A dialysis system (e.g., a hemodialysis (HD) system) can be designed to operate in alternative environments, such as disaster relief settings or underdeveloped regions. The dialysis system can include a solar panel for generating electricity to power the dialysis machine and an atmospheric water generator for extracting water from ambient air. The extracted water can be used to generate dialysate and saline on-site. One or more of the components of the dialysis machine can be discrete components that are configured to facilitate fast shipping and simple on-site assembly (e.g., at a remote location). In some implementations, the discrete components may be configured to be attached to an existing dialysis system (e.g., a dialysis system designed for operation in a traditional environment) to permit the dialysis system to operate in an alternative environment.

Described herein are implantable devices configured to detect an electrophysiological signal. Certain exemplary implantable devices comprise a first electrode and a second electrode configured to engage a tissue and detect an electrophysiological signal; an integrated circuit comprising a multi-transistor circuit and a modulation circuit configured to modulate a current based on the electrophysiological signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter encoding the electrophysiological signal from the tissue based on the modulated current. Also described herein are systems that include one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Further described are computer systems for operating one or more implantable devices, and methods of detecting an electrophysiological signal in a tissue.

Various methods and apparatus disclosed herein relate to apparatus and techniques for harvesting energy from operation of a syringe, and utilizing that energy for various purposes. In various embodiments, a method (400) for harvesting and using electrical energy during operation of a syringe (100, 300) may include: operating (402) the syringe, wherein operating includes displacing a plunger (112) of the syringe to draw fluid into a reservoir (114) of the syringe or expel fluid from the reservoir of the syringe; converting (404), by an electrical generator (120, 122) that is integral with the syringe, motion associated with displacing the plunger into electrical energy; and using (406) at least some of the electrical energy to at least temporarily store, in a memory component (136) integral with the syringe, one or more data points associated with operation of the syringe.

A dialysis system (e.g., a hemodialysis (HD) system) can be designed to operate in alternative environments, such as disaster relief settings or underdeveloped regions. The dialysis system can include a solar panel for generating electricity to power the dialysis machine and an atmospheric water generator for extracting water from ambient air. The extracted water can be used to generate dialysate and saline on-site. One or more of the components of the dialysis machine can be discrete components that are configured to facilitate fast shipping and simple on-site assembly (e.g., at a remote location). In some implementations, the discrete components may be configured to be attached to an existing dialysis system (e.g., a dialysis system designed for operation in a traditional environment) to permit the dialysis system to operate in an alternative environment.

Described herein are implantable devices configured to emit an electrical pulse. An exemplary implantable device includes an ultrasonic transducer configured to receive ultrasonic waves that power the implantable device and encode a trigger signal; a first electrode and a second electrode configured to be in electrical communication with a tissue and emit an electrical pulse to the tissue in response to the trigger signal; and an integrated circuit comprising an energy storage circuit. Also described are systems that include one or more implantable device and an interrogator configured to operate the one or more implantable devices. Further described is a closed loop system that includes a first device configured to detect a signal, an interrogator configured to emit a trigger signal in response to the detected signal, and an implantable device configured to emit an electrical pulse in response to receiving the trigger signal. Further described are computer systems useful for operating one or more implantable devices, as well as methods of electrically stimulating a tissue.

Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

Described herein are implantable devices configured to detect an electrophysiological signal. Certain exemplary implantable devices comprise a first electrode and a second electrode configured to engage a tissue and detect an electrophysiological signal; an integrated circuit comprising a multi-transistor circuit and a modulation circuit configured to modulate a current based on the electrophysiological signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter encoding the electrophysiological signal from the tissue based on the modulated current. Also described herein are systems that include one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Further described are computer systems for operating one or more implantable devices, and methods of detecting an electrophysiological signal in a tissue.

A bone conduction device includes: an enclosure; and an adhesive applied to a surface of the enclosure, in which the enclosure includes: a bone conduction transducer configured to cause the enclosure to vibrate; at least one sensor configured to sense a non-audible input from a region of the user's skin to which the adhesive adheres and produce a sensor output signal in response to sensing the non-audible input, the sensor output signal being indicative of a current state of the user; and a transceiver coupled to the bone conduction transducer and to the at least one sensor, in which the transceiver is configured to a) receive the output signal from the sensor and transmit the output signal to a remote processor and b) in response to transmitting the output signal, receive the bone-conduction control signal from the remote processor and transmit the bone-conduction control signal to the bone conduction transducer.

Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation. Further described are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also describe are computer systems for operating implantable devices, methods of detecting radiation, methods of treating a solid cancer in a subject, and methods of monitoring a subject for recurrence of a solid cancer.