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1.
Can Prosthet Orthot J ; 4(2): 36125, 2021.
Article in English | MEDLINE | ID: mdl-37614990

ABSTRACT

Reimbursement to U.S. healthcare service providers is largely transitioning from fee for service to fee for value for those clinicians who code using current procedural terminology and through their coding, describe their professional services. The Orthotic, Prosthetic and Pedorthic profession (O&P), currently codes using a system that describes the devices they evaluate for, fabricate, fit and maintain and their professional services are incorporated into their codes. These O&P codes, in contrast to those for other healthcare disciplines, are predominantly product based rather than service based, focusing on product features and function more than clinical service. This editorial manuscript provides a brief overview of the system the US O&P profession uses currently, particularly in the context of other healthcare professions transitioning to value based coding and reimbursement and culminates in a call to action for the profession to academically consider the strengths and weaknesses of the current system relative to alternative systems.

2.
J Phys Condens Matter ; 32(38): 385704, 2020 May 22.
Article in English | MEDLINE | ID: mdl-32442985

ABSTRACT

For graphitic materials, Raman technique is a common method for temperature measurements through analysis of phonon frequencies. Temperature (T) induced downshift of the bond-stretching G mode (ΔG) is well known, but experimentally obtained thermal coefficients ΔG/ΔT vary considerably between diverse works. Further, ΔG/ΔT coefficients usually were evaluated for relatively low temperatures and found to differ strongly for mono, a few and multilayer graphene. We studied G band behavior in freely suspended multilayer graphene flakes (or graphite nanoflakes) under localized heating by a laser beam. Analysis of Stokes and anti-Stokes signals showed that G band has a complex structure and can be deconvoluted into several peaks that demonstrate distinctly different behavior under heating. A plausible assumption is that these peaks correspond to several groups of graphitic layers (surface, near-surface and bulk) and then different thermal coefficients were determined for these groups. This behavior can be explained by decreasing interaction between surface layers and underlying material at high temperatures that affects especially vibrational properties of a few outermost layers. Estimates of temperatures using anti-Stokes/Stokes intensity ratio (I aS/I S) were also done to give results comparable with those obtained from G band downshift, T ΔG ≈ T aS/S, supporting the proposed model. The range of temperatures obtained by laser heating, as evaluated by both methods, was from 450 to 1200 K.

3.
J Endocrinol Invest ; 40(6): 645-652, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28211028

ABSTRACT

PURPOSE: While a good safety for recombinant human growth hormone (rhGH) therapy at replacement doses is recognized, a possible link between high concentration of the GH-IGF-I axis hormones and side negative effect has been reported. The aim of this pilot study was to assess whether a short-term exposure to supra-physiological doses of rhGH may affect DNA integrity in human lymphocytes (PBL). METHODS: Eighteen healthy Caucasian female (24.2 ± 3.5 years) were randomly included in a Control (n = 9) and rhGH administration group (n = 9, 3-week treatment). DNA damage (comet assay), chromosomal breaks, and mitotic index in phytohemagglutinin-stimulated PBL were evaluated before (PRE), immediately (POST), and 30 days (POST30) after the last rhGH administration (0.029 mg kg- 1 BW; 6 days/week), together with serum IGF-1 and IGFBP-3 concentrations. RESULTS: rhGH administration increased IGF-I, without evidence of persisting IGF-I and IGFBP-3 changes 30 days after withdrawal. Total DNA breakage (% DNA in tails) was not significantly different in subjects treated with rhGH in comparison with controls, although the rhGH-treated subjects showed an higher percentage of heavily damaged nuclei immediately after the treatment (POST30 vs. PRE: p = 0.003), with a lower mitogenic potential of lymphocytes, detectable up to the POST30 (PRE vs. POST: p = 0.02; PRE vs. POST30: p = 0.007). CONCLUSIONS: This pilot study showed that 3 weeks of short-term supra-physiological rhGH administration in healthy women induce a transient DNA damage and mitogenic impairment in PBL. The analysis of DNA damage should be explored as useful tool in monitoring the mid to long-term effects of high rhGH treatment or abuse.


Subject(s)
DNA Damage/drug effects , Human Growth Hormone/administration & dosage , Lymphocytes/pathology , Recombinant Proteins/administration & dosage , Adult , Female , Healthy Volunteers , Humans , Insulin-Like Growth Factor Binding Protein 3/metabolism , Insulin-Like Growth Factor I/metabolism , Lymphocytes/drug effects , Lymphocytes/metabolism , Male , Pilot Projects , Women's Health , Young Adult
4.
Arch. alerg. inmunol. clin ; 48(1): 21-25, 2017.
Article in Spanish | LILACS | ID: biblio-914820

ABSTRACT

Desde las observaciones de Quincke y Osler, que refirieron pacientes con una "tumefacción" diferente de las que provocaban habitualmente los mecanismos alérgicos hasta el descubrimiento de un nuevo mediador responsable de esos edemas dolorosos y deformantes, se han sucedido los aportes de los investigadores en el esclarecimiento de la patogenia y el tratamiento del AEH hasta la actualidad, en que el arsenal terapéutico se ve notablemente enriquecido por medicamentos altamente eficaces y específicos. Intentaremos describirlos. (AU)


From the observations of Quincke and Osler, who referred patients with a "swelling" different from those that usually provoked the allergic mechanisms until the discovery of a new mediator responsible for these painful and deforming edemas, have been the contributions of researchers in the Clarification of the pathogenesis and treatment of HAE to date, where the therapeutic arsenal is remarkably enriched by highly effective and specific drugs. We will try to describe them.(AU)


Subject(s)
Humans , Angioedemas, Hereditary/physiopathology , Angioedemas, Hereditary/drug therapy , Argentina , Pharmaceutical Preparations
5.
Nano Lett ; 16(4): 2363-8, 2016 Apr 13.
Article in English | MEDLINE | ID: mdl-26998817

ABSTRACT

Resonant Raman spectroscopy is a powerful tool for providing information about excitons and exciton-phonon coupling in two-dimensional materials. We present here resonant Raman experiments of single-layered WS2 and WSe2 using more than 25 laser lines. The Raman excitation profiles of both materials show unexpected differences. All Raman features of WS2 monolayers are enhanced by the first-optical excitations (with an asymmetric response for the spin-orbit related XA and XB excitons), whereas Raman bands of WSe2 are not enhanced at XA/B energies. Such an intriguing phenomenon is addressed by DFT calculations and by solving the Bethe-Salpeter equation. These two materials are very similar. They prefer the same crystal arrangement, and their electronic structure is akin, with comparable spin-orbit coupling. However, we reveal that WS2 and WSe2 exhibit quite different exciton-phonon interactions. In this sense, we demonstrate that the interaction between XC and XA excitons with phonons explains the different Raman responses of WS2 and WSe2, and the absence of Raman enhancement for the WSe2 modes at XA/B energies. These results reveal unusual exciton-phonon interactions and open new avenues for understanding the two-dimensional materials physics, where weak interactions play a key role coupling different degrees of freedom (spin, optic, and electronic).

6.
J Colloid Interface Sci ; 464: 117-25, 2016 Feb 15.
Article in English | MEDLINE | ID: mdl-26609931

ABSTRACT

A molecule with a π conjugated backbone built from aromatic thiophene and dialkoxyphenylene units and substituted imidazolium groups (TPO) is designed to obtain ultra-stable single walled carbon nanotube (SWCNT) dispersion in aqueous medium. The proposed mechanism of non-covalent interaction is accompanied by individualization of SWCNT and comprises of dominant nondisruptive π-π and cation-π interaction between them and the TPO conjugated oligomer. The individualization of SWCNT and dispersibility and stability of the ultra-stable suspensions were estimated using high resolution transmission electron microscopy, UV-Visible-NIR absorption spectroscopy, Raman spectroscopy, photoluminescence and zeta potential measurement. Nuclear magnetic resonance data provides direct evidence toward possible cation-π interaction.

7.
Arch. alerg. inmunol. clin ; 47(4): 146-151, 2016. ilus
Article in Spanish | LILACS | ID: biblio-915659

ABSTRACT

A pesar de que el angioedema hereditario es un padecimiento raro, tiene una amplia bibliografía que ratifica que la fisiopatología de esta enfermedad es compleja. La constante investigación de la industria farmacéutica no solo ha aportado nuevos recursos terapéuticos sino que ha logrado despertar un inusitado interés en la comunidad médica, permitiendo que tengamos una mayor comprensión sobre los mecanismos que presiden la aparición de las crisis. El Comité de Angioedema Hereditario de la AAAeIC ha desarrollado una puesta al día sobre esta entidad, que, por las características de sus síntomas, es abordada principalmente por los especialistas en alergia e inmunología clínica(AU)


Although hereditary angioedema is a rare condition, it has a large number of references that confirm that the pathophysiology of this disease is complex. The constant research of the pharmaceutical industry has not only brought new therapeutic resources, but also aroused an unusual interest in the medical community, allowing us to have a better understanding of the mechanisms that perform the onset of crises. The AAA e IC Hereditary Angioedema Committee has developed an update on this entity, which, due to the characteristics of its symptoms, is mainly addressed by specialists in allergy and clinical immunology.(AU)


Subject(s)
Humans , Female , Adult , Angioedemas, Hereditary/physiopathology , Angioedemas, Hereditary/genetics , Respiratory System , Skin , Bradykinin , Gastrointestinal Tract , Allergy and Immunology
8.
J Colloid Interface Sci ; 455: 78-82, 2015 Oct 01.
Article in English | MEDLINE | ID: mdl-26057106

ABSTRACT

We report a simple and easy formation of hybrids between multi-wall carbon nanotubes and gold nanorods by one-pot in situ photochemical synthesis. Measurements of surface-enhanced Raman scattering (SERS) through the effect "coffee ring" in visible and near infrared (NIR) show high sensitivity with detection of nanomolar concentrations of aromatic dyes. The formation of nanocomposites between carbon nanotubes and gold nanorods without chemical binders simplifies the preparation. Photochemical synthesis is an advance over the techniques previously published.


Subject(s)
Coloring Agents/analysis , Gold/chemistry , Nanocomposites/chemistry , Nanotubes, Carbon/chemistry , Nanotubes/chemistry , Benzoxazines/analysis , Methylene Blue/analysis , Nanocomposites/ultrastructure , Nanotubes/ultrastructure , Nanotubes, Carbon/ultrastructure , Photochemical Processes , Spectrum Analysis, Raman/methods , Ultraviolet Rays
9.
Physiol Behav ; 133: 223-9, 2014 Jun 22.
Article in English | MEDLINE | ID: mdl-24907692

ABSTRACT

The Italian National Law 281 of 1991 forbids the euthanatization of free-ranging dogs, unless they have an incurable illness or are proved to be dangerous. Without neglecting the undeniable benefits of the "no-kill" policy, nevertheless it has brought about a chronic overpopulation in shelters and, as a result, higher costs of management and welfare problems since some dogs remain in the shelter for life. In 2004-2008, the Istituto Zooprofilattico Sperimentale of the Lazio and Tuscany regions carried out a survey in the Lazio Region to verify the effects of the Italian National Law 281/91 on free-ranging dog management following 15 years from its implementation. One of the aims of the study was an assessment of the welfare of dogs in a shelter sample (8 shelters out of 47 censused in the Lazio Region). 97 mixed-breed dogs were selected, their behaviour was studied and a blood sample was taken for each dog in order to determine the individual blood concentration of cortisol and the amount of oxidative damage (level of dRoms), as well as the amount of antioxidants to cope with it. Moreover, the total leukocyte count (leukogram) was accomplished. We ran general backward stepwise regression models using "level of antioxidant", "level of dRoms" and "level of serum cortisol" as dependent variables respectively. The results showed that the most important variable that improved the level of welfare of dogs consisted in having the opportunity to regularly go out of the cage for a walk, whereas other variables like gender, size of the cage (small, medium, large), being alone in the cage, and being neutered/entire, had no significant effect on the physiological indicators of welfare. Dogs that enjoyed the regular walk had a higher total antioxidant capacity, and performed a lower frequency of displacing activities and stereotyped behaviour. Moreover, oxidative stress parameters seem to be indicators well matched with behavioural indicators of stress. Thus, for the first time, markers of oxidative status are utilised for the welfare evaluation in the domestic dog. Furthermore, the results of this paper give some suggestion about how small steps can help to improve shelters and, furthermore, this paper intends to solicit the debate on the no-kill policy.


Subject(s)
Animal Welfare , Behavior, Animal , Housing, Animal , Oxidative Stress/physiology , Stress, Physiological , Animals , Dogs , Humans , Hydrocortisone/blood , Italy , Longitudinal Studies , Male , Principal Component Analysis , Radioimmunoassay
10.
Free Radic Res ; 47(3): 202-11, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23297807

ABSTRACT

Aging is characterized by an impaired capacity to maintain the redox balance both in physiological and pathological situations associated with an increased production of reactive oxygen species. Since the extent of this phenomenon may be influenced by an antioxidants-rich diet, we investigated the effect of supplementation with fresh red orange juice (ROJ) on biochemical and cellular biomarkers of oxidative stress in healthy, trained elderly women after a single bout of exhaustive exercise (EE). To this purpose, a sample of 22 females, 15 (69.0 ± 5.1 years) taking the ROJ supplementation and 7 (68.1 ± 2.7 years) as Control group, was constituted. Blood samples were collected immediately before, 30 minutes, and 24 hr after a single bout of EE, at baseline and after 4 weeks. Our results demonstrate that markers of DNA damage or apoptosis were not affected by EE both in Control and ROJ group, and by ROJ, whereas, exercise temporarily affected the redox balance in both groups. Controls didn't change their response to EE after the experimental period, but experimental group after ROJ supplementation had lower EE-induced MDA, consumed less ascorbic acid, and had less activation of the hypoxanthine/xanthine system, i.e., they seemed to be protected from hypoxia/reoxygenation mechanisms.


Subject(s)
Antioxidants/administration & dosage , Beverages , Citrus sinensis/chemistry , Oxidative Stress/drug effects , Plant Extracts/administration & dosage , Administration, Oral , Aged , Ascorbic Acid/blood , Biomarkers/blood , DNA Damage , Dietary Supplements , Exercise , Female , Hemolysis , Homeostasis/drug effects , Humans , Hypoxanthine/blood , Malondialdehyde/blood , Middle Aged , Oxidation-Reduction , Physical Exertion , Xanthine/blood
12.
Nat Mater ; 9(10): 833-9, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20835232

ABSTRACT

There has been renewed interest in solar concentrators and optical antennas for improvements in photovoltaic energy harvesting and new optoelectronic devices. In this work, we dielectrophoretically assemble single-walled carbon nanotubes (SWNTs) of homogeneous composition into aligned filaments that can exchange excitation energy, concentrating it to the centre of core-shell structures with radial gradients in the optical bandgap. We find an unusually sharp, reversible decay in photoemission that occurs as such filaments are cycled from ambient temperature to only 357 K, attributed to the strongly temperature-dependent second-order Auger process. Core-shell structures consisting of annular shells of mostly (6,5) SWNTs (E(g)=1.21 eV) and cores with bandgaps smaller than those of the shell (E(g)=1.17 eV (7,5)-0.98 eV (8,7)) demonstrate the concentration concept: broadband absorption in the ultraviolet-near-infrared wavelength regime provides quasi-singular photoemission at the (8,7) SWNTs. This approach demonstrates the potential of specifically designed collections of nanotubes to manipulate and concentrate excitons in unique ways.


Subject(s)
Nanotubes, Carbon/chemistry , Nanotechnology , Temperature
13.
J Phys Condens Matter ; 22(33): 334222, 2010 Aug 25.
Article in English | MEDLINE | ID: mdl-21386512

ABSTRACT

Surface composition plays an important role in carbon nanotube dispersibility in different environments. Indeed, it determines the choice of dispersion medium. In this paper the effect of oxidation on the dispersion of HiPCO single-walled carbon nanotubes (SWNTs) in N-methyl-pyrrolidinone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-dodecyl-pyrrolidinone (N12P) and cyclohexyl-pyrrolidinone (CHP) was systematically studied. During the oxidation process, similar amounts of carboxylic acid and phenolic groups were introduced to mostly already existing defects. For each solvent the dispersion limits and the absorption coefficients were estimated by optical absorption analysis over a range of SWNT concentrations. The presence of acid oxygenated groups increased SWNT dispersibility in NMP, DMF and DMA, but decreased in N12P and CHP. The absorption coefficients, however, decreased for all solvents after oxidation, reflecting the weakening of the effective transition dipole of the π-π transition with even limited extension functionalization and solvent interaction. The analysis of the results in terms of Hansen and Flory-Huggins solubility parameters evidenced the influence of dipolar interactions and hydrogen bonding on the dispersibility of oxidized SWNTs.


Subject(s)
Amides/chemistry , Colloids/chemistry , Nanotubes, Carbon/chemistry , Nanotubes, Carbon/ultrastructure , Oxygen/chemistry , Solvents/chemistry , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Particle Size , Surface Properties
14.
Br J Surg ; 96(9): 1041-8, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19672933

ABSTRACT

BACKGROUND: Few studies have compared survival and recurrence rates between laparoscopic and open liver resection for hepatocellular carcinoma in patients with cirrhosis. METHODS: A retrospective analysis of a prospectively maintained database of 179 liver resections performed for HCC in cirrhotic liver between 2000 and 2007 was performed. RESULTS: Fifty-four patients underwent a laparoscopic resection and 125 patients had open surgery. Histopathological features were largely comparable in the two groups. Tumours operated laparoscopically were smaller than those removed at open operation and laparoscopic liver resection was less extensive. Laparoscopic surgery had a lower morbidity rate than open surgery (19 versus 36.0 per cent; P = 0.020), whereas 30-day mortality was similar (2 versus 4.0 per cent; P = 0.615). After a median follow-up of 24 months, 1- and 3-year survival rates were 94 and 67 per cent in the laparoscopic group. Recurrence rates were similar after laparoscopic and open procedures (45 versus 52.5 per cent; P = 0.381), as was disease-free survival (P = 0.864). CONCLUSION: Laparoscopic resection of HCC in cirrhotic liver is feasible and safe in selected patients. Adequate long-term survival and recurrence is achieved compared with open surgery, when stratified for tumour characteristics known to be related to survival outcome.


Subject(s)
Carcinoma, Hepatocellular/surgery , Laparoscopy , Liver Cirrhosis/complications , Liver Neoplasms/surgery , Aged , Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/pathology , Databases, Factual , Disease-Free Survival , Feasibility Studies , Female , Humans , Liver Cirrhosis/pathology , Liver Neoplasms/complications , Liver Neoplasms/pathology , Male , Middle Aged , Neoplasm Recurrence, Local/pathology , Postoperative Care , Retrospective Studies
15.
HPB (Oxford) ; 10(4): 234-8, 2008.
Article in English | MEDLINE | ID: mdl-18773104

ABSTRACT

BACKGROUND: The use of new technological devices has gained popularity and has been proposed to improve the safety of liver resection. This study was designed to evaluate the usefulness of the ultrasonically activated device (USAD) during open liver resection. MATERIALS AND METHODS: Indication for surgery, type of resection, need to perform a Pringle manoeuvre, operation time, blood loss, number of blood transfusions, morbidity and mortality rate were analyzed in 60 patients undergoing a formal open liver resection by means of USAD. RESULTS: The overall mean operation time was 172 minutes (range 120-255 min); an intermittent warm ischemia was applied in 9 cases (15%). The overall mean blood loss was 410 mL (median 400 mL, range 50-950 ml). A median of one blood transfusion was administered in six patients (10%). The mean hospital stay was 10.2 days (median 11, range 8-16). The overall morbidity rate was 20% (12 out of 60 patients). No in-hospital mortality was recorded. By subdividing the patients according to the presence or absence of cirrhosis no statistical significant differences were found between the two subgroups in all peri-and postoperative outcomes. CONCLUSIONS: In conclusion, though there is a lack of data based on well conducted controlled studies and further on a greater number of patients are needed, the utilization of USAD may help to minimize blood loss during liver resection regardless of the condition of the liver, even in case of cirrhosis.

16.
Surg Endosc ; 21(11): 2004-11, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17705086

ABSTRACT

BACKGROUND: Liver surgery, especially for cirrhotic patients, is one of the last areas of resistance to progress in laparoscopic surgery. This study compares the postoperative results and the 2-year patient outcomes between laparoscopic and open resection for hepatocellular carcinoma in patients with histologically proven cirrhosis. METHODS: From May 2000 to October 2004, 23 consecutive cirrhotic patients who underwent laparoscopic hepatectomy (LH) for HCC were compared in a retrospective analysis with a historic group of 23 patients who underwent open hepatectomy (OH). The two groups were well matched for age, gender, American Society of Anesthesiology (ASA) class, tumor location and size, type of liver resection, and severity of cirrhosis. The selection criteria for both groups specified a small (size < 5 cm), exophytic, or subcapsular tumor located in the left or peripheral right segments of the liver (II-VI segments, Couinaud); a well-compensated cirrhosis (Child-Pugh A); and an ASA score lower than 3. In the LH group, 15 subsegmentectomies, 3 segmentectomies, and 5 left lateral sectionectomies were performed, as compared with 12 subsegmentectomies, 5 segmentectomies, and 6 left lateral sectionectomies in the OH group. RESULTS: One patient in the LH group (4.3%) underwent conversion to laparotomy for inadequate exposition. The mean operative time was statistically longer for the LH group (LH, 148 min; OH, 125 min; p = 0.016), whereas blood transfusions (LH, 0%; OH, 17.3%; p = 0.036), Pringle maneuver (LH, 0%; OH, 21.73%; p = 0.017), mean hospital stay (LH, 8.3 days; OH, 12 days; p = 0.047), and postoperative complications (LH, 13%; OH, 47.8%; p = 0.010) were significantly greater in OH group. There was no statistically significant difference in mortality and 2-year survival rates between the two groups. CONCLUSION: This study shows that LH for HCC in properly selected cirrhotic patients results in fewer early postoperative complications and a shorter hospital stay than the traditional OH. The 2-year survival rate was the same for LH and OH.


Subject(s)
Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/surgery , Digestive System Surgical Procedures/statistics & numerical data , Laparoscopy/statistics & numerical data , Liver Cirrhosis/complications , Liver Neoplasms/complications , Liver Neoplasms/surgery , Aged , Digestive System Surgical Procedures/methods , Female , Follow-Up Studies , Humans , Laparoscopy/methods , Liver Cirrhosis/diagnosis , Male , Middle Aged , Retrospective Studies , Treatment Outcome
17.
Encephale ; 33(2): 117-23, 2007.
Article in French | MEDLINE | ID: mdl-17675906

ABSTRACT

UNLABELLED: Introduction. The development of a DNA based diagnostic test has allowed for the genetic screening of many hereditary diseases. In addition to the identification of the deleterious gene, this screening process has led to the recognition of developing illnesses at high risk. In recent years, a number of genes predisposing to an inherited cancer syndrome have been identified. AIM OF THE STUDY: Our purpose in this study was to determine whether subjects at risk who test for inherited colorectal cancer, are likely to develop a higher level of psychological distress than the norm, taking into consideration the particular history of this familial disease. METHODS: The demographic and psychosocial aspects of our population was described using: 1) the State Trait Anxiety Inventory (STAI), 2) the Center for Epidemiologic Studies Depression (CES-D), 3) a perceived risk for the gene carrier, 4) subjective perception of personal vulnerability and 5) the role of the medical status (affected or not), which places the subject in either predisposition or predictive testing. RESULTS: Results show that our population had a higher predisposition for depressive disorders (chi2=9,3. p=0.002) and a significantly higher state of anxiety (chi2=9,3. p=0.002), prior to genetic counselling, compared with other populations. We found no evidence in the medical status, nor the perceived risk. However, the assessment of one's own personal vulnerability is related to psychological distress. DISCUSSION: These results highlight the particular vulnerability of subjects undergoing genetic testing as well as showing the pertinence of proposing psychological help throughout the process of these new specific diagnoses.


Subject(s)
Anxiety Disorders , Colorectal Neoplasms , Depressive Disorder , Genetic Testing/methods , Adult , Anxiety Disorders/diagnosis , Anxiety Disorders/epidemiology , Anxiety Disorders/etiology , Attitude to Health , Colorectal Neoplasms/epidemiology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/psychology , Depressive Disorder/diagnosis , Depressive Disorder/epidemiology , Depressive Disorder/etiology , Female , Genetic Predisposition to Disease , Humans , Male , Prevalence , Severity of Illness Index
19.
Phys Rev Lett ; 93(14): 147406, 2004 Oct 01.
Article in English | MEDLINE | ID: mdl-15524844

ABSTRACT

This Letter reports the laser energy dependence of the Stokes and anti-Stokes Raman spectra of carbon nanotubes dispersed in aqueous solution and within solid bundles, in the energy range 1.52-2.71 eV. The electronic transition energies (E(ii)) and the radial breathing mode frequencies (omega(RBM)) are obtained for 46 different (18 metallic and 28 semiconducting) nanotubes, and the (n,m) assignment is discussed based on the observation of geometrical patterns for E(ii) versus omega(RBM) graphs. Only the low energy component of the E(M)(11) value is observed from each metallic nanotube. For a given nanotube, the resonant window is broadened and down-shifted for single wall carbon nanotube (SWNT) bundles compared to SWNTs in solution, while by increasing the temperature, the E(S)(22) energies are redshifted for S1 [(2n+m) mod 3=1] nanotubes and blueshifted for S2 [(2n+m) mod 3=2] nanotubes.


Subject(s)
Nanotubes, Carbon/chemistry , Spectrum Analysis, Raman/methods , Environment , Temperature
20.
Phys Rev Lett ; 93(8): 087401, 2004 Aug 20.
Article in English | MEDLINE | ID: mdl-15447223

ABSTRACT

Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm(-1) spectral region in single-wall carbon nanotubes. Sharp peaks are associated with the combination of zone folded optic and acoustic branches from 2D graphite. These combination modes exhibit a peculiar dependence on the excitation laser energy that is explained on the basis of a highly selective resonance process that considers phonons and electrons in low dimensional materials.

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