Activation of coherent lattice phonon following ultrafast molecular spin-state photo-switching: A molecule-to-lattice energy transfer.

We combine ultrafast optical spectroscopy with femtosecond X-ray absorption to study the photo-switching dynamics of the [Fe(PM-AzA)2(NCS)2] spin-crossover molecular solid. The light-induced excited spin-state trapping process switches the molecules from low spin to high spin (HS) states on the sub-picosecond timescale. The change of the electronic state (<50 fs) induces a structural reorganization of the molecule within 160 fs. This transformation is accompanied by coherent molecular vibrations in the HS potential and especially a rapidly damped Fe-ligand breathing mode. The time-resolved studies evidence a delayed activation of coherent optical phonons of the lattice surrounding the photoexcited molecules.

mTORC2-Akt signaling axis is implicated in myocardial compensation and fibrosis.

mTOR signaling has long been implicated in the mechanisms of cardiomyocyte survival in response to volume or pressure overload. Several studies have focused on the significance of mTORC1 in cardiomyocyte survival, questioning the role of mTORC2. mTORC2–Akt signaling is an emerging axis implicated in cardiomyocyte compensation and thus heart failure. Upon being subjected to chronic stress, cardiomyocytes activate mTORC2–Akt signaling pathway to promote survival by activating the ubiquitin proteasome system, inducing the degradation of pro-apoptotic proteins, and altering the actin cytoskeleton. Given the importance of mTORC2 in cardiomyocyte survival, studies suggest that loss of mTORC2 signaling would result in loss of cardiomyocytes, fibrosis, and heart failure. This review serves to elaborate on how mTORC2-Akt signaling plays a role in cardiomyocyte growth and survival under stress and how the loss of the axis would result in fibrosis and heart failure.

Mental health problems among labour children in the Gaza Strip.

BACKGROUND: There is increasing international concern over the rising number of children involved in labour, particularly in developing countries. Despite the multitude of related risk factors, and some evidence on their social needs, there has been limited research on these children's mental health. METHODS: The aim of this study was to establish the association between labour-related variables and mental health problems among 780 children in labour (aged 9-18 years, mean 15.8) in the Gaza Strip. Measures included a demographic checklist, the Strengths and Difficulties Questionnaire, the Spence Children's Anxiety Scale and the Depression Self-rating Scale for Children. RESULTS: Children came from large families (73.2% had eight or more siblings), mainly worked to increase family income, worked an average 6.8 h per day (range 1-16), and only 37.1% had regular rest. Ratings of mental health problems were predicted by different factors, i.e. total difficulties scores by poor friendship relationships and lack of health insurance; anxiety scores by selling in the streets, working to help family, low family income and lack of health insurance; and depression scores by parents' dissatisfaction with the job and longer working hours. CONCLUSIONS: Mental health problems of children in labour are likely to be associated with socio economic determinants, as well as factors related to their under age employment. Policy, legislation and preventive programmes from statutory and voluntary agencies should adopt an integrated approach in meeting their mental health needs, by enhancing protective factors such as return to school.

Influence of pressure on the magnetic ordering of CeNiSnH and CeNiSnH(1.8) hydrides.

The magnetic properties of the antiferromagnet CeNiSnH and of the ferromagnet CeNiSnH(1.8) on hydrostatic pressure (0≤P≤10.8 bar) have been determined using a miniature piston-cylinder CuBe pressure cell. With increasing P, the Néel temperature of CeNiSnH increases weakly from 4.77 to 5.01 K whereas the Curie temperature of CeNiSnH(1.8) decreases rapidly from 7.16 to 5.30 K. Similar pressure dependence is also observed in the critical field of the metamagnetic transition of CeNiSnH and in the coercive field of CeNiSnH(1.8). Electronic structure calculations for these hydrides within the density functional theory show agreement with the experimental findings. Detailed examination of the chemical bonding features point to the conclusion that the antibonding Ce-Ni states below the Fermi level for CeNiSnH(1.8) could be responsible for the decrease of its Curie temperature under applied pressure.

Influence of Ce-H bonding on the physical properties of the hydrides CeCoSiH(1.0) and CeCoGeH(1.0).

The hydrides CeCoSiH(1.0) and CeCoGeH(1.0) which crystallize like the parent antiferromagnetic compounds CeCoSi and CeCoGe in the tetragonal CeFeSi-type structure, have been investigated by specific heat and thermoelectric power measurements and (1)H nuclear magnetic resonance (NMR). CeCoSiH(1.0) is an intermediate valence compound whereas CeCoGeH(1.0) can be considered as a nearly trivalent cerium compound. This behaviour is corroborated by the occurrence of a slight broadening of the (1)H NMR signal in the sequence [Formula: see text]. The band structure calculations performed on these hydrides reveal the existence of strong bonding Ce-H interaction, found to be larger in CeCoSiH(1.0) than in CeCoGeH(1.0).

Investigation of the electronic and structural properties of potassium hexaboride, KB6, by transport, magnetic susceptibility, EPR, and NMR measurements, temperature-dependent crystal structure determination, and electronic band structure calculations.

The electronic and structural properties of potassium hexaboride, KB(6), were examined by transport, magnetic susceptibility, EPR, and NMR measurements, temperature-dependent crystal structure determination, and electronic band structure calculations. The valence bands of KB(6) are partially empty, but the electrical resistivity of KB(6) reveals that it is not a normal metal. The magnetic susceptibility as well as EPR and NMR measurements show the presence of localized electrons in KB(6). The EPR spectra of KB(6) have two peaks, a broad ( approximately 320 G) and a narrow (less than approximately 27 G) line width, and the temperature-dependence of the magnetic susceptibility of KB(6) exhibits a strong hysteresis below 70 K. The temperature-dependent crystal structure determination of KB(6) shows the occurrence of an unusual variation in the unit cell parameter hence supporting that the hysteresis of the magnetic susceptibility is a bulk phenomenon. The line width DeltaH(pp) of the broad EPR signal is independent of temperature and EPR frequency. This finding indicates that the line broadening results from the dipole-dipole interaction, and the spins responsible for the broad EPR peak has the average distance of approximately 1.0 nm. To explain these apparently puzzling properties, we examined a probable mechanism of electron localization in KB(6) and its implications.

Management of large dural defects in skull base surgery: an update.

The use of a ventriculoatrial shunt for long-term CSF diversion for reconstruction after resection of large skull base tumors with intradural extension has been discontinued. The concern about placing a permanent foreign body in a wound open for 12 to 18 hours is our primary reason for changing the technique. Our present approach uses a rectus abdominis microvascular free flap over the fascial closure of the dural defect. Although our experience with this technique is limited, the advantages over the technique used previously warrant its continued use.

The advantages of laser treatment of tumors of the larynx.

The carbon dioxide (CO2) laser is safe and efficacious when used in conjunction with endoscopic excision of selected premalignant and malignant tumors of the larynx. Cure rates parallel those obtained with traditional surgical instruments. Advantages of laser excision of early glottic carcinomas include greater accuracy in establishing the true extent of the disease, minimal morbidity, and cost effectiveness.