ASCH-PUF: A "Zero" Bit Error Rate CMOS Physically Unclonable Function with Dual-Mode Low-Cost Stabilization

Physically unclonable functions (PUFs) are increasingly adopted for low-cost and secure secret key and chip ID generations for embedded and IoT devices. Achieving 100% reproducible keys across wide temperature and voltage variations over the lifetime of a device is critical and conventionally requires large masking or Error Correction Code (ECC) overhead to guarantee. This paper presents an Automatic Self Checking and Healing (ASCH) stabilization technique for a state-of-the-art PUF cell design based on sub-threshold inverter chains. The ASCH system successfully removes all unstable PUF cells without the need for expensive temperature sweeps during unstable bit detection. By accurately finding all unstable bits without expensive temperature sweeps to find all unstable bits, ASCH achieves ultra-low bit error rate (BER), thus significantly reducing the costs of using ECC and enrollment. Our ASCH can operate in two modes, a static mode (S-ASCH) with a conventional pre-enrolled unstable bit mask and a dynamic mode (D-ASCH) that further eliminates the need for non-volatile memories (NVMs) for storing masks. The proposed ASCH-PUF is fabricated and evaluated in 65nm CMOS. The ASCH system achieves "0" Bit Error Rate (BER, < 1.77E-9) across temperature variations of -20{\deg}C to 125{\deg}C, and voltage variations of 0.7V to 1.4V, by masking 31% and 35% of all fabricated PUF bits in S-ASCH and D-ASCH mode respectively. The prototype achieves a measured throughput of 11.4 Gbps with 0.057 fJ/b core energy efficiency at 1.2V, 25{\deg}C.Comment: This paper has been accepted to IEEE Journal of Solid-State Circuits (JSSC

A Compact Operational Amplifier with Load-Insensitive Stability Compensation for High-Precision Transducer Interface

High-resolution electronic interface circuits for transducers with nonlinear capacitive impedance need an operational amplifier, which is stable for a wide range of load capacitance. Such operational amplifier in a conventional design requires a large area for compensation capacitors, increasing costs and limiting applications. In order to address this problem, we present a gain-boosted two-stage operational amplifier, whose frequency response compensation capacitor size is insensitive to the load capacitance and also orders of magnitude smaller compared to the conventional Miller-compensation capacitor that often dominates chip area. By exploiting pole-zero cancellation between a gain-boosting stage and the main amplifier stage, the compensation capacitor of the proposed operational amplifier becomes less dependent of load capacitance, so that it can also operate with a wide range of load capacitance. A prototype operational amplifier designed in 0.13-μ m complementary metal–oxide–semiconductor (CMOS) with a 400-fF compensation capacitor occupies 900-μ m² chip area and achieves 0.022–2.78-MHz unity gain bandwidth and over 65°phase margin with a load capacitance of 0.1–15 nF. The prototype amplifier consumes 7.6 μW from a single 1.0-V supply. For a given compensation capacitor size and a chip area, the prototype design demonstrates the best reported performance trade-off on unity gain bandwidth, maximum stable load capacitance, and power consumption. Keywords: analog integrated circuits; operational amplifiers; transducer interface circuit; Internet of Things (IoT) devic

Accelerated Degradation of Perfluorosulfonates and Perfluorocarboxylates by UV/Sulfite + Iodide: Reaction Mechanisms and System Efficiencies.

The addition of iodide (I-) in the UV/sulfite system (UV/S) significantly accelerated the reductive degradation of perfluorosulfonates (PFSAs, CnF2n+1SO3-) and perfluorocarboxylates (PFCAs, CnF2n+1COO-). Using the highly recalcitrant perfluorobutane sulfonate (C4F9SO3-) as a probe, we optimized the UV/sulfite + iodide system (UV/S + I) to degrade n = 1-7 PFCAs and n = 4, 6, 8 PFSAs. In general, the kinetics of per- and polyfluoroalkyl substance (PFAS) decay, defluorination, and transformation product formations in UV/S + I were up to three times faster than those in UV/S. Both systems achieve a similar maximum defluorination. The enhanced reaction rates and optimized photoreactor settings lowered the EE/O for PFCA degradation below 1.5 kW h m-3. The relatively high quantum yield of eaq- from I- made the availability of hydrated electrons (eaq-) in UV/S + I and UV/I two times greater than that in UV/S. Meanwhile, the rapid scavenging of reactive iodine species by SO32- made the lifetime of eaq- in UV/S + I eight times longer than that in UV/I. The addition of I- also substantially enhanced SO32- utilization in treating concentrated PFAS. The optimized UV/S + I system achieved &gt;99.7% removal of most PFSAs and PFCAs and &gt;90% overall defluorination in a synthetic solution of concentrated PFAS mixtures and NaCl. We extended the discussion over molecular transformation mechanisms, development of PFAS degradation technologies, and the fate of iodine species

Platelet-Membrane-Encapsulated Carvedilol with Improved Targeting Ability for Relieving Myocardial Ischemia–Reperfusion Injury

In recent years, cell membrane drug delivery systems have received increasing attention. However, drug-loaded membrane delivery systems targeting therapy in myocardial ischemia–reperfusion injury (MIRI) have been relatively rarely studied. The purpose of this study was to explore the protective effect of platelet-membrane-encapsulated Carvedilol on MIRI. We extracted platelets from the blood of adult SD rats and prepared platelet membrane vesicles (PMVs). Carvedilol, a nonselective β-blocker, was encapsulated into the PMVs. In order to determine the best encapsulation rate and drug-loading rate, three different concentrations of Carvedilol in low, medium, and high amounts were fused to the PMVs in different volume ratios (drugs/PMVs at 2:1, 1:1, 1:2, and 4:1) for determining the optimum concentration and volume ratio. By comparing other delivery methods, including abdominal injection and intravenous administration, the efficacy of PMVs-encapsulated drug-targeted delivery treatment was observed. The PMVs have the ability to target ischemic-damaged myocardial tissue, and the concentration and volume ratio at the optimum encapsulation rate and the drug-loading rate are 0.5 mg and 1:1. We verified that PMVs@Carvedilol had better therapeutic effects compared to other treatment groups, and immunofluorescence observation showed a significant improvement in the apoptosis indicators and infarction area of myocardial cells. Targeted administration of PMVs@Carvedilol may be a promising treatment for myocardial reperfusion injury, as it significantly improves postinjury cardiac function and increases drug utilization compared to other delivery methods

A wireless millimetric magnetoelectric implant for the endovascular stimulation of peripheral nerves.

Funder: NIH U18EB029353, NSF GRFPFunder: NIH U18EB029353Funder: NIH R01DE021798, NSF GRFPFunder: NIH R01DE021798Implantable bioelectronic devices for the simulation of peripheral nerves could be used to treat disorders that are resistant to traditional pharmacological therapies. However, for many nerve targets, this requires invasive surgeries and the implantation of bulky devices (about a few centimetres in at least one dimension). Here we report the design and in vivo proof-of-concept testing of an endovascular wireless and battery-free millimetric implant for the stimulation of specific peripheral nerves that are difficult to reach via traditional surgeries. The device can be delivered through a percutaneous catheter and leverages magnetoelectric materials to receive data and power through tissue via a digitally programmable 1 mm × 0.8 mm system-on-a-chip. Implantation of the device directly on top of the sciatic nerve in rats and near a femoral artery in pigs (with a stimulation lead introduced into a blood vessel through a catheter) allowed for wireless stimulation of the animals' sciatic and femoral nerves. Minimally invasive magnetoelectric implants may allow for the stimulation of nerves without the need for open surgery or the implantation of battery-powered pulse generators