ICSS thresholds

Liechti ME, Markou A (2007) Interactive effects of the mGlu5 receptor antagonist MPEP and the mGlu2/3 receptor antagonist LY341495 on nicotine self-administration and reward deficits associated with nicotine withdrawal in rats. Eur J Pharmacol 554 164-174 Lin D, Koob GP, Markou A (2000) Time-dependent alterations in ICSS thresholds associated with repeated amphetamine administrations. Pharmacol Biochem Behav 65 407-417... 

Precipitated DH 3E Self-stimulation (ICSS) threshold Brujijnzeel and Markou (2004)... 

Precipitated DH 3E Conditioned ICSS threshold Kenny and Markou (2005)... 

Injection of the opiate antagonist naloxone precipitates the somatic signs of nicotine withdrawal (Adams and Cicero 1998 Carboni et al. 2000 Malin et al. 1993a), but not affective signs, such as intracranial self-stimulation (ICSS) threshold elevation (Watkins et al. 2000). Yet naloxone injection in a nicotine-infused rat is robustly aversive (Ise et al. 2000 Watkins et al. 2000). Therefore, the somatic signs may actually correspond better than ICSS thresholds to an aversive motivational state. 

Fluoxetine and 5HT1A antagonist Reversed withdrawal-induced increased ICSS thresholds Harrison et al. (2001)... 

The pattern of data on the role of al receptors (pentamers of the al subunit) is far from clear. Nomikos et al. (1999) reported sharply reduced locomotor activity in nicotine-dependent rats injected with the selective al antagonist methyl-lycaconitine (MLA). Barik and Wonnacott (2006) found increased al sensitivity in the hippocampus of rats during nicotine withdrawal, as evidence by increased norepinephrine release in response to an al agonist. On the other hand, Markou and Paterson (2001) reported that systemically administered ML A failed to precipitate either somatically expressed withdrawal behaviors or altered ICSS thresholds. 

Early adolescent smoking onset is a risk factor for severe addiction and difficulty in smoking cessation in adulthood (Breslau and Peterson 1996). Therefore, it is significant that nicotine has more potent rewarding effects in adolescent as opposed to adult rodents (Adriani et al. 2004 Belluzzi et al. 2004 Vastola et al. 2002). However, several studies suggest that adolescent rodents develop physical nicotine dependence less readily than adults, as indicated by less severe nicotine withdrawal syndrome. Unlike adult rats, continuously nicotine-infused adolescent rats failed to display mecamylamine-precipitated withdrawal behaviors (O Dell et al. 2004, 2006). They also displayed less mecamylamine-precipitated conditioned place aversion than adults (O Dell etal. 2007). In addition, nicotine-infused adolescent rats experienced smaller mecamylamine-precipitated ICSS threshold elevations than adults (Kota et al. 2007). Nicotine-infused adolescent mice also displayed fewer spontaneous and mecamylamine-precipitated somatically expressed withdrawal behaviors... 

Seeger, Thomas F., and Kristin R. Carlson. 1981. "Amphetamine and Morphine Additive Effects on ICSS Threshold." Society for Neuroscience Abstracts 7 974. 

Let us consider the calculation of sensitivity threshold in the case when the cracks are revealing by PT method. Constant distance H between crack s walls along the whole defect s depth is assumed for the simplicity. The calculation procedure depends on the dispersity of dry developer s powder [1]. Simple formula has to be used in the case when developer s effective radius of pores IC, which depends mainly on average particle s size, is smaller than crack s width H. One can use formula (1) when Re is small enough being less than the value corresponding maximum sensitivity (0,25 - 1 pm). For example. Re = 0,25 pm in the case when fine-dispersed magnesia oxide powder is used as the developer. In this case minimum crack s width H that can be detected at prescribed depth lo is calculated as... 

The type of proteetion on this IC is a pulse-to-pulse eurrent sense that euts off the power switeh instantly upon exeeeding a 0.47 V threshold. I will allow a 25 pereent margin between the expeeted peak eurrent and the proteetion eutoff threshold (proteetion 1.25(2.8A) = 3.5A). 

The IC provides only a shutdown pin with an aetivation threshold of 0.4 V minimum. I plan to enter a hieeup mode of overeurrent proteetion as a form of baek-up proteetion. To minimize the size of the eurrent sensing resistor, I will employ a variation of the eurrent foldbaek sensing eireuit. Here 0.35 V will be eontributed by a resistor in the voltage sensing resistor divider (R14). The value of R15 is then... 

The MC34067 has only a simple eomparator with a 1.0 V threshold that then latehes an R-S flip-flop. Either the input voltage must be removed and then reapplied, or the Vee of the eontrol IC must be interrupted momentarily to reset the failure lateh. 

The voltage needed from the output of the eurrent transformer must overeome the forward drops of reetifiers and exeeed 1.0 V threshold on the eontrol IC, so... 

TLV-TWA, THRESHOLD LIMIT VALUE - TIME WEIGHTED AVERAGE (USa) A limit fOf the atmOSpliei ic concentration of a chemical, averaged over an 8-hr day, to which it is believed that most people can be exposed without harm. 

The mechanical concepts of stress are outlined in Fig. 1, with the axes reversed from that employed by mechanical engineers. The three salient features of a stress-strain response curve are shown in Fig. la. Initial increases in stress cause small strains but beyond a threshold, the yield stress, increasing stress causes ever increasing strains until the ultimate stress, at which point fracture occurs. The concept of the yield stress is more clearly realised when material is subjected to a stress and then relaxed to zero stress (Fig. Ih). In this case a strain is developed but is reversed perfectly - elastically - to zero strain at zero stress. In contrast, when the applied stress exceeds the yield stress (Fig. Ic) and the stress relaxes to zero, the strain does not return to zero. The material has irreversibly -plastically - extended. The extent of this plastic strain defines the residual strain. 

Similarly if you toggle the enable pin at a certain rate in many ICs you can get to see current overshoots too. This often depends on allowing the input capacitor to discharge below the UVLO threshold, but not to the point where it hits the internal POR (power on reset) threshold. Because in that case, if you suddenly enable the IC, it has no soft-start anymore, and you will hit max duty cycle, and possibly staircase if the current limit circuitry is not well designed. 

Benzene has a low threshold limit value or TLV. The time weighted average TLV (TWA) is the allowable exposure for an average 8 hr day or a 40 hr week. The short-term exposure limit TLV (STEL) is the maximum allowable exposure for any 15-min period. For benzene the TWA = 0.5 ppm and the STEL is 2.5 ppm, as given by the American Conference of Governmental Industrial Hygienists (ACGIH). This allowable exposure is much lower than those for toluene and xylene, probably because these latter two compounds have benzyl ic positions that are easily oxidized in vivo to compounds that can be eliminated from the body. 

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