Vibrations of a chain of Xe atoms in a groove of carbon nanotube bundle

We present a lattice dynamics study of the vibrations of a linear chain of Xe adsorbates in groove positions of a bundle of carbon nanotubes. The characteristic phonon frequencies are calculated and the adsorbate polarization vectors discussed. Comparison of the present results with the ones previously published shows that the adsorbate vibrations cannot be treated as completely decoupled from the vibrations of carbon nanotubes and that a significant hybridization between the adsorbate and the tube modes occurs for phonons of large wavelengths.Comment: 3 PS figure

Fluorodeoxyglucose-positron emission tomography/computed tomography in the staging and evaluation of treatment response in a patient with Castleman's disease: a case report

<p>Abstract</p> <p>Introduction</p> <p>Castleman's disease is a rare lymphatic polyclonal disorder that is characterised by unicentric or multicentric lymph node hyperplasia and non-specific symptoms and signs including fever, asthenia, weight loss, enlarged liver and abnormally high blood levels of antibodies.</p> <p>Case presentation</p> <p>We present the case of a 74-year-old man with Castleman's disease. The disease was detected with a contrast-enhanced computed tomography (CT) scan and a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT study; diagnosis was made with histopathology. After treatment with surgical excision followed by chemotherapy, the disease response was evaluated using both diagnostic techniques. However, only the PET study was able to identify the spread of the disease to the abdominal lymph nodes, which were both enlarged and normal size, and, after treatment, to evaluate the disease response.</p> <p>Conclusion</p> <p>Based on the results of previous case reports and on those of the present study, it seems that Castleman's disease has a high glucose metabolic activity. Therefore, the use of PET can be considered appropriate in order to stage or restage the disease and to evaluate the response of the disease to treatment.</p

Human herpes virus 8 replication during disseminated tuberculosis in a man with human immunodeficiency virus: a case report

INTRODUCTION: Human herpes virus 8 (HHV-8) is mainly responsible for the development of Kaposi's sarcoma and multicentric Castleman's disease in immunocompromised patients with untreated human immunodeficiency virus. Positive viral loads have been described in cases of Kaposi's sarcoma and multicentric Castleman's disease, with higher values found in the latter. We describe the case of a patient with HIV in whom a high level of HHV-8 replication was detected and who contracted an opportunistic disease other than multicentric Castleman's disease or Kaposi's sarcoma. CASE PRESENTATION: A 25-year-old man of West African origin with HIV complained of asthenia, weight loss, fever, and abdominal pain. Physical examination revealed that the patient had adenopathies and hepatosplenomegaly, but no skin or mucosal lesions were seen. Our first presumptive diagnosis was disseminated tuberculosis. However, since the cultures (sputum, bronchoalveolar lavage, blood, urine and lymph node biopsies) for mycobacteria were negative, the diagnosis was expanded to include multicentric Castleman's disease which was supported by high HHV-8 viral loads in the patient's blood: 196,000 copies/ml in whole blood, 39,400 copies/ml in plasma and 260 copies/10E5 in peripheral blood mononuclear cells. However, the histology and positive polymerase chain reaction assay for Mycobacterium tuberculosis complex of a second lymph node biopsy enabled us to conclude that the patient had disseminated tuberculosis and we started the patient on antituberculosis treatment. We analyzed the HHV-8 deoxyribonucleic acid in two other plasma samples (one from six months earlier and the other was 10 days after the positive test) and both yielded negative results. A search for latent and lytic HHV-8 antibodies confirmed that the patient was seropositive for HHV-8 before this episode. CONCLUSION: We describe the case of a patient with HIV who tested positive for asymptomatic HHV-8 replication during an opportunistic disease suggestive of multicentric Castleman's disease. The initial analysis was nullified by the diagnosis of a disease that was unrelated to HHV-8. This case report underlines the need to clarify the full clinical meaning and implication of a positive HHV-8 viral load in patients with AIDS. The diagnosis of multicentric Castleman's disease needs to be studied further to determine its sensitivity and specificity. Finally, when faced with the dilemma of urgently starting chemotherapy on a patient whose condition is deteriorating and whose clinical presentation suggests multicentric Castleman's disease, high HHV-8 viral loads should be interpreted with caution and histological analysis of lymph nodes or liver biopsies should be obtained first

The effect of age, gender, and time between blood draw and start of centrifugation on the size outcomes of platelet-rich fibrin (PRF) membranes.

OBJECTIVES Platelet-rich fibrin (PRF) has been utilized in regenerative dentistry as a supra-physiological concentrate of autologous growth factors capable of stimulating tissue regeneration. Due to the variability in the macroscopic morphology/size of PRF membranes observed between patients, we were interested in studying the effects of patient age, gender, and time between blood draw and the start of centrifugation on the size outcomes of PRF membranes. Despite PRF therapy being increasingly more popular in private practice, to date, no study has investigated the effects of the delay between blood draw and the start of centrifugation in a clinical setting. MATERIALS AND METHODS A total of 60 patients enrolled in this study were divided into 6 groups of 10 patients each, including male and female patients categorized into age groups 21-40, 41-60, and 61-80 years. From each patient, a total of five PRF membranes were fabricated from 10-mL tubes following centrifugation starting after 0, 30, 60, 90, and 120 s. In total, 300 PRF membranes were produced in this study to investigate the effects of patient age, gender, and time on the size outcomes of PRF membranes. RESULTS A longer delay by the clinician before starting centrifugation following blood draw led to a smaller final size of PRF membranes. At 90 s following blood draw, a significant (13%) reduction in PRF membrane size was observed. After 120 s, a significant (23%) reduction was observed. Additionally, female patients had on average 17% larger membranes compared to men (p < 0.05, 300 samples). Lastly, the size outcomes of the PRF membranes was largest in patients aged 61-80, followed by those aged 41-60 and 21-40. However, no statistically significant differences in PRF membrane sizes were reported between age groups. CONCLUSIONS The time at which a centrifugation procedure begins following blood draw is critical to optimize the size outcomes of PRF membranes. In general, approximately 15 s is required per tube to harvest 9-10 cc of blood. Therefore, a 60- to 90-s interval between blood draw and the start of centrifugation should be a parameter that is respected by clinicians to avoid significant changes in the macroscopic morphology/size of fabricated PRF membranes. Furthermore, females and older patients produced larger membranes, likely due to lower red blood cell counts derived from their peripheral blood. CLINICAL RELEVANCE The findings from the present study demonstrate that on average, a clinician has approximately 60-90 s between blood draw and the start of the centrifugation cycle to produce standard-sized PRF membranes. Shortly thereafter, a significant reduction in size is observed. Additionally, females and older patients were found to produce larger PRF membranes. Centrifugation protocols may therefore be adapted accordingly