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TPMS (triply periodic minimal surface) sheet structure consists of a spatially continuous surface, which forms a periodic porous structure, and has outstanding mechanical performance and ultralight...

Three bimetallic organic-inorganic hybrids based on the [V2O6]2- building unit, [Cu(pty)(V2O6)]·H2O (1), [Cu(pty)(V2O6)] (2), [Cu(tpy)(V2O6)] (3), (pty = 4'-(4″-pyridyl)-2,2':6',2″-terpyridine, tpy = 2,2':6',2″-terpyridine), were synthesized via a one-pot method. Hybrid 1 has a 1D straight chain architecture with [V2O6]2- clusters and Cu-pty complexes; hybrids 2 and 3 possess a 2D sheet structure including 10-membered rings assembled from four [Cu(pty)]2+ motifs and six [V2O6]2- clusters in 2, and two [Cu(tpy)]2+ units and eight [V2O6]2- clusters in 3. Noteworthy, hybrids 1-3 can be employed as bifunctional electrocatalysts for electroreduction of nitrite and electrooxidation of ascorbic acid. Additionally, theoretical calculations including the molecular electrostatic potential and the frontier molecular orbital were performed to estimate the electronic structure of hybrids 1-3. The natural bond orbital analysis was also calculated to interpret the electron charge distribution.

Self-assembly of [Hg(SeCN)4]2- tetrahedral building blocks, iron(II) ions, and a series of bis-monodentate pyridyl-type bridging ligands has afforded the new heterobimetallic HgII-FeII coordination polymers {Fe[Hg(SeCN)3]2(4,4'-bipy)2}n (1), {Fe[Hg(SeCN)4](tvp)}n (2), {Fe[Hg(SeCN)3]2(4,4'-azpy)2}n (3), {Fe[Hg(SeCN)4](4,4'-azpy)(MeOH)}n (4), {Fe[Hg(SeCN)4](3,3'-bipy)}n (5) and {Fe[Hg(SeCN)4](3,3'-azpy)}n (6) (4,4-bipy = 4,4'-bipyridine, tvp = trans-1,2-bis(4-pyridyl)ethylene, 4,4'-azpy = 4,4'-azobispyridine, 3,3-bipy = 3,3'-bipyridine, 3,3'-azpy = 3,3'-azobispyridine). Single-crystal X-ray analyses show that compounds 1 and 3 display a two-dimensional robust sheet structure made up of infinite linear [(FeL)n]2n+ (L = 4,4'-bipy or 4,4'-azpy) chains linked by in situ formed {[Hg(L)(SeCN)3]2}2- anionic dimeric bridges. Complexes 2 and 4-6 define three-dimensional networks with different topological structures, indicating, in combination with complexes 1 and 3, that the polarity, length, rigidity, and conformation of the bridging organic ligand play important roles in the structural nature of the products reported here. The magnetic properties of complexes 1 and 2 show the occurrence of temperature- and light-induced spin crossover (SCO) properties, while complexes 4-6 are in the high-spin state at all temperatures. The current results provide a new route for the design and synthesis of new SCO functional materials with non-Hofmann-type traditional structures.

The morphology of ZnS(en)0.5 (en is ethylenediamine) has a significant influence on its derived ZnS and ZnO. Herein, we study the impact of the amount of ethylenediamine (EDA) and ultrasonic device with different power on the preparation of ZnS(en)0.5 nanosheets. The more EDA and the lower power ultrasonic device make the thinner nanosheets. After annealing the ZnS(en)0.5 at a different temperature, the porous ZnS and composite nanostructure ZnO are obtained. The ZnS annealed at 450°C with sheet structure has many holes. For the ZnO annealed at 550°C, the unique edge belt-like structure is firstly discovered and the interior is still porous sheet. The belt-like structure is speculated to the topotactic transformation of the ZnS to ZnO.

Nowadays, due to the most application of montmorillonite, its purification from raw bentonite has great importance. More than 76% of bentonite is composed of montmorillonite, and its industrial applications are related to its montmorillonite content. In this study, the nanoclay was extracted from bentonite by the use of centrifugal force. The results of the field-emission scanning electron microscopy (FE-SEM) analysis show that the nanosized of purified montmorillonite has a sheet structure with a spacing of 22.41 nm and 45.0 nm. The sharp peaks in X-ray diffraction analysis (XRD) illustrated that the montmorillonite purified successfully, and the results of Fourier-transform infrared spectrophotometry (FT-IR) revealed the successful incorporation of the metabolic extraction within the montmorillonite. By comparison of Brunauer–Emmett–Teller (BET) results with IUPAC, it can be realized that the synthesized montmorillonite nanoclay has a microporous structure (

The results of an end-to-end quality evaluation of continuous cast SS400 steel slabs, followed by its hot-rolled thick-sheet products in ship-delivered batches, are presented. The evaluation of the frequency distribution of defects for each of the continuous casting machines (CCMs) revealed the following: even during control fire cleaning, the surface quality of slabs from CCM No. 1 was slightly lower (1.1–2.0%) than from CCM No. 2; the finished sheets from slabs casted at CCM No. 1 have a better quality than from slabs casted at CCM No. 2. At the same time, on both machines, the quality of slabs from strand No. 2 is better than from strand No. 1. The unstable internal quality of the sheet with a thickness of 30–45 mm was due to restrictions imposed on the maximum thickness of the sheet which was 25.0 mm. During microstructural analysis of the causes of cracks and segregation nature, it was found that the presence of non-metallic inclusions in the sheet structure serves, in fact, as a source of crack development. Analysis using energy-dispersive x-ray spectroscopy (EDX) showed that nonmetallic inclusions in the dominant mass are manganese sulfides.

Fracture or fault can control several geological or geophysical events and exploration, where the fault associated with mineralization or fluid flow can be used as a source for Self-Potential (SP) anomaly. The 2-D inclined sheet can be used for modeling for fault interpretation using SP data. In this paper, the improved crow search algorithm (ICSA) using Levy flight is proposed for SP data inversion in determining SP model parameters. In order to evaluate ICSA, the ICSA is compared with standard crow search algorithm (CSA) for determining synthetic SP data that contains multiple anomalies with inclined sheet type structures. It was found that CSA is more explorative than ICSA, and both algorithms can estimate the posterior distribution model (PDM) of SP data. Using uncertainty analysis within the applied threshold in the objective function, both algorithms are reliable to determine PDM. Furthermore, ICSA is tested and implemented to both synthetic and field of SP anomalies for providing the posterior distribution model of SP parameters. The experimental results demonstrate that the ICSA is feasible and effective for determining model parameters and its uncertainty of mono- and multi-SP anomalies. Furthermore, estimating both model parameter and its uncertainty are sufficient for validation with previous researchers. Finally, the interpretation of multiple anomalies in SP anomaly crossing the Grindulu Fault in Pacitan, East Java, Indonesia, is analyzed.

Two-dimensional (2D) nanomaterials possessing a unique sheet structure, compared to correlative bulk materials, exhibit excellent properties, especially in the energy storage and energy conversion ...

This letter presents a soft compact valve inducing self-excited vibration to be aimed for simplification of piping, power saving and downsizing the total system for pneumatic soft mobile robots generating traveling waves. The presented device is composed of flat tubes, permanent magnets, and restraint parts. It is capable of switching the inner pressure among three isolated chambers alternately and periodically by using the constant air pressure supplied from a single line. In this letter, we describe the driving principle of the valve to switch different chambers automatically, while detecting the pre-set pressure inside each chamber without sensors. The prototype has a flexible sheet structure with a mass of 5.1 g and a thickness of 10 mm, and was examined to induce a self-excited vibration of 0.6 Hz by air supply of 80 kPa. Moreover, it was also confirmed that when the developed valve was mounted on a flexible seat-type mobile, it was possible to propel through a narrow space with 25 mm gap smoothly while generating traveling waves. Finally, the effectiveness of the proposed valve is discussed through the experimental results.

Introduction Regenerative therapy using chondrocyte sheets is effective for osteoarthritis. The clinical application of chondrocyte sheet therapy is expected to be further advanced by the use of a feasible cryopreservation technique. Previously, we developed a chondrocyte sheet vitrification method; however, it was too complex to be used for routine clinical application. Here, we aimed to develop a prototype method for vitrifying chondrocyte sheets for clinical practice. Methods We developed a “circulating vitrification bag” as a container to process cell sheets for vitrification in an efficient and sanitary fashion. Moreover, we invented the “vitrification storage box”, which is useful for the vitrification of cell sheets, long-term preservation, and transportation. These devices were used to vitrify rabbit chondrocyte sheets, which were then assessed for their structural characteristics and the viability of the component cells after rewarming. Results In all cell sheet samples (n = 7) vitrified by the circulating vitrification bag method, the integrity of the sheet structure was maintained, and the cell survival rate was similar to that of non-vitrified samples (91.0 ± 2.9% vs. 90.0 ± 3.0%). Proteoglycan and type II collagen, which are major components of cartilage, were densely and evenly distributed throughout the chondrocyte sheet subjected to vitrification similarly to that observed in the non-vitrified sheet. After long-term storage using the vitrification storage box, the cell sheets maintained normal structure and cell viability (survival rate: 81.2 ± 1.0% vs. 84.3 ± 1.8%) compared to the non-vitrified sheet. Conclusion Our results indicate that the circulating vitrification bag method is an effective approach for realizing the clinical application of vitrified chondrocyte sheets. The vitrification storage box is also useful for the long-term preservation of vitrified cell sheets, further enhancing the feasibility of the clinical application of cryopreserved chondrocyte sheets., Highlights • We developed a new device and method for the cryopreservation of cell sheets. • The method and device efficacy were evaluated using vitrified rabbit chondrocyte sheets. • Our approach allows efficient clinical application of vitrified cell sheets.

Graphyne sheets and nanotubes (GyNTs) are known as novel low-dimensional, i.e., two-dimensional (2D) and one-dimensional (1D), semiconducting carbon allotropes that can be used in nanoelectronics and therefore merit fundamental investigation. Among such materials, attention is currently focused on γ-graphyne-1, a member of the graphyne family that exhibits a maximum cohesive energy of −8.37 eV and chemical stabilityhas been focused. In this research density functional tight binding (DFTB) method in the investigation of electrical property under geometrical variation is reported and a detailed description of electrical as well as stability properties for γ-graphyne-1 in uniform strain is illustrated. It is concluded that the γ-graphyne-1 family of materials exhibit semiconducting properties with large bandgap values from 1.34 eV for the sheet structure to 1.93 eV for (3,0) armchair γ-graphyne-1 nanotubes. The γ-graphyne-1 family also displays elastic properties, enabling the modulation of the bandgap and engineering of the effective mass using homogeneous strain. These properties, along with the nonmetallic behavior of GyNTs, make them perfect materials for the design of novel electronic devices.

As a new type of variable thickness sheet structure, the TRB (tailor rolled blank) has good prospects for the development of lightweight materials in the automotive industry. However, springback is a key issue in production. Research on TRB springback characteristics has great significance for further applications due to variations in the sheet thickness and gradient distribution of the material mechanical properties. In this study, the springback characteristics of TRBs were investigated by means of the finite element code ABAQUS/USDFLD and experiments taking cylindrical bending as an example. The results showed that the cylindrical bending process of the TRB gradually evolved from three-point bending to four-point bending and, finally, to multipoint bending. At same time, the gradient of the thickness leads to the nonuniform longitudinal distribution of the von Mises stress. On the contrary, larger bending angles can be achieved by reducing R and improving Rd, but t/T has little effect on the bending angles. In terms of the influence of springback, increasing Rd and reducing R and t/T can lead to a smaller springback angle. This project provided an important opportunity to advance the understanding of TRB springback characteristics.

Chiral analysis of bioactive molecules is of increasing significance in chemical and life sciences. However, the quantitative detection of a racemic mixture of enantiomers is a challenging task, which relies on complicated and time-consuming multiple steps of chiral derivatization, chiral separation, and spectroscopic measurement. Herein, we show that, without the use of chiral molecules or pretreatment steps, the co-assembly of amino acids with achiral TPPS4 monomers controlled by enantiomorphic microvortices allows quantitative detection of racemic or enantiomeric amino acids, through analysis of the sign and magnitude of supramolecular chirality in different outlets of a microfluidic platform. A model demonstrates that chiral microvortices can induce an initial chiral bias by bending the sheet structure, resulting in supramolecular self-assembly of TPPS4 and amino acids of compatible chirality by the self-sorting. This sensing system may find versatile applications in chiral sensing.

Two noncentrosymmetric haloplumbate hybrids, [C6H10(NH3)2][PbCl4] (1) and [C6H10(NH3)2][PbBr4] (2), have been synthesized. Crystals of 1 and 2 belong to the chiral space group P212121. The inorganic parts comprise a one-dimensional chain structure for 1 and a two-dimensional sheet structure for 2. Both compounds exhibit thermochromic luminescence originating from dual emission and have potential applications as self-referencing luminescent thermometers.

The title compound, C15H10I2O, is a halogenated chalcone formed from two iodine substituted rings, one para-substituted and the other meta-substituted, linked through a prop-2-en-1-one spacer. The crystal structure shows the mol­ecules contain halogen bonds which are always between equivalent iodine atoms, either para–para or meta–meta., The title compound, C15H10I2O, is a halogenated chalcone formed from two iodine substituted rings, one para-substituted and the other meta-substituted, linked through a prop-2-en-1-one spacer. In the mol­ecule, the mean planes of the 3-iodo­phenyl and the 4-iodo­phenyl groups are twisted by 46.51 (15)°. The calculated electrostatic potential surfaces show the presence of σ-holes on both substituted iodines. In the crystal, the mol­ecules are linked through type II halogen bonds, forming a sheet structure parallel to the bc plane. Between the sheets, weak inter­molecular C—H⋯π inter­actions are observed. Hirshfeld surface analysis showed that the most significant contacts in the structure are C⋯H/H⋯C (31.9%), followed by H⋯H (21.4%), I⋯H/H⋯I (18.4%). I⋯I (14.5%) and O⋯H/H⋯O (8.1%).

Two novel lead-based coordination polymers, namely [Pb(cbdcp)]·0.5H2O·0.5CH3OH (1) and [Pb(cbdcp)] (2), have been solvothermally constructed by using a zwitterionic ligand 4-carboxy-1-(3,4-dicarboxy-benzyl)-pyridinium chloride (abbreviated as H3cbdcpCl). Compound 1 has a three-dimensional framework displaying a valence-bonded SrAl2 topology with the 42·63·8 symbol, while compound 2 has a two-dimensional sheet structure that can be simplified into a three-dimensional ππ interaction-connected topology with the {44·62}2{48·615·85} symbol. Notably, compound 1 proved to be a promising potential luminescent sensor capable of selectively detecting anions, cations and small organic molecules, especially Cr2O72-, CrO42-, Fe3+ and nitrobenzene.

Pulp fiber airlaid nonwovens were bonded with three binder formulations in a spray and foam process. The binders were: a commercial acrylic dispersion binder, a commercial bio-containing acrylic binder; and a citric acid-carboxymethyl cellulose mixture (CACMC) (1:1 by-weight). The binder solutions were applied at same concentrations onto A4-size airlaid sheets (80 gsm) under a vacuum with 2-sided spraying and 1-sided foam coating. The sheet structure, dry and wet tensile properties, and total absorption capacity were compared. The foam application densified and bulk bonded the sheets, whereas the spray application induced surface bonding. These factors fundamentally influenced the measured sheet properties. The dry tensile strength was linearly correlated with the relatively low binder dosages. The CACMC binder exposed the differences in the binder application processes well, and lead to strong sheets with small elongation and highly application method-dependent absorption capacity compared to acrylic binders.

T he highest total color difference values ( ∆E) were found in the panels produced with the similar proportions of waste paper and OCC into gypsum (A4: 6.09; B4: 5.79). These boards have also show highest CIE whiteness reduction (A4: -33.19; B4: -28.44). With the help of FTIR, some chemical groups are modified to some extent but similar functional groups were observed in surface of boards. For A- and C-type boards, similar TGA degradation trends (spectra) were observed while the B-type panels show markedly higher mass loss, especially at initial temperature stage (100-120 0 C). This is probably because of the presence of some non-cellulosic materials (i.e. starch, silica, etc.) and the high rate of lignin in sheet structure of OCC material. The flame propagation characteristic of the surfaces of all test boards shows that the flame did not reach the threshold limit of 150 mm. These indicates, even if the source of fire is not removed, flame did not reach the threshold limit that boards that could be classified as non-flammable material class according to TS EN-ISO 11925-2 standard. The heat insulation properties of the test sample were found to be lowered with addition of lignocellulosic material to the gypsum structure. It was seen that waste paper ratio in gypsum structure higher than 10% (A3 to A6 boards) show better insulation properties than counterpart OCC (B-types) and secondary fiber based (C-types) gypsum boards. In general, reduction heat transfer in average values of samples attracted attention as compared with control specimens. Interestingly, the boards are indicated best insulation properties as mentioned above, show higher mass loss too. The highest mass loss for A-type boards found to be 3.52% (A6), for B-type boards 3.46% (B6) and for C-type boards 3.28% (C8).

An organic–inorganic hybrid CuII–ErIII heterometallic arsenotungstate Na3[Cu(en)2(H2O)][Cu(en)2]1.5[H3Er(α-AsW11O39)2]·4H2O (1) (en = ethylenediamine) has been hydrothermally synthesized and structurally characterized by elemental analyses, IR and UV spectra, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry and single-crystal X-ray diffraction. 1 displays an organic–inorganic 2-D sheet structure constructed by sandwich-type [H3Er(α-AsW11O39)2]8− fragments and [Cu(en)2]2+ connectors. From the topological viewpoint, if the [H3Er(α-AsW11O39)2]8− fragments are viewed as 3-connected nodes and [Cu(en)2]2+ connectors are considered as linkers, the 2-D sheet can be simplified into a 2-D (6,3)-network topology. Keywords: Polyoxometalate, Arsenotungstate, CuII–ErIII heterometallic derivative, Spectroscopic characterization

Hodgesmithite, ideally (Cu,Zn)6Zn(SO4)2(OH)10·3H2O, is a new copper zinc sulfate mineral from the Block 14 Opencut, Broken Hill, New South Wales, Australia. Electron microprobe analysis provided the empirical formula Cu4.84,Zn2.16,Cd0.04[(SO4)1.89,(SiO4)0.12]2.01(OH)9.82·3.15H2O based on 21 oxygen atoms per formula unit. Hodgesmithite is trigonal, space groupP3, witha= 8.1905 (12),c= 7.0990 (14) Å,V= 412.43 (12) Å3andZ= 1. The crystal structure of hodgesmithite,R1= 0.0272 for 5145 reflections withFo> 4σ(Fo) measured with synchrotron X-ray radiation (λ = 0.71080 Å), contains interrupted sheets of edge-sharing Cu(O,OH)6octahedra in the (001) plane. Every seventh octahedral site is vacant and capped by a ZnO4tetrahedron and an SO4tetrahedron which are attached to the sheet above and below this position. The sheets are additionally decorated on one side by SO4tetrahedra that share a vertex incident to three Cu—O(apical) bonds. Interstitial H2O groups lie between the sheets. ZnO4tetrahedra share vertices with SO4tetrahedra from the adjacent sheet to provide linkage between the sheets in thecdirection.

BiOBr nanosheets and BiOBr flower-like microspheres were prepared by hydrothermal method and solvothermal method, respectively. On this basis, BiOBr nanosheets were modified by reducing agent reduction, preparing successfully Bi/BiOBr nanosheets. The XRD, SEM, UV-VisDRS, XPS and UV-vis spectrophotometry were used to characterize the morphological structures, physical properties and surface element composition of the photocatalysts. In addition, photocatalytic activity was analyzed by the ability to degrade the antibiotic norfloxacin. The results indicated that after irradiation of 500 W xenon lamp for 180 min, the degradation rates for norfloxacin of BiOBr nanosheets, BiOBr flower like microspheres, and Bi/BiOBr photocatalyst were 34.7%, 72.1%, and 97.2%, respectively. And the degradation of norfloxacin was in accordance with the first order kinetic model. Compared with BiOBr nanosheets, the other two samples have better visible light photocatalytic activity, of which the photocatalytic activity of Bi/BiOBr was the highest. And the half-life of norbofloxacin degraded by Bi/BiOBr was shortened to 25 min. In addition, The results of capture experiments indicated that the main active groups involved in the degradation reaction of norfloxacin by Bi/BiOBr photocatalysts under visible light conditions were

Three new silver complexes based on 2,6-dichlorophenylacetate (dcpa), namely [Ag2(dcpa)2]n (1), [Ag(NH3)2](dcpa) (2), and [Ag3(N,N-eten)(dcpa)3]2 (3) (N,N-eten = N,N-diethylethylenediamine), were synthesized and structurally characterized. The dcpa ligand adopts a µ2-η1:η1 bridging coordination mode in silver complexes 1 and 3, whereas it is a non-coordinating counter anion in silver complex 2. Complex 1 shows a two-dimensional sheet polymer in which the dimeric [Ag(dcpa)]2 units with a short Ag···Ag separation of 2.783 A are linked to each other by weak Ag···O and Ag···Cl interactions. Complex 2 contains a linear [Ag(NH3)2]+ cation and a dcpa anion, which constructs a two-dimensional sheet structure via intermolecular N–H···O interactions. Complex 3 features an unusual discrete hexanuclear silver(I) dimer, [Ag3(N,N-eten)(dcpa)3]2, formed by Ag···O and argentophilic interactions (Ag3···Ag3# = 3.335 A), which are further connected by intermolecular N–H···O interactions to offer a one-dimensional ladder-like chain. The urease inhibitory activities of the obtained silver complexes 1, 2 and 3 were investigated and complex 3 was proven to be a potent inhibitor against jack bean urease.

Humanity has been continuously threatened by epidemics and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown greater epidemic potential. According to the World Health Organization, measures such as rapid diagnosis, immediate isolation, and precautionary contact tracing are key tools of epidemic control. The method of detection or testing is critical in this epidemiological control, where SARS-CoV-2-positive cases are increasingly growing, leading to community infection. Immunochromatographic test kits have been described for the diagnosis of various infectious diseases because of their rapid scalability, convenient use, and prompt validation. The benefits of the immunochromatographic test kits include evaluation of the sample in approximately 20 minutes, lower cost per sample, and simple directions to use. Such test kits are composed of an uncut sheet structure that is protein conjugated, labeled with markers, and reagents coated in a nitrocellulose membrane. The need for thorough vetting is a major concern for the Central Drugs Standard Control Organization, Indian Council of Medical Research and other regulators, as more businesses are rushing to produce serologic test kits for SARS-CoV-2 worldwide. Initial reports of 86%−89% sensitivity and 84.2%–98.6% specificity were reported for these kits. Nonetheless, many national reports show variability in test accuracy significantly among various commercial suppliers. The virus’s more recent mutated strains (B.1.1.7, B.1.617, and B.1.351) have also raised concerns about their detectability using these test kits. In India, manufacturers are developing rapid test kits to detect SARS-CoV-2 by importing pre-antigen or antibody-coated uncut sheets from vendors and then cutting them into strips. Such sheets also have problems with specificity and are expensive. The possibility of developing kits with an indigenous protein coating and conjugation to detect antigens and antibodies needs to be explored by Indian researchers. This communication describes techniques to develop precise rapid test kits for detecting SARS-CoV-2. © 2021

Conformational changes in amyloidogenic proteins, such as β-amyloid protein, prion proteins, and α-synuclein, play a critical role in the pathogenesis of numerous neurodegenerative diseases, including Alzheimer’s disease, prion disease, and Lewy body disease. The disease-associated proteins possess several common characteristics, including the ability to form amyloid oligomers with β-pleated sheet structure, as well as cytotoxicity, although they differ in amino acid sequence. Interestingly, these amyloidogenic proteins all possess the ability to bind trace metals, can regulate metal homeostasis, and are co-localized at the synapse, where metals are abundantly present. In this review, we discuss the physiological roles of these amyloidogenic proteins in metal homeostasis, and we propose hypothetical models of their pathogenetic role in the neurodegenerative process as the loss of normal metal regulatory functions of amyloidogenic proteins. Notably, these amyloidogenic proteins have the capacity to form Ca2+-permeable pores in membranes, suggestive of a toxic gain of function. Therefore, we focus on their potential role in the disruption of Ca2+ homeostasis in amyloid-associated neurodegenerative diseases.

Recently, two-dimensional transition metal dichalcogenides (2D TMDCs) have drawn certain attentions in many fields. The unique and diversified electronic structure and ultrathin sheet structure of 2D TMDCs offer opportunities for moving ahead of other 2D nanomaterials such as graphene and expanding the wide application of inorganic 2D nanomaterials in many fields. For a better understanding of 2D TMDCs, one needs to know methods for their synthesis and modification, as well as their potential applications and possible biological toxicity. Herein, we summarized the recent research progress of 2D TMDCs with particular focus on their biomedical applications and potential health risks. Firstly, two kinds of synthesis methods of 2D TMDCs, top-down and bottom-up, and methods for their surface functionalization are reviewed. Secondly, the applications of 2D TMDCs in the field of biomedicine, including drug loading, photothermal therapy, biological imaging and biosensor were summarized. After that, we presented the existing researches on biosafety evaluation of 2D TMDCs. At last, we discussed major research gap in current researches and challenges and coping strategies in future studies.

Background: The outbreak of coronavirus disease 2019 (COVID-19) has led to substantial infections and mortality around the world. Fast screening and diagnosis are thus crucial to quick isolation and clinical intervention. Methods: Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A/B, and respiratory syncytial virus (RSV), as well as healthy controls, were included in this study. All viral infections were confirmed by reverse transcriptase PCR (RT-PCR). The serum samples were measured by attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR). Multivariate and statistical analysis was performed to differentiate between or among groups. Findings: We found that the most discriminatory bands for COVID-19 vs. control classification were amide I, amide II, and νs(PO2−) in original spectra and centered at 1632, 1545, 1400, 1079, and 1037 cm-1 in the second derivative infrared (SD-IR) spectra. Normal controls, non-severe, and severe COVID-19 patients were well separated by unsupervised methods. ATR FT-IR coupled with partial least square discriminant analysis (PLS-DA) was effective to differentiate COVID-19 from normal controls and other respiratory viral infections with the area under the receiver operating characteristic curve (AUROC) of 0·9866 (95%CI 0·9721-0·9939). Interpretation: The band centered at 1633 cm-1 in the SD-IR spectra is mainly attributed to the β-pleated sheet structure from immunoglobulins. Increases in antibody levels and dysregulation of phospholipids can be derived from the measured spectra. The serum FT-IR spectra exhibited “chemical fingerprints” towards different viral infections. Funding Statement: This work was funded by the National Natural Science Foundation of China (52041701). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study was approved by the Ethics Committees from Tsinghua University and Peking Union Medical College Hospital.