Iron–sulfur clusters are essential cofactors found in all kingdoms of life and play essential roles in fundamental processes, including but not limited to respiration, photosynthesis, and nitrogen fixation. The chemistry of iron–sulfur clusters makes them ideal for sensing various redox environmental signals, while the physics of iron–sulfur clusters and its host proteins have been long overlooked. One such protein, MagR, has been proposed as a putative animal magnetoreceptor. It forms a rod-like complex with cryptochromes (Cry) and possesses intrinsic magnetic moment. However, the magnetism modulation of MagR remains unknown. Here in this study, iron–sulfur cluster binding in MagR has been characterized. Three conserved cysteines of MagR play different roles in iron–sulfur cluster binding. Two forms of iron–sulfur clusters binding have been identified in pigeon MagR and showed different magnetic properties: [3Fe–4S]-MagR appears to be superparamagnetic and has saturation magnetization at 5 K but [2Fe–2S]-MagR is paramagnetic. While at 300 K, [2Fe–2S]-MagR is diamagnetic but [3Fe–4S]-MagR is paramagnetic. Together, the different types of iron–sulfur cluster binding in MagR attribute distinguished magnetic properties, which may provide a fascinating mechanism for animals to modulate the sensitivity in magnetic sensing.

Reductive thermal treatment of lithium-ion battery (LIB) cathode material (LiCoO2) by H2 was investigated as an environmentally benign LIB recycling process. Thermogravimetric analysis of recovered LiCoO2 cathode material showed that complete reduction of LiCoO2 to Li compounds and Co by H2 took place at a lower temperature compared to that by carbothermal reduction with graphite in N2 atmosphere. Thermal reduction at 600 °C with 5% H2 demonstrated the conversion of LiCoO2 to Co and Li2O in 120 min. These compounds were successfully separated by water leaching and wet-magnetic separation. During reduction with H2 in the presence of carbon, Li2CO3 was found to form, indicating that the complete removal of carbon is necessary to produce LiOH. The activation energy for thermal reduction with hydrogen was determined by model-free kinetic analysis. In comparison with carbothermal reduction, thermal reduction using hydrogen results in a 65% decrease in activation energy.

magnetic field. From the discovery of electromagnetic induction to the quantum Hall effect, humans have strived for seeking applicability of novel mechanisms in the magneto-sensors. [2] Currently, the magneto-sensors are generally based on the quantum effects, which relies on a highly sensitive interface of semiconductor materials commonly fabricated by epitaxial growth. [3] With development of flexible electronics and bioelectronics, these semiconductor based technics seem increasingly unsuitable for the biomedical applications.Interestingly, some species possess an amazing capability of magneto-perception such as migratory birds, [4] butterflies, [5] and honeybees. [6] These animals perceive the geomagnetic field relying on special proteins. Cryptochrome (Cry) has been considered for a long time to mediate the magneto-perception via quantum spin dynamics of light-induced radical-pair, which are excited by sunlight and can be modulated by the geomagnetic field. [7][8][9] This principle was employed to sense the magnetic field because the life-time and the spectral characteristic of radical pair in singlet and triplet states can reflect the information about magnetic field. [10] Cry played an important role in the During billions of years of evolution, some species develop fantastic magnetoperception, offering a biomimetic route to develop the next generation of magneto-sensors. Recently, a novel principle was proposed to explain the navigation of pigeons in the presence of geomagnetic fields and sunlight. The key link is thought to lie in the magneto-optically involved conformational variation of magnetoreceptor protein (MagR)/cryptochrome (Cry4) complex. The MagR/Cry4 complex is fabricated and purified in vitro, creating a magnetosensing device by immobilization of this protein on a graphene-modified electrochemical electrode. By using electrochemical impedance spectroscopy, magneto-sensing with a current detectability of 10 mT is realized with MagR/ Cry4 complex. It is proved that this process requires the involvement of both magnetic fields and light, partly confirming in vitro the magneto-perceptive mechanism of MagR/Cry4 complex. It is also shows that this device can be used to reflect the anisotropic responses of nanomaterials to the external magnetic field. It is believed this protein-based magneto-sensing will greatly boost development of bioelectronics and deepen understanding of the phenomena of magneto-perception for organisms.

Cooling infrastructures contribute about 50% of total energy consumption in a typical data center. Computer models are pivotal in designing and optimizing energy-efficient cooling systems to reduce excessive cooling energy consumption. Compared to the conventional building energy simulation tools, equation-based object-oriented modeling language Modelica is an emerging approach that can enable fast modeling and simulation of the dynamic cooling system in data centers. In this paper, we introduce a newly developed open source data center package in the Modelica Buildings library to support the fast modeling and simulation of cooling and control systems of data centers. The data center package contains major thermal and control component models, such as Computer Room Air Handler, Computer Room Air Conditioner, models of different subsystem configurations such as chillers with differently configured waterside economizer, as well as templates for different systems. Furthermore, we utilize the new package to perform a case study on the operation of a cooling system in the data center. In this case study, we investigate the performances of the cooling system under normal conditions and emergency situations such as blackout. The case study shows that the dynamic modeling and multi-domain co-simulation in the Modelica-based tool make it convenient for users to investigate not only the thermal performance but also the electrical performance of the data centers.

The SWNTs/DDAB film modified glassy carbon electrode was successfully prepared to study the electrochemical behavior of hemoglobin (Hb). A better electrochemical response was observed than that on the DDAB or SWNTs film modified electrode. Cyclic voltammetry of Hb showed two pairs of well-defined and nearly reversible peaks. The electrochemical reaction of hemoglobin on the SWNTs/DDAB film modified electrode was controlled by absorption. Using the SWNTs/DDAB film modified electrode, the interaction between hemoglobin and tar was studied.