80% Valley Polarization of Free Carriers in Singly Oriented Single-Layer WS_{2} on Au(111).

We employ time- and angle-resolved photoemission spectroscopy to study the spin- and valley-selective photoexcitation and dynamics of free carriers at the K[over ¯] and K[over ¯]^{'} points in singly oriented single-layer WS_{2}/Au(111). Our results reveal that in the valence band maximum an ultimate valley polarization of free holes of 84% can be achieved upon excitation with circularly polarized light at room temperature. Notably, we observe a significantly smaller valley polarization for the photoexcited free electrons in the conduction band minimum. Clear differences in the carrier dynamics between electrons and holes imply intervalley scattering processes into dark states being responsible for the efficient depolarization of the excited electron population.

Free surfaces recast superconductivity in few-monolayer MgB2: Combined first-principles and ARPES demonstration.

Two-dimensional materials are known to harbour properties very different from those of their bulk counterparts. Recent years have seen the rise of atomically thin superconductors, with a caveat that superconductivity is strongly depleted unless enhanced by specific substrates, intercalants or adatoms. Surprisingly, the role in superconductivity of electronic states originating from simple free surfaces of two-dimensional materials has remained elusive to date. Here, based on first-principles calculations, anisotropic Eliashberg theory, and angle-resolved photoemission spectroscopy (ARPES), we show that surface states in few-monolayer MgB2 make a major contribution to the superconducting gap spectrum and density of states, clearly distinct from the widely known, bulk-like σ- and π-gaps. As a proof of principle, we predict and measure the gap opening on the magnesium-based surface band up to a critical temperature as high as ~30 K for merely six monolayers thick MgB2. These findings establish free surfaces as an unavoidable ingredient in understanding and further tailoring of superconductivity in atomically thin materials.

Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface.

Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local strain/deformation on the graphene layer whose magnitude is controlled by the intermolecular distance. The crystalline intercalated structure exhibits a superlattice peak in the local density of states. This work provides control of local strain in graphene.

NOD2 contributes to Porphyromonas gingivalis-induced bone resorption.

The NOD-like receptors are cytoplasmic proteins that sense microbial by-products released by invasive bacteria. Although NOD1 and NOD2 are functionally expressed in cells from oral tissues and play a role triggering immune responses, the role of NOD2 receptor in the bone resorption and in the modulation of osteoclastogenesis is still unclear. We show that in an experimental model of periodontitis with Porphyromonas gingivalis W83, NOD2(-/-) mice showed lower bone resorption when compared to wild type. Quantitative polymerase chain reaction analysis revealed that wild-type infected mice showed an elevated RANKL/OPG ratio when compared to NOD2(-/-) infected mice. Moreover, the expression of 2 osteoclast activity markers-cathepsin K and matrix metalloproteinase 9-was significantly lower in gingival tissue from NOD2(-/-) infected mice compared to WT infected ones. The in vitro study reported an increase in the expression of the NOD2 receptor 24 hr after stimulation of hematopoietic bone marrow cells with M-CSF and RANKL. We also evaluated the effect of direct activation of NOD2 receptor on osteoclastogenesis, by the activation of this receptor in preosteoclasts culture, with different concentrations of muramyl dipeptide. The results show no difference in the number of TRAP-positive cells. Although it did not alter the osteoclasts differentiation, the activation of NOD2 receptor led to a significant increase of cathepsin K expression. We confirm that this enzyme was active, since the osteoclasts resorption capacity was enhanced by muramyl dipeptide stimulation, evaluated in osteoassay plate. These results show that the lack of NOD2 receptor impairs the bone resorption, suggesting that NOD2 receptor could contribute to the progression of bone resorption in experimental model of periodontitis. The stimulation of NOD2 by its agonist, muramyl dipeptide, did not affect osteoclastogenesis, but it does favor the bone resorption capacity identified by increased osteoclast activity.

Subclinical interstitial lung abnormalities in stable renal allograft recipients in the era of modern immunosuppression.

BACKGROUND: Interstitial lung abnormalities have been detected in up to 24% of kidney transplant patients receiving traditional immunosuppressive therapies (eg, cyclosporine, azathioprine); they usually occur early after transplantation and tend to resolve over time. Newer immunosuppressants such as mycophenolic acid and, particularly, mammalian target of rapamycin (mTOR) inhibitors (eg, sirolimus) may cause significant lung toxicity. However, the prevalence and severity of interstitial lung lesions in long-term, stable kidney transplant patients receiving either traditional or newer immunosuppressants is not known. METHODS: We conducted a prospective, cross-sectional study examining high-resolution lung computed tomography (CT) scans in 63 stable kidney transplant recipients whose immunosuppressive therapy had remained unchanged for over 24 months. We compared CT findings of patients taking newer (mycophenolic acid and mTOR inhibitors) and traditional (calcineurin inhibitors and azathioprine) immunosuppressive drugs. RESULTS: Interstitial lung alterations were observed in only 3/63 patients (4.8%); the prevalence was 11.5% (3/26) versus 0% (0/37) among the newer versus traditional immunosuppressive therapy groups, respectively (P = .065). The CT patterns were usual interstitial pneumonia and nonspecific interstitial pneumonia-like. The median time between transplant and CT was 49 months in the three patients with CT alterations and 95 months in the remaining 23 patients on newer immunosuppressants. It was 75 months for all patients on newer immunosuppressive drugs and 133 months for those on traditional therapies (P = .0015). A follow-up CT, performed in 2/3 patients with interstitial abnormalities, showed that the lesions were stable in one, while they had disappeared in the other. CONCLUSIONS: Interstitial lung abnormalities are infrequent and mild in stable kidney transplant patients treated with newer as well as traditional immunosuppressive drugs. As such abnormalities were detected in patients screened earlier after transplantation, the time since transplantation rather than the drug type is probably the major determinant.

EBV-associated leukoencephalopathy with late onset of central nervous system lymphoma in a kidney transplant recipient.

Central nervous system (CNS) lymphoma is a rare posttransplant lymphoproliferative disorder (PTLD), which usually has a poor outcome. To date, no specific conditions predisposing to this complication have been identified. We here describe the case of a renal transplant patient who was initially diagnosed as having Epstein-Barr virus (EBV)-associated leukoencephalopathy and ultimately developed EBV-positive CNS lymphoma. The patient was a young lady who, 2 years after transplantation, presented with focal neurological and electroencephalographic abnormalities and diffuse white matter lesions on brain magnetic resonance imaging. EBV-DNA was detected in the cerebrospinal fluid (CSF) by polymerase chain reaction. After acyclovir therapy and immunosuppressive drug tapering, the symptoms and electroencephalographic abnormalities subsided, and EBV-DNA disappeared from the CSF. Ten years later, a bulky cerebral mass was found. After excision, a diagnosis of EBV-positive, Hodgkin-like monomorphic B-cell PTLD was made. This case illustrates the potential pathophysiological relationships between EBV infection, leukoencephalopathy and CNS lymphoma; although a long time elapsed from the initial neurological illness to CNS lymphoma, a link between these two conditions cannot be excluded. Therefore, a careful long-term follow-up of EBV-related encephalopathy is advisable.

Octreotide in the treatment of lymphorrhea after renal transplantation: a preliminary experience.

BACKGROUND: Lymphorrhea is a minor complication after kidney transplantation but may develop into a lymphocele and prolong hospital stay. Treatment is conservative based on percutaneous drainage until lymphatic leakage cessation. It has been reported that octreotide has beneficial effects to treat lymphorrhea after axillary node dissection and excision of lymphatic malformations. The aim of this study was to report preliminary experience about octreotide treatment in lymphorrea after kidney transplantation. MATERIALS AND METHODS: This retrospective study included 20 recipients of cadaveric kidney allografts with posttransplant lymphorrhea including 10 treated with instillation of povidone iodate solution, and the other 10 with octreotide (0.1 mg three times a day subcutaneously). We reviewed the daily amount of fluid collection, duration of lymphorrhea, complications, lymphocele formation, rejection episodes, graft outcomes, and hospital stay. RESULTS: The average duration of lymphorrhea was 8.5 (+/-4.5) and 16.3 (+/-7.3) days for the octreotide versus the povidone groups, respectively (P = .001). No complications occurred among the octreotide group, while three lymphoceles grew among patients treated with povidone solution. No differences were observed for acute rejection episodes or renal function between the groups. No octreotide-related adverse events were noted. CONCLUSION: The mean length of lymphorrhea was lower with octreotide versus iodate povidone solution treatment. There was a shorter hospital stay and minor patient discomfort. In conclusion, lymphatic leakage after kidney transplantation may be successfully managed by octreotide administration.

Renal vein extension in right kidney transplantation.

A short right renal vein may be associated with technical problems in renal transplantation. For this reason, a vena caval extension may be useful to improve exposure of the anastomosis and graft placement. This report evaluates the safety and the effectiveness of renal vein extension, which was routinely performed in right renal transplantation. From April 1986 to December 2002, we performed 371 right kidney transplantations with 252 using the standard technique (group A) and 119 using the renal vein extension (group B). No statistical differences were found between the 2 groups in terms of renal vein thrombosis incidence, delayed graft function, morbidity, and graft loss. Indeed, mean warm ischemia time was reduced in the venoplasty group. In conclusion, renal vein extension is an easy, safe technique that reduces warm ischemia time. We suggest more extensive use of this procedure in right kidney transplantation.

Molecular evidence of organ-related transmission of Kaposi sarcoma-associated herpesvirus or human herpesvirus-8 in transplant patients.

In transplant patients, Kaposi sarcoma (KS)-associated herpesvirus or human herpesvirus-8 (HHV-8) infection is associated with the development of KS, primary effusion lymphoma and Castleman disease. Whether HHV-8 is either reactivated in the recipient or transmitted by the donor has been investigated so far only by serologic studies. Thus, we addressed the issue of HHV-8 transmission in the transplantation setting by molecular methods. We exploited the high level variability of the orf-K1 gene and the polymorphism of the orf-73 gene of the HHV-8 genome to assess the genetic relatedness of the HHV-8 strains identified in the posttransplant KS lesions that developed, simultaneously, 20 months after transplantation, in 2 recipients of twin kidneys from the same cadaver donor. The 100% identity of nucleotide sequence of the most variable viral region and the presence of the same, single orf-73 type in both patients provides strong molecular evidence of organ-related transmission of HHV-8 in the setting of transplantation.

[Neoplasms and kidney transplantation. Case contribution]. / Neoplasie e trapianto renale. Contributo casistico.

BACKGROUND: The incidence of malignancies after transplantation is higher when compared with expected cancer in control patients, particularly skin and female genital cancer, non-Hodgkin's disease and Kaposi's sarcoma. The aim of this study is to evaluate the frequency and the efficacy of the treatment of cancer following renal transplantation. METHODS: A retrospective analysis of 404 recipients was performed and it showed the onset of 15 cancers (8 skin cancers, 3 Kaposi's sarcomas, 2 renal carcinomas, 1 urotelioma and 1 colon cancer) in 11 patients (3.7%). At the time of diagnosis, the mean period of immunosuppressive therapy (7 cases of double therapy, 4 cases of triple therapy) was 44.8 months. Skin cancer (53.3%) and Kaposi's sarcoma (20%) were the most frequent in personal experience as reported in literature. Neither lymphomas, nor female genital cancers were detected. RESULTS: All the cases were surgically treated, except patients with Kaposi's sarcoma, whose immunosuppressive therapy was reduced without alteration of renal function. Death-rate was 0.25% (1 case), the remaining patients show no signs of local recurrence or metastasis with preserved renal function except for the patient with renal carcinoma of the transplanted kidney, who underwent nephrectomy and returned in replacement therapy. CONCLUSIONS: The conclusion is drawn that the research of relationship between type of immunosuppressive therapy and cancer incidence and careful clinical and instrumental examination of transplant patients may contribute to reduce the onset of neoplastic degenerations and lead to an early diagnosis.

[Adenoid cystic carcinoma of the larynx: review of the literature and caseload]. / Carcinoma adenoide quístico de laringe: revisión de la literatura y aportación casuística.

Two cases of laryngeal adenoid cystic carcinoma (1 supraglottic, 1 subglottic) are reported, particular attention being paid to diagnosis and treatment. The literature on this topic has been reviewed, in order to describe the natural course and the different treatments of this tumour. The authors underline the difficulty in evaluating the effectiveness of treatment, due to the insufficient follow-up in most published cases.

Functional surgery of ceruminoma of the external and/or middle ear.

The paper describes two cases of "Ceruminoma" of the external and/or middle ear, treated by conservative surgery. The authors illustrate, besides morphological and histological features of ceruminoma, the surgical treatment modulated on the basis of an exact identification of the lesions.

Late recurrence of systemic vasculitis after kidney transplantation involving the kidney allograft.

A patient is described in whom a recurrence of vasculitis was observed in the kidney allograft six years after transplantation and one year after withdrawal of corticosteroid therapy. This case shows that systemic vasculitis may recur at any time after transplantation which implies a continuous and careful monitoring of these patients.

[Diagnostic role of ultrasound in the transplanted kidney]. / Ruolo diagnostico degli ultrasuoni nel rene trapiantato.

Among diagnostic postoperative procedures in renal cadaver transplantation echographic examination shows high sensitivity and specificity (over 80%). Urographic examination is in fact often dangerous and impossible in non-functioning grafts. Echography can reveal several liquid and solid collections such as hematomas, urinomas, abscesses, lymphatic collections and so on. Urinary obstructions caused by ureteral clots, calculi, external masses can be also detected through echographic examination. Vascular complications can be evaluated through echo and US Doppler examination showing arterial and venous complications. In most of cases acute and chronic graft rejection can be revealed through echo examination whereas in few cases diagnosis can be made only with the help of renal biopsy, laboratory findings and clinical conditions. In conclusion echography is a safe and reliable procedure in renal graft postoperative monitoring.

[Suprahyoid transpharyngeal approach to the median skull base in surgery of rhinoangiofibroma]. / L'accesso transfaringeo soprajoideo all'esobasicranio mediano nella chirurgia del rinoangiofibroma.

Ten young males with rhinopharyngeal angiofibroma (RAG) were studied. Except for one case of IIIb stage the others were all either I or IIIa. They all underwent surgery at the E.N.T. Clinic in Ferrara employing the transpharyngeal suprahyoid approach (TSA) originally described by Bocca. For the one case in the most advanced stage (IIIb), besides the TSA a paralateronasal approach and a complementary RT were also planned. In this series of cases, one recurrence due to a peritubaric residue was treated 8 months later through a transpalatal approach. The follow-up, with NED findings, varied from a maximum of 12 to minimum of 2 years (average 6.4 years), except for the last subject which underwent surgery in 1991. Three minor post-operative complications due to TSA were encountered, while 1 complication was attributed to the transpalatal approach used for the recurrence described. All cases healed completely. The data on the TSA from the international and national literature is reviewed underlining that the negative elements reported have, in the authors' opinion, been overcome by: perfecting the method for RAG exeresis and the method of the tracheotomy; making technological improvements: pre-operatory embolization, microsurgery applied to TSA in order to check any lateral branches and to the transnasal approach in order to check any residue in the choanal area.

[Subtotal reconstructive laryngectomy: author's experience]. / Laringectomia subtotale ricostruttiva: nostra esperienza.

The authors conclude 18 year's experience with reconstructive laryngectomy by adopting two surgical techniques for intrinsic laryngeal tumors. The first, where one or both of the arytenoids are conserved, can be applied in cases of supraglottic neoplasms extending to the glottis as well as in glottic cancers where a simple cordectomy is not feasible. In both cases this technique is indicated when at least one arytenoid is respected. The second technique involves removal of both arytenoids and is used in cases of intrinsic supraglottic or glottic tumors extended to both arytenoids. The anatomic-pathological criteria supporting these techniques are: 1) the presence of a fibrous ligament anterior to the arytenoid vocal process. This makes possible proper exeresis within healthy tissue (as can be done in supraglottic surgery due to the anatomic characteristics at the anterior commissure level); 2) neoplastic infiltration of the cricoid cartilage takes place exceptionally in supraglottic and glottic neoplasms; in such cases neoplastic manifestation can be radiographically identified. Generally removal of the soft tissues and of the perichondrium within the cricoid area grants conservative surgery the same oncological radicality as that of total laryngectomy. Insights into restoration of laryngeal function when employing the arytenoid-preserving technique are as follows: 1) conservation of the recurrent nerve(s) 2) pulling the base of the tongue back and downward; close to the crico-arytenoid structure can be achieved by crico-hyoid-pexy. In the technique involving removal of the arytenoid: 1) reconstruction of two pseudo-arytenoids 2) the base of the tongue has to be brought close to the edge of the cricoid cartilage possibly by crico-hyoid-pexy. A total of 21 patients have undergone surgery with these techniques since 1984 and to date no neoplastic recurrences have been observed. Those who underwent surgery where the arytenoids were preserved (16 cases) showed laryngeal functional recovery times similar to those for supraglottic surgery. The recovery times were longer for those undergoing bilateral arytenoidectomy (5) and this was especially so for swallowing.