Heterogeneities in biofilms from clinical isolates under flow conditions

2020 ◽  
Author(s):  
Cindy Cardenas ◽  
Roberto Rusconi
Keyword(s):  
Pancreatic Cancer ◽  
Obstructive Jaundice ◽  
Flow Rate ◽  
Bacterial Attachment ◽  
The Body ◽  
Biliary System ◽  
Plastic Stents ◽  
Microfluidic Channels ◽  
Biliary Stenting ◽  
Luminal Diameter

<p>Pancreatic cancer is the fourth leading cause of cancer death worldwide. The most common sign of presentation of pancreatic cancer is obstructive jaundice, which prevents the drainage of bile into the intestines and it is often associated with decreased survival in patients. Nowadays more than 70% of the patients with biliary obstructive jaundice is treated by biliary stenting; however, biliary stenting disrupts the natural anatomic barrier between the biliary and the gastrointestinal tract, strongly increasing the risk of a bacterial infection. Moreover, duodenal bacteria, by gaining access into the biliary system, can adhere to the stent surface and develop biofilms. Nevertheless, very little is known about the growth of biofilms on the stents and their role in infectious post-operative complications. In particular, the biliary system is an inherently fluid mechanical environment, where the gallbladder provides the driving pressure and the flow rate of the bile going through the ducts depends on the resistance between the gallbladder and the downstream end of the common bile duct. The average flow rate of the bile ranges between approximately 0.5 to 5 ml/min, which depends if the body is fasting or after a meal; this flow rate then corresponds – in the case for example of plastic stents, which are typically 2-4 mm in luminal diameter – to a maximum flow velocity of about 1-40 mm/s and to a shear rate at the inner surface of the stent of 1-80 s<sup>-1</sup>. Therefore, the mechanical stress induced by the bile flow in the stent is likely to play a significant role in the formation of biofilms, as shown by our data. Six clinically relevant isolates from preoperative biliary stents were selected to be grown inside microfluidic channels at different flow rates, in which bacterial attachment and biofilm dynamics were recorded and quantified. We found that fluid flow largely influences biofilm morphology in all the isolates, for which the conditions of flow and shear stress that trigger heterogeneities in biofilm structure have been determined. These results will help us to improve our understanding of biofilm formation in the presence of fluid dynamic environments and eventually consider optimal parameters of flow in the design of medical devices.</p>

scholarly journals Endoscopic Pancreatic Stenting in Pancreatic Cancer

1999 ◽  
Vol 13 (6) ◽  
pp. 481-487 ◽  
Author(s):  
Guido Costamagna ◽  
Petros Alevras ◽  
Francesco Palladino ◽  
Fernando Rainoldi ◽  
Massimiliano Mutignani ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Obstructive Jaundice ◽  
Pancreatic Duct ◽  
Main Pancreatic Duct ◽  
Positive Impact ◽  
Advanced Pancreatic Cancer ◽  
Outlet Obstruction ◽  
Plastic Stents ◽  
Main Concern ◽  
Number Of Patients

Most pancreatic carcinomas are unresectable at the time of diagnosis; therefore, palliative treatment is very often the main concern of clinicians in this setting. The main symptoms resulting in the need for palliation in pancreatic cancer are obstructive jaundice, duodenal obstruction and pain. Therapeutic endoscopy plays a major role in the palliation of obstructive jaundice by stent placement into the biliary ducts. Initial experience has also been gained recently with endoscopic placement of expandable metallic stents to treat gastric outlet obstruction. Much less is known about the possible role of endoscopic pancreatic stenting in patients with unresectable pancreatic carcinoma. The main indication for pancreatic ductal stenting is ‘obstructive’ pain related to meals in patients with dilated main pancreatic duct beyond the stricture and intraluminal brachyradiotherapy. The technique of endoscopic pancreatic stenting does not substantially differ from that applied on the biliary tree. When technically possible, placement of 10 French plastic stents is preferred. According to the authors’ indications, only about 15% of patients with advanced pancreatic cancer (55 of 355 in the present study) may potentially benefit from this technique. Pancreatic stenting may be obtained in more than 80% of these selected patients, with low morbidity (less than 10%) and no procedure-related mortality. According to the authors of the present and other studies reported in the literature, about 60% of patients treated because of ‘obstructive’ pain become symptom-free, and another 20% to 25% significantly reduce the amount of analgesic drugs required. Intraluminal brachyradiotherapy with 192iridium in the main pancreatic duct is a feasible and safe method to deliver high radiation doses to the tumour while sparing adjacent organs. Brachyradiotherapy may be performed alone or in conjunction with external beam radiotherapy. Because of the small number of patients suitable for this treatment, only a multicentre study will be able to detect whether intraluminal brachyradiotherapy in pancreatic cancer may have any positive impact on survival.

EFFECT OF BODY MASS INDEX ON PEAK EXPIRATORY FLOW RATE

2019 ◽  
Vol 3 (9) ◽  
Author(s):  
K. Subramanyam ◽  
Dr. P. Subhash Babu
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Peak Expiratory Flow ◽  
Flow Rate ◽  
Peak Expiratory Flow Rate ◽  
Normal Weight ◽  
The Body ◽  
Health Care Centre ◽  
Expiratory Flow ◽  
Group B

Obesity has become one of the major health issues in India. WHO defines obesity as “A condition with excessive fat accumulation in the body to the extent that the health and wellbeing are adversely affected”. Obesity results from a complex interaction of genetic, behavioral, environmental and socioeconomic factors causing an imbalance in energy production and expenditure. Peak expiratory flow rate is the maximum rate of airflow that can be generated during forced expiratory manoeuvre starting from total lung capacity. The simplicity of the method is its main advantage. It is measured by using a standard Wright Peak Flow Meter or mini Wright Meter. The aim of the study is to see the effect of body mass index on Peak Expiratory Flow Rate values in young adults. The place of a study was done tertiary health care centre, in India for the period of 6 months. Study was performed on 80 subjects age group 20 -30 years, categorised as normal weight BMI =18.5 -24.99 kg/m2 and overweight BMI =25-29.99 kg/m2. There were 40 normal weight BMI (Group A) and 40 over weight BMI (Group B). BMI affects PEFR. Increase in BMI decreases PEFR. Early identification of risk individuals prior to the onset of disease is imperative in our developing country. Keywords: BMI, PEFR.

scholarly journals The Aftermath of a Hepatic Artery Aneurysm—A Rare Etiology of Biliary Obstruction!

2017 ◽  
Vol 10 ◽  
pp. 117955221771143 ◽  
Author(s):  
Catherine Linzay ◽  
Abhishek Seth ◽  
Kunal Suryawala ◽  
Ankur Sheth ◽  
Moheb Boktor ◽  
...  
Keyword(s):  
Obstructive Jaundice ◽  
Hepatic Artery ◽  
Significant Risk ◽  
Artery Aneurysm ◽  
Biliary Tree ◽  
Visceral Artery ◽  
Biliary Stenting ◽  
Hepatic Artery Aneurysm ◽  
Skin Imaging ◽  
Visceral Artery Aneurysms

Background: Hepatic artery aneurysms (HAAs) constitute 14% to 20% of visceral artery aneurysms. Most HAAs are asymptomatic. Although rare, obstructive jaundice due to external bile duct compression or rupture of the HAA into the biliary tree with occlusion of the lumen from blood clots has been reported. Case presentation: A 56-year-old white man presented to an outside hospital with symptoms of obstructive jaundice, including abdominal pain and yellowing of the skin. Imaging showed a large HAA. Patient was transferred to our hospital where an endoscopic retrograde cholangiopancreatography with biliary stenting was performed. This was followed by coil embolization of the HAA with improvement in symptoms and liver chemistries. Conclusions: Most clinicians agree that management of HAA is highly variable and depends on clinical presentation and anatomic location. Biliary stenting provides temporary relief for patients with obstructive jaundice. Definitive options include open aneurysmal repair versus endovascular therapy. Hepatic artery aneurysms represent a significant risk for hemorrhage and therefore must be addressed promptly once discovered.

scholarly journals Effect of Cooling Flow on the Operation of a Hot Rotor-Gas Foil Bearing System

2012 ◽  
Author(s):  
Keun Ryu ◽  
Luis San Andrés
Keyword(s):  
Thermal Management ◽  
Flow Rate ◽  
System Integration ◽  
Damping Ratio ◽  
Temperature Drop ◽  
Test System ◽  
The Body ◽  
Air Cooling ◽  
Cooling Flow ◽  
Management Procedures

Gas foil bearings (GFBs) operating at high temperature rely on thermal management procedures that supply needed cooling flow streams to keep the bearing and rotor from overheating. Poor thermal management not only makes systems inefficient and costly to operate but could also cause bearing seizure and premature system destruction. This paper presents comprehensive measurements of bearing temperatures and shaft dynamics conducted on a hollow rotor supported on two first generation GFBs. The hollow rotor (1.36 kg, 36.51 mm OD and 17.9 mm ID) is heated from inside to reach an outer surface temperature of 120°C. Experiments are conducted with rotor speeds to 30 krpm and with forced streams of air cooling the bearings and rotor. Air pressurization in an enclosure at the rotor mid span forces cooling air through the test GFBs. The cooling effect of the forced external flows is most distinct when the rotor is hottest and operating at the highest speed. The temperature drop per unit cooling flow rate significantly decreases as the cooling flow rate increases. Further measurements at thermal steady state conditions and at constant rotor speeds show that the cooling flows do not affect the amplitude and frequency contents of the rotor motions. Other tests while the rotor decelerates from 30 krpm to rest show that the test system (rigid-mode) critical speeds and modal damping ratio remain nearly invariant for operation with increasing rotor temperatures and with increasing cooling flow rates. Computational model predictions reproduce the test data with accuracy. The work adds to the body of knowledge on GFB performance and operation and provides empirically derived guidance for successful rotor-GFB system integration.

scholarly journals The Level of Lungs Capacity of Highly Skilled Female Volleyball Players

2017 ◽  
pp. 195-200
Author(s):  
Anna Galytska
Keyword(s):  
Peak Expiratory Flow ◽  
Flow Rate ◽  
Peak Expiratory Flow Rate ◽  
Average Rate ◽  
The Body ◽  
Lung Capacity ◽  
Air Volume ◽  
Volleyball Players ◽  
Expiratory Flow ◽  
Forced Air

Actuality of Research. Scientific works proved that the greater the volume of the lungs, the better the physical abilities of athletes. So researching of the functional state of organism, namely the level of lung capacity of volleyball players is very important. The aim of the Researching. Determining of the level of lung capacity, forced air volume in 1 second and peak expiratory flow rate in volleyball qualifications. Results. The average rate of lung capacity of volleyball players is – 3,98 l, Forced air volume in 1 second – 3,32 liters, peak expiratory flow rate 5,77 – l/sec. Conclusions. The results of researching indicate that the level of vital capacity in girls is rather higher. So volleyball players (girls) have a high level of fitness of the body, providing adaptation to hight loads and hight endurance.

scholarly journals ANALISIS AERODINAMIKA PADA PERMUKAAN BODI KENDARAAN MOBIL LISTRIK GASKI (GANESHA SAKTI) DENGAN PERANGKAT LUNAK ANSYS 14.5

2017 ◽  
Vol 5 (2) ◽  
Author(s):  
Yudi Prihadnyana ◽  
Gede Widayana ◽  
Kadek Rihendra Dantes
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Body Modification ◽  
The Body ◽  
Vehicle Body ◽  
Maximum Pressure ◽  
Air Velocity ◽  
Electric Cars ◽  
Minimum Pressure ◽  
Electric Car

Dengan perkembangan teknologi yang semakin maju bentuk dari bodi sebuah kendaraan sangatlah diperhitungkan untuk mencapai tujuan-tujuan tertentu. Untuk itu, dilakukan analisis Aerodinamika pada pemukaan bodi mobil listrik gaski dengan menggunakan perangkat lunak Ansys 14.5, yang bertujuan untuk mengetahui aliran fluida dan nilai koefisient drag pada mobil listrik Gaski bodi standar dan modifikasi. Setelah proses analisis dilakukan, didapatkan hasil velocity udara maksimum body standar sebesar 17,4324 m/s dan body modifikasi sebesar 17,7321 m/s dan pressure maksimum yang terjadi pada mobil listrik Gaski body standar sebesar 83,2143 Pa, dan minimum sebesar -189,879 Pa. sedangkan pressure maksimum yang terjadi pada mobil listrik Gaski body modifikasi sebesar 83,2143 Pa. dan minimum pressure diperoleh -182,128 Pa. nilai Koefisient drag dari mobil listrik Gaski body standar sebesar 0,00474 sedangkan pada body modifikasi sebesar 0,00407. Dari hasil peneletian tersebut didapatkan bahwa setalah dilakukan modifikasi pada bodi mobil listrik gaski terdapat beberapa perubahan diantaranya terjadi peningkatan kecepatan laju aliran udara atau velocity udara meningkat 1,72 % sedangkan tekanan yang diterima oleh bodi setelah dimodifikasi menurun 1,39 % dan Nilai koefisien drag pada mobil listrik gaski dapat diturunkan 14,14 % setelah dimodifikasi.Kata Kunci : kata kunci : Aerodinamika, aliran fluida, bodi kendaraan, With the technological development of the more advanced form of the body of a vehicle is very calculated to achieve certain goals. For that purpose, Aerodynamic analysis was performed on the electric car body surface by using Ansys 14.5 software, which aims to find out the fluid flow and coefficient value of drag on electric car Gaski standard body and modification. After the analysis process is done, the result of the maximum air velocity of the standard body is 17,4324 m / s and body modification of 17,7321 m / s and the maximum pressure happened to electric car Gaski body standard equal to 83,2143 Pa, 189,879 Pa. While the maximum pressure that occurs on electric cars Gaski body modification of 83.2143 Pa. And the minimum pressure obtained -182.128 Pa. Coefficient value of drag from electric car Gaski body standard of 0,00474 while at body modification equal to 0,00407. From the results of the research was found that after modification on the body of electric car gaski there are some changes such as increase the speed of air flow rate or air velocity increased by 1.72%, while the pressure received by the body after modification decreased 1.39% and the value of drag coefficient on Electric car gaski can be derived 14.14% after modified.keyword : Keywords : Aerodynamic, fluid flow rate, Vehicle body.

scholarly journals TO STUDY AND ANALYSIS OF SOLAR WATER HEATER USING VARIOUS MASS FLOW RATE

2020 ◽  
Vol 5 (3) ◽  
pp. 139-144
Author(s):  
Sunaina Sailani
Keyword(s):  
Solar Radiation ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Storage Tank ◽  
The Body ◽  
Solar Water Heater ◽  
Water Heater ◽  
Water Pipes ◽  
Solar Water ◽  
Circulating Water

Solar water heater is a device which is used for heating the water using of sun energy. This system is connected like as storage tank, centrifugal pump, pipes and glass. The circulating flexible water pipes are connected with the metallic pipe, which are assembled with the body. The solar radiation are achieving from sun and passing although glass and collector for the purpose of the heating the circulating water. In this way we are achieving the various temperatures using of circulating pump.

Renal Function in Unanaesthetized River Lampreys (Lampetra FluviatilisL.): Effects of Anaesthesia, Temperature and Environmental Salinity

1983 ◽  
Vol 105 (1) ◽  
pp. 351-362 ◽  
Author(s):  
A. J. MCVICAR ◽  
J. C. RANKIN
Keyword(s):  
Renal Function ◽  
Flow Rate ◽  
Ventilation Rate ◽  
Urine Flow ◽  
The Body ◽  
Urine Flow Rate ◽  
Flow Rates ◽  
Gill Ventilation ◽  
Daily Excretion ◽  
The Mean

1. Improved estimates of urine flow rates of lampreys in various salinities were obtained by the collection of urine for periods of up to 48 h from minimally-stressed, unanaesthetized fish, following catheterization of the urinogenital papilla. 2. The mean urine flow rate of freshwater lampreys was 200.7 ±14.3 ml kg−1 day−1. 3. Urine flow in freshwater lampreys was correlated with spontaneous changes in gill ventilation rate. MS222 anaesthesia reduced both ventilation and urine flow rates, but pronounced effects were only observed at concentrations greater than those needed to induce light anaesthesia (50–55 mg 1−1). Urine flow rate in unanaesthetized fish was extremely sensitive to rapid (6°Ch−1) changes in temperature and Q10 (6–16°C) was approximately 5. 4. Urine flow rate decreased rapidly as the osmotic difference between the body fluids and environment approached zero, and the rate of flow in 30% seawater lampreys was only 7.6% that of freshwater fish. 5. There was no evidence for an effect of environmental calcium concentration on branchial osmotic permeability. 6. Extensive tubular reabsorption of ions occurred in freshwater lampreys. The total daily excretion rate of sodium ions generally decreased in salinities hyperosmotic to the plasma, indicating enhanced reabsorption, but secretion of magnesium and sulphate ions was greatly increased. Urine osmolarity was significantly increased in lampreys in hyperosmotic salinities. 7. Present data compare favourably with data obtained previously from anaesthetized animals, indicating that renal function in lampreys is not significantly impaired by light MS222 anaesthesia.

Sign in / Sign up

Export Citation Format

Share Document