Direct imaging of soft-hard interfaces enabled by graphene

Direct imaging of surface molecules and the interfaces between soft and hard materials on functionalized nanoparticles is a great challenge using modern microscopy techniques. We show that graphene, a single atomic layer of sp(2)-bonded carbon atoms, can be employed as an ultrathin support film that enables direct imaging of molecular layers and interfaces in both conventional and atomic-resolution transmission electron microscopy. An atomic-resolution imaging study of the capping layers and interfaces of citrate-stabilized gold nanoparticles is used to demonstrate this novel capability. Our findings reveal the unique potential of graphene as an ideal support film for atomic-resolution transmission electron microscopy of hard and soft nanomaterials.

Hyperfine fields at the Li site in LiFePO(4)-type olivine materials for lithium rechargeable batteries: a (7)Li MAS NMR and SQUID study

The (7)Li NMR isotropic shift for olivine LiMPO(4) (M = Fe, Mn, Co, Ni) is assigned to hyperfine coupling between the (7)Li nucleus and the transition metal unpaired electrons on the basis of the Curie-Weiss temperature dependence of the shift. The hyperfine shift arises from a linear combination of Li-O-M through-bond interactions wherein the unpaired A' electrons contribute a negative shift and the unpaired A' ' electrons contribute a positive shift. The hyperfine coupling constant is determined for each composition.

Observations on nursing home residents with a history of hip fracture

The authors evaluated nursing home residents with a prior history of hip fracture for osteopenia and its risk factors, and attempted to learn to what extent the residents' bone status had been considered by their primary care physicians. Thirty-one hip fracture residents in the Milwaukee VA nursing home were studied to determine their status with regard to bone mineral density of the proximal femur, and the following risk factors or predictors of osteopenia: history of smoking; history of fractures; calcium and vitamin D intake; underweight; immobility; hypogonadism; and administration of drugs that may accelerate bone demineralization. Data were also collected on the evaluation and management of the post hip fracture residents in three other nursing homes. In the Milwaukee nursing home, out of 31 hip fracture survivors, 74% had sustained a hip fracture before admission to the nursing home; 29% had a history of second fracture. In 84% of patients, there was no mention of osteopenia in the active medical problem list and, therefore, there was no intervention plan in place to improve or prevent further bone loss. Thirty-two percent were underweight, 36% were currently smoking, 55% were immobile, 64% were consuming at least one medication that might increase bone loss, calcium intake was less than 1,000 mg daily in 52%, and 66% were hypogonadal (serum testosterone level less than 300 ng/dL). Chart reviews of the hip fracture survivors at three other nursing homes revealed similar findings. Approximately 5-15% of nursing home residents are hip fracture survivors. They usually have severe osteopenia and multiple risk factors for further bone loss and future fractures.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of clinical indicators in two nursing homes

OBJECTIVE

Pressure ulcer prevalences in 30 VA nursing homes in 1986 ranged from 0% to 15%. The institutions with lowest ("A") and highest ("B") prevalence were selected for further examination.

DESIGN

Analysis of nursing home files for five study periods, each lasting 6 months.

SETTING

A and B were 60-bed rural and 280-bed urban facilities, respectively.

MEASUREMENTS

Eleven outcome indicators were calculated for each study period: prevalences and incidences of pressure ulcer, aggressive behavior and disruptive behavior, 6-month declines in each of the four activities of daily living (ADLs), and prevalence of underweight.

RESULTS

Populations in A and B were similar with regard to age, sex, length of stay, degree of dependency, and level of nursing care. All indicators for the first study period were more favorable in A than in B. In addition, underweight (body mass index < 22 kg/M2) was significantly less prevalent in A than in B. The differences between the two institutions in the indicators were persistent over the five study periods from 1988 to 1991.

CONCLUSIONS

The populations of A and B were similar in the available measures of severity of illness. Nevertheless, the residents in nursing home A were significantly less likely to experience adverse outcomes than were the residents in nursing home B. The virtual absence of pressure ulcers, physical aggression, and verbal disruption in nursing home A, despite the presence of many immobile and demented residents, suggested that these complications can mostly be prevented.

The occurrence of pressure ulcers in three nursing homes

BACKGROUND

In the 27 nursing homes located within the Veterans Affairs (VA) Central Region, the proportion of residents with pressure ulcers in 1986 varied from 2% to 16%. Three of these nursing homes were selected for study: nursing home A from the highest prevalence quintile, B from close to the median, and C from the lowest quintile.

METHODS

Two indicators of pressure ulcer occurrence were calculated: the point-in-time prevalence of bedsores and the percentage of residents who were free of pressure ulcers at the beginning of a six-month study period but who had bedsores six months later. Data were also collected in each nursing home to determine the bedsore status at the time of admission and the resident's location if and when a bedsore began.

RESULTS

The three institutions were generally similar in available measures of casemix and severity of illness. The ratio of nursing and medical personnel to residents was 29%-76% lower in nursing home A than in B or C. In nursing home A, the turnover of nursing personnel was about twice as rapid as that in B or C. In each institution the pressure ulcer statistics showed little variation from one six-month period to another. The average rates in nursing home A were 15.3% for prevalence and 10.3% for the six-month conversion from bedsore-negative to bedsore-positive status. The average rates in facilities B and C were, respectively, 6.9% and 3.5% for prevalence and 4.7% and 4.2% for the six-month conversion from negative to positive status. Furthermore, the number of new bedsores that developed during uninterrupted nursing home residence, per 100,000 resident days, was 36.5 in A, 10.8 in B, and 2.1 in C.

CONCLUSIONS

The pressure ulcer statistics in nursing homes B and C were consistently superior to those in A. the interinstitutional differences could not be explained by the comparisons of scoring methodologies and of casemixes that were made. It is hypothesized that more favorable staffing patterns in B and C than in A contributed to more effective prevention of bedsores in the former two institutions.

Essential fatty acid deficiency in four adult patients during total parenteral nutrition

Four undernourished adults (15%-37% below idealll body weight) received fat-free total parenteral nutrition for a period of 6 to 8 weeks. Chemical evidence of essential fatty acid deficiency (triene:tetraene ratio greater than 0.4) appeared in all patients during the first 3 weeks of treatment. Deficiency developed more rapidly in the two patients who were younger (ages 16 and 36) and more severely undernourished (26% and 37% below ideal body weight) than in the two older patients (62 and 76) who were less undernourished (15% and 16% below idea body weight). All patients continued to gain weight and maintain positive nitrogen balance throughout the course of total parenteral nutrition and developing essential fatty acid deficiency. Hepatomegaly and increased serum liver enzyme activities occurred in the two patients with evidence of the most severe essential fatty acid deficiency. Liver biopsy, in the cases with hepatomegaly, showed hepatocytes containing fat and what appeared to be enlarged, spherical mitochondria. There was no cellular infiltrate or significant degree of necrosis. Supplementation with oral linoleic acid (as safflower oil) reversed the essential fatty acid deficiency and the elevation of serum liver enzymes.

Elemental balances during intravenous hyperalimentation of underweight adult subjects

Intravenous hyperalimentation was done in 11 underweight adults whose body weight (body wt) was less than 85 percent of ideal. For the first 6 days, "complete formula" was infused furnishing per kilogram ideal body wt per day: 15 g glucose, 0.40 g N, 0.018 g P, 2.4 meq K, 3.0 meq Na, 2.3 meq C1, 0.5 meq Mg, 0.45 meq Ca, and 50 ml H20. Patients gained weight at an average rate of 9.0 g/kg ideal body wt/day and showed average balances/kilogram ideal body wt/day as follows: plus 0.14 g N; plus 0.012 g P; plus 0.43 meq K; plus 0.49 meq Na; plus 0.37 meq Cl; and plus 0.085 meq Ca. Application of standard equations to the elemental balances indicated weight gain consisted of 35-50 percent protoplasm, 35-50 percent extracellular fluid, 5-25 percent adipose tissus, and less than 1 percent bone. Withdrawas of N, P, Na, or K impaired or abolished retention of other elements. Removal of N halted retention P, K, Na and C1; withdrawal of K stopped retention of N and P; and removal of Na or P interrupted retention of all other elements. Weight gain continued at a rate of 1.4-3.1 g/kg ideal body wt/day despite zero or negative elemental balances of N, K, P, and sometimes Na and C1. Calculations showed that weight gain during infusion of fluids lacking N, P, K, or Na consisted largely of adipose tissue, with little or no contribution by protoplasm or extracellular fluid. Data show that repletion of protoplasm and extracellular fluid of wasted adults by intravenous hyperalimentation is retarded or abolished if N, P, Na, or K is lacking. Repletion of bone mineral does not occur in absence of Na or P but proceeds in absence of N, P, K, or Na. Thus, quality of weight gained by underfed adult patients during hyperalimentation depends on elemental composition of the infusate.