Spin-polarized Majorana zero modes in proximitized superconducting penta-silicene nanoribbons.

We theoretically propose penta-silicene nanoribbons (p-SiNRs) with induced p-wave superconductivity as a platform for the emergence of spin-polarized Majorana zero-modes (MZMs). The model explicitly considers the key ingredients of well-known Majorana hybrid nanowire setups: Rashba spin-orbit coupling, magnetic field perpendicular to the nanoribbon plane, and first nearest neighbor hopping with p-wave superconducting pairing. The energy spectrum of the system, as a function of chemical potential, reveals the existence of MZMs with a well-defined spin orientation localized at the opposite ends of both the top and bottom chains of the p-SiNR, associated with well-localized and nonoverlapping wave function profiles. Well-established experimental techniques enable the fabrication of highly ordered p-SiNRs, complemented by a thin lead film on top, responsible for inducing p-wave superconductivity through proximity effect. Moreover, the emergence of MZMs with explicit opposite spin orientations for some set of model parameters opens a new avenue for exploring quantum computing operations, which accounts for both MZMs and spin properties, as well as for new MZMs probe devices based on spin-polarized electronic transport mechanisms.

Main causes of bird-window collisions: a review.

Bird-window collisions are a major cause of bird mortality in the world; up to one billion birds die each year from collisions with glass panes in North America alone. However, relatively little attention had been given to this issue in the broad scientific literature, despite a recent increase in the number of papers. In this paper, the indexed literature on bird-window collisions was reviewed, specifically addressing the causal factors. The search retrieved 53 papers, mostly from North America. The factors linked to higher collision rates were large areas of continuous glass, the presence of nearby vegetation and feeders, bird migration, abundance, and behavior. Several factors were site-specific, preventing the global extrapolation of these findings. There is a lack of scientific knowledge regarding bird-window collisions in tropical countries. One of the challenges to mitigating this problem is the small amount of information and - frequently - the extrapolation of findings described for temperate regions to other areas. There is a need for a greater and urgent effort to fill this gap.

Two Weeks Too Long: Optimal Duration for Ureteral Prestenting and Its Physiologic Effects on the Ureter in a Yorkshire-Landrace Pig Model.

INTRODUCTION: Prestenting of the ureter is commonly performed to allow for passive dilation and better access to the urinary system during subsequent procedures. There is no level 1 evidence on the duration of prestenting and EAU guidelines suggest a 1-2 weeks duration. MATERIALS AND METHODS: Our primary aim is to investigate the optimal duration required for prestenting in a porcine model. Our secondary aim is to compare the ureteral wall compliance between the stented and the unstented ureters. METHODS: Three female pigs between 40 and 50 kg were used. We modified a human protocol for performing intravenous pyelograms in our study to obtain ureteral measurements on days 0, 5, 7, and 14. Unilateral stenting on days 0, 5, and 7 was performed. On day 14, bilateral nephroureterectomy was performed, and ureteral compliance was measured in the stent and unstented ureter. RESULTS: There were significant ureteral dilation between days 0 and 5 for all three pigs (p1 = 0.001, p2 ≤ 0.001 and p3 = 0.01). The rate of dilation appears to plateau after day 5 (p1 = 0.416, p2 = 0.344, and p3 = 0.774). Ureteral compliance in the stented ureter is better than in a nonstent ureter (p1 = 1.44 vs 0.13, p2 = 0.8 vs 0.04, p3 = 0.62 vs 0.2). An unexpected observation was the ureteral dilation and increased tortuosity in the unstented ureter in two of the three pigs (p1 = 0.152, p2 = 0.007). CONCLUSION: Our results suggest that optimal prestenting may be achieved in 5 days in a porcine model. It can potentially form the basis to start randomized human trials.

Growth and structural properties of silicene at multilayer coverage.

At monolayer coverage, silicene on Ag(1 1 1) may present different structural phases depending on the growth conditions. At multilayer coverage, only one structural phase has been reported: the [Formula: see text] phase. However, no link between the structural arrangement of the monolayer and that of the multilayer has been addressed. In this paper, reporting experimental work based on low-energy electron diffraction and scanning tunneling microscopy, we focus on the structural aspects of a multilayer film of silicene. We demonstrate that it exhibits one structural arrangement, namely the [Formula: see text] form, but with different domain orientations resulting from the structural properties of the initial wetting monolayer.

Bi-tangential hybrid IMRT for sparing the shoulder in whole breast irradiation.

BACKGROUND AND PURPOSE: A bi-tangential technique is proposed to reduce undesired doses to the shoulder produced by standard tangential irradiation. PATIENTS AND METHODS: A total of 6 patients affected by shoulder pain and reduced functional capacity after whole-breast irradiation were retrospectively analysed. The standard tangential plan used for treatment was compared with (1) a single bi-tangential plan where, to spare the shoulder, the lateral open tangent was split into two half-beams at isocentre, with the superior portion rotated by 10-20° medially with respect to the standard lateral beam; (2) a double bi-tangential plan, where both the tangential open beams were split. The planning target volume (PTV) coverage and the dose to the portion of muscles and axilla included in the standard tangential beams were compared. RESULTS: PTV95 % of standard plan (91.9 ± 3.8) was not significantly different from single bi-tangential plan (91.8 ± 3.4); a small but significant (p < 0.01) decrease was observed with the double bi-tangential plan (90.1 ± 3.7). A marked dose reduction to the muscle was produced by the single bi-tangential plan around 30-40 Gy. The application of the double bi-tangential technique further reduced the volume receiving around 20 Gy, but did not markedly affect the higher doses. The dose to the axilla was reduced both in the single and the double bi-tangential plans. CONCLUSION: The single bi-tangential technique would have been able to reduce the dose to shoulder and axilla, without compromising target coverage. This simple technique is valuable for irradiation after axillary lymph node dissection or in patients without dissection due to negative or low-volume sentinel lymph node disease.

Presence of gapped silicene-derived band in the prototypical (3 × 3) silicene phase on silver (111) surfaces.

By mapping the low-energy electronic dynamics using angle resolved photoemission spectroscopy (ARPES), we have shed light on essential electronic characteristics of the (3 × 3) silicene phase on Ag(111) surfaces. In particular, our results show a silicene-derived band with a clear gap and linear energy-momentum dispersion near the Fermi level at the Γ symmetry point of the (3 × 3) phase at several distinctive Brillouin zones. Moreover, we have confirmed that the large buckling of ~0.7 Å of this silicene structure induces the opening of a gap close to the Fermi level higher than at least 0.3 eV, in agreement with recent reported photoemission results. The two-dimensional character of the charge carriers has also been revealed by the photon energy invariance of the gapped silicene band, suggesting a limited silicene-silver hybridization, in disagreement with recent density-functional theory (DFT) predictions.

Comparative structural and electronic studies of hydrogen interaction with isolated versus ordered silicon nanoribbons grown on Ag(110).

We have investigated the geometry and electronic structure of two different types of self-aligned silicon nanoribbons (SiNRs), forming either isolated SiNRs or a self-assembled 5 × 2/5 × 4 grating on an Ag(110) substrate, by scanning tunnelling microscopy and high resolution x-ray photoelectron spectroscopy. At room temperature we further adsorb on these SiNRs either atomic or molecular hydrogen. The hydrogen absorption process and hydrogenation mechanism are similar for isolated or 5 × 2/5 × 4 ordered SiNRs and are not site selective; the main difference arises from the fact that the isolated SiNRs are more easily attacked and destroyed faster. In fact, atomic hydrogen strongly interacts with any Si atoms, modifying their structural and electronic properties, while molecular hydrogen has first to dissociate. Hydrogen finally etches the Si nanoribbons and their complete removal from the Ag(110) surface could eventually be expected.

[Exclusive intra-operative radiation therapy (IORT) for early stage breast cancer: pilot study of feasibility]. / Radioterapia intraoperatoria (IORT) esclusiva nel carcinoma iniziale della mammella: studio pilota di fattibilità.

AIM: To evaluate feasibility, tolerability and cosmetic outcome of intra-operative radiation therapy (IORT) as an exclusive post-surgery treatment of early stage breast cancer. PATIENTS AND METHODS: From October 2008 to October 2009 30 patients underwent wide breast cancer excision or quadrantectomy followed by IORT on tumor bed with accelerated electrons at the dose of 21Gy. The characteristics of the patients were: ductal breast cancer or invasive lobular cT1, cT2 ≤ 2,5 cm, cN0, G1-2, age over 35 years, M0. RESULTS: The average age was 51.7 (range 38 - 75) with an average follow up of 11.7 months (range 6 - 18). The pathologic stage of the lesions resulted pT1 in 29 cases (96,6%), in particular: one case pT1a (3,3%), 21 cases pT1b (70,0%) and 7 cases pT1c (23,3%). One case (3,3%) was pT2 with a diameter of 2.5 cm. The grading was G2 in 20 cases (66,6%) and G1 in 10 cases (33,3%). The toxicity, evaluated according to the EORTC-RTOG criteria, was G0 (33.3%) in 10 cases, G1 (63,3%) in 19 cases, G2 in one case (3,4%); there was no G3 toxicity. The time needed for a complete healing of the wound was less than 10 days in 96,7% of the cases, with one case of limphocele (3,3%). There were no infections of the surgical wound nor any mastitis, neither in the treated quadrant nor in the other ones. We observed a light fibrosis in 5 cases (16,6%), moderate in 2 cases (6,6%) but never severe. Cosmetics, evaluated in four levels, according to Danoff et al., was excellent in 3 cases (43,3%), good in 15 cases (50%), sufficient in 2 cases (6,7%), never insufficient. As regards local control, there was no local relapse. The global survival was 100%. CONCLUSIONS: The IORT in early breast cancer, at the doses used in this study, proved itself as a secure technique, repeatable, with limited complications. The advantages of its use are the possibility of a direct control, by the surgeon and the radiotherapist, of the structures to treat and those to protect; the absence of time needed for cellular repopulation between surgery and radiotherapy; a good cosmetic outcome; and logistic advantages. It is necessary to have a long term follow up to evaluate the efficacy in terms of long term cosmetic and local control.

CD133 expression predicts for non-response to chemotherapy in colorectal cancer.

The cancer stem cell hypothesis may explain why conventional chemotherapies are unable to fully eradicate cancers. In this study, we examined both the prognostic and predictive significance of putative cancer stem cell markers in colorectal cancer. In this study, immunohistochemistry for three candidate cancer stem cell markers (CD133, Oct-4 and Sox-2) and for six other postulated prognostic markers (CK7, CK20, Cox-2, Ki-67, p27 and p53) were performed using tissue microarrays containing 501 primary colorectal cancer cases. Receiver-operating characteristic analysis was used to determine cut-off scores for positive protein expression. Multivariate analysis revealed that positive expression for CD133 and Oct-4 was associated with significantly worse survival in patients treated by surgery alone (P=0.023 and P<0.001, respectively) and in patients treated with 5-fluorouracil-based chemotherapy (P=0.001 and P=0.021, respectively). Stage III patients with negative CD133 expression showed an apparent survival benefit from 5-fluorouracil treatment (P=0.002), but not those with positive CD133 expression. Positive expression of CD133 was also associated with poorer clinical response to chemotherapy in stage IV patients (P=0.006). In summary, the putative cancer stem cell markers CD133 and Oct-4 showed strong prognostic significance in colorectal cancer. Our results show for the first time that CD133+ colorectal tumors are more resistant to 5-fluorouracil-based chemotherapy.

Reduced genetic diversity, increased isolation and multiple introductions of invasive giant hogweed in the western Swiss Alps.

The giant hogweed (Heracleum mantegazzianum) has successfully invaded 19 European countries as well as parts of North America. It has become a problematic species due to its ability to displace native flora and to cause public health hazards. Applying population genetics to species invasion can help reconstruct invasion history and may promote more efficient management practice. We thus analysed levels of genetic variation and population genetic structure of H. mantegazzianum in an invaded area of the western Swiss Alps as well as in its native range (the Caucasus), using eight nuclear microsatellite loci together with plastid DNA markers and sequences. On both nuclear and plastid genomes, native populations exhibited significantly higher levels of genetic diversity compared to invasive populations, confirming an important founder event during the invasion process. Invasive populations were also significantly more differentiated than native populations. Bayesian clustering analysis identified five clusters in the native range that corresponded to geographically and ecologically separated groups. In the invaded range, 10 clusters occurred. Unlike native populations, invasive clusters were characterized by a mosaic pattern in the landscape, possibly caused by anthropogenic dispersal of the species via roads and direct collection for ornamental purposes. Lastly, our analyses revealed four main divergent groups in the western Swiss Alps, likely as a consequence of multiple independent establishments of H. mantegazzianum.

Ordered phthalocyanine superstructures on Ag(110).

Organic-metal interfaces, in particular, self-assembling systems, are interesting in the field of molecular electronics. In this study, we have investigated the formation of the Ag(110)-iron phthalocyanine (FePc) interface in a coverage range of less than 1 and up to 2 ML using synchrotron based photoelectron spectroscopy and low energy electron diffraction. As-deposited FePc forms a densely packed first layer exhibiting a 3 x 2c(6 x 2) symmetry. Upon thermal treatment the order at the interface is modified depending on the initial FePc coverage, resulting in less densely packed but still ordered superstructures. The first monolayer is relatively strongly bound to the substrate, leading to the formation of an interface state just below the Fermi level. The highest occupied molecular orbital of FePc in the second layer is found at 1 eV higher binding energy compared to the interface state.

Germanium adsorption on Ag(111): an AES-LEED and STM study.

The adsorption of germanium on Ag(111) has been investigated using Scanning Tunneling Microscopy, Auger Electron Spectroscopy and Low Energy Electron Diffraction. From the shape of the Auger peak-to-peak versus time curves, we deduce that at room temperature the growth mode is nearly layer-by-layer at least for the first two layers. In the sub-monolayer range, the growth starts by the formation of a (mean square root of 3 x mean square root of 3)R30 degrees surface superstructure which is complete at 1/3 monolayer coverage. Beyond this coverage a rectangular c(mean square root of 3 x 7) superstructure is observed. STM images reveal that this last reconstruction is formed by an ordered arrangement of self-assembled Ge tetramers giving rise to a surprising undulation of the surface.

Phase II study of preoperative irradiation and chemotherapy with capecitabine in patients with locally advanced rectal carcinoma.

Preoperative chemoradiotherapy has demonstrated to improve resectability and local control in locally advanced rectal cancer (LARC). 5-fluorouracil (5FU) has traditionally been the drug of choice in combination with radiation therapy. Early studies of capecitabine (CAP) have shown its potential to replace 5FU. Between March 2002 and April 2005, 31 patients with newly diagnosed LARC (T2 N+ 2 cases, T3 N0-N+ 25 cases, T4 N0-N+ 4 cases) received the combined treatment. Surgery was planned 6-8 weeks after chemoradiation. Adjuvant chemotherapy with 5FU plus leucovorin for 6 courses was given in pN+ patients. All patients completed the planned treatment. Grade 3 acute toxicity was observed in 5 patients (16%). Nineteen patients (61%) had a downstaging. A complete pathological remission was observed in 3 cases (10%). Median follow-up is of 23 months (range; 6-36 months). The results of this experience confirm the data of the literature about the feasibility and efficacy of a neoadjuvant treatment with radiation and CAP in LARC.

Langhans giant cells from M. tuberculosis-induced human granulomas cannot mediate mycobacterial uptake.

Tuberculosis is characterized by a tight interplay between Mycobacterium tuberculosis (M. tb) and host cells within granulomas. These cellular aggregates restrain M. tb spreading but do not kill all bacilli, which persist for years. A more detailed investigation of the interaction between M. tb and granuloma cells is needed to improve our understanding of this persistence and to explain the physiopathology of tuberculosis. In the present study, a recently developed in vitro human model of tuberculous granulomas has been used to analyse the modulation of granuloma cell differentiation by M. tb, in comparison to poorly virulent mycobacteria, which do not persist. It is reported that whilst all mycobacteria species induce granuloma formation, only M. tb triggers the differentiation of granuloma macrophages into very large multinucleated giant cells (MGCs) that are unable to mediate any bacterial uptake. This loss of function is not due to cell quiescence, as MGCs still display NADPH oxidase activity, but it correlates with decreased expression of phagocytosis receptors. This phenomenon is specific for the virulent species of M. tuberculosis complex, as poorly virulent species only induce the formation of small multinucleated cells (MCs) with conserved mycobacterial uptake ability, which never reach the MGC differentiation stage. The phenotype of MGCs thus strongly resembles mature dendritic cells with a loss of microbial uptake ability, despite conserved antigen presentation. In M. tb-induced granulomas, MGCs thus seem to be devoted to the destruction of bacilli that have been ingested in previous differentiation stages, ie in macrophages and MCs.

[Neoadjuvant radiochemotherapy treatment in locally advanced rectal adenocarcinoma]. / Trattamento radiochemioterapico neoadiuvante negli adenocarcinomi del retto localmente avanzati.

A prospective phase II study was conducted to evacuate toxicity and results of preoperative radiochemotherapy in locoregionally advanced rectal cancer (LARC). A total of 33 patients entered the study and received 45 Gy to the pelvis plus a supplemental boost of 5.4-9 Gy concurrently with 5 FU c.i. at a dose of 225-275 mg/m2. Thirty patients were operated after 5-7 weeks (20 anterior resection and 10 abdominoperineal excision). In 14 patients (47%) a downstaging was observed, 5 patients experienced a complete clearance of the primary tumor. After a median of 14 months (range, 5-27), 23 patients, are alive and well. And 8 patients experienced a disease progression (4 local-regional and 4 distant). Our results provide further evidence of the utility and effectiveness of preoperative radiochemotherapy in LARC.

Computerized map of risk to manage wildlife species in urban areas.

For the last 20 years, human-wildlife conflicts have been rapidly increasing in towns. Although people want "greener" cities, the expansion of disliked species causes problems that are difficult to manage and to reduce. The complexity of the numerous factors involved in these human-wildlife relations needs the development of a comprehensive tool for urban planners. Today, with the development of computers and geographical information systems, it is easier to analyze and combine different spatial data as methods used for the management of risks in studies of natural hazards. Here we present a method for assessing and mapping the risk in cases of human-wildlife conflict. An application to starling management in a town in western France will show the efficiency of our methods to combine information given by a network of experts and to highlight higher risk sites. The map of risk provides a spatial result useful for comprehension, communication between people and agencies, and public education.

Panmictic structure of Helicobacter pylori demonstrated by the comparative study of six genetic markers.

We compared the classifications of strains obtained by analysis of several genetic markers to demonstrate the panmictic structure of Helicobacter pylori, previously suggested by the study of multilocus enzyme electrophoresis. A series of 39 strains, including 37 clinical isolates from patients with gastritis or ulcers from two regions of France, reference strain CIP 101260 and the Sydney strain (strain SSI), were used. They were studied by restriction fragment length polymorphism analysis of ribosomal DNA (ribotyping) using HindIII and HaeIII, by polymorphism analysis of the ureA-ureB and flaA genes by PCR-RFLP using HaeIII and MboI, by vacA genotyping and by the presence or absence of the cagA gene and of the insertion sequence IS605 detected by PCR. There was a high level of genetic polymorphism over the studied strains, with 38 ribotypes, 38 restriction profiles for the ureA-ureB gene, 19 restriction profiles for the flaA gene and five combinations of the signal and mid-region sequences of the vacA gene. Factorial analysis of correspondence and hierarchical clustering performed using each marker revealed that the different classifications of the strains were not correlated. This suggests there is much genetic recombination between strains and supports the hypothesis of a panmictic structure for the H. pylori species.

[Tick-transmitted arbovirus in Maghreb]. / Arbovirus transmis par des tiques au Maghreb.

The problem of arbovirus infections in Maghreb has been relatively neglected in the pst in spite of a rich diversity of biotopes, the presence of potential reservoirs and vectors, and their position on the flight path of the Palearctic-african bird migration systems, western branch. Moreover, West Nile virus has been isolated from southern Algeria since 1968. From 1979 to 1989, ticks were collected from wild birds, pigeons, bats, rodents, poultry, camels, wild boars, domestic mammals and man, and assayed for viruses. On the whole, 424 ticks were virologically studied from Morocco, 582 from Algeria and 601 from Tunisia. Four tick-borne arboviruses have been isolated so far: three from Morocco, Soldado (Nairovirus), Essaouria (Orbivirus) and Kala Iris (Orbivirus) from Ornithodoros (A.) maritimus ticks parasitizing marine birds, and one from Tunisia, Tunis (Phlebovirus), from Argas reflexus hermanni infesting domestic pigeons. Soldado virus may infect man working into colonies of gulls for ornithological or entomological purposes and this infection is associated with a self-limited febrile illness and pruritus. In addition, antibody to Essaouira virus was detected in a wild rodent in Morocco. On the contrary it is unlike that Tunis virus may infect man because A. r. hermanni is a strickly ornithophilic tick. However, Uukuniemi group antibody has been previously evidenced in wild rodents in Tunisia. Finally, it is not excluded that other, more pathogenic, arboviruses such as Congo-Crimean haemorrhagic fever might be accidentally introduced in this sensitive geographical area.