Aerosol Filtration Efficiency

ACSNano |  The emergence of a pandemic affecting the respiratory system can result in a significant demand for face masks. This includes the use of cloth masks by large sections of the public, as can be seen during the current global spread of COVID-19. However, there is limited knowledge available on the performance of various commonly available fabrics used in cloth masks. Importantly, there is a need to evaluate filtration efficiencies as a function of aerosol particulate sizes in the 10 nm to 10 μm range, which is particularly relevant for respiratory virus transmission. We have carried out these studies for several common fabrics including cotton, silk, chiffon, flannel, various synthetics, and their combinations. Although the filtration efficiencies for various fabrics when a single layer was used ranged from 5 to 80% and 5 to 95% for particle sizes of <300 and="" nm="">300 nm, respectively, the efficiencies improved when multiple layers were used and when using a specific combination of different fabrics. Filtration efficiencies of the hybrids (such as cotton–silk, cotton–chiffon, cotton–flannel) was >80% (for particles <300 and="" nm="">90% (for particles >300 nm). We speculate that the enhanced performance of the hybrids is likely due to the combined effect of mechanical and electrostatic-based filtration. Cotton, the most widely used material for cloth masks performs better at higher weave densities (i.e., thread count) and can make a significant difference in filtration efficiencies. Our studies also imply that gaps (as caused by an improper fit of the mask) can result in over a 60% decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of “fit” and leakage, while allowing the exhaled air to vent efficiently. Overall, we find that combinations of various commonly available fabrics used in cloth masks can potentially provide significant protection against the transmission of aerosol particles.

murmuration

Kunstler | On last week's podcast, Duncan and I yakked about an important concept introduced by Nicole Foss at The Automatic Earth blog site. This concept was "the trust horizon," which outlines how legitimacy is lost in the political hierarchy. That is, people stop trusting larger institutions like the federal or state government and end up vesting their interests much closer to home. Thus, life de-centralizes and becomes more local by necessity. Your own trust horizon extends only as far as other persons, businesses, institutions, and authorities immediately around you - the banker who will meet with you face-to-face, the mayor of your small town, the local food-growers. At the same time, distant ones become impotent and ludicrous - or possibly dangerous as they flounder to re-assert their vanishing influence.

It is obvious that we are in the early stages of this process in the USA (and Europe), as giant institutions such as the Federal Reserve, the Executive branch under Mr. Obama, the US Congress (the ECB), the SEC, the Department of Justice, the Treasury Department, and other engines of management all fail in one way or another to discharge their obligations.

The people of the USA, having been let down and swindled in so many ways by the people they placed their trust in, and even freely elected, appear to be in a daze of injury. Maybe this accounts for the obsession with zombies and persons drained of blood - who yet seem to carry on normal lives (at least in TV shows). This odd condition is best defined by the familiar cry from non-zombies: "where's the outrage?" Which brings me to today's point.

Investment guru James Dines introduced another seminal idea on Eric King's podcast last week. Dines's work over the years has focused much more on human mob psychology than technical market analysis - which he seems to regard as akin to augury with chicken entrails. Dines now introduces the term "murmuration" to describe the way that rapid changes occur in the realm of human activities. The word refers to behaviors also seen in other living species, such as the way a large flock of starlings will all turn in the sky at the same instant without any apparent communication. We don't know how they do that. It seems to be some kind of collective cognitive processing beyond our understanding.

Dines goes on to suggest that the political stirrings and upheavals of the past year represent an instance of human "murmuration" that will lead to even greater epochal changes in geopolitical and economic life. Now, I've often said 1) history doesn't repeat, but it rhymes [thank you, Mark Twain], and 2) that these times are like the 1850s. To be more precise today, these two concepts of "the trust horizon" and "murmuration" point to a moment in time that I believe we are now rhyming with: the revolutions of 1848 and the events that grew out of it.

smells like change?

declineofempire | Writing in Salon, Glenn Greenwald reports on Jack Lew, Hopey-Changey's choice to replace William Daley as his chief of staff. Glenn gives us some background on Daley, who I used to illustrate just how screwed we truly are in my post America's Elites Own You. I believe that was the first post in which I used the classic George Carlin video on the "American Dream"—you've got to be asleep to believe it.

When President Obama last January announced the departure of Rahm Emanuel as White House Chief of Staff, many liberals were furious that his replacement was the Midwest Chairman of JP Morgan and Boeing Director William Daley, who was also an opponent of the Consumer Financial Protection Bureau and a critic of Obama’s health care bill as too leftist...

Rachel Maddow harshly condemned the choice ... and sardonically observed: “mmm – a banker and a lobbyist: smells like change.”

I don't have much use for Rachel Maddow, but she got that right. What will Daley do now?

Yesterday, the White House announced Daley’s departure — he will now co-chair Obama’s re-election campaign, which basically means raising huge amounts of money from his Wall Street friends — and unveiled his replacement as Chief of Staff: Jacob "Jack" Lew.

And what about the new guy? What was he doing prior to the financial crisis?

that explains my weakness for flawless mature women...,

Video - Catherine Deneuve conveying the sweet scent of Chanel No. 5.

ScienceDirect | Rats can display a conditioned partner preference for individuals that bear an odor previosuly associated with sexual reward. Herein we tested the possibility that odors associated with the reward induced by social play in prepubescent rats would induce a conditioned partner preference in adulthood. Two groups of 31-day-old, single-housed female rats were formed, and were given daily 30-min periods of social play with scented females. In one group, almond scent was paired with juvenile play during conditioning trials, whereas lemon scent functioned as a novel odor in the final test. The counterbalanced group received the opposite association. At age 42, females were tested for play partner preference with two males, one almond-scented and one lemon-scented. In both groups females displayed a play partner preference only for males scented with the paired odor. They were ovariectomized, hormone-primed, and at age 55 were tested for sexual partner preference with two scented stud males. Females displayed a sexual preference towards males scented with the paired odor as observed with more visits, solicitations, hops & darts, intromissions and ejaculations. These results indicate that olfactory stimuli paired with juvenile play affects later partner choice for play as well as for sex in female rats.

Highlights

► Neutral odors paired with juvenile play induce an olfactory conditioned play partner preference in prepubescent female rats ► The same conditioned odors (CS+) induce conditioned sexual partner preference in adult female rats. ► Sexual partner preference is observed with more proceptive behaviors directed towards the CS + male, which responds with more mounts, intromissions and ejaculations. ► This conditioned preference may be strong enough to support assortative mating.

Keywords: sexual behavior; conditioning; reward; odors; play; partner preference; copulation

The experimental protocols in this study were approved by a committee of the graduate program in Neuroethology, Universidad Veracruzana Mexico, following the Official Mexican Standard NOM-062-ZOO-1999 (Technical Specifications for the Production, Care and Use of Laboratory Animals).

body malodours and their topical treatment agents

Wileyonline | Body odour, which encompasses axillary and foot odour, can communicate a strong non-verbal signal [1, 2]. These odours are often unnoticed by the offender because that person has specific anosmia [3]. As a result, the individual is embarrassed when alerted, and his or her self-confidence is compromised. The offensive body odour also has economical consequences stemming from the need to replace damaged/stained clothes and shoes [4, 5].

In contrast to clear findings in animals, the presence of human vomeronasal organs is still being debated. Clearly, the ability to appreciate underarm and foot odours depends solely on an individual’s evolutionary culture and perceptual development. However, the emission of odourless human pheromones has been reviewed and is becoming a popular discussion topic [6].

The human scent is genetically controlled and systemically influenced by dietary and medicinal intake, as well as the application of fragrance products [6–8]. Heavy sweating or hyperhidrosis, particularly at axillary sites, leads to unpleasant odours that cause social embarrassment and reduce self-confidence, especially among women. Hyperhidrosis results from the oversecretion of sweat. Because there is an excessive amount of water in which bacteria can grow, hyperhidrosis is often accompanied by bromhidrosis or osmidrosis or offensive body odour. Both conditions can be treated by topically applying anti-perspirant and deodourant products. Body odour treatment products are part of a multibillion dollar industry [9]. High levels of fragrance are often used in these products to mask malodour [10]. Surprisingly, there is little discussion of odour treatment products in the literature [6], in contrast to other personal care products [11, 12].

This review will summarize the chemical composition and formation of body odour, the use of anti-perspirant, deodourant and herbal products to treat body odour, and a new class of treatment agents that do not change the balance of the skin’s bacterial population.