scholarly journals Variations of TSNA Levels in Tobaccos Upon Heating at Moderate Temperatures

2020 ◽  
Vol 29 (2) ◽  
pp. 84-96
Author(s):  
Serban C. Moldoveanu ◽  
Marlene Adams ◽  
Frank K. St.Charles
Keyword(s):  
Heat Exposure ◽  
Glass Tube ◽  
Time Intervals ◽  
Glass Tubes ◽  
Tobacco Specific Nitrosamines

SummaryTobacco-specific nitrosamines (TSNAs) including nitrosoanabasine (NAB), nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and nitrosonornicotine (NNN) are naturally present at trace levels in tobacco. During tobacco processing, preparation of expanded tobacco, and when tobacco is used in heat-not-burn type cigarettes, the tobacco is exposed to different degrees of heat. Heating of tobacco has been reported in the literature to increase the level of TSNAs. Since the increase of TSNAs in heated tobacco is still not well understood, the present study evaluated TSNA levels in six types of tobacco as a function of moderate heat exposure. These tobaccos included: flue-cured lower stalk, flue-cured upper stalk (US), Burley lower stalk, Burley upper stalk (US), and two Oriental blends (Turkey, Greece, Bulgaria, Northern Republic Macedonia). Heating was performed in sealed glass tubes at oven temperatures of 100 °C, 150 °C, 200 °C, and 250 °C for time intervals of 2 min and 5 min. The temperatures inside the glass tubes were lower than the targets and were monitored separately as a function of glass tube heating. The study showed no meaningful differences within tobacco type (by stalk position) but showed considerable differences in the levels of TSNAs between different tobaccos, with the Burley tobaccos having the highest levels, and the Orientals the lowest. For all tobacco types, TSNAs increase to some extent when temperature increases. For 2-min heating, the increase in TSNAs is relatively small up to about 200 °C, but the levels almost double when the oven temperature increases to 250 °C. For 5-min heating, the increase in TSNAs starts at about 150 °C with a maximum at 200 °C which can reach more than double the initial TSNA level. Longer heating at 250 °C (5 min) starts to cause TSNAs decomposition and the levels are reduced.

Bulk Cryopreservation of Isolated Islets of Langerhans

1996 ◽  
Vol 5 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Jonathan R.T. Lakey ◽  
Garth L. Warnock ◽  
Ziliang Ao ◽  
Ray V. Rajotte
Keyword(s):  
Islets Of Langerhans ◽  
Stimulation Index ◽  
Glass Tube ◽  
Human Islets ◽  
Isolated Islets ◽  
Freezing And Thawing ◽  
Slow Cooling ◽  
Glass Tubes ◽  
Multiple Donors

Current methods to isolate human islets of Langerhans are limited and multiple donors are required for successful reversal of longstanding Type 1 diabetes mellitus. Cryopreservation of isolated islets is an effective method of storing and pooling islets. Current cryopreservation protocols are cumbersome due to current practices of placing small aliquots of islets per individual freezer tube. In the present study, we examined the application of a blood freezer bag for the cryopreservation of isolated islets by slow cooling and rapid thawing. Freezing and thawing profiles generated using thermocouples placed inside a 500 mL Cryocyte (Baxter) blood freezer bag showed that a longer equilibration period at −7.4°C was necessary to consistently achieve nucleation and cooling profiles similar to those observed in glass tubes. When known numbers of rat islets were placed in the freezer bag and the cryoprotectant dimethyl sulfoxide (DMSO) was added in a stepwise fashion and removed using a sucrose dilution, the islet recovery compared with glass tubes was 92 ± 4.8 vs. 90 ± 2.3% (n = 4, p = ns, Mann-Whitney U-test). When purified canine islets were cryopreserved in a single freezer bag or in multiple glass tubes, the recovery was similar (78.8 ± 12.5% recovery for freezer bag vs. 82.3 ± 5.3% for glass tubes; n = 6, p = ns). In vitro function was equivalent for both groups. The stimulation index of insulin release during glucose perifusion (stimulated over basal insulin secretion) for canine islets cryopreserved in a freezer bag vs. glass tubes was 3.2 ± 1.0 and 2.3 ± 1.3, respectively (n = 6, p = ns). These values were significantly lower than the nonfrozen control islets (6.9 ± 2.4, p < 0.05). When 2000 canine islets cryopreserved in either a freezer bag, or glass tubes were transplanted into diabetic nude mice, the animals became and remained normoglycemic posttransplant. We conclude that the survival of freshly isolated canine islets cryopreserved in a single freezer bag is equivalent to the glass tube method. Bulk cryopreservation of islets in a single freezer bag will facilitate effective low temperature tissue banking to support ongoing clinical trials of islet transplantation.

scholarly journals The Bakerian lecture: On the gaseous state of matter

1876 ◽  
Vol 24 (164-170) ◽  
pp. 455-459 ◽  
Keyword(s):  
High Pressures ◽  
Carbonic Acid ◽  
Glass Tube ◽  
Gaseous State ◽  
Acid Gas ◽  
Original Memoir ◽  
Glass Tubes ◽  
The Mean ◽  
State Of Matter ◽  
Mean Time

After referring to certain modifications in his former method of working at high pressures, the author describes some preliminary experiments which were undertaken to determine the change of capacity in the capillary bore of the glass tubes under the pressures employed. From these experiments it appears that, on raising the pressure from 5 to 110 atmospheres, the capacity was increased for each atmosphere by only 0·0000036, and that this change of capacity was chiefly due to compression of the internal walls of the glass tube. Another set of experiments was made to ascertain whether air or carbonic-acid gas is absorbed at high pressures to any appreciable extent by mercury. For the method of operating and other details reference must be made to the original memoir; but the general result is that no absorption whatever takes place, even at pressures of 50 or 100 atmospheres. The pressures are given according to the indications of the air-manometer in the absence of sufficient data (which the author hopes will be soon supplied) for reducing them to true pressures. In the mean time it is probable, from the experiments of Cailletet, that the indications of the air-manometer are almost exact at 200 atmospheres, and for lower pressures do not in any case deviate more than from the true amount. In a note which was published last year in the ‘Proceedings’ of the Society (No. 163), it was staffed that the coefficient of expansion ( a ) for heat under constant pressure changes in value both with the pressure and with the temperature. The experiments on this subject are now completed, and are described at length in this paper. The final results will be found in the two following Tables. In the first Table the values of a are referred to a unit volume at 0º and under one atmosphere. In the first column the pressure p in atmospheres is in terms of the air-manometer.

scholarly journals The measurement of pressures developed in explosion waves

1932 ◽  
Vol 137 (832) ◽  
pp. 380-396 ◽  
Keyword(s):  
Detonation Wave ◽  
Wave Front ◽  
Short Interval ◽  
Glass Tube ◽  
Closed Vessel ◽  
Gaseous Mixtures ◽  
Glass Tubing ◽  
Explosion Wave ◽  
Glass Tubes ◽  
Short Time

The measurement of the pressure produced in the “explosion-wave” in gaseous mixtures is difficult because of the rapidity of movement of the wave and the short time for which the pressure over any given area lasts. In 1894 Dixon and Cain pointed out that the pressures obtained by firing a mixture in a closed vessel did not correspond to pressures in the wave front. Following a suggestion of Mallard and Le Chatelier, they used a method in which glass tubes of known strength were fractured by the explosion-wave, it being assumed that “if a pressure is produced in a glass tube greater than it can stand, the glass will be broken although the pressure may only last for a very short interval of time.” The strength of the glass tubes was found by determining the static pressures required to break similar pieces. It was found that three lengths from the same piece of glass tubing required respectively 890, 950 and 1220 lbs. per square inch to fracture them: the accuracy of the results was therefore not very great. Dixon and Cain estimated that the pressure in the explosion-wave in C 2 N 2 + O 2 lay, probably, between 70 and 120 atmospheres and that in C 2 N 2 O + 2N 2 between 63 and 84 atmospheres. Jones and Bower cast some doubt on the pressures given by Dixon and Cain, and suggested that they were the pressures produced just after detonation had been re-established when the explosion-wave had been damped down at a junction. The pressure in the wave front of the fully established detonation wave in the mixture C 2 N 2 + O 2 was estimated by Jones and Bower to lie between 58 and 75 atmospheres.

scholarly journals GLASS TUBE CLEAVING WITH PHASE-CORRECTED NON-DIFFRACTING LASER PULSES

2021 ◽  
Author(s):  
Daniel Flamm ◽  
Jonas Kleiner ◽  
Myriam Kaiser ◽  
Felix Zimmermann ◽  
Tim Hesse
Keyword(s):  
Chemical Etching ◽  
Glass Tube ◽  
Laser Pulses ◽  
Phase Correction ◽  
Ultrashort Laser Pulses ◽  
Full Thickness ◽  
Sensitive Phase ◽  
Glass Tubes ◽  
Final Article ◽  
Ultrashort Laser

Ultrashort laser pulses are used to modify complex inner and outer contours from glass tubes. The processing optics is designed to shape non-diffracting beams and to apply a sensitive phase correction for the processing behind curved interfaces. This enables single-pass, full-thickness modifications with feed rates in the order of 100 mm/s are demonstrated. Final article separation is performed by thermal stress or via chemical etching.

scholarly journals Mode Bifurcation on Contact Line Dynamics at Oil/Water Interface Depending on the Contact Line Length

2021 ◽  
Vol 9 ◽  
Author(s):  
Daigo Yamamoto ◽  
Jumpei Maeno ◽  
Yuki Manabe ◽  
Yasunao Okamoto ◽  
Erika Nawa-Okita ◽  
...  
Keyword(s):  
Contact Line ◽  
Glass Tube ◽  
Glass Container ◽  
Line Length ◽  
Water Interface ◽  
Wave Patterns ◽  
Glass Tubes ◽  
Inner Diameter ◽  
Contact Line Motion ◽  
Oil Water

The motion of the contact line at the oil/water interface caused by chemical reactions is well known as a typical example of artificial active matter in the field of nonlinear science. When water (containing trimethylstearylammonium chloride) and nitrobenzene (containing iodide anion) phases are in contact, the regulated traveling-wave patterns appear along the inner wall of the glass container. In this study, we demonstrate a new dynamical mode of the contact line, an up-and-down motion, which becomes dominant with the decrease in the size of a glass tube, and the probability of occurrence is extremely high when the diameter of the glass tube is below 1 mm. A physicochemical model of the contact line motion that incorporates the spatiotemporal variation of the surfactant concentration on a glass surface is proposed, and its effect on the wettability of oil/water phases on the walls of the glass tubes is studied. The present model can reproduce the mode bifurcation of the dynamical motion depending on the inner diameter of the glass tubes.

Effects of gravity and branching on longitudinal gas mixing in glass tube models

1982 ◽  
Vol 52 (6) ◽  
pp. 1476-1486 ◽  
Author(s):  
H. Shibata ◽  
T. Okubo ◽  
T. Fuyuki ◽  
T. Takishima ◽  
N. Imaishi
Keyword(s):  
Flow Distribution ◽  
Glass Tube ◽  
Low Flow ◽  
Gas Mixture ◽  
Straight Tube ◽  
Gas Mixing ◽  
Mixed Gas ◽  
Flow Rates ◽  
Glass Tubes ◽  
Flow Through

We investigated the effects of gravity and branching on gas mixing in glass tube models. The mixed gas (5% He and 5% SF6) was made to flow through a straight tube and tubes with bifurcated branches, and the effective axial diffusion coefficient (Deff) was measured. The direction of the branches was varied from upward to downward by 90% turns, and the flow distribution to each branch was separately controlled. In the case of a straight horiontal tube, the flow velocity dependency of the Deff of He and SF6 was observed as we expected from Aris' equation. In the case of glass tubes with branches, the Deff of SF6 was greater in the downward-directed branches than it was in the upward-directed branches when gas mixing occurred at the front of the gas mixture; however, when gas mixing occurred at the tail, the opposite effects were observed. These characteristics were more marked at slower flow rates and when the flow to each branch was different. Our findings suggest that gravity has an effect on gas mixing in glass tube airway models, especially at a low flow rate and uneven flow distribution.

Tritium Application: Self-Luminous Glass Tube (SLGT)

2005 ◽  
Vol 277-279 ◽  
pp. 698-702 ◽  
Author(s):  
Kyeong Sook Kim ◽  
Sook Kyung Lee ◽  
Eun Su Chung ◽  
Kwang Sin Kim ◽  
Wi Soo Kim ◽  
...  
Keyword(s):  
New Technology ◽  
Glass Tube ◽  
Main Process ◽  
Fluorescent Lamp ◽  
Coating Technology ◽  
Design Basis ◽  
Recovery System ◽  
Glass Tubes ◽  
Pulse Type ◽  
Injection Technology

To manufacture SLGTs (Self-Luminous Glass Tubes), 4 core technologies are needed: coating technology, tritium injection technology, laser sealing/cutting technology and tritium handling technology. The inside of the glass tubes is coated with greenish ZnS phosphor particles with sizes varying from 4~5 [µm], and Cu, and Al as an activator and a co-dopant, respectively. We also found that it would be possible to produce a phosphor coated glass tube for the SLGT using the well established cold cathode fluorescent lamp (CCFL) bulb manufacturing technology. The conceptual design of the main process loop (PL) is almost done. A delicate technique will be needed for the sealing/cutting of the glass tubes. Instead of the existing torch technology, a new technology using a pulse-type laser is under investigation. The design basis of the tritium handling facilities is to minimize the operator's exposure to tritium uptake and the emission of tritium to the environment. To fulfill the requirements, major tritium handling components are located in the secondary containment such as the glove boxes (GBs) and/or the fume hoods. The tritium recovery system (TRS) is connected to a GB and PL to minimize the release of tritium as well as to remove the moisture and oxygen in the GB.

In Vitro Interaction between Venous Blood Clots and Radiopharmaceuticals

1985 ◽  
Vol 24 (04) ◽  
pp. 173-179 ◽  
Author(s):  
B. R. R. Persson ◽  
V. Kempi
Keyword(s):  
Room Temperature ◽  
Venous Blood ◽  
Gel Chromatography ◽  
Time Intervals ◽  
Ph Values ◽  
Blood Clots ◽  
Glass Tubes ◽  
Ph Range ◽  
In Vitro Interaction

SummaryClots of 1 ml venous blood formed in glass tubes after 10 min at room temperature were incubated at 37° C with the radiopharmaceutical to be studied. Methods for quality control of the radiopharmaceuticals were compared. Gel chromatography scanning was found to give reliable information. The incorporation into the clot was studie’d at different pH values and after various time intervals. The highest incorporation was found for 125I-fibrinogen and for 99mTc-mac-roaggregates of albumin, followed by 99mTc-sulphur colloid and 99mTc-strep-tokinase at pH less than 2. The titrated initial dose of 99mTc-streptoki-nase was studied at various pH levels. The lysing effect was less in the pH range 1-2.5, where the best labeling yield was obtained. The inactivation of streptokinase by the labeling procedure was also studied with im-munoelectrophoresis and decomposition of casein. In vitro studies of the interaction of radiopharmaceuticals with clots add information for the clinical use of radiopharmaceuticals for thrombus localization.

scholarly journals XXXIV. Description and use of a portable wind gage.

1775 ◽  
Vol 65 ◽  
pp. 353-365 ◽  
Keyword(s):  
Glass Tube ◽  
The Other ◽  
Round Hole ◽  
Simple Instrument ◽  
Glass Tubes

This simple instrument consists of of two glass tubes AB, CD, of five or six inches in length (TAB. X. fig. 1.). Their bores, which are so much the better always for being equal, are each about 4/10ths of an inch in diameter. They are connected together, like a siphon, by a small bent glass tube <italic>a b</italic>, the bore of which is 1/10th of an inch in diameter. On the upper end of the leg AB there is a tube of latten brass, which is kneed or bent perpendicularly outwards, and has its mouth open towards F. On the other leg CD is a cover, with a round hole G in the upper part of it, 2/10ths of an inch in diameter. This cover and the kneed tube are connected together by a slip of brass <italic>c d</italic>, which not only gives strength to the whole instrument, but also serves to hold the scale HI. The kneed tube and cover are fixed on with hard cement or sealing wax.

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