Charcot-Marie-Tooth (CMT) disease, the most common hereditary peripheral neuropathy, is highly clinically and genetically heterogeneous, and mutations in at least 18 genes have been identified. ...Recently, mutations in small heat shock protein 27 (Hsp27) were reported to cause CMT disease type 2F and distal hereditary motor neuropathy.
To investigate the frequency and phenotypic features of an Hsp27 mutation in Chinese patients with CMT disease.
DNA samples from 114 unrelated patients with CMT disease were screened for mutations in Hsp27 by polymerase chain reaction and direct sequencing. A cosegregated study was performed using the MbiI restriction endonuclease, and 50 healthy control subjects were analyzed. Haplotype analysis was performed using 5 short tandem repeat markers to analyze whether the families with the same mutation probably had a common ancestor.
One missense mutation, C379T, was detected in 4 autosomal dominant families with CMT disease type 2, and haplotype analysis indicated that the 4 families probably had a common founder. The frequency of the Hsp27 mutation is 0.9% (1/111) in Chinese patients with CMT disease in our study, and the phenotypes were characterized by later onset (age, 35-60 years) and mild sensory impairments. Electrophysiological findings showed moderately to severely slowed nerve conduction velocities in lower limb nerves but normal or mildly reduced velocities in upper limb nerves.
To our knowledge, this is the first report of an Hsp27 mutation in the People's Republic of China. The C379T mutation in Hsp27 also causes CMT disease type 2, except for distal hereditary motor neuropathy, and the phenotypes are distinct from the family with CMT disease type 2F described previously. A mutation of Hsp27 may be uncommon in Chinese patients with CMT disease.
Methyl jasmonate (MeJA) interacted significantly with both indole-3-acetic acid (IAA) and 6-benzylaminopurine (BA) to influence cell growth of cultured Onosma paniculatum cells. Cell growth decreased ...with increasing concentrations of MeJA from 0.004-4.45 mu M with or without IAA and BA. The same concentrations of MeJA (0-4.45 mu M) increased the cell growth with IAA and BA, when administered to the cultured cells in M sub(9) medium. This was found to enhance the production of shikonin. The optimum time for MeJA addition for enhanced shikonin formation was 4 d after cell inoculation in M sub(9) medium. Furthermore, shikonin formation was affected significantly by both MeJA/IAA and MeJA/BA combinations. Shikonin content was enhanced by increasing MeJA concentrations with IAA concentrations in the range of 0-28 mu M and with BA concentrations in the range of 0-44.38 mu M in MeJA /IAA and MeJA/BA experiments, respectively. The optimal combination of MeJA and IAA was 4.45 mu M and 0.28 mu M, while MeJA and BA concentrations of 4.45 mu M and 2.22 mu M were optimal for shikonin formation. The result also showed that MeJA increased phenylalanine ammonia-lyase (PAL) and p-hydroxybenzoic acid-geranyltransferase (PHB-geranyltransferase) activities during the course of shikonin formation, but decreased the activity of PHB-O-glucosyltransferase within 9 d after inoculation. These results suggest that enhanced shikonin formation in cultured Onosma paniculatum cells induced by MeJA involves regulation of the key enzyme activities.
Dynamic fracture toughness of Laurentian granite (LG) subjected to heat treatment was tested by means of a notched core-based semi-circular bend (SCB) specimen with a modified split Hopkinson ...pressure bar (SHPB) apparatus. The samples for testing the fracture toughness were manufactured and heat treatment up to 850D according to the requirements of experiment. The relationship between the fracture toughness and temperature were investigated of rocks subjected to thermal treatment. The experimental results showed that fracture toughness decreases with increasing temperature. Furthermore, the fracture surfaces of rocks in thermal treated were observed by means of the scanning electronic microscope (SEM). These results provide the theoretic direction for engineering application in thermal treatment.
We discuss cooling of a nanomechanical resonator to its mechanical ground state by coupling it to a collective system of two interacting flux qubits. We find that the collectivity crucially improves ...cooling by two mechanisms. First, cooling transitions proceed via sub-radiant Dicke states, and the reduced line width of these sub-radiant states suppresses both the scattering and the environmental contribution to the final phonon number. Second, detrimental carrier excitations without change in the motion of the resonator are suppressed by collective energy shifts.
We have performed an experimental study of impact fragmentation with a focus on the dependence on the energy input. Long glass rods were dropped horizontally onto the ground from seven different ...heights. We find that the energy dependence is better characterized by studying the differential mass distribution rather than the cumulative mass distribution. For lower dropping heights, the differential mass distribution is well approximated by one power law while for higher heights, it has to be represented by two power laws. Moreover, the power-law exponent for small mass fragments increases and approaches an asymptotic value as the dropping height is increased.
The spatial structure of the velocity field in turbulent Rayleigh-Bénard convection in water has been measured using the particle image velocimetry technique, with the Rayleigh number Ra varying from ...9 x 10(8) to 9 x 10(11) and the Prandtl number remaining approximately constant (Pr approximately 4). The study provides a direct confirmation that a rotatory mean wind indeed persists for the highest value of Ra reached in the experiment. The measurement reveals that the mean flow in the central region of the convection cell is of the shape of a coherent elliptical rotating core for Ra below 1 x 10(10). Above this Ra, the orientation of the elliptical core changes by a 90 degrees angle and an inner core rotating at a lower rate inside the original bulk core emerges. It is further found that the rotation frequencies of the inner core and the outer shell have distinct scalings with Ra; the scaling exponent for the outer-shell is 0.5 and it is 0.4 for the inner core. From the measured rms and skewness distributions of the velocity field, we find that velocity fluctuations at the cell center are neither homogeneous nor isotropic. The turbulent energy production fields further reveal that the mean wind is not driven by turbulent fluctuations associated with Reynolds stress.
S5; It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the ...development of photoperiod-sensitive maize cultivars. The objective of this study is to determine the photoperiod-sensitive inductive phase using reciprocal transfer between longday (LD) (15 h d-1) and short-day conditions (SD) (9 h d-1). For Huangzao 4 and CML288, days to tassel and pollen shedding were recorded, and stem apical meristems (SAM) were observed by a laser scanning confocal microscope. The results show that the seedlings are insensitive to photoperiod when they are very young (juvenile). However, after this period, LD delays flowering and increases the leaf numbers below the inflorescence, and the length of the interval of the photoperiod-sensitive inductive phase is longer under LD conditions than under SD conditions. Transferred from SD to LD, plants show a sudden decrease in leaf numbers once sufficient SD has been received for flower commitment. While transferred from LD to SD, plants have a continuous increase in leaf numbers during the photoperiod sensitive inductive phase under LD conditions. At the same time, when plants are competent to flowers, the obvious morphology is the elongation of maize SAM. There is an obvious variance of the photoperiod sensitive phase under LD and SD conditions in different maize.
Four-point bending creep tests were carried out in air on an alumina matrix composite reinforced with 9.3 vol.% of silicon carbide whiskers. Typical three-stage creep was observed. In the temperature ...range of 1673–1823 K, the composite exhibited an average stress exponent of 3.8. The activation energy for creep was estimated as ∼820–830 kJ mol−1. Microstructure of the composite was characterized before and after deformation. Dislocation networks and other configurations were observed in samples deformed to large strains. It is concluded that the deformation mechanism consists of intragranular dislocation movement controlled by the lattice diffusion of oxygen ions.
Mass spectrometric uranium-series dating and C–O isotopic analysis of a stalagmite from Lynds Cave, northern Tasmania, Australia provide a high-resolution record of regional climate change between ...5100 and 9200 yr before present (BP). Combined δ18O, δ13C, growth rate, initial 234U/238U and physical property (color, transparency and porosity) records allow recognition of seven climatic stages: Stage I (>9080 yr BP) – a relatively dry period at the beginning of stalagmite growth evidenced by elevated 234U/238U; Stage II (9080–8600 yr BP) – a period of unstable climate characterized by high-frequency variability in temperature and bio-productivity; Stage III (8600–8000 yr BP) – a period of stable and moderate precipitation and stable and high bio-productivity, with a continuously rising temperature; Stage IV (8000–7400 yr BP) – the warmest period with high evaporation and low effective precipitation (rainfall less evaporation); Stage V (7400–7000 yr BP) – the wettest period with highest stalagmite growth and enhanced but unstable bio-productivity; Stage VI (7000–6600 yr BP) – a period with a significantly reduced precipitation and bio-productivity without noticeable change in temperature; Stage VII (6600–5100 yr BP) – a period of lowest temperature and precipitation marking a significant climatic deterioration. Overall, the records suggest that the warmest climate occurred between 8000 and 7400 yr BP, followed by a wettest period between 7400 and 7000 yr BP. These are broadly correlated with the so-called ‘Mid Holocene optimum’ previously proposed using pollen and lake level records. However, the timing and resolution of the speleothem record from Lynds Cave are significantly higher than in both the pollen and lake level records. This allows us to correlate the abrupt change in physical property, δ18O, δ13C, growth rate, and initial 234U/238U of the stalagmite at ∼8000 yr BP with a global climatic event at Early–Mid Holocene transition.
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