AN EVALUATION OF ISOTHERMS IN THE DESCRIPTION OF COMPETITIVE ADSORPTION EQUILIBRIA

Since adsorption isotherm equations are widely used in the industry to model adsorption on substances like activated carbon, an investigation was done to determine the applicability of three of these equations, viz, the multi-component Freundlich, multi-component Langmuir and the isotherm equation proposed by Fritz and Schluender. Based on statistical thermodynamic principles a discrete adsorption model was recently proposed. This model was used to create sets of binary adsorption data with some non-ideal characteristics. These data sets were used to evaluate the isotherm equations

It was found that the Langmuir isotherm gave the best fits, except where the visible adsorption energy changes with the surface loading or where selective adsorption occurs. Under these conditions, the Freundlich equation or that proposed by Fritz and Schluender should be used. It is recommended that these equations should be used to model low coverage-low concentration regions, while the high coverage-high concentration regions should be modelled using the Langmuir isotherm if possible

Some recommendations are made in connection with the procedure to estimate parameters for these isotherm equations.     

Treatment of male urethral strictures: is repeated dilation or internal urethrotomy useful?

PURPOSE: We evaluate the efficacy of repeated dilation or urethrotomy as treatment of male urethral strictures. MATERIALS AND METHODS: Between January 1991 and January 1994, 210 men with proved urethral strictures were prospectively randomized to undergo filiform dilation (106) or internal urethrotomy (104). Followup was scheduled at 3, 6, 9, 12, 24, 36 and 48 months. Dilation or internal urethrotomy was repeated at the first and second stricture recurrence. The Kaplan-Meier method was used to estimate survivor function for the treatment methods (survival time being the time to first stricture recurrence) and the log rank test was used to compare the efficacy of different treatments. RESULTS: Followup (mean 24 months, range 2 to 63) was available in 163 patients (78%). After a single dilation or urethrotomy not followed by re-stricturing at 3 months, the estimated stricture-free rate was 55 to 60% at 24 months and 50 to 60% at 48 months. After a second dilation or urethrotomy for stricture recurrence at 3 months the stricture-free rate was 30 to 50% at 24 months and 0 to 40% at 48 months. After a third dilation or urethrotomy for stricture recurrence at 3 and 6 months the stricture-free rate at 24 months was 0 (p <0.0001). CONCLUSIONS: Dilation and internal urethrotomy are useful in a select group (approximately 70% of all patients) who are stricture-free at 3 months, and of whom 50 to 60% will remain stricture-free up to 48 months. A second dilation or urethrotomy for early stricture recurrence (at 3 months) is of limited value in the short term (24 months) but of no value in the long term (48 months), whereas a third repeated dilation or urethrotomy is of no value.     

Biological dynamics and distribution of 3-hydroxy fatty acids in the yeast Dipodascopsis uninucleata as investigated by immunofluorescence microscopy. Evidence for a putative regulatory role in the sexual reproductive cycle

PURPOSE: This study investigated the pathologic characteristics and some related factors of cerebral damage associated with maxillofacial high-velocity missile wounds. MATERIALS AND METHODS: Sixty dogs, divided into two groups, were wounded randomly by steel spheres weighting 1.03 g at impact velocities of 1,400 m/s (46 dogs) and 800 m/s (14 dogs). Six dogs served as controls. The maxillofacial wounds and cerebral injuries were examined grossly. The distance between the center of wound and the base of skull and the largest diameter of the wound were measured, and the incidence of the brain injury in the two groups was compared. The cerebral specimens, dissected at 1 and 6 hours after trauma, were observed by light and electron microscopy. RESULTS: Cerebral hyperemia, contusion, spotty hemorrhage, and intracerebral hematoma were found in some of the dogs. In the 1,400 m/s velocity missile wound group, the incidence of the brain injury was 71.7% (33 of 46), and in the 800 m/s group it was 7.1% (1 of 14) on macroscopic examination. Microscopic observation showed intracerebral microhemotomas and degeneration and necrosis of the nervous cells. CONCLUSION: High-velocity projectile maxillofacial wounds can induce associated brain injury.     

Implantable catheter systems. Experiences with 1000 patients with central venous ports

OBJECTIVE: To assess retrospectively duration of functioning and rate of complications of a totally implantable venous access system used for long-term chemotherapy. PATIENTS AND METHODS: Between 1985 and 1993, a central venous access system (Port-a-Cath) had been implanted subcutaneously for long-term chemotherapy in 1000 patients (479 males, 521 females; mean age 49 [15-86] years). Follow-up observations lasted until the end of the chemotherapy or the removal of the system. RESULTS: Mean time of functioning of the catheter system was 284 (2-1563) days. The complication rate was 12.8%: catheter infection in 4.9% and catheter thrombosis in 3.2%. A further 4.7% of patients had less common complications (malfunction, catheter dislocation, skin necrosis, catheter break or disconnection, pneumothorax). A total of 119 (11.9%) systems had to be removed because of complications. The rates of infection and of other complications were significantly lower in patients with solid tumours (2 and 4%, respectively) than in those with haematological disease (6 and 8%) (P < 0.05 for each). CONCLUSION: Totally implantable venous access systems are suitable for long-term chemotherapy and cause few complications.     

Polygonum viviparum L. inhibits the lipopolysaccharide‐induced inflammatory response in RAW264.7 macrophages through haem oxygenase‐1 induction and activation of the Nrf2 pathway

BACKGROUND: Polygonum viviparum L. (PV) is a member of the family Polygonaceae and is widely distributed in high‐elevation areas. It is used as a folk remedy to treat inflammation‐related diseases. This study was focused on the anti‐inflammatory response of PV against lipopolysaccharide (LPS)‐induced inflammation in RAW264.7 macrophages. RESULTS: Treatment with PV did not cause cytotoxicity at 0–50 µg mL^?1 in RAW264.7 macrophages, and the IC₅₀ value was 270 µg mL^?1. PV inhibited LPS‐stimulated nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)‐1β and tumour necrosis factor (TNF)‐α release and inducible NO synthase (iNOS) and cyclooxygenase (COX)‐2 protein expression. In addition, PV suppressed the LPS‐induced p65 expression of nuclear factor (NF)‐κB, which is associated with the inhibition of IκB‐α degradation. These results suggest that, among mechanisms of the anti‐inflammatory response, PV inhibits the production of NO and these cytokines by down‐regulating iNOS and COX‐2 gene expression. Furthermore, PV can induce haem oxygenase (HO)‐1 protein expression through nuclear factor E2‐related factor 2 (Nrf2) activation. A specific inhibitor of HO‐1, zinc(II) protoporphyrin IX, inhibited the suppression of iNOS and COX‐2 expression by PV. CONCLUSION: These results suggest that PV possesses anti‐inflammatory actions in macrophages and works through a novel mechanism involving Nrf2 actions and HO‐1. Thus PV could be considered for application as a potential therapeutic approach for inflammation‐associated disorders. © 2012 Society of Chemical Industry     

Would repeated consumption of sports drinks with different acidulants lead to hedonic adjustment?

Repeated exposure to sports drinks with different acidulants added at equal sour concentrations led to hedonic adjustment when consumers (n = 128) evaluated a Lemon & Lime flavoured sports drink over a period of 14 days. Consumer preferences after repeated exposure could not have been predicted from the initial small sample single exposure consumer taste test. Product exposure and time on trial influenced the preferences of consumers. Products that were initially preferred became less preferred after 14 days. The findings of this study challenge the validity of sensory evaluation test strategies that rely on single exposure testing to predict long term consumer preferences.