Wednesday, May 27, 2015
Two years ago this blog proposed a challenge to solar and wind supporters that if solar and wind were indeed the energy mediums of the future and did not require the assistance of other energy mediums (most notably fossil fuels like coal and natural gas) then they should empirically demonstrate this potential by transitioning a single medium sized city (10,000 – 15,000 individuals) to a grid where at least 70% of the electricity, not even all energy, was produced by solar and/or wind sources. Unfortunately despite the passage of two years and the so-called further expansion of solar and wind technology no such experiment has been conducted.
This lack of attention to detail in producing a model city that would empirically represent and support the actual ability of solar and wind to produce the bulk of electricity and even possibly all energy in the future beyond simple hype is troubling. Are solar and wind proponents so irresponsible that they are willing to gamble the future of society on merely their hopes, dreams, and personal preferences rather than raw data? Do they think that incorporation of solar and wind to a grid steadily advancing from 10% to 20% then 30% then 40% then 50%, etc. will run perfectly with no significant problems? If so, then the solar and wind supporters who believe these things should be stripped of all of their credibility and influence; those who do not believe in such a perfect transition should begin immediately petitioning to accept the challenge.
To the solar and wind proponents who object to the above characterization due to the notion that in March Georgetown, Texas (population approximately 48,000) proposed a plan to get all electricity from solar and wind sources, in essence meet this challenge, hold your horses. While it is true that there has been an initial arrangement between the Georgetown Utility Systems and Spinning Spur Wind Farm (owned by EDF Renewable Energy) and SunEdison to purchase 294 MW (144 MW wind and 150 MW solar) from their installations, this is only an initial arrangement, no actual testing or application has occurred yet.
A more pertinent issue regarding the use of Georgetown as an example is that there is no specific information pertaining to the details of how Georgetown Utility Systems will manage this change in supplier. Basically the only public reporting on this strategy have been puff-hype pieces with no real substance or details. Both Spinning Spur Wind Farm and the yet to be identified SunEdison site have not been fully constructed, are not operational and do not have any secondary storage capacity; thus any electricity produced by these institutions will be live and when those institutions are not producing electricity there will be no electricity to provide to Georgetown.
Initially there are at least three major questions that must be addressed to legitimize Georgetown as a model for a solar/wind only powered city. First, where is the detailed analysis of how electricity, and possibly even energy flows, would be properly compensated to avoid brownouts in times when there is insufficient electricity being produced by solar and wind sources? Simply saying “the sun shines in the day and the wind blows when the sun is not shining” is laughable and severely damages credibility. Anyone who thinks that there will not be periods of intermittence from both Spinning Spur and the SunEdison site is harboring an inaccurate belief. Basically show that 100% renewable can be done using math, not flowery words and misplaced hype; note that it is important to also include any transmission and inverter losses in the calculation and separate nameplate capacity from actual operational capacity.
Second, it stands to reason that proponents of a solar/wind only city will not allow the use of natural gas or coal to act in a backup capacity during these periods of intermittence; therefore, during periods of excess solar and wind, electricity must be stored in a battery for use at a future time. So what type of battery structure(s) is going to be utilized to store that excess energy and what is the economic feasibility of using this structure? If no battery infrastructure is believed to be feasible or economical then what type of energy medium will be tapped to act as backup in lieu of a fossil fuel medium and how will it be properly incorporated?
Third, how will consumer costs for energy change from the transition away from fossil fuels over time, i.e. what will costs be in year 1, what will costs be in year 10…? To simply say it will cost less is not sufficient. It must be demonstrated that it will cost less both now and in the future and if it will not cost less in the future what forms of compensation, if any, will be provided to the residents of Georgetown?
Overall these are just the three most basic questions that must be addressed before anyone should accept the idea of Georgetown, Texas being a legitimate 100% solar/wind powered city when their plan is put into place a few years from now. If these questions are not answered with accurate specifics that are later properly executed over time then Georgetown loses all significance as both a legitimate and symbolic experiment for the validity of a solar and wind “future”.
Of course it must be understood that the results in Georgetown are only an initial step, success only provides support to the possibility, not any guarantee for national eventuality. So how about it solar and wind supporters are you actually ready to put your theories to the test or are you simply content with the unscientific and irrational belief that everything will magically work out without the need for essential specifics, realistic assumptions, honest economics (which is incredibly lacking in most pro-solar and wind papers) and valid proof of concepts?
Wednesday, May 6, 2015
While there has been a general slowing in the progression of global obesity, especially in the developed world, there has yet to be a reversal of this detrimental trend. A recent study has suggested that one aspect of influence regarding obesity progression lies with the consumption of foods that have incorporated emulsifiers and how they interact with intestinal bacteria including increasing the probability of developing negative metabolic syndromes in mice.1 Based on this result understanding the digestive process may be an important element to understanding how emulsifiers and emulsions may influence weight outcomes.
An emulsion is a mixture of at least two liquids where multiple components are immiscible, a characteristic commonly seen when oil is added to water resulting in a two-layer system where the oil floats on the surface of the water before it is mixed to form the emulsion. However, due to this immiscible aspect most emulsions are inherently unstable as “similar” droplets join together once again creating two distinct layers. When separated these layers are divided into two separate elements: a continuous phase and a droplet phase depending on the concentrations of the present liquids. Due to their inherent instability most emulsions are stabilized with the addition of an emulsifier. These agents are commonly used in many food products including various breads, pastas/noodles, and milk/ice cream.
Emulsifier-based stabilization occurs by reducing interfacial tension between immiscible phases and by increasing the repulsion effect between the dispersed phases through either increasing the steric repulsion or electrostatic repulsion. Emulsifiers can produce these effects because they are amphiphiles (have two different ends): a hydrophilic end that is able to interact with the water layer, but not the oil layer and a hydrophobic end that is able to interact with the oil layer, but not the water layer. Steric repulsion is born from volume restrictions from direct physical barriers while electrostatic repulsion is based on exactly its namesake electrically charged surfaces producing repulsion when approaching each other. As previously mentioned above some recent research has suggested that the consumption of certain emulsifiers in mice have produced negative health outcomes relative to controls. Why would such an outcome occur?
A typical dietary starch, which is one of the common foods that utilize emulsifiers is composed of long chains of glucose called amylose, a polysaccharide.2 These polysaccharides are first broken down in the mouth by chewing and saliva converting the food structure from a cohesive macro state to scattered smaller chains of glucose. Other more complex sugars like lactose and sucrose are broken down into their glucose and secondary sugar (galactose, fructose, etc.) structures.
Absorption and complete degradation begins in earnest through hydrolysis by salivary and pancreatic amylase in the upper small intestine with little hydrolyzation occurring in the stomach.3 There is little contact or membrane digestion through absorption on brush border membranes.4 Polysaccharides break down into oligosaccharides that are then broken down into monosaccharides by surface enzymes on the brush borders of enterocytes.5 Microvilli in the entercytes then direct the newly formed monosaccharides to the appropriate transport site.5 Disaccharidases in the brush border ensure that only monosaccharides are properly transported, not lingering disaccharides. This process differs from protein digestion, which largely involves degradation in gastric juices comprised of hydrochloric acid and pepsin and later transfer to the duodenum.
Within the small intestine free fatty acid concentration increases significantly as oils and fats are hydrolyzed at a faster rate than in the stomach due to the increased presence of bile salts and pancreatic lipase.3 It is thought that droplet size of emulsified lipids influences digestion and absorption where the smaller sizes allow for gastric lipase digestion in the duodenal lipolysis.6,7 The smaller the droplet size the finer the emulsion in the duodenum leading to a higher degree of lipolysis.8 Not surprisingly gastric lipase activity is also greater in thoroughly mixed emulsions versus coarse ones.
Typically hydrophobic interactions are responsible for the self-assembly of amphiphiles where water molecules react to a disordered state gaining entropy as the hydrophobes of the amphiphilic molecules are buried in the cores of micelles due to repelling forces.9 However, in emulsions the presence of oils produce a low-polarity interaction that can facilitate reverse self-assembly10,11 with a driving force born from the attraction of hydrogen bonding. For example lecithin is a zwitterionic phospholipid with two hydrocarbon tails that form reverse spherical or ellipsoidal micelles when exposed to oil.21 Basically emulsions could have the potential to significantly increase the hydrogen concentration of the stomach.
This potential increase in free hydrogen could be an important aspect to why emulsions produce negative health outcomes in model organisms.1 One of the significant interactions that govern the concentrations and types of intestinal bacteria is the rate of interspecies hydrogen transfer between hydrogen producing bacteria to hydrogen consuming methanogens. Note that non-obese individuals have small methanogen-based intestinal populations whereas obese individuals have larger populations where it is thought that the population of methanogen bacteria expands first before one gains significant weight.13,14 The importance behind this relationship is best demonstrated by understanding the biochemical process involved in the formation of fatty acids in the body.
Methanogens like Methanobrevibacter smithii enhance fermentation efficiency by removing excess free hydrogen and formate in the colon. A reduced concentration of hydrogen leads to an increased rate of conversion of insoluble fibers into short-chain fatty acids (SCFAs).13 Proprionate, acetate, butyrate and formate are the most common SCFAs formed and absorbed across the intestinal epithelium providing a significant portion of the energy for intestinal epithelial cells promoting survival, differentiation and proliferation ensuring effective stomach lining.13,15,16 Butyric acid is also utilized by the colonocytes.17 Formate also can be directly used by hydrogenotrophic methanogens and propionate and lactate can be fermented to acetate and H2.13
Overall the population of Archaea bacteria in the gut, largely associated to Methanobrevibacter smithii, is tied to obesity with the key factor being availability of free hydrogen. If there is a lot of free hydrogen then there is a higher probability for a lot of Archaea, otherwise there is a very low population of Archaea because there is a limited ‘food source’. Therefore, the consumption of food products with emulsions or emulsion-like characteristics or components could increase available free hydrogen concentrations, which will change the intestinal bacteria composition in a negative manner that will increase the probability that an individual becomes obese. This hypothesis coincides with existing evidence from model organisms that emulsion consumption has potential negative intestinal bacteria outcomes. One possible methodology governing this negative influence is how the change in bacteria concentration influences the available concentration of SCFAs, which could change the stability of stomach lining.
In addition to influencing hydrogen concentrations in the gut, emulsions also appear to have a significant influence on cholecystokinin (CCK) concentrations. CCK plays a meaningful role in both digestion and satiety, two components of food consumption that significantly influence both body weight and intestinal bacteria composition. Most of these concentration changes occur in the small intestine, most notably in the duodenum and jejunum.18 The largest influencing element for CCK release is the amount and level of fatty acid presence in the chyme.18 CCK is responsible for inhibiting gastric emptying, decreasing gastric acid secretion and increased production of specific digestive enzymes like hepatic bile and other bile salts, which form amphipathic lipids that emulsify fats.
When compared against non-emulsions, emulsion consumption appears to reduce the feedback effect that suppresses hunger after food intake. This effect is principally the result of changes in CCK concentrations versus other signaling molecules like GLP-1.19 Emulsion digestion begins when lipases bind to the surface of the emulsion droplets; the effectiveness of lipase binding increases with decreasing droplet size. Small emulsion droplets tend to have more complex microstructures, which produce more surface area that allow for more effective digestion.
This higher rate of breakdown produces a more rapid release of fatty acids as the presences of free fatty acids in the small intestinal lumen is critical for gastric emptying and CCK release.20 This accelerated breakdown creates a relationship between CCK concentration and emulsion droplet size where the larger the droplet size the lower the released CCK concentration.21 One of the main reasons why larger emulsions produce less hunger satisfaction is that with the reduced rate of CCK concentration and emulsion breakdown there is less feedback slowing of intestinal transit. Basically the rate at which the food is traveling through the intestine proceeds at a faster rate because there are fewer cues (feedback) due to digestion to slow transit for the purpose of digestion.
As alluded to above the type of emulsifier used to produce the emulsion appears to be the most important element to how an emulsion influences digestion. For example the lipids and fatty acid concentrations produced from digestion of a yolk lecithin emulsion were up to 50% smaller than one using polysorbate 20 (i.e. Tween 20) or caseinate.7 Basically if certain emulsifiers are used the rate of emulsion digestion can be reduced potentially increasing the concentration of bile salts in the small intestine, which could produce a higher probability for negative intestinal related events.
Furthermore studies using low-molecular mass emulsifiers (two non-ionic, two anionic and one cationic) demonstrated three tiers of TG lipolysis governed by emulsifier-to-bile salt ratio.3 At low emulsifier-bile ratios (<0.2 mM) there was no change in solubilization capacity of micelles whereas at ratios between 0.2 mM and 2 mM solubilization capacity significantly increased, which limited interactions between the oil and destabilization reaction products reducing oil degradation.3 At higher ratios (> 2 mM) emulsifier molecules remain in the adsorption layer heavily limiting lipase activity, which significantly reduces digestion and oil degradiation.3
Another possible influencing factor could be change in glucagon concentrations. There is evidence suggesting that increasing glucagon concentration in already fed rats can produce hypersecretory activity in both the jejunum and ileum.22-24 It stands to reason that due to activation potential of glucagon-like peptide-1 (GLP-1) in consort with CCK, glucagon plays some role. However, there are no specifics regarding how glucagon directly interacts with intestinal bacteria and the changes in digestion rate associated with emulsions.
The methodology behind why emulsions and their associated emulsifiers produce negative health outcomes in mice is unknown, but it stands to reason that both how emulsions change the rate of digestion and the present hydrogen concentration play significant roles. These two factors have sufficient influence on the composition and concentration of intestinal bacteria, which have corresponding influence on a large number of digestive properties including nutrient extraction and SCFA concentration management. SCFA management may be the most pertinent issue regarding the metabolic syndrome outcomes seen in mice born from emulsifiers.
It appears that creating emulsions that produce smaller drop sizes could mitigate negative outcomes, which can be produced by using lecithin over other types of emulsifiers. Overall while emulsifiers may be a necessary element in modern life to ensure food quality, instructing companies on the proper emulsifier to use at the appropriate ratios should have a positive effect on managing any detrimental interaction between emulsions and gut bacteria.
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