Pheromones in sex and reproduction: Do they have a role in humans?

Temporal relation between pubertal development and peer victimization in a prospective sample of US adolescents

Peer victimization typically peaks in early adolescence, leading researchers to hypothesize that pubertal timing is a meaningful predictor of peer victimization. However, previous methodological approaches have limited our ability to parse out which puberty cues are associated with peer victimization because gonadal and adrenal puberty, two independent processes, have either been conflated or adrenal puberty timing has been ignored. In addition, previous research has overlooked the possibility of reverse causality-that peer victimization might drive pubertal timing, as it has been shown to do in non-human primates. To fill these gaps, we followed 265 adolescents (47% female) prospectively across three-time points (Mage : T1 = 9.6, T2 = 12.0, T3 = 14.4) and measured self-report peer victimization and self- and maternal-report of gonadal and adrenal pubertal development on the Pubertal Development Scale. Multilevel modeling revealed that females who were further along in adrenal puberty at age 9 were more likely to report peer victimization at age 12 (Cohen's d = 0.25, p = .005). The relation between gonadal puberty status and peer victimization was not significant for either sex. In terms of the reverse direction, the relation between early peer victimization and later pubertal development was not significant in either sex. Overall, our findings suggest that adrenal puberty status, but not gonadal puberty status, predicted peer victimization in females, highlighting the need to separate gonadal and adrenal pubertal processes in future studies.

Maintaining vulvar, vaginal and perineal health: Clinical considerations

Knowledge of female genital anatomy and physiology is often inadequate or incorrect among women. Precise patient-physician conversations can be inhibited by a reluctance or inability to speak accurately about the vulva and vagina, with the terms often being used interchangeably. There is a paucity of scientific evidence and clinical guidelines to support women and physicians in ensuring best practices in feminine hygiene. In this review, the unmet needs in the field are highlighted. Evidence is provided for the complex array of physiological and pathological systems, mechanisms and behaviours that either protect or, if inappropriate, predispose the vulva and vagina to infections, irritation or other conditions. The need for attention to perineal health is recommended, given the interdependence of perineal and vulvar microbiota and the risk of colonic pathogens reaching the vulva and the vagina. Differences in feminine hygiene practices can vary widely across the world and among varying age groups, and suboptimal habits (such as vaginal douching or the use of certain cleansers) can be associated with increased risks of vulvar and vaginal conditions. Critical areas for discussion when advising women on their intimate health include: advice surrounding aesthetic vulvar cosmetic trends (such as depilation and genital cosmetic surgery), bowel health and habits, and protection against sexually transmitted infections. Routine, once-daily (maximum twice-daily) washing of the vulva with a pH-balanced, mild cleanser is optimal, ideally soon after bowel voiding, when feasible. Due to the finely balanced ecosystems of the vulva, the vagina and the perineal area, a scientific and clinical perspective is essential when determining the most appropriate vulvar cleansers based on their components. Correct intimate care may contribute to improved genital and sexual health and overall well-being. An increased awareness of correct practices will empower women to be the advocates of their own intimate health.

Comparison of Aromatherapy with Citrus aurantium and Lavender on Sexual Satisfaction in Breastfeeding Women: A Randomized Controlled Trial

Objective: The aim of this study was to investigate the effects of aroma of Citrus aurantium and Lavender essence on sexual satisfaction in breastfeeding women. Materials and Methods: This was a double-blind randomized controlled trial that was conducted on 180 breastfeeding women from January to May 2019. The participants were allocated to three groups of Citrus aurantium (n = 60), Lavender (n = 60), and control (n = 60) groups. Two groups of intervention used 2 drops of essential oil, twice a day, for 40 days as inhalation. The control group received almond oil in the same. The sexual satisfaction was evaluated using the Linda Berg's Sexual Satisfaction Questionnaire before the intervention and 40 days after the intervention started. The data were analyzed using the SPSS statistical software, version 21, and p < 0.05 was considered statistically significant. Results: After the 40 days of intervention, the mean score of sexual satisfaction was significantly higher in the Citrus aurantium and Lavender groups compared with the control group (59.3 ± 11.7, 59.3 ± 11.6 vs. 52.02 ± 11.5, p < 0.001). There was no significant difference between Lavender and Citrus aurantium groups. Conclusions: The results of this study showed that the aroma of Citrus aurantium and Lavender essence could significantly improve the sexual satisfaction of breastfeeding women. Therefore, it is recommended that health care providers should inform the breastfeeding women and advise them to use these interventions for increase of the sexual satisfaction. Trial Registration Number: IRCT20160427027633N3.

Judgements of attractiveness of the opposite sex and nostril differences in self-rated mood: The effects of androstenol

Androstenol has been reported to influence judgements of attractiveness and to affect participants' mood. In the present study, participants were asked to sniff androstenol or a control odour (pure ethanol) unilaterally with the left or right nostril. Subsequently, they rated the attractiveness of photographs of the opposite sex and their own feelings on four mood scales. Participants rated the photographs as significantly more attractive after sniffing androstenol compared with the control odour. This did not depend upon androstenol being perceived as pleasant. Androstenol made male participants feel more lively, and both male and female participants more sexy, when sniffed through the right compared with the left nostril. Participants rated themselves as more irritable and aggressive when exposed to androstenol through the left nostril. The findings are discussed in relation to the effects of arousal on attraction and in the context of current theories of hemispheric differences in emotion.

Interpersonal Chemistry: What Is It, How Does It Emerge, and How Does It Operate?

Although chemistry is a well-known, sought-after interpersonal phenomenon, it has remained relatively unexplored in the psychological literature. The purpose of this article is to begin articulating a theoretically grounded and precise definition of interpersonal chemistry. To that end, we propose a conceptual model of interpersonal chemistry centered around the notion that when two or more individuals experience chemistry with one another, they experience their interaction as something more than the sum of their separate contributions. Our model stipulates that chemistry encompasses both behavior (i.e., what chemistry "looks like") and its perception (i.e., what it "feels like"). The behavior involves interaction sequences in which synchronicity is high and in which people's goals are expressed and responded to in supportive and encouraging ways. The perception of chemistry includes cognitive (i.e., perception of shared identity), affective (i.e., positive affect and attraction), and behavioral (i.e., perceived goal-relevant coordination) components. We review existing research on chemistry as well as supporting evidence from relevant topics (e.g., attraction, similarity, perceived partner responsiveness, synchrony) that inform and support this model. We hope that this conceptual model stimulates research to identify the circumstances in which chemistry arises and the processes by which it affects individuals, their interactions, and their relationships.

Prior exposure to Hedione, a model of pheromone, does not affect female ratings of male facial attractiveness or likeability

The existence of pheromones in humans is controversial, partly because of definitional difficulties and partly because of the question of possible chemical substances. The synthetic compound Methyl dihydrojasmonate (Hedione) is potent to bind to vomeronasal-type 1 receptors (VN1R1s) and activate limbic areas of the brain in a sex-specific manner. However, one of the most important definitional points for a human pheromone effect has not yet been investigated, i.e., whether smelling Hedione, a model of pheromone, has a behavioral effect. We tested in females whether Hedione leads to altered perception of male social stimuli. Each of the included women were sensitive to Hedione and were tested around the time of ovulation in three consecutive sessions, during each they were exposed to either Hedione or Phenylethyl alcohol or Odorless air. We measured the speed of male face recognition (implicit priming task) and collected ratings of facial attractiveness and likeability of men (explicit task). Only about half of the women tested were sensitive to Hedione. Those women did not show any effect of Hedione exposure in the implicit priming task and moderate, but non-significant effects in the explicit task. We therefore assume that Hedione is not a potent model of pheromone in humans and this observation may be due to the fact that the artificially produced substance is not suited for signaling the proximity of other humans. Furthermore, the high rate of Hedione-specific anosmia leads to the hypothesis that a substantial proportion of individuals has a poor V1NR1 receptor expression.

Chemosensory Perception: A Review on Electrophysiological Methods in “Cognitive Neuro-Olfactometry”

Various brain imaging techniques are available, but few are specifically designed to visualize chemical sensory and, in particular, olfactory processing. This review describes the results of quantitative and qualitative studies that have used electroencephalography (EEG) and magneto-encephalography (MEG) to evaluate responses to olfactory stimulation (OS). EEG and MEG are able to detect the components of chemosensory event-related potentials (CSERPs) and the cortical rhythms associated with different types of OS. Olfactory studies are filling the gaps in both the developmental field of the life cycle (from newborns to geriatric age) and the clinical and basic research fields, in a way that can be considered the modern “cognitive neuro-olfactometry”.

Exposure to Hedione Increases Reciprocity in Humans

Cooperation among unrelated humans is frequently regarded as a defining feature in the evolutionary success of our species. Whereas, much research has addressed the strategic and cognitive mechanisms that underlie cooperation, investigations into chemosensory processes have received very limited research attention. To bridge that gap, we build on recent research that has identified the chemically synthesized odorant Hedione (HED) as a ligand for the putative human pheromone receptor (VN1R1) expressed in the olfactory mucosa, and hypothesize that exposure to HED may increase reciprocity. Applying behavioral economics paradigms, the present research shows that exposure to the ligand causes differentiated behavioral effects in reciprocal punishments (Study 1) as well as rewards (Study 2), two types of behaviors that are frequently regarded as essential for the development and maintenance of cooperation.

Putative sex-specific human pheromones do not affect gender perception, attractiveness ratings or unfaithfulness judgements of opposite sex faces

Debate continues over the existence of human sex pheromones. Two substances, androstadienone (AND) and estratetraenol (EST), were recently reported to signal male and female gender, respectively, potentially qualifying them as human sex pheromones. If AND and EST truly signal gender, then they should affect reproductively relevant behaviours such as mate perception. To test this hypothesis, heterosexual, Caucasian human participants completed two computer-based tasks twice, on two consecutive days, exposed to a control scent on one day and a putative pheromone (AND or EST) on the other. In the first task, 46 participants (24 male, 22 female) indicated the gender (male or female) of five gender-neutral facial morphs. Exposure to AND or EST had no effect on gender perception. In the second task, 94 participants (43 male, 51 female) rated photographs of opposite-sex faces for attractiveness and probable sexual unfaithfulness. Exposure to the putative pheromones had no effect on either attractiveness or unfaithfulness ratings. These results are consistent with those of other experimental studies and reviews that suggest AND and EST are unlikely to be human pheromones. The double-blind nature of the current study lends increased support to this conclusion. If human sex pheromones affect our judgements of gender, attractiveness or unfaithfulness from faces, they are unlikely to be AND or EST.

Design and development of indoor device for recycling of domestic vegetable scrap

Since the municipal waste management and community garbage-treating systems are in vogue, there is a growing need for the waste minimization to keep our vicinity clean and green. Therefore, a feasible indoor device is designed for recycling domestic vegetable scrap by adopting the principle of soil ecosystem. To arrive at the composting process control parameters in the proposed device, the soil from landfill and quarry along with supplements namely sawdust, cow dung/yeast and the resident thermophilic bacteria are analysed. The soil parameters namely pH, electrical conductivity, Organic carbon, P, K, Fe, moisture content and the presence of thermophilic bacteria varied significantly between negative control sample (NCS) and positive control sample (PCS) and post-treatment positive control group with dried cow dung (PPC-C)-derived compost is soft-textured and homogenous. Furthermore, the double-compartment-based device would be more feasible and appealing as a recycling bin rather than as a refuse storage bin primarily due to the inclusion of dish-plantation. The standardization of composting control parameters is discussed in this article.

Supercritical water oxidation of dioxins and furans in waste incinerator fly ash, sewage sludge and industrial soil

Three environmental samples containing dioxins and furans have been oxidized in the presence of hydrogen peroxide under supercritical water oxidation conditions. The samples consisted of a waste incinerator fly ash, sewage sludge and contaminated industrial soil. The reactor system was a batch, autoclave reactor operated at temperatures between 350 degrees C and 450degrees C, corresponding to pressures of approximately 20-33.5 MPa and with hydrogen peroxide concentrations from 0.0 to 11.25 vol%. Hydrogen peroxide concentration and temperature/pressure had a strong positive effect on the oxidation of dioxins and furans. At the highest temperatures and pressure of supercritical water oxidation of 4500C and 33.5 MPa and with 11.25 vol% of hydrogen peroxide, the destruction efficiencies of the individual polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) isomers were between 90% and 99%. There did not appear to be any significant differences in the PCDD/PCDF destruction efficiencies in relation to the different sample matrices of the waste incinerator fly ash, sewage sludge and contaminated industrial soil.

Human skin volatiles: a review

Odors emitted by human skin are of great interest to biologists in many fields; applications range from forensic studies to diagnostic tools, the design of perfumes and deodorants, and the ecology of blood-sucking insect vectors of human disease. Numerous studies have investigated the chemical composition of skin odors, and various sampling methods have been used for this purpose. The literature shows that the chemical profile of skin volatiles varies greatly among studies, and the use of different sampling procedures is probably responsible for some of these variations. To our knowledge, this is the first review focused on human skin volatile compounds. We detail the different sampling techniques, each with its own set of advantages and disadvantages, which have been used for the collection of skin odors from different parts of the human body. We present the main skin volatile compounds found in these studies, with particular emphasis on the most frequently studied body regions, axillae, hands, and feet. We propose future directions for promising experimental studies on odors from human skin, particularly in relation to the chemical ecology of blood-sucking insects.

Sex for fun: a synthesis of human and animal neurobiology

Sex is a fundamental pleasure, and crucial to the survival of our species. Though not many people would disagree with the proposition that sexual behaviour depends on the brain, the neuroscientific study of human sex is still relatively taboo and much remains to be discovered. On the contrary, excellent experimental animal models (mostly rat) are available that have uncovered major behavioural, neurochemical, and neuroanatomical characteristics of sexual behaviour. Restructuring sexual behaviour into broader terms reflecting behavioural states (wanting, liking, and inhibition) facilitates species comparison, revealing many similarities between animal and human sexual pleasure cycles, some of which can serve as potential avenues of new human sex research. In particular, behavioural and brain evidence clearly shows that motivational and consummatory phases are fundamentally distinct, and that genitally-induced sexual reward is a major factor in sexual learning mechanisms.

The human sexual response cycle: brain imaging evidence linking sex to other pleasures

Sexual behavior is critical to species survival, yet comparatively little is known about the neural mechanisms in the human brain. Here we systematically review the existing human brain imaging literature on sexual behavior and show that the functional neuroanatomy of sexual behavior is comparable to that involved in processing other rewarding stimuli. Sexual behavior clearly follows the established principles and phases for wanting, liking and satiety involved in the pleasure cycle of other rewards. The studies have uncovered the brain networks involved in sexual wanting or motivation/anticipation, as well as sexual liking or arousal/consummation, while there is very little data on sexual satiety or post-orgasmic refractory period. Human sexual behavior also interacts with other pleasures, most notably social interaction and high arousal states. We discuss the changes in the underlying brain networks supporting sexual behavior in the context of the pleasure cycle, the changes to this cycle over the individual's life-time and the interactions between them. Overall, it is clear from the data that the functional neuroanatomy of sex is very similar to that of other pleasures and that it is unlikely that there is anything special about the brain mechanisms and networks underlying sex.