Intestinal macromolecular transport supporting adaptive immunity

The gastrointestinal tract performs opposing functions of nutrient absorption, barrier maintenance, and the delivery of luminal substances for the appropriate induction of tolerogenic or protective adaptive immunity. The single-layer epithelium lining the gastrointestinal tract is central to each of these functions by facilitating the uptake and processing of nutrients, providing a physical and chemical barrier to potential pathogens, and delivering macromolecular substances to the immune system to initiate adaptive immune responses. Specific transport mechanisms allow nutrient uptake and the delivery of macromolecules to the immune system while maintaining the epithelial barrier. This review examines historical observations supporting macromolecular transport by the intestinal epithelium, recent insights into the transport of luminal macromolecules to promote adaptive immunity, and how this process is regulated to promote appropriate immune responses. Understanding how luminal macromolecules are delivered to the immune system and how this is regulated may provide insight into the pathophysiology of inflammatory diseases of the gastrointestinal tract and potential preventative or therapeutic strategies. Keywords: Antigen Transport, Mucosal Tolerance, Goblet Cell

Aggregate Shape and Skid Resistance

Natural sands and sands manufactured by crushing larger parent materials are characterized and service tested. Singular attributes are usually confounded with other variables in service tests. Dry-bulking tests and photomicrography are used to established qualities. High-stability porous mixtures are achieved in laboratory tests. Crushing some materials to coarse chip sizes leaves many smooth facets on particles that then tend to become oriented horizontally in the pavement surface. Open-graded friction courses and sprinkle treatments are included. Damage by winter freezing of porous courses is illustrated

Highway Pavement Maintenance Costs and Pavement Type Selection

A long-term analysis of pavement maintenance cost has been performed. The analysis does not include construction or resurfacing costs. The sample of pavement sections investigated were chosen to best represent the entire state. These sections were classified by pavement type; either bituminous concrete, portland cement concrete, or composite. The cost per lane mile (kilometer) per year was calculated for each pavement type by year and by age of pavement. Apparent differences in pavement maintenance costs between the two basic types of pavements were adjudged insignificant from the standpoint of determining pavement type. Because of poor or erroneous cost reporting, actual maintenance costs shown should be interpreted to be accurate in order of magnitude only

Electron Shock Waves with a Large Current Behind the Shock Front

The propagation of breakdown waves in a gas, which is primarily driven by electron gas pressure, is described by a one-dimensional, steady-state, three-component (electrons, ions, and neutral particles) fluid model. We consider the electron gas partial pressure to be much larger than that of the other species and the waves to have a shock front. Our set of equations consists of the equations of conservation of the flux of mass, momentum, and energy coupled with Poisson’s equation. This set of equations is referred to as the electron fluid dynamical equations. In this study we are considering breakdown waves propagating in the opposite direction of the electric field force on electrons (return stroke in lightning) and moving into a neutral medium. For Breakdown waves with a significant current behind the shock front, the set of electron fluid dynamical equations and also the boundary condition on electron temperature need to be modified. For a range of experimentally observed current values and also some larger current values which few experimentalists have been able to observe, we have been able to solve the set of electron fluid dynamical equations through the dynamical transition region of the wave. Some experimentalists have reported the existence of a relationship between return stroke lightning wave speed and current behind the shock front; however, some others are skeptical of the existence of such a relationship. Our solutions to the set of electron fluid dynamical equations within the dynamical transition region of the wave confirm the existence of such a relationship. We will present the method of solution of the set of electron fluid dynamical equations through the dynamical transition region of the wave and also the wave profile for electric field, electron velocity, electron temperature and electron number density, within the dynamical transition region of the wave

Resurfacing, Restoration, and Rehabilitation of Interstate Highways: Criteria and Logic Used to Determine January 3, 1977, Needs and Estimates of Costs

This report documents the method, criteria, and/or rules of thumb used for the January 3, 1977, submission to FHWA for Resurfacing, Restoration, and Rehabilitation of Kentucky interstate pavements. The period of time covered was 1977 through 1995 and the unit costs used were those for the year 1975

Development of a Thickness Design System for Portland Cement Concrete Pavements

This report covers the merger of criteria used in the Portland Cement Association\u27s and MSHTO\u27s pavement thickness design systems. The combined criteria is coupled with the principle of equal work as defined in classical physics to produce thickness design curves for portland cement concrete pavements. The thickness of portland cement concrete varied by approximately 0.15 inches for the same CBR and design EAL when the thickness of crushed-stone base varied from 3 to 6 inches. Therefore, the design thickness of the portland cement concrete is relatively insensitive to changes in thickness of the crushed stone base

Diagnostic yield of upper gastrointestinal endoscopy in patients attending a UK centre with symptoms compatible with Rome IV functional dyspepsia

Background: Dyspeptic symptoms are common and mainly due to functional dyspepsia (FD). The Rome IV criteria mandate a normal upper gastrointestinal (UGI) endoscopy before diagnosing FD. However, endoscopies are costly, resource-intensive procedures that generate substantial waste. Hence, simpler means of diagnosing FD are desirable. Objectives: To determine what proportion of UGI endoscopies are represented by patients with symptoms compatible with Rome IV FD, and the diagnostic yield in this cohort stratified according to alarm features. Methods: Adult patients attending a UK centre for outpatient UGI endoscopy completed a preprocedure questionnaire on demographics, medical history, alarm features, mood, somatisation and GI symptoms. Alarm features were defined as age ≥55 years, dysphagia, anaemia, unintentional weight loss, UGI bleed or a family history of UGI cancer. Clinically significant endoscopic findings were cancers, Barrett’s oesophagus, erosive oesophagitis, peptic ulcers or strictures. Results: Of 387 patients attending for an outpatient non-surveillance diagnostic UGI endoscopy, 221 had symptoms compatible with FD whereas 166 did not. Approximately 80% in both groups had alarm features, with a similar prevalence of clinically significant endoscopic findings at ~10%. UGI endoscopy was normal in a cohort of 9% (n=35) with symptoms compatible with FD and no alarm features, while benign peptic ulcer was noted in two of 29 cases without FD symptoms and no alarm features. Conclusion: 1-in-10 UGI endoscopies are performed in patients with symptoms compatible with FD and no alarm features, in whom there is no diagnostic yield. We recommend such patients receive a positive diagnosis of FD without endoscopy

Characteristics of long-duration inhibitory postsynaptic potentials in rat neocortical neurons in vitro

1. The characteristics of long-duration inhibitory postsynaptic potentials (l-IPSPs) which are evoked in rat frontal neocortical neurons by local electrical stimulation were investigated with intracellular recordings from anin vitro slice preparation. 2. Stimulation with suprathreshold intensities evoked l-IPSPs with typical durations of 600–900 msec at resting membrane potential. Conductance increases of 15–60% were measured at the peak amplitude of l-IPSPs (150–250 msec poststimulus). 3. The duration of the conductance increases during l-IPSPs displayed a significant voltage dependence, decreasing as the membrance potential was depolarized and increasing with hyperpolarization. 4. The reversal potential of l-IPSPs is significantly altered by reductions in the extracellular potassium concentration. Therefore it is concluded that l-IPSPs in rat neocortical neurons are generated by the activation of a potassium conductance. 5. l-IPSPs exhibit stimulation fatigue. Stimulation with a frequency of 1 Hz produces a complete fatigue of the conductance increases during l-IPSPs after approximately 20 consecutive stimuli. Recovery from this fatigue requires minutes. 6. l-IPSPs are not blocked by bicuculline but are blocked by baclofen

Noodles made from high amylose wheat flour attenuate postprandial glycaemia in healthy adults

Previous research has not considered the effect of high amylose wheat noodles on postprandial glycaemia. The aim of the study is to investigate the effect of consumption of high amylose noodles on postprandial glycaemia over 2-h periods by monitoring changes in blood glucose concentration and calculating the total area under the blood glucose concentration curve. Twelve healthy young adults were recruited to a repeated measure randomised, single-blinded crossover trial to compare the effect of consuming noodles (180 g) containing 15%, 20% and 45% amylose on postprandial glycaemia. Fasting blood glucose concentrations were taken via finger-prick blood samples. Postprandial blood glucose concentrations were taken at 15, 30, 45, 60, 90 and 120 min. Subjects consuming high amylose noodles made with flour containing 45% amylose had significantly lower blood glucose concentration at 15, 30 and 45 min (5.5 ± 0.11, 6.1 ± 0.11 and 5.6 ± 0.11 mmol/L; p = 0.01) compared to subjects consuming low amylose noodles with 15% amylose (5.8 ± 0.12, 6.6 ± 0.12 and 5.9 ± 0.12 mmol/L). The total area under the blood glucose concentration curve after consumption of high amylose noodles with 45% amylose was 640.4 ± 9.49 mmol/L/min, 3.4% lower than consumption of low amylose noodles with 15% amylose (662.9 ± 9.49 mmol/L/min), p = 0.021. Noodles made from high amylose wheat flour attenuate postprandial glycaemia in healthy young adults, as characterised by the significantly lower blood glucose concentration and a 3.4% reduction in glycaemic response