Cinzia Casiraghi

Bio: Cinzia Casiraghi is an academic researcher from University of Manchester. The author has contributed to research in topics: Graphene & Raman spectroscopy. The author has an hindex of 53, co-authored 129 publications receiving 29830 citations. Previous affiliations of Cinzia Casiraghi include Free University of Berlin & University of Cambridge.

Gamma Radiation-Induced Oxidation, Doping, and Etching of Two-Dimensional MoS2 Crystals

Abstract: Two-dimensional (2D) MoS2 is a promising material for future electronic and optoelectronic applications 2D MoS2 devices have been shown to perform reliably under irradiation conditions relevant for a low Earth orbit However, a systematic investigation of the stability of 2D MoS2 crystals under high-dose gamma irradiation is still missing In this work, absorbed doses of up to 1000 kGy are administered to 2D MoS2 Radiation damage is monitored via optical microscopy and Raman, photoluminescence, and X-ray photoelectron spectroscopy techniques After irradiation with 500 kGy dose, p-doping of the monolayer MoS2 is observed and attributed to the adsorption of O2 onto created vacancies Extensive oxidation of the MoS2 crystal is attributed to reactions involving the products of adsorbate radiolysis Edge-selective radiolytic etching of the uppermost layer in 2D MoS2 is attributed to the high reactivity of active edge sites After irradiation with 1000 kGy, the monolayer MoS2 crystals appear to be completely etched This holistic study reveals the previously unreported effects of high-dose gamma irradiation on the physical and chemical properties of 2D MoS2 Consequently, it demonstrates that radiation shielding, adsorbate concentrations, and required device lifetimes must be carefully considered, if devices incorporating 2D MoS2 are intended for use in high-dose radiation environments

Stable, concentrated, biocompatible, and defect-free graphene dispersions with positive charge

Abstract: The outstanding properties of graphene offer high potential for biomedical applications. In this framework, positively charged nanomaterials show better interactions with the biological environment, hence there is strong interest in the production of positively charged graphene nanosheets. Currently, production of cationic graphene is either time consuming or producing dispersions with poor stability, which strongly limit their use in the biomedical field. In this study, we made a family of new cationic pyrenes, and have used them to successfully produce water-based, highly concentrated, stable, and defect-free graphene dispersions with positive charge. The use of different pyrene derivatives as well as molecular dynamics simulations allowed us to get insights on the nanoscale interactions required to achieve efficient exfoliation and stabilisation. The cationic graphene dispersions show outstanding biocompatibility and cellular uptake as well as exceptional colloidal stability in the biological medium, making this material extremely attractive for biomedical applications.

Exploiting the Surface Properties of Graphene for Polymorph Selectivity

Abstract: Producing crystals of the desired form (polymorph) is currently a challenge as nucleation is yet to be fully understood. Templated crystallization is an efficient approach to achieve polymorph selectivity; however, it is still unclear how to design the template to achieve selective crystallization of specific polymorphs. More insights into the nanoscale interactions happening during nucleation are needed. In this work, we investigate crystallization of glycine using graphene, with different surface chemistry, as a template. We show that graphene induces the preferential crystallization of the metastable α-polymorph compared to the unstable β-form at the contact region of an evaporating droplet. Computer modeling indicates the presence of a small amount of oxidized moieties on graphene to be responsible for the increased stabilization of the α-form. In conclusion, our work shows that graphene could become an attractive material for polymorph selectivity and screening by exploiting its tunable surface chemistry.

Quantitative composition of a single-walled carbon nanotube sample: Raman scattering versus photoluminescence

Abstract: We investigated the spectral data of three carbon nanotube (CNT) species obtained by Raman spectroscopy and photoluminescence (PL) measurements. The corresponding relative signal intensities without further corrections yielded significantly different relative distributions of the CNT species. Theoretical calculations of optical transition probabilities and electron-phonon coupling were included, providing simple models in order to estimate the relative distribution of the three species within the sample. We proposed the product of PL and PL excitation intensities to be a candidate for quantitative analysis of CNT species. Applying the models, we confirmed that both spectroscopic methods agree on one nanotube species dominating the distribution.

The rise of graphene

Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The electronic properties of graphene

Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene

Abstract: We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.