Double-Deck Metal Solenoids 3D Integrated in Silicon Wafer for Kinetic Energy Harvester

A silicon-chip based double-deck three-dimensional (3D) solenoidal electromagnetic (EM) kinetic energy harvester is developed to convert low-frequency (<100 Hz) vibrational energy into electricity with high efficiency. With wafer-level micro electro mechanical systems (MEMS) fabrication to form a metal casting mold and the following casting technique to rapidly (within minutes) fill molten ZnAl alloy into the pre-micromachined silicon mold, the 300-turn solenoid coils (150 turns for either inner solenoid or outer solenoid) are fabricated in silicon wafers for saw dicing into chips. A cylindrical permanent magnet is inserted into a pre-etched channel for sliding upon external vibration, which is surrounded by the solenoids. The size of the harvester chip is as small as 10.58 mm × 2.06 mm × 2.55 mm. The internal resistance of the solenoids is about 17.9 Ω. The maximum peak-to-peak voltage and average power output are measured as 120.4 mV and 43.7 μW. The EM energy harvester shows great improvement in power density, which is 786 μW/cm3 and the normalized power density is 98.3 μW/cm3/g. The EM energy harvester is verified by experiment to be able to generate electricity through various human body movements of walking, running and jumping. The wafer-level fabricated chip-style solenoidal EM harvesters are advantageous in uniform performance, small size and volume applications

Analysis of Motor Complication and Relative Factors in a Cohort of Chinese Patients with Parkinson’s Disease

Objective. Motor complications are common in Parkinson’s disease (PD). The reported occurrence of motor complications varies across regions and races. The aim of our study was to describe the development of dyskinesias and motor fluctuations among Chinese PD patients and the relative risk factors. Methods. In the current cross-sectional survey study, PD patients with motor fluctuations and dyskinesia were enrolled from March to November 2018 in Shaanxi province, a northwest area of China. Data were collected by the movement disorder specialists. A self-designed questionnaire was utilized during face-to-face interviews. In addition, the relevant factors of motor complications were analyzed by univariable and multivariable analyses. Results. Of the166 PD patients recruited, 52 (31.33%) and 25 (15.06%) patients had motor fluctuations and dyskinesia, respectively, which occurred in 6.76 ± 3.77 and 8.61 ± 4.46 years after the onset of motor symptoms and 5.37 ± 3.33 and 6.80 ± 3.43 years after the treatment of levodopa therapy, respectively. Patients with motor fluctuations and dyskinesias had longer disease duration, younger onset age, higher Hoehn–Yahr stages and UPDRS III scores, higher daily levodopa dosage and levodopa equivalent daily dose (LEDD), and longer duration of levodopa treatment (P<0.05). Bradykinesia-rigidity dominant patients had higher incidences of motor fluctuations (61.54% vs 38.46%) and dyskinesias (68.00% vs 32.00%) than tremor-dominant patients (P<0.05). Results of the multivariate logistic regression analyses showed that the duration of levodopa therapy, age of the onset, and bradykinesia-rigidity dominant type were independent risk factors of motor fluctuations (P<0.05). In addition, duration of disease and bradykinesia-rigidity dominant type were independent risk factors of dyskinesia (P<0.05). Conclusions. The rate of motor fluctuations was higher than dyskinesias in Chinese patients with Parkinson’s disease. Patients with younger age onset, bradykinesia-rigidity dominant type, longer disease duration, and longer duration of levodopa therapy are more likely to develop motor complications

An Energy Harvester with Temperature Threshold Triggered Cycling Generation for Thermal Event Autonomous Monitoring

This paper proposes a temperature threshold triggered energy harvester for potential application of heat-event monitoring. The proposed structure comprises an electricity generation cantilever and a bimetallic cantilever that magnetically attract together. When the structure is heated to a pre-set temperature threshold, the heat absorption induced bimetallic effect of the bimetallic cantilever will cause sufficient bending of the generation cantilever to get rid of the magnetic attraction. The action triggers the freed generation cantilever into resonance to piezoelectrically generate electricity, and the heated bimetallic cantilever dissipates heat to the environment. With the heat dissipated, the bimetallic cantilever will be restored to attract with the generation cantilever again and the structure returns to the original state. Under continual heating, the temperature threshold triggered cycle is repeated to intermittently generate electric power. In this paper, the temperature threshold of the harvester is modeled, and the harvester prototype is fabricated and tested. The test results indicate that, with the temperature threshold of 71 °C, the harvesting prototype is tested to generate 1.14 V peak-to-peak voltage and 1.077 μW instantaneous power within one cycle. The thermal harvesting scheme shows application potential in heat event-driven autonomous monitoring

MEMS-Casting Fabricated Chip-Style 3D Metal Solenoidal Transformers towards Integrated Power Supply

A silicon-chip-based 3D metal solenoidal transformer is proposed and developed to achieve AC-DC conversion for integrated power supply applications. With wafer-level micro electromechanical systems (MEMS) fabrication technique to form the metal casting mold and the following micro-casting technique to rapidly (within 6 min) fill molten ZnAl alloy into the pre-micromachined silicon mold, 45-turns primary solenoid and 7-turns secondary solenoid are fabricated in silicon wafers, where the two intertwining solenoids are located at inner deck and outer deck, respectively. Permalloy soft magnetic core is inserted into a pre-etched channel in the silicon chip, which is surrounded by the solenoids. The size of the chip-style transformer is as small as 8.5 mm × 6.6 mm × 2.5 mm. The internal resistance of the primary solenoid is 1.82 Ω and that of the secondary solenoid is 0.16 Ω. The working frequency of the transformer is 60 kHz. Combined with the testing circuit of the switch mode power supply, the DC voltage of 13.02 V is obtained when the input is 110 V at 50 Hz/60 Hz. Furthermore, the on-chip 3D solenoidal transformer is used for lighting four LEDs, which shows great potential for AC-DC power supply. The wafer-level fabricated chip-style solenoidal AC-DC transformer for integrated power supply is advantageous in uniform fabrication, small size and volume applications

Understanding the pH-Dependent Reaction Mechanism of a Glycoside Hydrolase Using High-Resolution X-ray and Neutron Crystallographyülcih

Glycoside hydrolases (GHs) commonly use the retaining or inverting mechanisms to hydrolyze carbohydrates, and the rates of catalysis are usually pH dependent. Deeper understanding of these pH-dependent reaction mechanisms is of great importance for protein engineering and drug design. We used high-resolution X-ray crystallography to analyze the sugar ring configurations of an oligosaccharide ligand during hydrolysis for the family 11 GH, and the results support the 1S3 → 4H3 → 4C1 conformational itinerary. These results indicate that sugar ring flexibility may help to distort and break the glycosidic bond. Constant pH molecular dynamics simulations and neutron crystallography demonstrate that the catalytic glutamate residue (E177) has alternate conformational changes to transfer a proton to cleave the glycosidic bond. Furthermore, a neutron crystallography analysis shows that the H-bond length between E177 and its nearby tyrosine residue (Y88) is shortened when the pH increases, preventing E177 from rotating downward and obtaining a proton from the solvent for catalysis. This result indicates that the H-bond length variation may play a key role in the pH-dependent reaction mechanism. In summary, our results demonstrate that both sugar ring flexibility and protein dynamics are important in the pH-dependent reaction mechanism and may help to engineer GHs with different pH optima

Understanding the pH-Dependent Reaction Mechanism of a Glycoside Hydrolase Using High-Resolution X‑ray and Neutron Crystallography

Glycoside hydrolases (GHs) commonly use the retaining or inverting mechanisms to hydrolyze carbohydrates, and the rates of catalysis are usually pH dependent. Deeper understanding of these pH-dependent reaction mechanisms is of great importance for protein engineering and drug design. We used high-resolution X-ray crystallography to analyze the sugar ring configurations of an oligosaccharide ligand during hydrolysis for the family 11 GH, and the results support the ¹S₃ → ⁴H₃ → ⁴C₁ conformational itinerary. These results indicate that sugar ring flexibility may help to distort and break the glycosidic bond. Constant pH molecular dynamics simulations and neutron crystallography demonstrate that the catalytic glutamate residue (E177) has alternate conformational changes to transfer a proton to cleave the glycosidic bond. Furthermore, a neutron crystallography analysis shows that the H-bond length between E177 and its nearby tyrosine residue (Y88) is shortened when the pH increases, preventing E177 from rotating downward and obtaining a proton from the solvent for catalysis. This result indicates that the H-bond length variation may play a key role in the pH-dependent reaction mechanism. In summary, our results demonstrate that both sugar ring flexibility and protein dynamics are important in the pH-dependent reaction mechanism and may help to engineer GHs with different pH optima