Effect of lipid excipients on in vitro pancreatic lipase activity

PURPOSE: To study the effects of two lipid excipients, Peceol and Gelucire 44/14 on the in vitro pancreatic lipase activity. METHODS: A 50 microL reaction mixture, consisting of 45 microL (3H) triolein as the radiolabeled substrate, 2.5 microL Peceol or Gelucire 44/14 (0.05-0.5%), either alone or in combination, 2.5 microL colipase (100 microg/mL), and 2.5 microL pancreatic lipase (1 mg/mL), was incubated for 10 min at room temperature. At the end of incubation, the reaction was stopped by the addition of an extraction solvent containing chloroform, methanol, and n-heptane (12.5:14:10), and the mixture vortexed briefly. Subsequently, 250 microL of 50 mM sodium carbonate was added and the aqueous and organic phase separated by centrifugation for 5 min at 1000 g. One hundred microliters of the supernatant was transferred to a scintillation counter and then radioactivity measured after the addition of 3.6 mL of scintillation fluid. Pancreatic lipase activity was determined by measuring the amount of free fatty acid released into the incubation medium and expressed as micromol free fatty acid released/min. RESULTS: When used alone, Peceol inhibited the pancreatic lipase activity significantly in a concentration-dependent manner, with a maximum inhibition of 57% at 0.4% of the excipient [p < 0.05, one-way analysis of variance (ANOVA)]. Similarly, Gelucire 44/14 alone caused inhibition of lipase activity in a concentration-dependent manner. However, the maximum inhibition (30%) was smaller in magnitude compared with the former agent. When the two excipients were used in combination, the inhibitory effects on the enzyme activity were similar to those observed with the individual agents (p < 0.05, one-way ANOVA). However, the maximum inhibition of 30% was lower than that observed with Peceol alone. CONCLUSIONS: The results from this study suggest that these lipid excipients inhibit in vitro pancreatic lipase activity and should be taken into consideration when developing oral formulations using these agents.     

Novel Optical Phase Demodulator Based on a Sampling Phase-Locked Loop

A novel phase-locked coherent demodulator, based on a sampling phase-locked loop, is presented and investigated theoretically. The demodulator is capable of operating at high frequencies, by using optical sampling to downconvert the high-frequency input radio-frequency signal to the frequency range of the baseband loop. We develop a detailed theoretical model of the (sampling) phase-locked coherent demodulator and perform detailed numerical simulations. The simulation results show that the operation of the sampling demodulator resembles the operation of the baseband demodulator for very short optical pulses (<2 ps). Furthermore, we investigate how the signal-to-noise ratio of the demodulator is affected by timing and amplitude jitter of the pulsed optical source     

Structure of CheA, a signal-transducing histidine kinase

BACKGROUND/AIMS: After liver transplantation for autoimmune hepatitis, the long-term results and the incidence of recurrence of primary disease are unknown. METHODS: In this retrospective study we reviewed the clinical course of 25 patients transplanted for autoimmune hepatitis and followed for a mean of 5.3 years (2-8.5 years). RESULTS: The actuarial 5-year patient and graft survival rates were 91% (+/-6%) and 83% (+/-8%). The actuarial 1-year rate of acute rejection was 50% (+/-10.2%), which was comparable to that of patients transplanted for primary biliary cirrhosis and primary sclerosing cholangitis. Autoantibodies persisted in 77% of patients, at a lower titer than before liver transplantation. Ten patients were excluded from the study of autoimmune hepatitis recurrence, one because of an early postoperative death and nine because of hepatitis C virus infection acquired before or after liver transplantation. In the remaining 15 patients, who were free of hepatitis C virus infection, 5-year patient and graft survivals were 100% and 87%, respectively. Despite triple immunosuppressive therapy, three patients (20%) developed chronic hepatitis with histological and serological features of autoimmune hepatitis in the absence of any other identifiable cause. The disease was severe in two patients, leading to graft failure and asymptomatic in another, despite marked histological abnormalities. In one of these three patients, autoimmune hepatitis recurred on the second liver graft as well. CONCLUSIONS: Patients undergoing liver transplantation for autoimmune hepatitis have an excellent survival rate although severe primary disease may recur, suggesting the need for stronger post-operative immunosuppressive therapy.     

Conflict detection during plan integration for multi-agent systems

This paper describes techniques developed for conflict detection during plan integration. Agents' intensions are represented with intended goal structure (IGS) and the E-PERT diagrams. Conflicts are classified as goal, plan, and belief conflicts. Before integrating individual plans and detecting plan conflicts, agents first detect and eliminate their goal conflicts by exchanging their IGS. Plan integration is done through merging individual E-PERT diagrams. Project estimation and review technique (PERT) diagrams have been used extensively in the systems analysis area since the 1980s to provide a global consistent view of parallel activities within a project. We extended the PERT diagrams for use in the plan integration activity within multi-agent systems (MAS). The E-PERT diagram contributes to maintain traceable temporal relations among agents' local scheduled actions. Combined with pattern matching, plan conflicts due to resource sharing, or conflicting conditions (i.e., postconditions of one action disabling preconditions of another action) can be detected. The conflict detection techniques are implemented in a sensible agent testbed to promote deployment and performance analysis.     

A variational finite-difference method for analyzing channel waveguides with arbitrary index profiles

A variational, finite-difference method for computing the normalized propagation constants and the normalized field profiles of channel waveguides with arbitrary index profiles as well as aspect ratios is presented. Mode dispersion curves and the field profiles of the fundamental mode of channel waveguides having profiles of practical interest are included.     

Dielectric properties of Indian Basmati rice flour slurry

Dielectric properties of Indian Basmati rice samples (dry ground flour and wet aqueous slurry) were measured over the frequency range 500–2500 MHz. Temperature dependence of dielectric properties of rice flour slurries (20, 30 and 50 g flour per 100 g water yielding approximately 1:5, 1:3 and 1:2 flour to water ratio) were studied between 30 and 80 °C. Results indicated that dielectric constants (ε′) generally did not vary with frequency while the loss factor (ε″) showed an increasing trend. A sharp change in dielectric parameters were noted above 70 °C attributable to rice starch gelatinization, an observation confirmed later by differential scanning calorimetry. An increase in flour slurry concentration systematically reduced ε′ during the entire frequency range while variations in ε″ values were mixed. Addition of 1% salt markedly increased ε″ of slurries whereas butter resulted in significant reduction in ε′ values. Rice flour slurry containing both salt and butter exhibited intermediate values of dielectric properties. Both ε′ and ε″ data of rice slurries generally fitted a 2nd order polynomial relationship with temperature. These results suggest that dielectric measurements could be used to study frequency, concentration, ingredient and temperature dependent changes in starch–water systems during heating.     

Modelling of cooking-cooling processes for meat and poultry products

Traditional cooking‐cooling of processed meat and poultry products is industrially carried out in smokehouses or autoclaves. A mathematical model was developed to simulate these operations. Equations, describing heat transfer and thermal destruction of micro‐organisms and quality characteristics, were solved numerically. The model was validated experimentally for heat transfer and energy consumption and was used to perform a sensitivity analysis. Input variables were: process time (PT), smokehouse temperature (T_SH), bologna size (diameter, D and height, H), surface heat transfer coefficients (h_heat and h_cool), product thermal diffusivity (α_heat and α_cool). Output variables were: product core temperature (T_c), core and volume‐average lethality (P_cm and P_vm) and cook (C_c and C_v) values as well as surface (Q_s) and volume‐average (Q_v) quality retention, total specific energy consumption (En) and energy efficiency (Ce). Multiple linear regression models were developed to predict C_c and C_v from five inputs and used to obtain acceptable deviation ranges.