Nucleon Spin and Momentum Decomposition Using Lattice QCD Simulations.

We determine within lattice QCD the nucleon spin carried by valence and sea quarks and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass. We find that the total angular momentum carried by the quarks in the nucleon is J_{u+d+s}=0.408(61)_{stat}(48)_{syst} and the gluon contribution is J_{g}=0.133(11)_{stat}(14)_{syst}, giving a total of J_{N}=0.54(6)_{stat}(5)_{syst} that is consistent with the spin sum. For the quark intrinsic spin contribution, we obtain 1/2ΔΣ_{u+d+s}=0.201(17)_{stat}(5)_{syst}. All quantities are given in the modified minimal subtraction scheme at 2 GeV. The quark and gluon momentum fractions are also computed and add up to ⟨x⟩_{u+d+s}+⟨x⟩_{g}=0.804(121)_{stat}(95)_{syst}+0.267(12)_{stat}(10)_{syst}=1.07(12)_{stat}(10)_{syst}, thus satisfying the momentum sum.

Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point.

We evaluate the light, strange, and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the disconnected quark loops to sufficient accuracy to determine the strange and charm nucleon σ terms in addition to the light quark content σ_{πN}. We find σ_{πN}=37.2(2.6)(4.7/2.9) MeV, σ_{s}=41.1(8.2)(7.8/5.8) MeV, and σ_{c}=79(21)(12/8) MeV, where the first error is statistical and the second is the systematic error due to the determination of the lattice spacing, the assessment of finite volume, and residual excited state effects.

The antibacterial activity of plant extracts containing polyphenols against Streptococcus mutans.

The minimum inhibitory concentrations (MIC) of commercially available and 70% aqueous propanone (P70) extracts from plants chosen for polyphenol content on Streptococcus mutans and other bacteria were determined using a standard susceptibility agar dilution technique to investigate their potential use as anticariogenic agents. The effects on adhesion of S. mutans to glass were also studied. The lowest MICs were for the P70 extracts of red grape skin (0.5 mg ml(-1)) and green tea and sloe berry skin (2 mg ml(-1)). The commercial extracts generally had a lower activity with a minimum MIC of 2 mg ml(-1) for tea extracts, grape seed extracts and Pynogenol (extract of maritime pine). All other extracts had MICs of > or = 4 mg ml(-1). Unfermented cocoa had greater antimicrobial activity than fermented cocoa and the activity of the fractionated extract increased with the extent of epicatechin polymerization. Epicatechin polymer had an MIC of 1 mg ml(-1) and an MBC of 64 mg ml(-1). Selected extracts were tested against other oral bacteria and showed activity against gram-positive organisms. P70 extracts of unfermented cocoa, epicatechin polymer fraction, green tea and red grape seed were bacteriostatic and prevented acid production when added at the MIC to cultures of S. mutans grown in a chemically defined medium supplemented with either glucose or sucrose. There was a reduction in viability which was greater when added to washed cells, but there were some viable cells after 24 h. The extracts also reduced adherence of S. mutans to glass.

Gastrointestinal tolerance of gamma-cyclodextrin in humans.

The gastrointestinal tolerance of gamma-cyclodextrin (gamma-CD) was examined in 24 healthy human volunteers. In a double-blind, placebo-controlled, randomized cross-over study, single acute doses of 8 g maltodextrin (placebo) or 8 g gamma-CD (test) were consumed as a mid-morning snack after addition to 100 g yogurt. Gastrointestinal symptoms as well as frequency and consistency of stools were recorded before and after lunch at between 3-4 and 7-8 h after intake respectively. The perception of the symptoms was rated on a subjective scale ranging from 1 ('more than normal') to 3 ('exceptionally more than normal'). Following consumption of maltodextrin, five subjects reported a total of 12 symptoms of which seven, two and three were rated as having grade 1, 2 and 3, respectively. Following consumption of gamma-CD, five subjects reported six symptoms all of which were graded as 1. Two subjects reported flatulence, which is a frequent consequence of the consumption of malabsorbed carbohydrates, after placebo and test treatment. The incidence of individual and combined side-effects as well as the number and consistency of faeces passed was not significantly different between placebo and test treatment. It is concluded that single doses of 8 g gamma-CD and maltodextrin are tolerated equally well. This is in keeping with a good digestibility of gamma-CD by salivary and pancreatic amylase.

Tolerance and breath hydrogen excretion following ingestion of maltitol incorporated at two levels into milk chocolate consumed by healthy young adults with and without fasting.

Little is known about the gastrointestinal effects of ingesting maltitol in chocolate. This study was designed to determine whether it leads to increased gastrointestinal symptomatology and if that symptomatology is dose related. It was also designed to discover whether breath hydrogen excretion in response to maltitol is dose related. In a double-blind, crossover study, 20 healthy volunteers aged 18-24 y ingested 100 g chocolate containing 40 g sucrose, 10 g sucrose plus 30 g maltitol or 40 g maltitol after fasting (abstinence from food and liquids from 2200 h on the night before chocolate consumption) and not fasting. There was no difference in symptomatology between fasting and nonfasting periods, and consumption order had no effect on symptomatology. Relative to ingestion of sucrose, 30 g maltitol caused no significant difference in symptoms, but 40 g resulted in more mild borborygmi (P < 0.05) and mild flatulence (P < 0.01) but not moderate or severe symptoms. Neither 30 nor 40 g maltitol caused significantly greater laxation than sucrose ingestion (P > 0.05). In a separate study, 10 healthy volunteers aged 18-24 y ate the same test products before breath H2 testing; 40 g maltitol in chocolate caused a greater total breath H2 excretion compared with 30 g maltitol (P < 0.05) or sucrose (P < 0.01). Total breath hydrogen excretion was also greater with 30 g maltitol compared with sucrose (P < 0.05). This dose-related response was consistent with the lower symptomatology after ingestion of 30 vs. 40 g maltitol. We have shown that 30 g maltitol in chocolate causes no significant symptomatology in young adults; however, 40 g caused mild borborygmi and flatus but no increased laxation. An increased breath H2 response indicates colonic fermentation of this polyol.

Dose-related gastrointestinal response to the ingestion of either isomalt, lactitol or maltitol in milk chocolate.

OBJECTIVES: To determine whether there were differences between different polyols (sugar alcohols) in terms of their ability to stimulate intolerance symptoms when consumed in milk chocolate. Also to discover whether symptomatology can be related to the dose of polyol ingested. DESIGN: The study was of a randomised double-blind cross-over design. SUBJECTS: 59 healthy volunteers aged 18-24 years were recruited from the student population of the University of Salford. All subjects successfully completed the trial. INTERVENTIONS: Subjects ingested 100 g milk chocolate containing 40 g bulk sweetner as either sucrose, isomalt, lactitol or maltitol or a mixture (10:30 w/w) of sucrose and isomalt, sucrose and lactitol or sucrose and maltitol. Each bar was taken as breakfast on one day with following products consumed at 1-week intervals. Subjects reported the incidence and severity of the symptoms of flatulence, borborygms, colic, motion frequency and loose stools. RESULTS: The ingestion of 30 g or 40 g lactitol resulted in a significant increase in the incidence and severity of all symptoms examined compared to reactions after the consumption of standard sucrose-containing chocolate (P <0.01). Similarly, 40 g isomalt led to an increased incidence of all symptoms, including mild laxation (P <0.01), but unlike lactitol none was rated as being severe. A reduction in isomalt to 30 g was marked by increased tolerance with evidence of only mild borborygms (P <0.01), mild flatulence, colic, and laxation (P <0.05), with no increase in motion frequency (P <0.35). Ingestion of 40 g maltitol caused less intolerance than 40 g isomalt, with evidence of only flatulence, borborygms and colic (P <0.01), symptoms being rated as only mild. A reduction to 30 g led to a decrease in all symptoms except mild flatulence. Maltitol did not have any laxative effect when ingested at either 30 g (P = 0.32) or 40 g (P = 0.13) per day. CONCLUSIONS: This work has shown that there are significant differences in the reporting of gastrointestinal symptomatology following the consumption of isomalt, lactitol and maltitol incorporated into milk chocolate. However, with all three polyols the incidence and severity of symptomatology was dose dependent.