Local pressure and matrix component effects on verteporfin distribution in pancreatic tumors (Conference Presentation)

Author(s):  
Michael D. Nieskoski ◽  
Kayla Marra ◽  
Jason R. Gunn ◽  
Marvin M. Doyley ◽  
Kimberly S. Samkoe ◽  
...  
Author(s):  
J. J. Kelsch ◽  
A. Holtz

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.


1956 ◽  
Vol 31 (5) ◽  
pp. 551-565 ◽  
Author(s):  
Frank B. McGlone ◽  
Donald S. Robertson ◽  
John M. Grogan
Keyword(s):  

2017 ◽  
Vol 23 ◽  
pp. 88
Author(s):  
Maria Ramos Guifarro ◽  
Luis Guifarro ◽  
Daniel Guifarro
Keyword(s):  

Phlebologie ◽  
2006 ◽  
Vol 35 (05) ◽  
pp. 349-355 ◽  
Author(s):  
E. O. Brizzio ◽  
G. Rossi ◽  
A. Chirinos ◽  
I. Cantero ◽  
G. Idiazabal ◽  
...  

Summary Background: Compression therapy (CT) is the stronghold of treatment of venous leg ulcers. We evaluated 5 modalities of CT in a prospective open pilot study using a unique trial design. Patients and methods: A group of experienced phlebologists assigned 31 consecutive patients with 35 venous ulcers (present for 2 to 24 months with no prior CT) to 5 different modalities of leg compression, 7 ulcers to each group. The challenge was to match the modality of CT with the features of the ulcer in order to achieve as many healings as possible. Wound care used standard techniques and specifically tailored foam pads to increase local pressure. CT modalities were either stockings Sigvaris® 15-20, 20-30, 30-40 mmHg, multi-layer bandages, or CircAid® bandaging. Compression was maintained day and night in all groups and changed at weekly visits. Study endpoints were time to healing and the clinical parameters predicting the outcome. Results: The cumulative healing rates were 71%, 77%, and 83% after 3, 6, and 9 months, respectively. Univariate analysis of variables associated with nonhealing were: previous surgery, presence of insufficient perforating and/or deep veins, older age, recurrence, amount of oedema, time of presence of CVI and the actual ulcer, and ulcer size (p <0.05-<0.001). The initial ulcer size was the best predictor of the healing-time (Pearson r=0.55, p=0.002). The modality of CT played an important role also, as 19 of 21 ulcers (90%) healed with stockings but only 8 of 14 with bandages (57%; p=0.021). Regression analysis allowed to calculate a model to predict the healing time. It compensated for the fact that patients treated with low or moderate compression stockings were at lower risk of non-healing. and revealed that healing with stockings was about twice as rapid as healing with bandages. Conclusion: Three fourths of venous ulcers can be brought to healing within 3 to 6 months. Healing time can be predicted using easy to assess clinical parameters. Irrespective of the initial presentation ulcer healing appeared more rapid with the application of stockings than with bandaging. These unexpected findings contradict current believes and require confirmation in randomised trials.


2016 ◽  
pp. 514-516
Author(s):  
Martin Bruhns

The massecuite circulates in a loop within the evaporating crystallizing vessel. The massecuite flows upwards through the heating tubes. In the room above the calandria the massecuite flow changes its direction to radial inwards and then to vertical downwards. An impeller in the central tube forces the circulation. Below the calandria the main direction of flow is radially outwards until threads of the massecuite stream enter the heating tubes in upwards direction. Within the tubes heat is transferred to the massecuite. At low temperature differences between heating steam and massecuite and higher levels of the massecuite in the crystallizer vapor bubbles are not found in the tubes. Vapor bubbles can be formed at a massecuite level in the crystallizer where the temperature of the massecuite is higher than the local boiling temperature of water, which depends on the local pressure (including the static pressure of the massecuite at this point) and the boiling point elevation of the mother liquor. The surface tension of the liquid is a resistance against the bubble formation, which has to be overcome by the local superheating i.e. the part of the enthalpy of the massecuite exceeding the local boiling temperature. The formation and the flow of the bubbles change the density of the massecuite/bubbles mixture and has an influence on the massecuite flow. The formation of a vapour bubble is connected with a local drop of the massecuite temperature which changes the local supersaturation. Today the heat transfer into the magma is quite well known but the process of bubble formation is quite unknown. Some basic considerations about the formation of bubbles and its influence on local supersaturation based on calculation of heat and mass balances and models of bubble formation are be given and discussed. Experiments for basic investigations are proposed.


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