Slow Feeding Research Articles

Effects of Nipple Feeding and 2 Different Methods of Gavage Feeding on Oxygenation in Preterm Infants 196

Objective: To determine the effect of nipple feeding and 2 methods of gavage feeding, on apnea, bradycardia and desaturation frequency. Patients: 30 preterm infants breathing room air; GA 28.6±2.1 wk at birth and 34.0±1.4 wk at study. Methods: 9 h recordings of pulse oximeter saturation (SpO2), pulse waveforms, ECG, breathing movements and nasal airflow. Administration of 21±1.5 ml/kg of milk in 3 h intervals using 3 different feeding techniques in random order: nipple feeding, bolus gavage feeding, and slow gavage feeding (1 h). Analysis of recordings for apneas (>4 s), bradycardias (heart rate <2/3 of baseline), and episodic desaturation (SpO2 ≤80%).Results: There were 3 times more desaturations with nipple feeding than with bolus gavage feeding (p<0.001), but no further reduction with slow gavage feeding. With all 3 feeding techniques, there were significantly more desaturations during the hour the feedings were given than during the following 2 hours. The deleterious effects of nipple feeding became most evident during the hour of feeding, but desaturation frequency still remained significantly higher than with gavage feeding during the following 2 hours. There was no significant effect of feeding technique on the frequency of apnea or bradycardia. Conclusions: Preterm infants who are normally oxygenated in room air may have significant desaturation during nipple feeding. The latter can be effectively reduced by gavage feeding. Slow gavage feeding offers no advantage over bolus gavage feeding.

Selective Removal of Hydrpphobic Peptides from Protein Hydrolysates in a Continuous Supported Liquid Membrane Process

Abstract The removal of hydrophobic peptides from a casein hydrolysate solution through a supported liquid membrane (SLM) was investigated in a continuous flow system. The liquid membrane was formulated with an anionic surfactant (Aerosol OT) as the carrier and oleyl alcohol as the organic phase on a Celgard 2500 as support. A mixture of amino acid (tryptophan) and dipeptide (tryptophan-leucine) was examined to determine the pH at which the transport of peptide is preferentially faster than that of the amino acid. At this feed pH the effects of the following variables were examined: hydrolysate concentration, feed and strip phase flow rate, and carrier concentration in membrane preparation. The stability of SLM for long-term continuous operation was studied, and the regeneration of SLM was tried for repeated use. It was demonstrated that the following conditions are favourable for the selective removal of peptides: 1) a feed solution pH of 4.5, 2) a dilute feed concentration (<20 g/L), 3) slower feed and ...

Infant and Toddler Feeding Patterns and Problems

To fill information gaps, predominantly non-Hispanic white parents in five Chicago-area pediatric offices were surveyed concerning infant (n = 130) and toddler (n = 151) feeding times and behaviors. Feeding time distributions did not differ by age. Percentiles (in minutes) were: 10th, 9.4; 50th, 17.7; and 90th, 29.3. The most common infant problematic feeding behavior (PFB) was "not always hungry at mealtime" (33%). Toddler PFB included "not always hungry at mealtime" (52%), "trying to end meals after a few bites" (42%), "picky eating" (35%), and strong food preferences (33%). Toddler picky eaters ate more slowly (means 23.3 vs 19.7 minutes, p < .04). Toddlers with recalled PFB at 6 and 12 months ate most slowly (mean 37.5 minutes). We conclude that: (1) infants and toddlers who take >30 minutes to feed are slow feeders; (2) reports of behavioral feeding problems are common in toddlers and are related to slow feeding; (3) and these data can guide clinical care and future studies.

Whole body withdrawal circuit and its involvement in the behavioral hierarchy of the mollusk Clione limacina

1. The behavioral repertoire of the holoplanktonic pteropod mollusk Clione limacina includes a few well-defined behaviors organized in a priority sequence. Whole body withdrawal takes precedence over slow swimming behavior, whereas feeding behavior is dominant over withdrawal. In this study a group of neurons is described in the pleural ganglia, which controls whole body withdrawal behavior in Clione. Each pleural withdrawal (Pl-W) neuron has a high threshold for spike generation and is capable of inducing whole body withdrawal in a semi-intact preparation: retraction of the body-tail, wings, and head. Each Pl-W neuron projects axons into the main central nerves and innervates all major regions of the body. 2. Stimulation of Pl-W neurons produces inhibitory inputs to swim motor neurons that terminate swimming activity in the preparation. In turn, Pl-W neurons receive inhibitory inputs from the cerebral neurons involved in the control of feeding behavior in Clione, neurons underlying extrusion of specialized prey capture appendages. Thus it appears that specific inhibitory connections between motor centers can explain the dominance of withdrawal behavior over slow swimming and feeding over withdrawal in Clione.

The Development of Validated Standards of Nutrition Care for Patients Post-Percutaneous Endoscopic Gastrostomy Placement: An Interdisciplinary Approach

Forty-eight patients referred for percutaneous endoscopic gastrostomy (PEG) tube placement from April 1, 1994 to March 15, 1995 underwent successful PEG placement. Nutrition classification, nutritional status, weight, electrolytes, albumin and total lymphocyte counts were assessed pre-procedure. Twenty-six patients were randomized to a fast feeding protocol with advancement of feedings every 8 hours to full feedings (100ml/hr of isotonic formula) over 24 hours. Twenty-two patients were randomized to a slow feeding protocol with advancement of feedings every 24 hours to full feedings over 72 hours. Both protocols used pre-printed orders that were developed by an interdisciplinary team of dietitians, physicians and nurses. The patients were evaluated daily by the PEG assessment team and residuals were monitored.Reasons for obtaining a PEG were poor oral intake (66%), risk of aspiration (27%) and dysphagia (8%). The twenty-four swallowing studies performed were all abnormal. Only 29 of the patients had been on tube feedings prior to PEG placement with 50% on chronic tube feedings.Nutrition classification in our patients were marasmus (21%), hypoalbuminemia (25%) and combination state malnutrition (19%). Nutritional status in our patients were mild compromise (4%), moderate compromise (65%) and severe compromise (31%). Twenty-five percent of patients were less than 80% ideal body weight, 42% had an albumin less than 2.7gm/dl and 52% had an abnormal lymphocyte count as defined to be less than or equal to 1200.All but one patient were able to be advanced to full feedings. Nursing compliance with the orders was 92%. There was no significant difference in residuals, compliance or the very few complications between the fast and slow feeding groups. Thirty patients were tried on bolus feedings with 90% success and the average time to bolus feedings was three days.We have shown that an interdisciplinary approach can produce a protocol which are clear, comprehensive and allow rapid advancement of feeding in the post-PEG period.

Effects of Feed Allocation on Female Broiler Breeders

The objective of this study was to determine if feed allotment during rearing had an impact on the reproductive performance of cage-housed broiler breeders. Broiler breeder pullets were reared on one of three feed allocation programs to result in divergent body weight curves from 1 to 24 wk of age. All three feed allocation regimens were within the range of commercial practice. The treatments included 1) a conventional, relatively linear growth curve (Standard), 2) and “Early Slow” program characterized by slow growth rates during the early rearing period followed by a more generous feed allocation after 19 wk, and 3) an “Early Fast” program with body weights above normal early in rearing, followed by more conservative body weight gains late in rearing. The Early Slow feed allocation program resulted in fewer settable eggs and hatched chicks than the Standard and Early Fast programs. There was a tendency for birds reared on the Early Slow program to commence lay with reduced carcass protein levels.

Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions. Part II. Effect of mating on feeding and fecundity of females.

The effect of mating on the feeding and fecundity of Ixodes (Pholeoixodes) hexagonus females was studied under controlled laboratory conditions of 22-23 degrees C and 98% relative humidity. The feeding period of mated females was 6-15 days and 11-13 days for unmated females. The mean weight of the engorged mated females was 114.84 +/- 45.89 mg, whereas, that of the engorged unmated females was significantly lower (80.61 +/- 28.84 mg). During the initial slow feeding period, the weight of mated females increased 6.6 times. At the end of the blood feeding, they had increased their initial weight 35.5 times. Unmated females never entered the rapid engorgement phase and up to 12 days of feeding period their mean weight did not increase more than 9.2 times. The pre-oviposition periods of mated and unmated females were 6-15 days and 4-12 days, respectively. The mean of the egg production efficiency was 40.26 +/- 12.47% for mated females and 35.68 +/- 12.2% for unmated females. The mean of the mass conversion efficiency was 73.6 +/- 13.7% for mated females and 66.48 +/- 16.55% for unmated females. Sixty per cent of the eggs deposited by mated females hatched whereas only 1% of the eggs deposited by unmated females hatched. These results indicate that I. hexagonus females possess some predisposition for parthenogenesis and only fertility and not fecundity depends on mating.

Fed-batch fermentation of xylose by a fast-growing mutant of xylose-assimilating recombinant Saccharomyces cerevisiae

Mutants of xylose-assimilating recombinant Saccharomyces cerevisiae carrying the xylose reductase and xylitol dehydrogenase genes on plasmid pEXGD8 were selected, after ethyl methanesulfonate treatment, for their rapid growth on xylose medium. The fastest growing strain (strain IM2) showed a lower activity of xylose reductase but a higher ratio of xylitol dehydrogenase to xylose reductase activities than the parent strain, as well as high xylulokinase activity. Southern hybridization of the chromosomal DNA indicated that plasmid pEXGD8 was integrated into the chromosome of mutant IM2, resulting in an increase in the stability of the cloned genes. In batch fermentation under O2 limitation, the yield and production rate of ethanol were improved 1.6 and 2.7 times, respectively, compared to the parent strain. In fed-batch culture with slow feeding of xylose and appropriate O2 supply at a low level, xylitol excreted from the cells was limited and the ethanol yield increased 1.5 times over that in the batch culture, with a high initial concentration of xylose, although the production rate was reduced. The results suggested that slow conversion of xylose to xylitol led to a lower level of intracellular xylitol, resulting in less excretion of xylitol, and an increase in the ethanol yield. It was also observed that the oxidation of xylitol was strongly affected by the O2 supply.

Microstructures in hot wire laser beam welding of HY 80 steel

AbstractLaser beam welding of 13 mm plates of HY 80 steel resulted in different microstructures in the fusion zone depending on the welding process. Autogenous welds resulted in an untempered martensitic structure, whereas, with the introduction of a hot wire filler metal, the microstructures depended on the wire feed. A slow feed resulted in a mixed martensite–bainite microstructure and a fast wire feed resulted in a microstructure that is primarily acicular ferrite. The chemistry of the as deposited weld metals was different in each case. The thermal profiles for the autogenous weldment were calculated based on a two parameter model of laser welding that utilises the fusion zone boundary as a measure of ‘best fit’. Based on the cooling rate of the autogenous fusion zone, cooling rates for the two welds with hot wire filler metal were rationalised. Using these cooling rates, the chemistry of the weld metal and a model of microstructural development of the weld metal, a computer calculation was made which...

Microstructures in hot wire laser beam welding of HY 80 steel

Laser beam welding of 13 mm plates of HY 80 steel resulted in different microstructures in the fusion zone depending on the welding process. Autogenous welds resulted in an untempered martensitic structure, whereas, with the introduction of a hot wire filler metal, the microstructures depended on the wire feed. A slow feed resulted in a mixed martensite–bainite microstructure and a fast wire feed resulted in a microstructure that is primarily acicular ferrite. The chemistry of the as deposited weld metals was different in each case. The thermal profiles for the autogenous weldment were calculated based on a two parameter model of laser welding that utilises the fusion zone boundary as a measure of ‘best fit’. Based on the cooling rate of the autogenous fusion zone, cooling rates for the two welds with hot wire filler metal were rationalised. Using these cooling rates, the chemistry of the weld metal and a model of microstructural development of the weld metal, a computer calculation was made which gave volume fractions of the phases similar to those observed experimentally.MST/1845

Analysis of Elastomer Vulcanizate Composition by TG-DTG Techniques

Abstract Two common problems and probable solutions in the TG-DTG analysis of unknown elastomer vulcanizates have been discussed. The first problem concerns the difficulty in quantitatively determining the oil and elastomer in compounds where their volatilization temperature ranges overlap. After a review of the published works in this area, isothermal TG (with or without vacuum) is recommended. The “High Resolution” TG also shows promise and should be explored further. The second problem concerns separate determination of the elastomer-carbon residue and added carbon black in the compound, since both often oxidize together. Subtraction of the predetermined elastomer-carbon residue from the total weight loss in oxygen, was suggested in the literature. However, the quantity of char found depends on the type of the elastomer, its concentration, and the curative composition, as well as the TG temperature profile. The problem is not, therefore, fully resolved. Experiments using a slow feed of lean oxygen gas and isothermal conditions were also suggested in the literature. Under this condition, oxidation of carbon black and char may occur at slightly different temperatures and overlapping is minimized. However, this could be achieved only for large- and mediumparticle-size blacks (soft blacks) which oxidize at higher temperatures and not for the smaller particle size blacks used mostly in tire treads. Further work using the slow feed of lean oxygen with a superimposed isothermal program and/or vacuum conditions is recommended.

Cellular responses of laboratory mice to feedings of Ornithodoros talaje (Acari: Argasidae) larvae.

Studies were carried out in which laboratory mice were subjected to sequential feedings by slow feeding Ornithodoros talaje (Guerín-Méneville) larvae to detect and characterize the host cellular response. After the first exposure, histological evidence showed a strong neutrophil infiltration at the site of attachment and feeding. By the third exposure, a marked shift to lymphocytes was noted in the mouse tissues using histological preparations of the feeding ticks. Lymphocyte proliferation tests also provided indirect evidence of a host lymphocyte response as a result of the three tick exposures and feedings.

Oral Secretion Elicited by Effectors of Signal Transduction Pathways in the Salivary Glands of Amblyomma americanum (Acari: Ixodidae)

The abilities of various effectors of signal pathways in tick salivary glands to stimulate oral secretions in partially fed Amblyomma americanum (L.) female ticks were compared. Pilocarpine stimulated secretion the most rapidly following tick stimulation, but its effectiveness declined with time and subsequent injections. Secretion rates induced by dopamine and theophylline increased with time of collection and additional injections and were as effective as pilocarpine after 60 min. Activators of protein kinase C, phorbol 12-myristate 13-acetate (PMA), and 1-oleoyl-2-acetyl-sn-glycerol inhibited dopamine, and theophylline stimulated secretion. gamma-amino-butyric acid either by itself or in combination with other drugs had no effect on volume of oral secretions. Peptides were visible in the oral secretion stimulated by the various drugs after separation and staining in SDS-polyacrylamide gels. More peptides were present in the oral secretion obtained from the smallest partially fed (slow feeding) ticks. In some ticks, proteins were observed in oral secretions obtained from the same tick at one collection time but not another in response to the same pharmacological agent.

Development of a large‐scale continuous substrate feed process for the biotransformation of simvastatin by Nocardia s.p.

This article describes a process for microbial hydroxylation of simvastatin by a Nocardia sp. Simvastatin (Zocor) belongs to the family of HMGCoA reductase inhibitors used as cholesterol-lowering drugs. Studies at 14 L scale showed that high substrate (simvastatin) concentrations inhibited product formation; consequently, continuous slow feeding of the substrate was introduced to maintain low residual simvastatin concentrations. Dissolved oxygen levels above 50% air saturation were desirable for the biotransformation. The process was scaled up to 19,000-L fermentors using an on-line filter sterilization system for substrate feeding. The feed rate was regulated by off-line high-pressure liquid chromatography (HPLC) assays to keep the substrate concentration below 20 mg/L. Intermittent addition of nutrients helped to boost the bioconversion rate to give final titers of 400 mg/L 6-beta-hydroxymethyl simvastatin. Enrichment of the nutrient medium led to bioconversion titers of 800 mg/L 6-beta-hydroxymethyl simvastatin. Bioconversion efficiencies (desired product/substrate) of 22-25% with a ratio of desired product/side products of 0.7 were obtained by this process.

Turbulent mixing and the selectivity of fast chemical reactions

Assuming that complete information is available about (a) the chemical reactions (mechanism, stoichiometry, thermodynamics, and kinetics) and (b) the turbulent flow field in a reactor (mean velocities and turbulence parameters), we would like to calculate directly the time evolution of the temperature and the concentrations of all species present. No general method is yet available to satisfy this goal. Starting from the phenomena of reaction, molecular diffusion, and laminar deformation in laminated structures, which are formed by the action of vorticity, mixing in liquids at sub-Kolmogorov scales can be quantitatively described. This approach requires the compositions of the fluids incorporated into the vortices to be known. Thus, for example, when a reagent solution (B) is slowly added to a huge volume of a second reagent solution (A) in a stirred tank reactor, fresh B mixes with the average A composition. (Slowly means that the addition time is much greater than the time needed for turbulent and molecular transport to homogenize the tank contents.) Progress of the reactions is then determined essentially by the interaction between the fine-scale mixing (near the Batchelor concentration scale) and the chemical kinetics. A convenient way to evaluate this modeling compares predicted and measured product distributions (or selectivities) for fast multiple reactions. (Up to now, this has been done for dilute solutions, which exhibited concentration, rather than also temperature segregation.) Advantages compared to working with single reactions can include enhanced sensitivity, inclusion of a wider range of flow fields than turbulent pipe flow, e.g., well-stirred systems, and practical relevance of controlling product distributions in the manufacture of chemicals. The effects on the product distributions of fast reactions of operating parameters such as stoichiometric and volumetric feed ratios, reagent concentrations, feed location, impeller speed, size and shape, viscosity, and type of reaction can be well described. Present efforts concentrate on relaxing the assumption of slow feed addition and of describing reactors where not only fine-scale, but also coarse-scale inhomogeneities occur. A simplified model for the engulfment frequency between fluids having different compositions is being evaluated. Some progress has been made, but the way in which fluid elements mix with each other is still not fully known.

Determination of Vitellogenin Titer in the Hemolymph of Dermacentor variabilis (Acarina: Ixodidae) Using an Indirect Enzyme-Linked Immunosorbent Assay

Using polyclonal antibodies against Dermacentor variabilis (Say) egg vitellin, we developed an indirect, competitive enzyme-linked immunosorbent assay (ELISA). Vitellogenin in the hemolymph of females was quantitatively monitored through feeding (slow feeding and rapid engorgement feeding periods) and postfeeding (preoviposition and oviposition) until death. Vitellogenin concentrations in hemolymph ranged from 1 microgram/ml on the first day of feeding to a maximum of 430 micrograms/ml on the third day of oviposition. The temporal pattern of vitellogenin production in this tick shows a gradual increase in the hemolymph vitellogenin titer throughout the slow feeding period followed by a rapid and substantial rise during the rapid engorgement feeding period and a continuation of this rise in titer through the most productive egg laying part of oviposition. The vitellogenin titer rapidly falls toward the end of oviposition as the tick nears death. There was a 170-fold increase in vitellogenin concentration as measured from the onset of rapid engorgement to the maximum vitellogenin titer. The rapid engorgement feeding period signaled a sharp increase in vitellogenin production.

Chaos in business cycles

The business cycle is studied in terms of the mapping Z t = λZ t−1 − (λ+1)Z 3 t−1 − σY t−1 Y t = Z t−1 + Y −1 where the variables Y, Z denote income and rate of income change respectively, and λ, σ are two structural parameters. The model produces chaotic or periodic output for income differences. For small σ income acts as a slow feed back causing bifurcations between periodic and chaotic behaviour over the cycle. Typically, transitions between prosperity and depression set in with chaos after which there follows a period halving route to order.

Synthesis of carbon‐13 and carbon‐14 labeled paldimycin tri‐sodium salt

AbstractCarbon‐14 labeled paldimycin trisodium salt was prepared by addition of N‐acetyl‐L‐cysteine to [14C]paulomycin, the radioactive antibiotic produced by fermentation of Streptomyces paulus in the presence of L‐methionine labeled with carbon‐14 in the S‐methyl group Carbon‐13 nuclear magnetic resonance (NMR) spectra of paulomycin produced when the fermentation was carried out in the presence of L‐[S‐methyl‐13C]methionine showed that isotope incorporation had occurred specifically at the methoxy group of ring C, i.e., the 2‐deoxy sugar portion of paulomycin. With sustained slow feed of labeled precursors during the optimum antibiotic production period, carbon‐14 isotope yields of up to 17.5% with specific activity of up to 11.4 μCi per milligram of paulomycin, and carbon‐13 isotope yields of up to 24% with 17‐fold isotope enrichment over natural abundance, were achieved.

Differentiated Tissue Cultures of Panax ginseng and their Response to Various Carbon Sources

Summary Differentiated cultures of Panax ginseng were grown various carbon sources. The effects on growth, ginsenoside accumulation, sugar uptake and enzyme activities were investigated. The responses were dependent on the degree of differentiation. A root culture had an optimal biomass production grown on 30 g1−1 sucrose and a maximal ginsenoside content (5.2–5.7 mg g dry weight− 1) grown on both sucrose and fructose (30 g1−1) . A less differentiated culture, which grew as rigid granules, showed optimal growth on fructose and maltoso (30 gl−1) . The ginsensoide content was less than 0.6 mg g dry weight for all sugars tested. The low content of ginsenosides in the Rb-group could be raised to the concentration obtained in the root culture by successively adding fructose at a rate of 2g1−1 day−1 . A similar stimulatory effect of slow feeding on ginsenoside accumulation was observed for several feeding rates of different sugars. In addition, slow feeding of sugars generally increased the carbon conversion efficiency for both cultures. Enzymes for sucrose and maltose degradation were present in the cell wall. Both cultures hydrolyzed sucrose at equal velocities but their preferential uptake of monosaccharides differed. Glucose and fructose were utilized simultaneously by the root culture. The less differentiated culture used all glucose available until glucose exhaustion before fructose was utilized.

Behaviour of group-housed sows fed individually using a computer-controlled feeding system

In a comparison of computer controlled (transponder) individual feeding system with a group feeding system based on biological fixation (slow feeding system in which the feed trough was divided into 40-cm wide sections using 30-cm long paritions), there were no significant differences in the average behaviour of gestating sows between the two systems. Social behaviour at the transponder feeding station is also described.