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The quasi-skutterudite superconductor La3Co4Sn13 with the Yb3Rh4Sn13-type cage-structure presents structural transition at T* = 152 K. As in the case with isostructural compound Sr3Rh4Sn13, it has been shown that T* can be suppressed to 0 K by applying external physical pressure in La3Co4Sn13. In order to investigate chemical pressure effect on La3Co4Sn13, we have synthesized single crystals of La1−xAx)3Co4Sn13 (A = Sr, Ca) and measured magnetic susceptibilities and specific heats. From magnetic susceptibility and specific heat measurements, it has been suggested that T* can change sensitively to the composition. [ABSTRACT FROM AUTHOR]

Mutations in the gene encoding the MECP2 underlies Rett syndrome, a neurodevelopmental disorder in young females. Although reduced pain sensitivity in Rett syndrome patients and in partial MeCP2 deficient mice had been reported, these previous studies focused predominantly on motor impairments. Therefore, it is still unknown how MeCP2 is involved in these sensory defects. In addition, the human disease manifestations where males with mutations in MECP2 gene normally do not survive and females show typical neurological symptoms only after 18 months of age, is profoundly different in MeCP2-deficient mouse where all animals survived, and males but not females displayed Rett syndrome phenotypes at an early age. Thus, the mecp2-deficient zebrafish serves as an additional animal model to aid in deciphering the role and mechanisms of Mecp2 in neurodevelopment. Here, we used two independent methods of silencing expression of Mecp2 in zebrafish to uncover a novel role of Mecp2 in trigeminal ganglion sensory neurons during the embryonic development. mecp2-null mutation and morpholino-mediated silencing of Mecp2 in the zebrafish embryos resulted in defects in peripheral innervation of trigeminal sensory neurons and consequently affecting the sensory function. These defects were demonstrated to be dependent on the expression of Sema5b and Robo2. The expression of both proteins together could better overcome the defects caused by Mecp2 deficiency as compared to the expression of either Sema5b or Robo2 alone. Sema5b and Robo2 were downregulated upon Mecp2 silencing or in mecp2-null embryos, and Chromatin immunoprecipitation (ChIP) assay using antibody against Mecp2 was able to pull down specific regions of both Sema5b and Robo2 promoters, showing interaction between Mecp2 and the promoters of both genes. In addition, cell-specific expression of Mecp2 can overcome the innervation and sensory response defects in Mecp2 morphants indicating that these MeCP2-mediated defects are cell-autonomous. The sensory deficits caused by Mecp2 deficiency mirror the diminished sensory response observed in Rett syndrome patients. This suggests that zebrafish could be an unconventional but useful model for this disorder manifesting defects that are not easily studied in full using rodent models. [ABSTRACT FROM AUTHOR]

The biological changes in recurrent laryngeal cancer following radiotherapy are not fully understood. The authors investigated differences in the expression of p53, proliferating cell nuclear antigen (PCNA) and bcl-2 in laryngeal cancer specimens before radiotherapy and in recurrent laryngeal cancer specimens following radiotherapy in the same patients. The authors investigated the expression of p53, PCNA and bcl-2 by immunohistochemical stain in 30 specimens from 15 patients with primary laryngeal cancer and recurrent laryngeal cancer after radiotherapy.The expression of p53 protein was significantly different in laryngeal cancer before radiotherapy (4/15, 26.7 per cent) compared with recurrent laryngeal cancer after radiotherapy (8/15, 53.3 per cent) (p < 0.05). The PCNA index was also significantly different in laryngeal cancer specimens before radiotherapy (mean, 11.9 per cent) compared with recurrent laryngeal cancer after radiotherapy (mean, 18.0 per cent) (p < 0.05). However, there was no statistically significant alteration of bcl-2 expression in primary compared with recurrent laryngeal cancer. The expression of p53 and PCNA increased in recurrent laryngeal cancers after radiotherapy, compared with that in laryngeal cancers before radiotherapy. Recurrent laryngeal cancers arising following radiotherapy became biologically aggressive. [ABSTRACT FROM AUTHOR]

The reduction of microcrystalline C 60 fullerene, adhered at a carbon electrode and immersed in aqueous electrolyte, has been studied under various voltammetric conditions. This work reports mainly the voltammetric studies carried out principally in electrolyte containing potassium ions. Comparison of adherence techniques, such as solvent casting and mechanical transfer methods, are made to assess if the type of adhered techniques has any significant influence on the observed electrochemistry. The solvent casting method is found to produce three peaks in the potential for C 60 0/n- in the presence of K 60 is compared with other cations, such as Li, Na, Rb and Cs, it is observed that the shift of reduction potential follows the change in the hydration energy in the order Cs>Rb>K>Na>Li. In a mixed electrolyte study of CsCl/KCl, the reduction potential and peak shape of C + is compared with other cations, such as Li, Na, Rb and Cs, it is observed that the shift of reduction potential follows the change in the hydration energy in the order Cs>Rb>K>Na>Li. In a mixed electrolyte study of CsCl/KCl, the reduction potential and peak shape of C 60 is irreversible in aqueous electrolyte containing alkaline cations as the re-oxidation process does not produce any observed electro-activity. Evidence of the formation of a passive coating of K 0/n-redox couple during cyclic voltammetry is observed to change with concentration of the cations and the observed electrochemistry can be attributed to a cation-exchange mechanism. The reduction of C 60 is irreversible in aqueous electrolyte containing alkaline cations as the re-oxidation process does not produce any observed electro-activity. Evidence of the formation of a passive coating of K nC 60 fulleride, which does not appear to undergo dissolution is obtained under cyclic voltametric conditions. This coating remains electrochemically active in the presence of tetrabutylammonium ions in acetonitrile. Scan rate, chronocoulometric, and scanning electron microscopic studies provide evidence of the presence of a surface process involving solid–solid transformation. [ABSTRACT FROM AUTHOR]

Describes the development of a hospitality training program to provide basic job skills to minority welfare recipients and the creation of a class of undergraduate hospitality students to serve as mentors for welfare recipients as they attempted to enter the hospitality workforce. Change in students' perceptions after their mentoring experiences; Effectiveness of mentoring programs in promoting cultural understanding.

Background: The pattern of nodal metastasis in previously untreated nasopharyngeal carcinoma (NPC) has been studied and reported. In order to analyse the pattern of recurrent nodal disease in previously treated NPC, a retrospective study on 68 patients who underwent radical neck dissection for regionally recurrent NPC was conducted. Methods: Seventy-four neck dissections were performed on 68 patients who developed nodal recurrence after a mean disease-free interval of 39.2 months. None of the patients had evidence of local or systemic disease at the time of surgery. Histopathological reports of the 74 neck dissections were analysed with regard to the number of positive nodes as well as the number of involved nodal levels. Results: Of the 65 neck dissection specimens with analysable data, 31 showed metastatic disease at a single nodal level with a mean number of positive nodes of 1.2, while 34 showed metastatic disease at multiple levels with a mean number of positive nodes of 6.6. Nodal recurrence occurred at level Il with the greatest frequency (78.5%). Of the 31 specimens with single level nodal involvement, 21 (67.7%) occurred at level I1. Isolated involvement at the other levels did occur, but was uncommon (range 3-16%). Of the 34 specimens with multiple level nodal involvement, 3(t (88.2%) showed involvement at level 11. Once more than one level was involved, the frequency of involvement at any given level was at least 30%. Conclusion: The predominant involvement at level 11 and the high frequencies of involvement at all levels support the use ora classical radical neck dissection in treating recurrent nodal disease in NPC. [ABSTRACT FROM AUTHOR]

The realization of new classes of ground states in strongly correlated electron systems continues to be a major issue in condensed matter physics. Heavy fermion materials, whose electronic structure is essentially three-dimensional, are one of the most suitable systems for obtaining novel electronic states because of their intriguing properties associated with many-body effects. Recently, a state-of-the-art molecular beam epitaxy technique was developed to reduce the dimensionality of heavy electron systems by fabricating artificial superlattices that include heavy fermion compounds; this approach can produce a new type of electronic state in two-dimensional (2D) heavy fermion systems. In artificial superlattices of the antiferromagnetic heavy fermion compound CeIn3 and the conventional metal LaIn3, the magnetic order is suppressed by a reduction in the thickness of the CeIn3 layers. In addition, the 2D confinement of heavy fermions leads to enhancement of the effective electron mass and deviation from the standard Fermi liquid electronic properties, which are both associated with the dimensional tuning of quantum criticality. In the superconducting superlattices of the heavy fermion superconductor CeCoIn5 and nonmagnetic metal YbCoIn5, signatures of superconductivity are observed even at the thickness of one unit-cell layer of CeCoIn5. The most remarkable feature of this 2D heavy fermion superconductor is that the thickness reduction of the CeCoIn5 layers changes the temperature and angular dependencies of the upper critical field significantly. This result is attributed to a substantial suppression of the Pauli pair-breaking effect through the local inversion symmetry breaking at the interfaces of CeCoIn5 block layers. The importance of the inversion symmetry breaking in this system has also been supported by site-selective nuclear magnetic resonance spectroscopy, which can resolve spectroscopic information from each layer separately, even within the same CeCoIn5 block layer. In addition, recent experiments involving CeCoIn5/YbCoIn5 superlattices have shown that the degree of the inversion symmetry breaking and, in turn, the Rashba splitting are controllable, offering the prospect of achieving even more fascinating superconducting states. Thus, these Kondo superlattices pave the way for the exploration of unconventional metallic and superconducting states. [ABSTRACT FROM AUTHOR]