Patent Application
20240189617
Not Applicable
The present invention relates to systems and methods for inactivating a distinct group of microbes in the reticulorumen of ruminants with light for a prolonged time using power source controls and second power sources.
This invention relates generally to an encapsulated luminaire designed to be deposited in a stomach of a ruminant animal, such as a cow, for inactivating some of the bacteria in the animal's digestive system. More particularly, the invention pertains to a method of promoting animal growth and health that can substitute for the use of sub-therapeutic dosages of antibiotics, without inducing antimicrobial resistance, which has become a public health crisis.
The ruminant digestive system exploits bacteria. Vast numbers (hundreds of trillions) of fermentative bacteria flow into their stomachs. These bacteria digest foodstuffs and are themselves a major source of protein. The abomasum secretes large amounts of lysozymes, enzymes that hydrolyze the glycosidic bonds in bacterial cell wall mucopolysaccharides. Once ruptured, the bacterium's internal material is consumed by other bacteria, or absorbed by the animal. Bacterial residues make up a significant part of a ruminant's protein source.
This dual use of bacteria by ruminants establishes a competitive equilibrium. Higher bacteria levels can lead to higher levels of protein consumption, and increased fermentation can lead to more carbohydrate and energy consumption. But bacteria also compete with the animal for food, particularly when they are in a state of equilibrium. Killing some bacteria with interventions like antibiotics pushes bacteria below the equilibrium, increasing the exponential growth phase optimal for protein production.
When a ruminant eats, particles flow down the esophagus and into the rumen, where they flow freely between the rumen and reticulum, hence the term reticulorumen. This area contains about half the digestive capacity, in a full grown cow perhaps 40 liters of an 80 liter digestive capacity. It contains the majority of microbial activity. The rumen contracts severely to mix its contents. Most animals cannot digest cellulose. Ruminants delegate the process to microbes. These digest cellulose to produce their own energy, and release volatile fatty acids that provide 70% of the cow or steer's energy supply. Microorganisms also produce prodigious amounts of CO2 and methane.
The lower layers of bovine reticulorumen are ideal for organisms that can't compete with oxygen-users but need their by-products. These include methanogens. The enteric methane they produce and which animals eruct (belch) generates 5% of global warming gasses. Various methods have been proposed to control methanogen activity in ruminant reticulorumen. Enteric methane controls include vaccines and antibiotics, which are expensive and resistance prone, and exotic chemicals and foodstuffs whose effect, production and availability on a global scale are doubtful and also costly as they are used continuously.
It has been shown that 420 nm light kills methanogens. It has be shown that 405 nm light kills bacteria. 405 nm light is promoted by the U.S. Food and Drug Administration for use in blood transport, to prevent pathogen transmission without use of antibiotics.
U.S. application Ser. No. 16/729,399, of which this is a continuation in part, describes bolus-shaped light capsules that contain light sources, emitting wavelengths that inactivate some microbes. These light capsules are shot into cows with a bolus gun, and settle in the reticulorumen anaerobic fraction layer where methanogens concentrate. The light capsule light sources emit specific wavelengths that inactivate distinct groups of microbes. The light capsule is of sufficient weight and size to be retained in the rumen for the life of the animal. It contains a battery which can operate the light sources for a prolonged period, defined as multi-month to multi-year.
Prior art does not describe detailed mechanisms to extend battery life. These are needed, particularly for dairy cows, whose lifespans are commonly at least five years. There are 10 million dairy cows in the United States, 23 million dairy cows in Europe, 25 million dairy cows in Brazil, and 300 million dairy cows in India.
The present invention provides a bolus-shaped light capsule that contains light sources that inactivate some microbes. In its basic form the invention comprises a light emitting assembly adapted to be located in the reticulorumen of a ruminant animal. In embodiments described herein, the luminaire power sources are operated to maximize power source lifespan and treatment effect. Some embodiments are recharged by the reticulorumen environment. The methods, systems and apparatus include the generation of electricity to drive the light sources in the bolus-shaped light capsule as it is retained in the reticulorumen of an animal.
The light capsule may emit microbe inactivating light continuously, periodically, at predetermined times, determined by one or more of: sensor-detected local environmental conditions, instructions of an external operator, predetermined energy management settings, reprogrammed energy management settings, feedback-driven energy management systems, and other energy management methods that extend the life of a power source. A reduction in emitted light may be caused by fouling of light apertures. These may be cleaned with ultrasonic vibration, from a transducer vibrator embedded or enclosed near the emitting light.
The light capsule provides a first power sources sufficient to operate the light sources for an extended, multi-year period, a controller that manages electrical power, and thermal management. In some embodiments the controller includes Pulse Width Modification (PWM) to pulse device light sources on and off, on a schedule that generates sufficient light energy to inactivate specific microbes while preserving available power sources. This is called a duty cycle, and pulses may be emitted at a Nyquist rate for specific microbes, the frequency that inactivates the specific microbes. Some microbes have subpicosecond electron transfer dynamics, which require small energetic driving forces. In an embodiment the PWM will emit light for 1 millionth of a second out of every 10 millionths seconds, or 9 MHz OFF, 1 MHz ON. This is a 0.1 periodic operation, and extends power source operation 10 times, minus conduction, switching, and gate loss. Other embodiments use duty cycles with longer or shorter ON and OFF periods, including PWM that flexibly modify these periods in response to regeneration power provided by a second power source.
A further embodiment of the light capsule employs a Triboelectric Generator (TG) as the second power source to supply regeneration power to the first power source. TGs use contact electrification of two materials with different electro-polarization capabilities caused by kinetic energy of a movable system. Piezoelectric TGs generate electric recharge energy through the mechanical deformation of piezoelectric materials; they harvest small mechanical energy. Electromagnetic TGs are larger. Cattle rumen cause large mass displacements, with more kinetic energy potential than human activity. To harvest relatively large kinetic energy found in cattle rumen, an embodiment uses electromagnetic TGs with low damping values. This causes greater displacements during oscillations, which harvests energy >500 μW. An embodiment uses Schottky TGs whose components remain in contact during energy harvesting and generate 3-6 Volts with sufficient kinetic movement.
Within a cow's rumen, a cycle of contractions occurs 1 to 3 times per minute. Primary contractions start in the reticulum and pass towards the rear of the rumen then circle forwards. A contraction wave is followed by a relaxation wave. Part of the rumen contracts while other parts dilate, which in an embodiment provide movement transferred to a TG. Secondary contractions are associated with eructation (belching.) Although less frequent than primary contractions, eructed gas can travel up the esophagus at 160 to 225 cm per second (around 5 mph). On average, about 30-50 liters of gas is belched by an adult cattle per hour; this causes significant tissue movement, which in an embodiment is transferred to a TG.
Although a light capsule's density and size cause it to remain in a certain location of the cow's rumen, it is jostled and rocked by the energetic forces around it. In an embodiment, this constant stimulus generates electrical power through the TG. In an embodiment a TG is housed inside the light capsule body. In another embodiment a TG is housed in a container that is outside the light capsule, with a conduit tube connecting it to the light capsule. In a preferred embodiment, a voltage conditioner regulates the discharge power from the TG. This transforms TG output to an electronically useful voltage, which is then used to recharge a capacitor. The capacitor is replenished by the TG during rumenoreticulum contractions. The voltage conditioner maximizes output power, transforming voltage of output power sufficient to operate a plurality of high-power LEDs.
In one embodiment a TG produces ˜1 mW at a current of ˜1.5 mA with ˜200 V resistance, for maximum power and current density of about 110 mW/m2 and 175 mA/m2, and a stable power density of ˜50 mW/m2 (0.96 V). In another embodiment a stable power density of ˜1.75 V is obtained. Other embodiments achieve different stable power densities. The reticulorumen environment maintains daily power generation. Further embodiments include a system to store and accumulate power. In tandem with the controller, the TG system may operate 4 LEDs of 500 mA with luminous flux at a sufficient forward current to inactivate targeted microbes over a prolonged period.
Another embodiment uses a microbial fuel cell (MFC) to generate electricity using the metabolic energy of an animal's digestive microbes, which use cellulose as their food and produce energy. Ruminal microbes hydrolyze cellulose anaerobically, and are electrochemically active. These microbes include metabolically active species that have high power densities. Rumen microbes maintain constant power generation without exogenous electron transfer mediators, for as long as cellulose is available. The diversity of these microbes, in the tens of thousands of species, are needed to digest the very great number of metabolic intermediates produced in cellulose degradation. A fuel cell has an anode and a cathode. Microbes oxidize the anode and electrons flow to the cathode, which is electrically coupled to the anode but separated by a membrane. The cathode needs an electron acceptor, usually oxygen because of its high redox potential. However there is almost no dissolved or gaseous oxygen in a cow reticulorumen. An embodiment uses a microbial fuel cell that employs an alternative oxide as the cathode reactant, instead of oxygen. A preferred embodiment uses manganese oxides. A matrix formed of a carbon fibers with manganese oxide centers provides cathode reaction sites and an electron transport network. Electron movements are generated by strong electrostatic attraction towards manganese oxide cations. Electrons flow spontaneously through the membrane to an external circuit, creating a flow of electricity. The manganese ions dissolved from manganese oxide reversibly deposit back to the cathode and preserve the manganese oxides for energy storage. In an embodiment manganese-oxidizing prokaryotes produce the cathode reactant.
Further aspects, elements and advantages of the present invention will be understood by those of skill in the art upon reading of the description set forth below.
The following detailed description and the accompanying drawings are intended to describe some, but not necessarily all, examples of embodiments of the invention. The contents of this detailed description and the accompanying drawings do not limit the scope of the invention in any way.
While the invention has been described in multiple embodiments, the words which have been used are words of description rather than limitation. Changes may be made within the purview of the claims without departing from the scope and spirit of the invention. For example, any element or attribute of one embodiment or example may be incorporated into or used with another embodiment or example, unless otherwise indicated or unless doing so would render the embodiment or example unsuitable for its intended use. For example, materials may be used for membranes, electrodes, anodes, cathodes, and/or other components as may be sourced and utilized, other than the materials described herein. Also, each embodiment was shown as containing LEDs, but light sources of differing sizes and shapes may be used. The dimensions may be varied as appropriate to user needs and manufacturing specifications. All reasonable additions, deletions, modifications and alterations are to be considered equivalents of the described examples and embodiments are to be included within the scope of the following claims.
Controlling high brightness LEDs with PWM signals is a well-known and a widely implemented method of adjusting LED performance. The ‘ON’ part of the pulse train drives the LED at a forward voltage specification, preserving color temperature. A duty cycle will decrease the LED's luminosity, since fewer photons reach a destination. The switching frequency can be tailored to microbial electron absorbance, which is determined by frequency as well as luminosity. A preferred embodiment uses a PWM signal generator to extend power source lifetime. The circuitry includes a power source that delivers the desired current to the LED. The current is turned on and off by the PWM control signal. The instantaneous current supplied to the LED remains constant. Numerous microprocessors have PWM control hardware built in.
However research indicates that PWM duty cycles change the junction temperature of the LED; and junction temperature alters the color emitted by the chip. The light capsule emits specific wavelengths known to inactivate specific microbes. If duty cycles change the LED wavelength, they pose a problem. Researchers varied PWM from 3 to 100%, and measured wavelength output. Peak wavelengths moved toward shorter, bluer wavelengths as the PWM decreased. At the briefest PWM (ON 3%) wavelength shifted 2.5 nm towards blue.
An embodiment solves this problem. A light of specific wavelength must be emitted. It is determined that the light is operated at a PWM that is ON a specific percentage of time, between 0.1% and 99.9% of the time. Depending on the percent of time ON of the embodiment, the emitted wavelength is adjusted to be longer or shorter, in the opposite direction of the change due to the impact of the junction temperature. The lower the duty cycle, the lower the junction temperature of the LED, which would cause shorter wavelengths and bluer light, but the adjusted wavelength emitted is longer by the same amount.
The light capsule may have a second power source with a regenerative capacity, in which energy is recovered from kinetic motion in the rumen, or from microbial activity, or from external inputs such as from a radio frequency emitter. In these cases the external inputs may not be used directly to effectively power the light capsule without a control interface. In accordance with the present invention, an embodiment with one or more second regenerative energy sources is connected to one or more first power sources in the light capsule. Because second regenerative power sources may not permit continuous light capsule operation, a duty cycle embodiment resolves the mismatch between input power and operations. An embodiment with a second regenerative power source uses voltage measurements, rather than predetermined cycles, to determine the duty cycle. In this case the ON period when the resistor is connected ends when voltage decreases below a predetermined threshold.
Resistance mismatch between the second regenerative power source and the electrical load can be resolved through periodic connection and disconnection of the load at a relatively high frequency, defined as 0.05 to 50 Hz.
In a further embodiment, the regenerative power system is a microbial fuel cell (MFC).
While the invention has been described in multiple embodiments, the words which have been used are words of description rather than limitation. Changes may be made within the purview of the claims without departing from the scope and spirit of the invention. For example, any element or attribute of one embodiment or example may be incorporated into or used with another embodiment or example, unless otherwise indicated or unless doing so would render the embodiment or example unsuitable for its intended use. For example, materials may be used for membranes, electrodes, anodes, cathodes, and/or other components as may be sourced and utilized, other than the materials described herein. Also, each embodiment was shown as containing LEDs, but light sources of differing sizes and shapes may be used. The dimensions may be varied as appropriate to user needs and manufacturing specifications. All reasonable additions, deletions, modifications and alterations are to be considered equivalents of the described examples and embodiments are to be included within the scope of the following claims.
This present application is a continuation-in-part of co-pending U.S. application Ser. No. 16/729,399 filed Dec. 29, 2019, and entitled “LIGHT CAPSULE”, the entire disclosure of which is expressly incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16729399 | Dec 2019 | US |
| Child | 18241822 | US |
