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21.
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Bernard Junod Adrian Griffiths Roland Lüthi Hannes B. St?helin Heikki Savolainen et al. 《International journal of biometeorology》1992,36(3):179-189
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Our Planet, Our Health Report of the who commission on health and environment 相似文献23.
G Li W F Pralong D Pittet G W Mayr W Schlegel C B Wollheim 《The Journal of biological chemistry》1992,267(7):4349-4356
Signal generation during the stimulation of insulin secretion by arginine vasopressin (AVP) was investigated in RINm5F cells. AVP (0.1 microM) caused a biphasic cytosolic Ca2+ ([Ca2+]i) rise, namely a rapid transient marked elevation after stimulation followed by a series of oscillations. In the absence of extracellular Ca2+, the sustained oscillations were abolished, while the initial [Ca2+]i transient was only partly decreased, indicating that the former are due to Ca2+ influx and the latter due mainly to mobilization from internal Ca2+ stores. AVP also evoked a transient depolarization of the average membrane potential. AVP-induced Ca2+ influx during the sustained phase, which was strictly dependent on receptor occupancy, was attenuated by membrane hyperpolarization with diazoxide. However, blockade of Ca2+ channels of the L- or T-type was ineffective. AVP stimulated production of diacylglycerol and inositol phosphates; for the latter both [3H] inositol labeling and mass determinations were performed. A transient increase in Ins(1,4,5)P3 was followed by a marked enhancement of Ins(1,3,4,5)P4 (8-fold) peaking at 15 s and gradually returning to basal values. Ins(1,3,4,6)P4 and Ins(3,4,5,6)P4 exhibited the most long-lasting augmentation (4- and 1.7-fold, respectively), and therefore correlated best with the period of sustained [Ca2+]i oscillations. InsP5 and InsP6 were not elevated. The effects of AVP, including the stimulation of insulin secretion from perifused cells, were obliterated by a V1 receptor antagonist. In conclusion, AVP induces protracted [Ca2+]i elevation in RINm5F cells which is associated with long-lasting increases in InsP4 isomers. The accumulation of InsP4 isomers reflects receptor occupancy and accelerated metabolism of the inositol phosphates. Activation of second messenger-operated Ca2+ channels is not necessarily implicated because of the attenuating effect of membrane hyperpolarization. 相似文献
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Homogeneity-time is defined and introduced as the criterion for mixing quality in bioreactors. The criterion could replace the mixing time, in the case, when more than one measuring point (sensors) is included in the measuring system. Results based on the homogeneity-time and the temperature pulse method, achieved in stirred tank reactors under aerated conditions as well as in a jet-mixed tank, are presented.List of Symbols
C
p,p
kJ/kg K
Heat capacity of the pulse medium
-
C
p,s
kJ/kg K
Heat capacity of the reactor-medium
-
F m3/s
Flow rate of the pulse-input
-
i
Inhomogeneity
-
I
N
Inhomogeneity-number
-
M (t) °C
Ideal response curve
-
m
deNumber of combinations for certain number of sensors acc. to Table 1
-
n
Number of sensor
-
p
kg/m3
Density of the pulse medium
-
kg/m3
Density of the tank medium
-
s
1
°C
Mean absolute deviation of the sensor temperatures related on the ideal response curve s2 s Mean absolute deviation of the homogeneity-times related on the time achieved with 6 sensors
-
t s
Time
-
t (i) s
Homogeneity-time
-
t
ps
s
Starting time of tracer injection
-
t
PE
s
End time of tracer injection
-
T
E
°C
Mean medium temperature at the end of experiment
-
T
k
°C
Temperature at k-th sensor position
-
T
p
°C
Pulse temperature
-
T
s
°C
Mean medium temperature before the tracer injection
-
V
s
m3
Tank volume before pulse input 相似文献
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We present a general model for the evolution of chromosome-specific satellite DNA subfamilies.Sus scrofa domestica has a bimodal karyotype with two autosomal subsets of 12 meta-/submetacentric (Mc) and 6 acrocentric (Ac) chromosome types (Mc and Ac subgenomes). We show that the centromeric heterochromatin is characterised by two distinct satellite DNA families designed Mc1 and Ac2. Mc1 is a diverse satellite family of the Mc subgenome of which certain members with a 100 bp repeat unit are found to occur at the pericentromeric regions of each Mc autosome, while others are chromosome-specific, e.g. clone Mc pAv1.5, a higher order repeat variant, which hybridises specifically to chromosome 1. Ac2 is a homogeneous satellite occurring at the subterminal pericentromeric regions of all Ac autosomes. DNA sequence analyses showed that all clones investigated are built up from a 14 bp repeat unit which is highly conserved. In situ hybridisation to meiotic pachytene nuclei revealed a distinct spatial arrangement of the Ac2 centromeric satellite. 相似文献
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Sequential staining with a counterstain-contrasted fluorescent R-banding technique (chromomycin A3/distamycin A-DAPI) followed by DAPI-actinomycin D-induced quinacrine-fluorescence-Hoechst 33258 (QFH)-type banding allowed the identification of quail chromosomes up to chromosome 19. The chromomycin A3-positive staining behavior of the W chromosome and of the heterochromatic areas of most microchromosomes indicated their GC-rich nature. 相似文献