A CONCEPTUAL REVIEW ON PURISA (STOOL) PARIKSHA

In Ayurved; Astasthana pariksha is one of the important examinations to find the various causes behind diseases. In Ayurvedic text, different methods have been described for diagnosis of various aspect of disease, the Purisa pariksha (Stool examination) is one of them. Purisa pariksha is the main laboratory investigation tool which is necessary to diagnosis the disease described under samanya pariksha regarding the abnormalities in terms of col- or, odor, quality, consistency etc. In all ancient days, the identification of ama is used to be done by purisa parik- sha only. This review article aims to focus on the importance of Purisa pariksha. This conceptual study is helpful in the management of various progressive chronic diseases. Keywords: Astasthana pariksha, Mala pariksha, Purisa pariksha, Stool.

Olfactory Perception in Relation to the Physicochemical Odor Space

A growing body of research aims at solving what is often referred to as the stimulus-percept problem in olfactory perception. Although computational efforts have made it possible to predict perceptual impressions from the physicochemical space of odors, studies with large psychophysical datasets from non-experts remain scarce. Following previous approaches, we developed a physicochemical odor space using 4094 molecular descriptors of 1389 odor molecules. For 20 of these odors, we examined associations with perceived pleasantness, intensity, odor quality and detection threshold, obtained from a dataset of 2000 naïve participants. Our results show significant differences in perceptual ratings, and we were able to replicate previous findings on the association between perceptual ratings and the first dimensions of the physicochemical odor space. However, the present analyses also revealed striking interindividual variations in perceived pleasantness and intensity. Additionally, interactions between pleasantness, intensity, and olfactory and trigeminal qualitative dimensions were found. To conclude, our results support previous findings on the relation between structure and perception on the group level in our sample of non-expert raters. In the challenging task to relate olfactory stimulus and percept, the physicochemical odor space can serve as a reliable and helpful tool to structure the high-dimensional space of olfactory stimuli. Nevertheless, human olfactory perception in the individual is not an analytic process of molecule detection alone, but is part of a holistic integration of multisensory inputs, context and experience.

Olfactory Cues From Host- and Non-host Plant Odor Influence the Behavioral Responses of Adult Drosophila suzukii (Diptera: Drosophilidae) to Visual Cues

While trapping methods for Drosophila suzukii Matsumura (Diptera: Drosophilidae) have typically relied on fermentation volatiles alone or in association with a visual stimulus, the relative contribution of visual and olfactory stimuli to the food- and host-seeking behavior of D. suzukii is poorly understood. This study quantified the type of response exhibited by male and female D. suzukii to color and the effects that volatiles (fermentation, fresh fruit, and leaf) exert on the outcome. Seven-, four- and two-choice assays were used to quantify interactions between visual and olfactory cues. When no volatiles were present in a seven-choice assay, D. suzukii preferred red, black, and green pigments. Black and red were preferred when yeast odors were present, and black alone was the most attractive color when blueberry odor was present. A strawberry leaf terpenoid, β-cyclocitral, seemed to have overridden the flies’ response to color. In four-choice assays, blueberry odor was more likely to interact synergistically with color than yeast or β-cyclocitral. This study demonstrates that D. suzukii modulates the response to multimodal sensory modalities (vision and olfaction) depending, to some extent, on the type of olfactory stimuli. Our findings also provide insight into the relative importance of vision as a function of odor quality in this invasive species.

Configural perception of a binary olfactory mixture in honey bees, as in humans, rodents and newborn rabbits

ABSTRACTHow animals perceive and learn complex stimuli, such as mixtures of odorants, is a difficult problem, for which the definition of general rules across the animal kingdom remains elusive. Recent experiments conducted in human and rodent adults as well as newborn rabbits suggested that these species process particular odor mixtures in a similar, configural manner. Thus, the binary mixture of ethyl isobutyrate (EI) and ethyl maltol (EM) induces configural processing in humans, who perceive a mixture odor quality (pineapple) that is distinct from the quality of each component (strawberry and caramel). Similarly, rabbit neonates treat the mixture differently, at least in part, from its components. In the present study, we asked whether the properties of the EI.EM mixture extend to an influential invertebrate model, the honey bee Apis mellifera. We used appetitive conditioning of the proboscis extension response to evaluate how bees perceive the EI.EM mixture. In a first experiment, we measured perceptual similarity between this mixture and its components in a generalization protocol. In a second experiment, we measured the ability of bees to differentiate between the mixture and both of its components in a negative patterning protocol. In each experimental series, the performance of bees with this mixture was compared with that obtained with four other mixtures, chosen from previous work in humans, newborn rabbits and bees. Our results suggest that when having to differentiate mixture and components, bees treat the EI.EM in a robust configural manner, similarly to mammals, suggesting the existence of common perceptual rules across the animal kindgdom.

Olfactory Language Differs across Orthonasal and Retronasal Routes

Olfactory research in humans has largely focused on odors perceived via sniffing, orthonasal olfaction, while ignoring odors perceived from the mouth, or retronasal perception. Prior work on retronasally presented odors use animal models and focus mainly on odor sensitivity, but little is known about retronasal olfactory perception and cognition in humans. In this study, we compared orthonasal and retronasal routes of odor presentation to investigate differences in odor descriptions. Thirty-six individuals participated in a within-subjects study using twelve odors (varying in pleasantness and edibility) in perceptual and semantic tasks. As expected, we found route-dependent differences in perceptual odor quality (pleasantness, edibility, and familiarity ratings), and a better ability to identify odors during orthonasal presentation. Additionally, more concrete (and source-based) language was used when describing odors presented orthonasally. Interestingly, sensitivity and intensity did not explain these observed route-dependent differences in descriptor usage, suggesting two different central processing mechanisms among the two routes of odor presentation. Our results have implications for the study of food perception, where retronasal olfaction is predominant.

Human Olfactory Perception is Sensitive to Temporal Information within a Single Sniff

A sniff in humans typically lasts 1-2 seconds and is considered to produce a “snapshot” of the chemical environment that also sets the temporal resolution of olfactory perception. To examine whether the temporal order of events within a sniff influences the perceptual “snapshot”, we devised an apparatus that enabled us to phase-lock odor delivery to sniff onset and precisely manipulate onset asynchronies of odorants in humans. Psychophysical testing showed that participants were able to tell apart two odorants presented in the same or different order when the onset asynchrony was as low as 40 milliseconds. The performance improved with longer onset asynchronies and was not based on the molar ratio difference of the two odorants. Meanwhile, they were consistently at chance in reporting which odorant arrived first. These results provide behavioral evidence that human olfaction is sensitive to temporal patterns within a single sniff and indicate that timing of odor-evoked responses in relation to the sniff contributes to the perceived odor quality.

From Extra Virgin Olive Oil to Refined Products: Intensity and Balance Shifts of the Volatile Compounds versus Odor

To explore relationships between the volatile organic compounds (VOCs) of different grades of olive oils (OOs) (extra virgin olive oil (EVOO), refined olive oil (ROO), and pomace olive oil (POO)) and odor quality, VOCs were measured in the headspace of the oils by proton transfer reaction quadrupole ion guide time-of-flight mass spectrometry. The concentrations of most VOCs differed significantly between the grades (EVOO > ROO > POO), whereas the abundance of m/z 47.012 (formic acid), m/z 49.016 (fragments), m/z 49.027 (fragments), and m/z 115.111 (heptanal/heptanone) increased in that order. Although the refined oils had considerably lower VOC abundance, the extent of the decline varied with the VOCs. This results in differences in VOCs proportions. The high VOC abundance in the EVOO headspace in comparison to ROO and POO results in a richer and more complex odor. The identified C5–C6 compounds are expected to contribute mainly to the green odor notes, while the identified C1–C4 and C7–C15 are mainly responsible for odor defects of OOs. Current results reveal that processing strongly affects both the quantitative and relative abundance of the VOCs and, therefore, the odor quality of the various grades of OOs.