Transvaginal follicle aspiration in Thai swamp buffalo heifers using different vacuum pressures after FSH pretreatment (Bubalus bubalis).
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The objective of the experiment was to study oocyte recovery by transvaginal, ultrasound-guided, follicle aspiration, from Thai swamp buffalo using different vacuum pressures. Six adult buffalo heifers, aged 2.5-3.0 yrs were treated with a total dose of 280 mg FSH, given twice a day in a divided doses over a three day period (60/60 mg, 50/50 mg, 30/30 mg) at d7 after progesterone implant. Three vacuum pressures were used; 100 (n=12), 80 (n=12) and 60 mmHg (n=12) and all of the pressures were performed in each animal. The animals were treated repeatedly and collection took place using 2 sets of each pressure every 2 months, giving a total of 36 collections from each animal. The oocyte recovery rates from each pressure were 81.2% (69/85) 79.1% (53/67) and 90.3% (93/103) for 100, 80 and 60 mmHg respectively. The number of oocytes collected per donor were 5.33 +/- 3.27, 4.42 +/- 2.71 and 7.75 +/- 4.31 respectively. The quality of the oocytes did not improved with the lower vacuum pressure. In conclusion, the application of FSH pretreatment improves the yield of oocytes from Thai, swamp buffalo heifers after gonadotropin treatment when using the vacuum pressures between 60-100 mmHg. (+info)
The value of suction wound drain after carotid and femoral artery surgery: a randomised trial using duplex assessment of the volume of post-operative haematoma.
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BACKGROUND: The use of vacuum suction drains after carotid endarterectomy (CEA) and groin dissection for arterial reconstruction surgery remains controversial. A large multicentre prospective randomised trial would be needed to show any difference if clinical end points (infection and haematoma) are used. Therefore, we conducted a study to evaluate the value of wound drainage using accurate duplex measurement of haematoma expecting a 25% difference in volume between drained and non-drained wounds. PATIENTS AND METHODS: Seventy consecutive patients undergoing CEA and 73 patients who underwent 106 groins dissection were separately and blindly randomised into two groups: group (a) with wound drain and group (b) without wound drain. A duplex scan was carried out post-operatively to document the presence and volume of any wound haematoma. RESULTS: The majority of wounds did not show any evidence of collections. 1. In the CEA patients duplex scan revealed wound haematoma in 8 patients with a median volume of 25 ml (5-65) in group (a) in comparison to 7 wound haematomas 31 ml (3-72) in group (b). Median suction drain drainage was 42 ml (10-120) when used. There was no significant difference between the two groups. Three patients 4.3% (two from the drain group) underwent evacuation of haematoma post-operatively.2. In the groin dissection patients most of the documented collections were trivial. Ultrasound scans showed 21 collections (20%), of these 7 (34%) were in group (a) and 14 (66%) were in group (b). There was no significant difference in wound collections between the two groups (p = 0.28). Only 5 collections (75%) exceeded 10 ml, three of them were in the drain group. One patient (1%), who did not have a drain, developed a wound collection, which needed re-exploration. When a drain was used the median drainage was 64.5 ml (range 10-220). CONCLUSION: These results based on accurate measurement of wound collection suggest that there is no benefit in terms of reduction of the volume of haematoma on wound drainage after CEA or arterial reconstruction surgery involving the groin. A selective policy of use of drainage is therefore recommended. (+info)
AP and vacuum MALDI on a QqLIT instrument.
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This article presents a comparative study of the performance, operational, and instrumental characteristics of AP and vacuum MALDI for the analysis of peptides and protein digests. Spectra generated with the two ion sources were surprisingly similar, both qualitatively and quantitatively, with vacuum MALDI generating ion count rates that were approximately a factor of 2 greater than those generated with AP MALDI on this system. Even though the peptide signals were 2X greater with vacuum MALDI, the background intensities also increased by a similar amount, leading to approximately equivalent signal/background ratios for digests and peptide mixtures. The results suggest that when AP MALDI conditions are properly optimized, the sensitivity can approach that of vacuum MALDI. However, AP MALDI performance is critically affected by source gas flows, potentials, and temperature, making it operationally more complex. In addition, evidence is provided for thermal degradation of samples stored on a target plate within a heated AP MALDI ion source. An improved interface for atmosphere to vacuum ion transfer substantially improved these characteristics. (+info)
Vacuum assisted closure: a review of development and current applications.
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Vacuum assisted closure is being increasingly used for wound management. This review examines the history of its development and appraises the current evidence on its use so far. (+info)
Formulation design and optimization of mouth dissolve tablets of nimesulide using vacuum drying technique.
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The purpose of this research was to develop mouth dissolve tablets of nimesulide. Granules containing nimesulide, camphor, crospovidone, and lactose were prepared by wet granulation technique. Camphor was sublimed from the dried granules by exposure to vacuum. The porous granules were then compressed. Alternatively, tablets were first prepared and later exposed to vacuum. The tablets were evaluated for percentage friability, wetting time, and disintegration time. In the investigation, a 32 full factorial design was used to investigate the joint influence of 2 formulation variables: amount of camphor and crospovidone. The results of multiple linear regression analysis revealed that for obtaining a rapidly disintegrating dosage form, tablets should be prepared using an optimum concentration of camphor and a higher percentage of crospovidone. A contour plot is also presented to graphically represent the effect of the independent variables on the disintegration time and percentage friability. A checkpoint batch was also prepared to prove the validity of the evolved mathematical model. Sublimation of camphor from tablets resulted in superior tablets as compared with the tablets prepared from granules that were exposed to vacuum. The systematic formulation approach helped in understanding the effect of formulation processing variables. (+info)
Advances in wound healing: topical negative pressure therapy.
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In clinical practice many wounds are slow to heal and difficult to manage. The recently introduced technique of topical negative pressure therapy (TNP) has been developed to try to overcome some of these difficulties. TNP applies a controlled negative pressure to the surface of a wound that has potential advantages for wound treatment and management. Although the concept itself, of using suction in wound management is not new, the technique of applying a negative pressure at the surface of the wound is. This paper explores the origins and proposed mechanisms of action of TNP therapy and discusses the types of wounds that are thought to benefit most from use of this system. (+info)
Scanning tunneling microscopy experiments on single molecular landers.
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Molecular landers are molecules comprising of a central rigid molecular wire maintained above a metallic surface by organic spacers, which allows specific ultrahigh vacuum-scanning tunneling microscopy experiments to be performed at the single-molecule level. The understanding of the molecule-surface interactions, intramolecular mechanics, and the possibility to perform extremely precise tip-induced manipulation permit these molecules to be brought in contact with a nanoelectrode and the resulting electronic interaction to be analyzed in well controlled conditions. (+info)
Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy.
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A cryogenic variable-temperature ultra-high vacuum scanning tunneling microscope is used for measuring the electrical properties of isolated cyclopentene molecules adsorbed to the degenerately p-type Si(100)-2x1 surface at a temperature of 80 K. Current-voltage curves taken under these conditions show negative differential resistance at positive sample bias, in agreement with previous observations at room temperature. Because of the enhanced stability of the scanning tunneling microscope at cryogenic temperatures, repeated measurements can be routinely taken over the same molecule. Taking advantage of this improved stability, we show that current-voltage curves on isolated cyclopentene molecules are reproducible and possess negligible hysteresis for a given tip-molecule distance. On the other hand, subsequent measurements with variable tip position show that the negative differential resistance voltage increases with increasing tip-molecule distance. By using a one-dimensional capacitive equivalent circuit and a resonant tunneling model, this behavior can be quantitatively explained, thus providing insight into the electrostatic potential distribution across a semiconductor-molecule-vacuum-metal tunnel junction. This model also provides a quantitative estimate for the alignment of the highest occupied molecular orbital of cyclopentene with respect to the Fermi level of the silicon substrate, thus suggesting that this experimental approach can be used for performing chemical spectroscopy at the single-molecule level on semiconductor surfaces. Overall, these results serve as the basis for a series of design rules that can be applied to silicon-based molecular electronic devices. (+info)