Assessment of the energy dissipation parameters inside the draft tube of a liquid spout-fluid bed

Spouted beds are fluid-particle contactors in which the fluid is introduced centrally through a nozzle instead of a distributor plate, resulting in a regular particle circulation pattern. To assess the suitability of such sytems to environmental engineering applications such as filter backwashing and biofilm systems, a priori knowledge of the energy dissipation parameters is essential. A new model is developed for evaluating the energy dissipation parameters inside the draft tube of spout-fluid beds. The shear stress, velocity gradient, and turbulence fluctuation parameters in the draft tube of a liquid spout-fluid bed are calculated with the help of an energy equation for flows carrying suspensions and the experimentally determined pressure losses inside the draft tube and compared with results for particulately fluidized beds. A spout-fluid bed with a draft tube provides higher shear stress inside the draft tube than a fluidized bed. The mean velocity gradient in the draft tube is comparable to and higher than in a fluidized bed and increases with solids fraction. The turbulence dissipation coefficient decreases very slightlywith increasing solids fraction for both systems. Consequently, according to the model calculations, a spout-fluid bed with a draft tube can be an alternative to the classical fluidized bed filter backwashing system.

Modification of organo-zeolite surface for the removal of reactive azo dyes in fixed-bed reactors

Modification of zeolite (clinoptilolite) surface with a quaternary amine, hexadecyl trimethyl ammonium bromide (HTAB), to improve the removal efficiency of reactive azo dyes in a zeolite fixed bed was investigated. A series of adsorption tests were conducted to find out the uptake of three types of reactive dyes, i.e. CI Reactive Black 5, Red 239 and Yellow 176. Each run consisted of modifying zeolite with HTAB in the column followed by removal of color from the modified zeolite bed. The breakthrough curves for modification process were constructed under different conditions by plotting the normalized effluent concentration (C/C(0)) versus time or bed volumes (BV). Optimization studies show that 3g/l of HTAB dosage at a flowrate of 0.025l/min showed the best performance. Examination of the dye removal under the optimum modification conditions reveals that the black dye gives the highest breakthrough point among the three dyes tested. This is ascribed to the hydrophobic/hydrophilic match of the zeolite surface with the dye molecule, which depends upon the way zeolite is modified with HTAB. Calculations of the HTAB coverage on zeolite surface indicate that a bilayer formation is the most viable packing that enables maximum removal of the dye.

Do vascular endothelial growth factor and basic fibroblast growth factor promote phenytoin's wound healing effect in rat? An immunohistochemical and histopathologic study

BACKGROUND

This study was designed to determine the possible correlation between phenytoin and vascular endothelial growth factor and basic fibroblast growth factor in the wound healing process.

METHODS

Sixty Wistar albino rats were divided into four groups, each containing 15 animals. The experimental groups received a daily phenytoin treatment (10 mg) for 3 or 7 days following 3-cm dorsal skin incisions on the midline; the control group incisions were treated with 0.5 mL of saline solution during the same time periods. After completion of treatments, all animals were killed, and skin tissue samples were obtained.

RESULTS

Histopathologic examination of all groups revealed that there were significantly increased (p<0.05) amounts of fibroblasts, collagen deposition, and blood vessels in the phenytoin-treated groups when compared to the control groups. Although immunolocalization of vascular endothelial growth factor and basic fibroblast growth factor was weak in the 3-day phenytoin treatment groups, they were strongly expressed in the 7-day treatment group when compared to the control groups.

CONCLUSION

The findings of this study demonstrate that the tissue alterations of the wound healing process could be accelerated by phenytoin and the potential local pathways of vascular endothelial growth factor and basic fibroblast growth factor.

Different ELR (+) angiogenic CXC chemokine profiles in synovial fluid of patients with Behçet's disease, familial Mediterranean fever, rheumatoid arthritis, and osteoarthritis

The aim of the present study was to determine synovial levels of ELR (+) CXC chemokines, known to attract mainly neutrophils to inflamed tissues by binding the neutrophil chemokine receptors CXCR1 and CXCR2 and promoting neovascularization in patients with various inflammatory disorders. The study group consisted of 14 patients with Behçet's disease and nine with familial Mediterranean fever. Fourteen patients with rheumatoid arthritis and 16 with osteoarthritis served as controls. Synovial chemokine levels were measured by two-step sandwich enzyme-linked immunosorbent assay, and significant differences were found in the various chemokines studied. In addition to its angiogenic properties, increased synovial levels of interleukin-8 by attraction of more neutrophils to synovial fluids might also be responsible for the acute synovitis in patients with Behçet's disease. However, the absence of chronic changes with the eventual development of pannus and erosions might result from relatively lower expression of interleukin-8 and the transient, short-lived nature of the arthritis observed in these patients.

The importance of A3 allele in response to hepatitis B vaccine in end-stage renal disease patients

BACKGROUND

Hemodialysis (HD) patients are at high risk for hepatitis B virus (HBV) infection due to intravenous interventions and therapies: Our aim was to examine how genetic factors affect the response to HBV vaccination in HD patients.

METHODS

The frequencies of HLA class I and II alleles were investigated in responders and nonresponders. Response to vaccination was defined as anti-HBsAg > 10 SI U/L (group I). Nonresponders (anti-HBsAg < 10 SI U/L) were defined as group II. The study included HD patients who were negative for antibodies to hepatitis B surface antigen during pretransplantation evaluation.

RESULTS

Group I consisting of 166 patients and group II, of 90 patients showed a significantly higher frequency of the HLA A3 allele in group I (n = 20) than group II (n = 3) (P = .02). There were no statistical differences between the two groups regarding age and gender distribution (P > .05). Graft outcome was not different between responders and nonresponders (P > .05).

CONCLUSIONS

This preliminary study shows that HLA alleles may have immunomodulatory effects in end-stage renal failure patients. The response to hepatitis B vaccination is affected in multifactorially fashion; HLA A3 may be a genetic predictor for responders, but further studies in larger series are required.

Pneumatosis cystoides intestinalis : report of two cases

We present two cases of Pneumatosis Cystoides Intestinalis (PCI) involving the small intestine: emergency operations was mandatory. At surgery, the affected ileal segments were resected. After surgery, clinical courses were uneventful. PCI is a sign, not a disease, and therefore its significance is directly related to the patient's overall clinical status. Treatment is not indicated in asymptomatic patients, whereas immediate surgical intervention is necessary in patients with abdominal catastrophes.

Isolated hepatic tuberculous pseudometastasis co-existent with adenocarcinoma of the stomach; report of a case

A 10 x 9 mm metastasis-like lesion in segment V of the liver was detected, when a 70-year-old man was operated on for adenocarcinoma of the stomach. Since exact diagnosis of the hepatic lesion could not be made by frozen sections, the lesion was excised, considering it to be a metastasis of gastric adenocarcinoma. Bacteriologic and pathologic studies established a diagnosis of isolated tuberculosis of the liver. A good response to antituberculous drug therapy was noted.

Startup of an anaerobic fluidized bed reactor for landfill leachate treatment

Anaerobic treatment of the young landfill leachate in a pilot-scale fluidized bed reactor was performed to observe the effects of startup on COD removal, biogas production and biomass attachment. During the experiments, the organic loading rate (OLR) was increased gradually from 2.5 to 27 g COD l(-1) day(-1) with varying the feed rate and the hydraulic retention time in the range of 5.5-13 1 day(-1) and 1-2.35 days, respectively. The anaerobic fluidized bed reactor (AFBR) showed an excellent performance and attained steady state conditions with COD removal of 90% after 80 days. Biogas production in the reactor continuously increased and its average yield (Y(gas)) was defined as 0.531 biogas g(-1) COD(rem)(-1) with a correlation of 99%. Greater microbial attachment was found at the increased loading rates and the attached biomass concentration (X(attach)) consisted of about 90% of the total biomass concentration. In addition, the substrate utilization rate indicated a linear increase as a function of time during the process.

A functioning-desensitization paraganglioma which caused hemodynamic instability during tumoral resection: report of a case

Paragangliomas are uncommon tumors arising from the neuroendocrine elements of the paraganglia. Their successful management is associated with many problems. We herein present the findings of a 22-year-old man in whom a paraganglioma was incidentally found and in which the clinical and previous operative behavior was functioning desensitization. As a result, preoperative medication was not performed; however, during the tumor resection the patient demonstrated hemodynamic instability.

Peripancreatic tuberculous lymphadenitis mimicking carcinoma: report of a case

Peripancreatic tuberculous lymphadenitis is a rare clinical entity and it usually raises serious diagnostic problems. We report a case of a solitary abdominal tuberculoma. A 45-year old woman was admitted to hospital with obstructive jaundice. An exploratory laparotomy was performed. A conglomerated mass, penetrating into the pancreas was found. Since exact diagnosis could not be obtained by peroperative frozen sections, standard Whipple procedure, segmental portal vein resection and reconstruction with autogenous saphenous vein were performed. Histopathological examination of the resected specimen revealed tuberculous lymphadenitis. The patient was given an anti-tuberculous treatment and a good response was noted. Abdominal tuberculoma is often mistaken for a malignant neoplasm and a high grade of suspicion is neccessary in order to make the exact diagnosis and optimal medical treatment of this entity.

Effect of nifedipine on the healing of left colonic anastomoses in rats

PURPOSE

Ca(2+) channel blockers inhibit collagenase production and have a vasodilatatory effect. They also restrict the formation of ischemia-reperfusion induced free oxygen radicals. The aim of this study was to assess the effect of nifedipine on the healing of colonic anastomoses in a rat model.

METHODS

Sixty Wistar rats weighing 240-290 g were divided into four groups of 15 rats each: a 3rd day control group (group A), a 3rd day treatment group (group B), a 7th day control group (group C), and a 7th day treatment group (group D). The treatment groups were given Nifedipine 3 mg/kg per day orally as three divided doses.

RESULTS

The bursting pressure values of the anastomoses in the treatment groups were significantly higher than those in the control groups ( P < 0.05). The hydroxyproline content was also significantly higher in the treatment groups than in the control groups ( P < 0.05). Histologic examination confirmed that nifedipine treatment significantly increased collagen deposition and fibroblast ingrowth compared with controls ( P < 0.05).

CONCLUSIONS

These results clearly showed that nifedipine enhanced the stability of colonic anastomoses during the first postoperative week.

Positive effects of phenytoin on experimental colonic anastomoses

BACKGROUND AND AIMS

Anastomotic dehiscence following colorectal surgery is a significant cause of morbidity and mortality. Phenytoin has wound-healing promoting and collagenase inhibitory effects. This study assessed these effects on healing of experimental colonic anastomoses in a rat model.

MATERIALS AND METHODS

Ninety Wistar rats weighing 240-290 g were divided into six groups: 3rd-day control group (n=15), 3rd-day oral administration of phenytoin (n=15), 3rd-day rectal administration of phenytoin (n=15), 7th-day control group (n=15), 7th-day oral administration of phenytoin (n=15), and 7th-day rectal administration of phenytoin (n=15). In oral phenytoin groups the agent was given at 10 mg/kg daily per orogastric route by 4-F fine feeding catheter; in rectal phenytoin RAP groups the agent was administered at 10 mg/0.5 cc daily to the anastomoses transrectally via a fine anal catheter.

RESULTS

There were significantly higher anastomosis bursting pressure values and hydroxyproline contents in phenytoin groups than in controls. In histopathological examination it was seen that phenytoin treatment caused greater collagen deposition, fibroblast, and blood vessel ingrowth than in controls. Immunohistochemical analysis showed the stimulatory effect of phenytoin in expression of vascular endothelial growth factor and basic fibroblast growth factor. Anastomosis bursting pressure, histopathological analysis, hydroxyproline content, and immunohistochemical results were better in the groups with rectal administration than in those with oral administration.

CONCLUSION

These results had showed us that phenytoin administration resulted in enhanced stability of colonic anastomoses during the first postoperative week and rectal administration showed better results than oral administration.

Our sigmoid colon volvulus experience and benefits of colonoscope in detortion process

BACKGROUND/AIMS

The sigmoid colon is the most frequent site for a volvulus. In this report, we review our experience with sigmoid colon volvulus.

METHODOLOGY

We present our experience of 81 cases of sigmoid volvulus admitted to our department.

RESULTS

Preoperative endoscopic volvulus detortion was attempted in all patients, and in 39 of them the procedure was successful. The success rate of endoscopic detortion for sigmoid colon volvulus with a flexible colonoscope (60%) was higher than with a rigid rectosigmoidoscope (42%). In 19 of these 39 non-operatively devolvulated patients, sigmoid resection with primary anastomosis was performed within 7-10 days after reduction, but 20 patients did not accept the elective operation after a non-operative treatment. Among the 61 patients undergoing urgent or elective operation for sigmoid volvulus, there were 17 laparotomies with only detortion, 19 resections with elective anastomosis, 6 resections with primary anastomosis, and 19 resections with a Hartmann's pouch. There were 9 deaths (21%) among 42 patients who underwent an emergency operation, and one (5.2%) among the 19 patients who had elective surgery died because of a cerebral embolus.

CONCLUSIONS

Initial therapy with endoscopy affords decompression and an adequate preparation of patients for surgical resection, and a flexible colonoscope has notable advantages over rigid instruments for the detortion process.

Mesoporous mineral columns for color removal from aqueous solutions

The removal efficiency of natural minerals (e.g., zeolite and sepiolite) from aqueous solutions of azo dyes was investigated. The adsorption of three types of reactive dyes, Black, Red, and Yellow dissolved in distilled and/or deionized water on zeolite and sepiolite have been performed using column adsorption experiments. Distilled water containing 50 mg/L dyestuff was used to identify the ability of natural mesoporous minerals and their modified forms. The adsorption results indicate that both natural sepiolite and zeolite have limited adsorption capacities of the reactive dyes but are substantially improved upon modifying their surfaces with quaternary amines (HTAB). The removal of Yellow dye showed an excellent performance in sepiolite column compared to that in zeolite column.

Skin test positivity to aeroallergens in the patients with chronic urticaria without allergic respiratory disease

The etiology of chronic urticaria and angioedema remains uncertain in most of the patients. There are several agents and factors including medications, foods and food additives, infections, contactants, inhalants, physical factors and autoimmunity that implicated in provoking urticaria symptoms. In addition, the possible role of house dust mites has been considered in a few reports. We investigated skin test positivity to house dust mites and other inhalants in 259 patients with chronic idiopathic urticaria and angioedema but without allergic rhinitis and/or asthma. Results were compared with both 300 healthy controls and 300 atopic patients. Immediate cutaneous reactivity to one or more allergens was detected in 71 patients in the study group (27.4%). The most common allergens were house dust mites (24.7%). Skin prick test sensitivity to other inhalant allergens including pollens, molds and cockroach were 7.7%, 0.4% and 0.8%, respectively. In the healthy control group 7% of patients were found as atopic with respect to skin prick test results. The most common allergens in healthy controls were pollens (6%), and house dust mites (4.7%). In atopic control group, pollens and mites are also the most common allergens detected in skin prick test (62% and 50.3%, respectively). The difference between study and healthy control group was statistically significant with respect to presence of atopy and mite sensitivity (p < 0.001). Similar differences were not established in other inhalant allergens. Significant mite sensitivity in the study group is not a coincidence. Because, ratio of skin test positivity to house dust mites in the study group was higher than the healthy controls, but was not as high as atopic patients. Furthermore, the rate of skin reactivity to other aeroallergens was not different from healthy controls. Urticaria as a sole clinical manifestation in mite sensitive patients was unusual.

Anaerobic fluidized bed reactor for the treatment of landfill leachates

Treatability of the sanitary young landfill leachate in a pilot-scale anaerobic fluidized bed reactor during reactor startup and steady-state phases was investigated. All runs were carried out at 35 degrees C due to environmental conditions in the mesophilic anaerobic fluidized bed reactor (AFBR) while organic loading rate (OLR) was increased from 2.5 to 37gCOD/L-day during the 220 days of operation. The AFBR process attained steady-state conditions about on day 80 and a good and stable COD removal were achieved at about 90%. Biogas production in the bed continuously increased during the process. The mean specific biogas production was found 0.52 L biogas/gCODrem while the methane content was about 75%. The attached biomass concentration, measured as volatile solids rapidly increased as containing about 90% of the total biomass concentration. Furthermore, an increase in the suspended solid concentration was found as an evidence of biomass detachment from the media.

Color removal of reactive dyes from water by clinoptilolite

The adsorption of reactive dyes on Gordes (Turkey) clinoptilolite was investigated by a series of batch and column adsorption experiments. Three reactive dyes (Everzol Black, Everzol Red, Everzol Yellow) were used in laboratory studies. Synthetic wastewaters were used and the ability of natural zeolite (clinoptilolite) and their modified form were examined. The adsorption results, in batch and column reactor, indicate that natural zeolite have limited adsorption capacities of the reactive dyes but are substantially improved upon modifying their surfaces with quaternary amines (HTAB). The degree of hydrophilicity is found to play an important role in the uptake of reactive dyes.

Comparison of different thyroidectomy techniques for benign thyroid disease

Extent of thyroidectomy in the management of benign thyroid disease remains controversial. In this clinical study, three different thyroidectomy techniques were compared by means of the complication, short period recurrence and L-thyroxin requirement rates. Two hundred consecutive patients who had bilateral subtotal thyroidectomy (BST) (n = 71), unilateral total lobectomy + contralateral subtotal lobectomy (Dunhill Procedure (DP)) (n = 71), or total thyroidectomy (TT) (n = 58) for benign thyroid disorders were included in this study. One patient was re-operated due to bleeding in BST group. Wound infection was observed in 1 patient both in BST and DP group and 2 patients in TT group. Temporary hypocalcaemia was seen in 14 (19.7%) of BST group, in 19 (26.7%) of DP group, and in 14 (24.1%) patients of TT group (p>0.05). Transient recurrent laryngeal nerve palsy developed in 1 patient both in DP and TT group. One patient of DP group had secondary thyroidectomy due to postoperative diagnosis of papillary carcinoma. There was no significant difference in the mean durations of hospitalization between the groups. Mean postoperative follow-up periods were 27.7 months (6-56), 34.8 months (8-55), 26.5 months (6-54) in BST, DP and TT groups, respectively. While all patients were administered L-thyroxin in TT group, 26 (36.6%) patients in DP group and 34 (47.8%) patients in BST group needed no L-thyroxin supplementation and L-thyroxin requirement rates were not different in either group. We think that total thyroidectomy should be adopted for benign thyroidal diseases, because its complications are no different than those for BST and DP. If individual factors and patient's preference are not in favor of lifelong L-thyroxin supplementation, however, DP may be carried out for benign thyroidal diseases instead of BST.

Changes in immunological recovery in patients who received post-transplant G-CSF or GM-CSF after autologous peripheral blood stem cell transplantation (PBSCT)

In this prospective study, the effects of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on immunological reconstitution after autologous peripheral blood stem cell transplantation (PBSCT) were investigated for 6 months. Thirty-five patients received G-CSF 5 microg/kg per day and 26 patients received GM-CSF SC 5 microg/kg per day from day 1 to leukocyte engraftment (>1000 per mm3). Peripheral blood samples were obtained on 14, 28, 100, and 180 days after transplantation for immunological evaluation. CD3+, CD4+, CD8+, CD19+, and CD56+ cells were analysed by flow cytometry. Immunoglobulin levels (IgG, IgA, and IgM) and complement levels (C3c and C4) were measured by nephelometry. Both G-CSF and GM-CSF groups were comparable with respect to age, sex, the period from diagnosis to transplantation, total nucleated cells infused, the number of CD34+ cells, conditioning regimens (TBI and non-TBI), and post-transplant infection. CD3+ and CD8+ cells on day 14 following autologous PBSCT + G-CSF were significantly higher than following autologous PBSCT + GM-CSF (p = 0.008 and p = 0.021, respectively). The number of CD4 cells and the CD4/CD8 ratio were not different at several time points between the two groups. CD19+, CD56+ cells and immunoglobulin levels showed a faster recovery pattern in the autologous PBSCT + G-CSF group. The effect of G-CSF on immune reconstitution after autologous PBSCT is more prominent than that of GM-CSF. The possible role of haematopoietic growth factor on immune recovery and its clinical importance should be investigated in further studies.