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Human organoid models recapitulate many aspects of the complex composition and function of native organs. One of the main challenges in developing these models is the growth and maintenance of three-dimensional tissue structures and proper cellular organization that enable function. Biomaterials play an important role by providing a defined and tunable three-dimensional environment that is required for complex cellular organization and organoid growth in vitro or in vivo. This review summarizes organoids of the respiratory and digestive system, and the use of biomaterials to improve upon these model systems.
Foods and dietary patterns that enhance satiety may provide benefit to consumers. The aim of the present review was to describe, consider and evaluate research on potential benefits of enhanced satiety. The proposal that enhanced satiety could only benefit consumers by a direct effect on food intake should be rejected. Instead, it is proposed that there is a variety of routes through which enhanced satiety could (indirectly) benefit dietary control or weight-management goals. The review highlights specific potential benefits of satiety, including: providing appetite control strategies for consumers generally and for those who are highly responsive to food cues; offering pleasure and satisfaction associated with low-energy/healthier versions of foods without feeling ‘deprived’; reducing dysphoric mood associated with hunger especially during energy restriction; and improved compliance with healthy eating or weight-management efforts. There is convincing evidence of short-term satiety benefits, but only probable evidence for longer-term benefits to hunger management, possible evidence of benefits to mood and cognition, inadequate evidence that satiety enhancement can promote weight loss, and no evidence on which consumers would benefit most from satiety enhancement. The appetite-reducing effects of specific foods or diets will be much more subtle than those of pharmaceutical compounds in managing hunger; nevertheless, the experience of pharmacology in producing weight loss via effects on appetite suggests that there is potential benefit of satiety enhancement from foods incorporated into the diet to the consumer.
Since early studies in language development, scholars have noticed that function words, in particular auxiliaries, often appear to be missing in early speech, with the result that child utterances sometimes exhibit verbs with non-finite morphology in seemingly matrix clauses. This has led to the idea of a ‘deficit’ in the child's syntactic representations. In contrast with previous studies, this article explores the possibility that the child's phonology may considerably impact her overt realization of auxiliaries. Specifically, it examines the hypothesis that non-finite verbs in early speech are in fact attempted periphrastics (i.e. auxiliary/modal+non-finite verb) in which the auxiliaries are just reduced phonetically, often to the point where they remain unpronounced. We studied 28 normally developing French-speaking children aged between 23 and 37 months. New observational data uncovered a continuum in a given child's phonetic realizations of auxiliaries. Children showed various levels of auxiliary reduction, suggesting that their non-finite verbs are best analyzed as being part of periphrastics involving an auxiliary form that represents the endpoint on this continuum, i.e. is (completely) deleted. Further examination of these verbs revealed that their semantics corresponds to the semantics of adult periphrastics. Additionally, the results of an experiment where children imitated sentences with either periphrastic or synthetic verbs showed that responses with non-finite verbs were predominantly produced when the target sentence involved a periphrastic, rather than a synthetic verb.
A prospective longitudinal survey of cutaneous leishmaniasis (Leishmania peruviana) was carried out in Peru on a study population of 4716 persons living in 38 villages (Departments of Lima, Ancash and Piura). Demographic and clinical data were collected from all individuals, and a Montenegro skin test (MST) was carried out on 72% (3418) of the study population. Each household was revisited at 3-monthly intervals for up to 2 years to detect new leishmaniasis cases; 497 people received a second MST at the end of the study. Analysis of the epidemiological data indicated that (i) 17% (16/94) of all infections were subclinical, (ii) this percentage increased significantly with age, (iii) clinical infections led to 73·9 % protective immunity (95 % C.I. 53·0–85·5 %) and relatively permanent MST responsiveness (recovery rate = 0·0098/year; 95% C.I. 0·000–0·020/year), (iv) sub-clinical infections led to protective immunity, which was positively correlated with their MST induration size (increasing by 17·9% per mm; P < 0·0001), and a mean MST recovery rate of 0·114/year (4/421 man-months), and (v) recurrent leishmaniasis was dominated by reactivations, not by reinfections.
We present a direct detection of the growth of large-scale structure, using weak gravitational lensing and photometric redshift data from the COMBO-17 survey. Deep $R$-band imaging of two $0.5\times0.5$ square degree fields is used to provide shear estimates for over 52000 galaxies; these are combined with photometric redshift estimates from our 17 band survey, in order to obtain a 3-D shear field. We discuss how theoretical models for evolving matter power spectra and correlation functions cab be used to find a best fit to this 3-D shear field. We present the detection of the evolution of the power, and measurements of the rate of evolution for $0<z<1$. We discuss future refinements which will improve the accuracy with which the effect can be measured.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
The anthelmintic ivermectin has a number of effects on nematodes
which result in changes in behaviour, particularly
locomotion, including paralysis and an inhibition of feeding. This paper
describes the application of an in vitro pharmacological
approach to further delineate the action of ivermectin on feeding behaviour.
Contraction of Ascaris suum pharyngeal
muscle was monitored using a modified pressure transducer system
which detects changes in intrapharyngeal pressure and
therefore contraction of the radial muscle of the pharynx. The pharynx
not contract spontaneously. However, serotonin
(5-HT, 100 μm) stimulated rhythmic contractions and relaxations
(pumping) at a frequency of 0·5 Hz. γ-Aminobutyric
acid (GABA) and glutamic acid inhibited the pumping elicited by 5-HT. The
duration of inhibition was concentration
dependent (1–1000 μm) with a threshold of 1 μm
and 10 μm respectively (n=8). Ivermectin
also inhibited pharyngeal
pumping (1–1000 nM). At lower concentrations, ivermectin
(1–10 pM) potentiated the GABA and glutamate inhibition,
so that inhibition occurred at concentrations which were below threshold
absence of ivermectin. These data provide
evidence that the pharynx is a site for the action of ivermectin. Thus
interruption of pharyngeal processes such as, feeding,
regulation of hydrostatic pressure and secretion may provide a new site
Everyone knows that the condition for the quadratic to have two equal roots, i.e. to have a repeated root, is that its discriminant should be zero. We should remark, at the outset, that we are concerned only with ordinary polynomials whose coefficients are complex numbers. Indeed, little is lost if a reader assumes that all our polynomials are real, i.e. have real numbers for all their coefficients, though their complex roots must be considered as well as their real ones.
Peptides belonging to the FMRFamide family are widely distributed amongst invertebrates. We report here on the isolation of the FMRFamide neuropeptide AF2 (Lys-His-Glu-Tyr-Leu-Arg-Phe-NH2) from the parasitic nematode Haemonchus contortus. Immunocytochemical techniques showed that FMRFamide-like material was distributed in several regions of these organisms including nerve cords and cell bodies of the central nervous system. AF2 was isolated using a method that employed 6 steps of reverse-phase HPLC. The concentration of AF2 in this organism was approximately 30 pmol/g of nematode.
The pharyngeal component of the enteric nervous system of the parasitic nematode, Ascaris suum exhibits immunoreactivity for serotonin (5-hydroxytryptamine or 5-HT) and for FMRFamide-like peptides. This paper describes the application of an in vitro pharmacological approach to investigate the functional role of 5-HT and FMRFamide-like peptides. The pharyngeal pumping behaviour of Ascaris suum was monitored using a modified pressure transducer system which measures pharyngeal pressure changes and therefore pumping. The pharynx did not contract spontaneously; however, 5-HT (10-1000 μM) stimulated pumping at a frequency of 0·5 Hz. FMRFamide had no apparent effect on pharyngeal pumping. The native nematode FMRFamide-related peptide (FaRP), KSAYMRFamide inhibited the pumping elicited by 5-HT. The duration of inhibition was dose-dependent (0·1-1000 nM) with a threshold of 0·1 nM. In 4 preparations, the inhibition of the pharyngeal muscle was preceded by an initial excitation and increase in the amplitude of pharyngeal pressure changes. The pharynx is involved in various nematode processes, including feeding, regulation of hydrostatic pressure and excretion. The role of 5-HT and KSAYMRFamide in the pharyngeal function of nematodes is discussed.