Clinical and genetic characteristics of Multiple Endocrine Neoplasia type 1 (MEN 1) syndrome in a small cohort of Swiss patients

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a polyglandular autosomal dominant transmitted disease characterized by the combined occurrence of several endocrine gland tumors. The main features of the syndrome include parathyroid (95%), enteropancreatic (40-70%), and anterior pituitary (30-40%) tumors. Tumors in MEN1 syndrome display a more aggressive behavior than sporadic tumors and are more resistant to treatment. The disease's prevalence has been estimated between 1:10'000 - 1:100'000, affecting all age groups and demonstrating a very high penetrance with clinical and biochemical manifestations having developed in respectively 80 % and more than 98 % of MEN1 patients by the fifth decade. Primary hyperparathyroidism has been shown to be the first manifestation of the syndrome amongst more than 85% of patients. MEN1, the gene responsible for the disease, is located on chromosome 11q13. It consists of 10 exons and is translated into a 610-amino acid protein named menin that behaves as a tumor suppressor in endocrine organs. Menin has an important role in cell division and proliferation, transcription, DNA replication and repair, apoptosis and genome stability. More that 450 different mutations, scattered through the whole sequence and mostly inactivating or leading to a missing or truncated protein have been described. We studied the MEN1 patients that were treated or followed-up at CHUV between 1995- 2015. The objective was to review and analyze clinical and genetic characteristics of MEN1 syndrome among these patients as well as the inter- and intra-familial variability of expression and to search for possible genotype-phenotype correlations. A large amount of data was collected for each patient and entered into a database. Epidemiological data such as age ratio, mean age at first symptoms and at diagnosis, prevalence of each tumor and proportion of patients who underwent MEN1 mutational analysis was calculated. The data was then analyzed and compared to the literature. 21 patients being part of 11 different pedigrees and 80% of whom having developed clinical, radiological or biological signs of MEN1 at the time of the study were identified. Among 17 out of 21 patients displaying signs or symptoms of MEN1, 82% were affected by primary hyperparathyroidism, 76% had enteropancreatic NET, 18% pituitary tumors and 47% extended spectrum tumors, such as lipomas, carcinoids or adrenal tumors. Mutations of the MEN1 gene were found in only four out of eleven pedigrees and consisted of two large deletions, one missense and one nonsense. Mutational analysis was either not performed or not documented in the other pedigrees. Pedigree 1 being well documented, particularly interesting and displaying some unusual features, we focused our research and analysis on it. We report here the case of the proband, a 40 years old patient with a metastatic pituitary carcinoma, and his family. Several patients whose records were reviewed had benefited from a suboptimal care with no genetic testing being made and what seemed to be an insufficient screening and follow- up. We recommend that MEN1 patients should be identified and gathered in qualified centers. Follow-up should be coordinated by an endocrinologist with expertise in the subject

The emergence of classical behavior in magnetic adatoms

A wide class of nanomagnets shows striking quantum behavior, known as quantum spin tunneling (QST): instead of two degenerate ground states with opposite magnetizations, a bonding-antibonding pair forms, resulting in a splitting of the ground state doublet with wave functions linear combination of two classically opposite magnetic states, leading to the quenching of their magnetic moment. Here we study how QST is destroyed and classical behavior emerges in the case of magnetic adatoms, as the strength of their coupling, either to the substrate or to each other, is increased. Both spin-substrate and spin-spin coupling renormalize the QST splitting to zero allowing the environmental decoherence to eliminate superpositions between classical states, leading to the emergence of spontaneous magnetization.Comment: 5 pages, 4 figure

Optical spin transfer in ferromagnetic semiconductors

Circularly polarized laser pulses that excite electron-hole pairs across the band gap of (III,Mn)V ferromagnetic semiconductors can be used to manipulate and to study collective magnetization dynamics. The initial spin orientation of a photocarrier in a (III,V) semiconductors is determined by the polarization state of the laser. We show that the photocarrier spin can be irreversibly transferred to the collective magnetization, whose dynamics can consequently be flexibly controlled by suitably chosen laser pulses. As illustrations we demonstrate the feasibility of all optical ferromagnetic resonance and optical magnetization reorientation.Comment: 8 pages, 3 figure

Optical control of the spin state of two Mn atoms in a quantum dot

We report on the optical spectroscopy of the spin of two magnetic atoms (Mn) embedded in an individual quantum dot interacting with either a single electron, a single exciton and single trion. As a result of their interaction to a common entity, the Mn spins become correlated. The dynamics of this process is probed by time resolved spectroscopy, that permits to determine the optical orientation time in the range of a few tens of $ns$. In addition, we show that the energy of the collective spin states of the two Mn atoms can be tuned through the optical Stark effect induced by a resonant laser field

Space station integrated propulsion and fluid systems study

The program study was performed in two tasks: Task 1 addressed propulsion systems and Task 2 addressed all fluid systems associated with the Space Station elements, which also included propulsion and pressurant systems. Program results indicated a substantial reduction in life cycle costs through integrating the oxygen/hydrogen propulsion system with the environmental control and life support system, and through supplying nitrogen in a cryogenic gaseous supercritical or subcritical liquid state. A water sensitivity analysis showed that increasing the food water content would substantially increase the amount of water available for propulsion use and in all cases, the implementation of the BOSCH CO2 reduction process would reduce overall life cycle costs to the station and minimize risk. An investigation of fluid systems and associated requirements revealed a delicate balance between the individual propulsion and fluid systems across work packages and a strong interdependence between all other fluid systems

Adaptability

Adaptability is usually conceived as a psychological capacity that sustains adaptive behaviors, allowing one to face and manage stressors. It promotes adjustment between a person and its environment through a constant, dynamic, and dialectic interaction between them. Adaptability is conceptually and empirically distinct from dispositions such as personality or intelligence, but can be considered as a self-regulation process promoting an adequate person-environment fit (P-E fit), psychological health, and positive career-related outcomes, such as employability, employment, or work engagement. Adaptability evolves according to the circumstances and people can activate their adaptive abilities in adverse situations. Brief psychological interventions increase adaptability, which in turn improves employability and career success

Coherent transport in graphene nanoconstrictions

We study the effect of a structural nanoconstriction on the coherent transport properties of otherwise ideal zig-zag-edged infinitely long graphene ribbons. The electronic structure is calculated with the standard one-orbital tight-binding model and the linear conductance is obtained using the Landauer formula. We find that, since the zero-bias current is carried in the bulk of the ribbon, this is very robust with respect to a variety of constriction geometries and edge defects. In contrast, the curve of zero-bias conductance versus gate voltage departs from the $(2n+1) e^2/h$ staircase of the ideal case as soon as a single atom is removed from the sample. We also find that wedge-shaped constrictions can present non-conducting states fully localized in the constriction close to the Fermi energy. The interest of these localized states in regards the formation of quantum dots in graphene is discussed.Comment: 9 pages, 9 figure

Magnetic and orbital blocking in Ni nanocontacts

We address the fundamental question of whether magneto-resistance (MR) of atomic-sized contacts of Nickel is very large because of the formation of a domain wall (DW) at the neck. Using {\em ab initio} transport calculations we find that, as in the case of non-magnetic electrodes, transport in Ni nanocontacts depends very much on the orbital nature of the electrons. Our results are in agreement with several experiments in the average value of the conductance. On the other hand, contrary to existing claims, DW scattering does {\em not} account for large MR in Ni nanocontacts.Comment: 5 pages, 3 Figure