Waveguide Schottky photodetector with tunable barrier based on Ti3C2T
                     x
                  /p-Si van der Waals heterojunction

Abstract MXene, a new advanced two-dimensional material, has attracted great attention in energy storage, transparent electrodes, and electromagnetic shielding due to its high conductivity, high specific surface area, and hydrophilic surface. Given the solution-processability and tunable work function, MXene also holds great potential for wide-range photodetection and integrated optics. Here, we demonstrate a waveguide integrated Schottky photodetector based on Ti3C2T x /Si van der Waals heterojunction. Specifically, the barrier of the Schottky photodetector can be adjusted by using simple surface treatment. The work function of the Ti3C2T x is reduced from 4.66 to 4.43 eV after vacuum annealing, and the barrier height of Ti3C2T x /p-Si Schottky junction is correspondingly increased from 0.64 to 0.72 eV, leading to 215 nm working wavelength blue-shift. The photodetector exhibits working wavelength tunability in short-wavelength infrared regions due to the engineered Schottky barrier. To our best knowledge, this is the first demonstration of utilizing MXene in waveguide-integrated photodetection, showing the potential applications for various scenarios thanks to the flexible working wavelength range induced by the tunable barrier.

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Extrusion-Based 3D Printing for Highly Porous Alginate Materials Production

Gels ◽

10.3390/gels7030092 ◽

2021 ◽

Vol 7 (3) ◽

pp. 92

Author(s):

Natalia Menshutina ◽

Andrey Abramov ◽

Pavel Tsygankov ◽

Daria Lovskaya

Keyword(s):

3D Printing ◽

Sodium Alginate ◽

Complex Geometry ◽

Three Dimensional ◽

Supercritical Drying ◽

High Specific Surface Area ◽

Wide Range ◽

Potential Applications ◽

3D Printed ◽

Highly Porous

Three-dimensional (3D) printing is a promising technology for solving a wide range of problems: regenerative medicine, tissue engineering, chemistry, etc. One of the potential applications of additive technologies is the production of highly porous structures with complex geometries, while printing is carried out using gel-like materials. However, the implementation of precise gel printing is a difficult task due to the high requirements for “ink”. In this paper, we propose the use of gel-like materials based on sodium alginate as “ink” for the implementation of the developed technology of extrusion-based 3D printing. Rheological studies were carried out for the developed alginate ink compositions. The optimal rheological properties are gel-like materials based on 2 wt% sodium alginate and 0.2 wt% calcium chloride. The 3D-printed structures with complex geometry were successfully dried using supercritical drying. The resulting aerogels have a high specific surface area (from 350 to 422 m2/g) and a high pore volume (from 3 to 3.78 cm3/g).

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Epitaxial ferroelectric thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170591 ◽

1994 ◽

Vol 52 ◽

pp. 572-573

Author(s):

S. G. Ghonge ◽

E. Goo ◽

R. Ramesh ◽

R. Haakenaasen ◽

D. K. Fork

Keyword(s):

Single Crystal ◽

Work Function ◽

Nonvolatile Memory ◽

Ferroelectric Properties ◽

Electrical Contact ◽

Memory Devices ◽

Ferroelectric Films ◽

Si Substrates ◽

Electro Optic ◽

Wide Range

Microstructure of epitaxial ferroelectric/conductive oxide heterostructures on LaAIO3(LAO) and Si substrates have been studied by conventional and high resolution transmission electron microscopy. The epitaxial films have a wide range of potential applications in areas such as non-volatile memory devices, electro-optic devices and pyroelectric detectors. For applications such as electro-optic devices the films must be single crystal and for applications such as nonvolatile memory devices and pyroelectric devices single crystal films will enhance the performance of the devices. The ferroelectric films studied are Pb(Zr0.2Ti0.8)O3(PLZT), PbTiO3(PT), BiTiO3(BT) and Pb0.9La0.1(Zr0.2Ti0.8)0.975O3(PLZT).Electrical contact to ferroelectric films is commonly made with metals such as Pt. Metals generally have a large difference in work function compared to the work function of the ferroelectric oxides. This results in a Schottky barrier at the interface and the interfacial space charge is believed to responsible for domain pinning and degradation in the ferroelectric properties resulting in phenomenon such as fatigue.

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Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

10.26434/chemrxiv.6254756.v1 ◽

2018 ◽

Author(s):

Sherif Tawfik ◽

Olexandr Isayev ◽

Catherine Stampfl ◽

Joseph Shapter ◽

David Winkler ◽

...

Keyword(s):

Machine Learning ◽

Band Gap ◽

Density Functional ◽

2D Materials ◽

Van Der Waals ◽

Building Blocks ◽

Machine Learning Techniques ◽

Interlayer Distance ◽

Computational Screening ◽

Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

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A Slot-Die Technique for the Preparation of Continuous, High-Area, Chitosan-Based Thin Films

Polymers ◽

10.3390/polym13101566 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1566

Author(s):

Oliver J. Pemble ◽

Maria Bardosova ◽

Ian M. Povey ◽

Martyn E. Pemble

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

High Volume ◽

Mechanical Anisotropy ◽

Diverse Range ◽

Direction Parallel ◽

High Area ◽

Wide Range ◽

Slot Die ◽

Potential Applications

Chitosan-based films have a diverse range of potential applications but are currently limited in terms of commercial use due to a lack of methods specifically designed to produce thin films in high volumes. To address this limitation directly, hydrogels prepared from chitosan, chitosan-tetraethoxy silane, also known as tetraethyl orthosilicate (TEOS) and chitosan-glutaraldehyde have been used to prepare continuous thin films using a slot-die technique which is described in detail. By way of preliminary analysis of the resulting films for comparison purposes with films made by other methods, the mechanical strength of the films produced was assessed. It was found that as expected, the hybrid films made with TEOS and glutaraldehyde both show a higher yield strength than the films made with chitosan alone. In all cases, the mechanical properties of the films were found to compare very favorably with similar measurements reported in the literature. In order to assess the possible influence of the direction in which the hydrogel passes through the slot-die on the mechanical properties of the films, testing was performed on plain chitosan samples cut in a direction parallel to the direction of travel and perpendicular to this direction. It was found that there was no evidence of any mechanical anisotropy induced by the slot die process. The examples presented here serve to illustrate how the slot-die approach may be used to create high-volume, high-area chitosan-based films cheaply and rapidly. It is suggested that an approach of the type described here may facilitate the use of chitosan-based films for a wide range of important applications.

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Health Benefits of Uses and Applications of Moringa oleifera in Bakery Products

Plants ◽

10.3390/plants10020318 ◽

2021 ◽

Vol 10 (2) ◽

pp. 318

Author(s):

Paula García Milla ◽

Rocío Peñalver ◽

Gema Nieto

Keyword(s):

Moringa Oleifera ◽

Essential Amino Acids ◽

Bakery Products ◽

Unani Medicine ◽

Functional Value ◽

Organoleptic Characteristics ◽

Wide Range ◽

Potential Applications ◽

Medicinal Properties ◽

Excellent Source

Moringa oleifera belongs to the Moringaceae family and is the best known of the native Moringa oleifera genus. For centuries, it has been used as a system of Ayurvedic and Unani medicine and has a wide range of nutritional and bioactive compounds, including proteins, essential amino acids, carbohydrates, lipids, fibre, vitamins, minerals, phenolic compounds, phytosterols and others. These characteristics allow it to have pharmacological properties, including anti-diabetic, anti-inflammatory, anticarcinogenic, antioxidant, cardioprotective, antimicrobial and hepatoprotective properties. The entire Moringa oleifera plant is edible, including its flowers, however, it is not entirely safe, because of compounds that have been found mainly in the root and bark, so the leaf was identified as the safest. Moringa oleifera is recognised as an excellent source of phytochemicals, with potential applications in functional and medicinal food preparations due to its nutritional and medicinal properties; many authors have experimented with incorporating it mainly in biscuits, cakes, brownies, meats, juices and sandwiches. The results are fascinating, as the products increase their nutritional value; however, the concentrations cannot be high, as this affects the organoleptic characteristics of the supplemented products. The aim of this study is to review the application of Moringa oleifera in bakery products, which will allow the creation of new products that improve their nutritional and functional value.

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Sporulation in solventogenic and acetogenic clostridia

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11289-9 ◽

2021 ◽

Author(s):

Mamou Diallo ◽

Servé W. M. Kengen ◽

Ana M. López-Contreras

Keyword(s):

Current Knowledge ◽

Carbon Sources ◽

Cost Effective ◽

Biotechnological Production ◽

Key Points ◽

Wide Range ◽

Potential Applications ◽

A Cell ◽

Sporulation Initiation ◽

Solventogenic Clostridia

AbstractThe Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.

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Click Chemistry Enabling Covalent and Non-Covalent Modifications of Graphene with (Poly)saccharides

Polymers ◽

10.3390/polym13010142 ◽

2020 ◽

Vol 13 (1) ◽

pp. 142

Author(s):

Hu Li ◽

Raffaello Papadakis

Keyword(s):

Click Chemistry ◽

Life Science ◽

Environmental Applications ◽

Energy Materials ◽

Sensors And Actuators ◽

Polar Solvents ◽

Wide Range ◽

Potential Applications ◽

Covalent Modifications

Graphene is a material with outstanding properties and numerous potential applications in a wide range of research and technology areas, spanning from electronics, energy materials, sensors, and actuators to life-science and many more. However, the insolubility and poor dispersibility of graphene are two major problems hampering its use in certain applications. Tethering mono-, di-, or even poly-saccharides on graphene through click-chemistry is gaining more and more attention as a key modification approach leading to new graphene-based materials (GBM) with improved hydrophilicity and substantial dispersibility in polar solvents, e.g., water. The attachment of (poly)saccharides on graphene further renders the final GBMs biocompatible and could open new routes to novel biomedical and environmental applications. In this review, recent modifications of graphene and other carbon rich materials (CRMs) through click chemistry are reviewed.

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State of the Science in Dried Blood Spots

Clinical Chemistry ◽

10.1373/clinchem.2017.275966 ◽

2018 ◽

Vol 64 (4) ◽

pp. 656-679 ◽

Cited By ~ 51

Author(s):

Jeffrey D Freeman ◽

Lori M Rosman ◽

Jeremy D Ratcliff ◽

Paul T Strickland ◽

David R Graham ◽

...

Keyword(s):

Systematic Approach ◽

Full Range ◽

Dried Blood Spots ◽

Blood Spots ◽

Highly Sensitive ◽

Wide Range ◽

Potential Applications ◽

Review Of Reviews ◽

Near Term ◽

State Of The Science

Abstract BACKGROUND Advancements in the quality and availability of highly sensitive analytical instrumentation and methodologies have led to increased interest in the use of microsamples. Among microsamples, dried blood spots (DBS) are the most well-known. Although there have been a variety of review papers published on DBS, there has been no attempt at describing the full range of analytes measurable in DBS, or any systematic approach published for characterizing the strengths and weaknesses associated with adoption of DBS analyses. CONTENT A scoping review of reviews methodology was used for characterizing the state of the science in DBS. We identified 2018 analytes measured in DBS and found every common analytic method applied to traditional liquid samples had been applied to DBS samples. Analytes covered a broad range of biomarkers that included genes, transcripts, proteins, and metabolites. Strengths of DBS enable its application in most clinical and laboratory settings, and the removal of phlebotomy and the need for refrigeration have expanded biosampling to hard-to-reach and vulnerable populations. Weaknesses may limit adoption in the near term because DBS is a nontraditional sample often requiring conversion of measurements to plasma or serum values. Opportunities presented by novel methodologies may obviate many of the current limitations, but threats around the ethical use of residual samples must be considered by potential adopters. SUMMARY DBS provide a wide range of potential applications that extend beyond the reach of traditional samples. Current limitations are serious but not intractable. Technological advancements will likely continue to minimize constraints around DBS adoption.

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Biodiversity of Secondary Metabolites Compounds Isolated from Phylum Actinobacteria and Its Therapeutic Applications

Molecules ◽

10.3390/molecules26154504 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4504

Author(s):

Muhanna Al-shaibani ◽

Radin Maya Saphira Radin Mohamed ◽

Nik Sidik ◽

Hesham Enshasy ◽

Adel Al-Gheethi ◽

...

Keyword(s):

Secondary Metabolites ◽

Bioactive Compounds ◽

Extreme Environments ◽

Software Tool ◽

Gene Clusters ◽

Well Being ◽

Bioactive Substances ◽

Diverse Range ◽

Wide Range ◽

Potential Applications

The current review aims to summarise the biodiversity and biosynthesis of novel secondary metabolites compounds, of the phylum Actinobacteria and the diverse range of secondary metabolites produced that vary depending on its ecological environments they inhabit. Actinobacteria creates a wide range of bioactive substances that can be of great value to public health and the pharmaceutical industry. The literature analysis process for this review was conducted using the VOSviewer software tool to visualise the bibliometric networks of the most relevant databases from the Scopus database in the period between 2010 and 22 March 2021. Screening and exploring the available literature relating to the extreme environments and ecosystems that Actinobacteria inhabit aims to identify new strains of this major microorganism class, producing unique novel bioactive compounds. The knowledge gained from these studies is intended to encourage scientists in the natural product discovery field to identify and characterise novel strains containing various bioactive gene clusters with potential clinical applications. It is evident that Actinobacteria adapted to survive in extreme environments represent an important source of a wide range of bioactive compounds. Actinobacteria have a large number of secondary metabolite biosynthetic gene clusters. They can synthesise thousands of subordinate metabolites with different biological actions such as anti-bacterial, anti-parasitic, anti-fungal, anti-virus, anti-cancer and growth-promoting compounds. These are highly significant economically due to their potential applications in the food, nutrition and health industries and thus support our communities’ well-being.

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A Structurally Variable Hinged Tetrahedron Framework from DNA Origami

Journal of Nucleic Acids ◽

10.4061/2011/360954 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 18

Author(s):

David M. Smith ◽

Verena Schüller ◽

Carsten Forthmann ◽

Robert Schreiber ◽

Philip Tinnefeld ◽

...

Keyword(s):

Self Assembly ◽

Gel Electrophoresis ◽

Imaging Techniques ◽

Building Blocks ◽

Dna Origami ◽

Microscopy Technique ◽

Wire Frame ◽

Wide Range ◽

Potential Applications ◽

Linker Molecules

Nanometer-sized polyhedral wire-frame objects hold a wide range of potential applications both as structural scaffolds as well as a basis for synthetic nanocontainers. The utilization of DNA as basic building blocks for such structures allows the exploitation of bottom-up self-assembly in order to achieve molecular programmability through the pairing of complementary bases. In this work, we report on a hollow but rigid tetrahedron framework of 75 nm strut length constructed with the DNA origami method. Flexible hinges at each of their four joints provide a means for structural variability of the object. Through the opening of gaps along the struts, four variants can be created as confirmed by both gel electrophoresis and direct imaging techniques. The intrinsic site addressability provided by this technique allows the unique targeted attachment of dye and/or linker molecules at any point on the structure's surface, which we prove through the superresolution fluorescence microscopy technique DNA PAINT.

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