Early Days of Two-Dimensional Ion Cyclotron Resonance

This contribution is an attempt to evoke the favorable atmosphere that prevailed in Lausanne around 1986 and provided the backdrop of our invention of two-dimensional ion cyclotron resonance mass spectroscopy (2D ICR-MS). To avoid a self-centered histoire d’ancien combattant, we shall try to emphasize the context: the contributions of key players within our nascent research group at UNIL and the established group of Tino Gäumann at EPFL, the role of external speakers, and the open atmosphere that was not yet polluted by bibliometrics, obsessive concern with impact factors, and top–down management of research. We shall also explain why the idea of 2D ICR-MS has been ignored for many years and still has a limited impact: different scientific cultures in the ICR and NMR communities, different concerns with fundamental vs. applied research, different status of theory and numerical simulations, different levels of commitment of instrument manufacturers, not to mention many theoretical problems that appear to be at least as challenging in ICR as in NMR.     

Gravitational Influence on Human Living Systems and the Evolution of Species on Earth

Gravity constituted the only constant environmental parameter, during the evolutionary period of living matter on Earth. However, whether gravity has affected the evolution of species, and its impact is still ongoing. The topic has not been investigated in depth, as this would require frequent and long-term experimentations in space or an environment of altered gravity. In addition, each organism should be studied throughout numerous generations to determine the profound biological changes in evolution. Here, we review the significant abnormalities presented in the cardiovascular, immune, vestibular and musculoskeletal systems, due to altered gravity conditions. We also review the impact that gravity played in the anatomy of snakes and amphibians, during their evolution. Overall, it appears that gravity does not only curve the space–time continuum but the biological continuum, as well.     

Topical advances in nanomaterials based electrochemical sensors for resorcinol detection

The ever-increasing environmental pollution is a severe threat to the ecosystem’s healthy sustainability, and therefore environmental monitoring of these pollutants has become a burning issue throughout the world. In recent years, cost-effective, selective, portable, sensitive, and rapid sensing devices must be developed in urgent need. Advancement in nanotechnology has urged the use of different types of nanomaterials as an excellent electrode material to amplify the electrochemical detection in terms of long-term stability and electrocatalytic activity of the electrochemical sensors in addition to fulfill the aforementioned desires. This review article intimates significant advancement in developing the enzymatic and non-enzymatic electrochemical sensors based on different nanomaterials for the detection of resorcinol (RS) in the absence or presence of other phenolic compounds. This also concludes the current associated challenges as well as future perspectives for the analysis of RS in the environment. There is plethora of reported articles on RS sensors, but this review mainly discusses the selective reports on the applications of RS sensors.     

Chemically Modified Carbon Nanotubes for Use in Electroanalysis

The discovery of carbon nanotubes has had a profound impact on many areas of science and technology, not least that of electroanalysis. The properties and applications of carbon nanotubes themselves have been well reviewed in the literature and a number of reviews with an electrochemical emphasis have been published. However, the modification of carbon nanotubes has recently been the focus of much research, primarily to improve their solubility in various solvents. Yet modified carbon nanotube electrodes also allow the electrochemist to tailor the properties of the carbon nanotubes, or the electrode surface to impart desired properties such as enhanced sensing capabilities. In this review we attempt to comprehensively cover the different chemical and electrochemical modification strategies and research carried out using modified carbon nanotubes for electroanalytical and bioanalytical applications. Furthermore we also discuss the use of modified carbon nanotubes in electrocatalysis and biocatalysis from an analytical aspect, as well as seeking to dispel some of the myths surrounding the “electrocatalytic” properties of carbon nanotubes.     

Fourier Transform Surface Plasmon Resonance (FTSPR) with Gyromagnetic Plasmonic Nanorods

An unprecedented active and dynamic sensing platform based on a LSPR configuration that is modulated by using an external magnetic field is reported. Electrochemically synthesized Au/Fe/Au nanorods exhibited plasmonically active behavior through plasmonic coupling, and the middle ferromagnetic Fe block responded to a magnetic impetus, allowing the nanorods to be modulated. The shear force variation induced by the specific binding events between antigens and antibodies on the nanorod surface is used to enhance the sensitivity of detection of antigens in the plasmonics‐based sensor application. As a proof‐of‐concept, influenza A virus (HA1) was used as a target protein. The limit of detection was enhanced by two orders of magnitude compared to that of traditional LSPR sensing.     

Versatile Nickel(II) Scaffolds as Coordination-Induced Spin-State Switches for 19F Magnetic Resonance-Based Detection

¹⁹F magnetic resonance (MR) based detection coupled with well-designed inorganic systems shows promise in biological investigations. Two proof-of-concept inorganic probes that exploit a novel mechanism for ¹⁹F MR sensing based on converting from low-spin (S=0) to high-spin (S=1) Ni²⁺ are reported. Activation of diamagnetic NiL₁ and NiL₂ by light or β-galactosidase, respectively, converts them into paramagnetic NiL₀ , which displays a single ¹⁹F NMR peak shifted by >35 ppm with accelerated relaxation rates. This spin-state switch is effective for sensing light or enzyme expression in live cells using ¹⁹F MR spectroscopy and imaging that differentiate signals based on chemical shift and relaxation times. This general inorganic scaffold has potential for developing agents that can sense analytes ranging from ions to enzymes, opening up diverse possibilities for ¹⁹F MR based biosensing.     

Immunosensor Based on Surface Plasmon Resonance for Antigen Recognition

A novel immunosensor based on surface plasmon resonance（SPR） has been developed for the recognition of antigen. The sensor was designed on the basis of the fixed angle of incidence and measuring the reflected intensities in a wavelength range of 430--750 nm in real-time. An ultra-bright white light-emitting diode（LED） was used as the light source. Molecular self-assembling in solution was used to form the sensing membrane on gold substrate. It has been seen that the sensitivity of the SPR sensor with 3-mercaptopropionic acid（MPA）/protein A（SPA） sensing membrane is considerably higher than that with MPA or SPA modified sensing membrane. The kinetic processes on the sensing membrane were studied. The human B factor（Bf）, an activator of complement 3（C3）, was recognized among the other antigens. This sensor can also be used for other antigen/antibody or adaptor/receptor recognition. Under optimized experimental conditions, the sensor has good selectivity, repeatability, and reversibility.     

Recent advances in terpenoid syntheses from China

Total syntheses of terpenoids play an essential role in the development of synthetic organic chemistry and medicinal science. Chinese synthetic community has made more and more profound contribution to this field and has gradually grown into a major force in the world over the past years. In this review, we shall celebrate the achievement by surveying the recent terpenoid syntheses from China since 2010.     

Discourse on the utilization of polyaniline coatings for surface plasmon resonance sensing of ammonia vapor

Surface plasmon resonance spectroscopy is sensitive to near-surface (<300 nm) chemical and physical events that result in refractive index changes. The non-specific nature of the stimulus implies that chemical selectivity in SPR sensing configurations entirely relies upon the chemical recognition scheme employed. Biosensing applications commonly use surface layers composed of antibodies or enzymes for biomolecular recognition. Monitoring of volatile compounds with SPR spectroscopy, however, has not been widely discussed due to the difficulty in selectively responding to small molecules (<100 Da) in addition to the limited refractive index changes resulting from the interaction between the plasmon wave and volatile compounds.Different strategies explored thus far for sensing of small molecules have relied on optical and electrical changes of the recognition layer upon exposure to the analyte, yielding an indirect measurement. Examples of coatings used for gas-phase sensing with SPR include conducting metal oxides, polymers and organometallic dyes. Electrically conducting polymers, like polyaniline and polypyrrole, display dramatic conductivity changes in the presence of certain compounds. This property has resulted in their routine incorporation into different sensing schemes. However, application of electrically conducting polymers to SPR gas-phase sensing has been limited to a few examples, despite encouraging results.The emeraldine salt form of polyaniline (PAni) demonstrates a decreased electrical conductivity correlated to NH₃ concentration. In this contribution, PAni doped with camphorsulfonic acid (PAni-CSA) was applied to gas-phase sensing of NH₃ by way of SPR spectroscopy. Spectroscopic ellipsometry was used to determine the optical constants (n and k) for emeraldine salt and emeraldine base forms of PAni, confirming the wavelength-dependent response observed via SPR. The analytical performance of the coatings show that a limit of detection of 32 ppm NH₃ based on precision of the mass-flow controllers used and an estimated method limit of detection of ∼0.2 ppm based on three standard deviations of the blank. This is directly comparable to other, more established sensing architectures.     

Progress in patterned paper sizing for fabrication of paper-based microfluidic sensors

In this paper, we report the progress in using paper sizing chemistry to fabricate patterned paper for chemical and biological sensing applications. Patterned paper sizing uses paper sizing agents to selectively hydrophobize certain area of a sheet. The hydrophilic-hydrophobic contrast of the pattern so created has an excellent ability to control capillary penetration of aqueous liquids in channels of the pattern. Incorporating this idea with digital ink jet printing technique, a new fabrication method of paper-based microfluidic devices is established. Ink jet printing can deliver biomolecules and chemicals with precision into the microfluidic patterns to form biological/chemical sensing sites within the patterns, forming the complete sensing devices. This study shows the potential of combining paper sizing chemistry and ink jet printing to produce paper-based sensors at low cost and at commercial volume.     

Benchmarking of density functionals for a soft but accurate prediction and assignment of 1H and 13C NMR chemical shifts in organic and biological molecules

A number of programs and tools that simulate ¹H and ¹³C nuclear magnetic resonance (NMR) chemical shifts using empirical approaches are available. These tools are user‐friendly, but they provide a very rough (and sometimes misleading) estimation of the NMR properties, especially for complex systems. Rigorous and reliable ways to predict and interpret NMR properties of simple and complex systems are available in many popular computational program packages. Nevertheless, experimentalists keep relying on these “unreliable” tools in their daily work because, to have a sufficiently high accuracy, these rigorous quantum mechanical methods need high levels of theory. An alternative, efficient, semi‐empirical approach has been proposed by Bally, Rablen, Tantillo, and coworkers. This idea consists of creating linear calibrations models, on the basis of the application of different combinations of functionals and basis sets. Following this approach, the predictive capability of a wider range of popular functionals was systematically investigated and tested. The NMR chemical shifts were computed in solvated phase at density functional theory level, using 30 different functionals coupled with three different triple–ζ basis sets. © 2016 Wiley Periodicals, Inc.     

基于表面等离子体子共振的B因子传感器

以分辨率较高的一米光栅单色仪为分光系统,光电倍增管为检测系统,改进了自行组装的表面等离子体子共振(SPR)传感装置,提高了仪器的检测能力约50倍,对于发展改变波长模式的SPR传感器具有重要意义。以对金和抗体均有较强吸附作用的葡萄球菌A蛋白为基底膜,观测了人的B因子抗体和抗原之间免疫反应的动力学过程,并研究了B因子的定量测定。结果表明,B因子抗原的浓度在0.02～5μg/mL范围内与信号的响应值呈线性关系。该传感器灵敏度高,选择性和重现性均好。     

Benchmarking compressed sensing,super‐resolution,and filter diagonalization

Signal processing techniques have been developed that use different strategies to bypass the Nyquist sampling theorem in order to recover more information than a traditional discrete Fourier transform. Here we examine three such methods: filter diagonalization, compressed sensing, and super‐resolution. We apply them to a broad range of signal forms commonly found in science and engineering in order to discover when and how each method can be used most profitably. We find that filter diagonalization provides the best results for Lorentzian signals, while compressed sensing and super‐resolution perform better for arbitrary signals. © 2016 Wiley Periodicals, Inc.     

Plasma enhanced synthesis of N doped vertically aligned carbon nanofibers on 3D graphene

Graphene and carbon nanotubes/fibers (CNT/CNF) hybrid structures are emerging as frontier materials for high-efficiency electronics, energy storage, thermoelectric, and sensing applications owing to the utilization of extraordinary electrical and physical properties of both nanocarbon materials. Recent advances show a successful improvement in the structure and surface area of layered graphene by incorporating another dimension and structural form—three-dimensional graphene (3DG). In this study, vertically aligned CNFs were grown using plasma enhanced chemical vapor deposition on a relatively new form of compressed 3DG. The latter was synthesized using a conventional thermal chemical vapor deposition. The resulting free-standing hybrid material is in-situ N doped during synthesis by ammonia plasma and is produced in the form of a hybrid paper. Characterization of this material was done using electrochemical and spectroscopic measurements. The N doped hybrid showed relatively higher surface area and improved areal current density in electrochemical measurements than compressed pristine 3DG, which makes it a potential candidate for use as an electrode material for supercapacitors, sensors, and electrochemical batteries.     

Qualitative and quantitative analysis of proteins and peptides in milk products by capillary electrophoresis

Milk protein is an important component of the human diet throughout much of the world. The ability to assess the relative composition and integrity of milk proteins or peptides in dairy foods or food ingredients is important because these molecules have a profound effect on product functionality and quality. This communication describes two capillary electrophoretic methods that are useful for the analysis of proteins and casein-derived peptides in cheese and milk products. One technique, which uses a buffer containing citrate/phosphate (pH 3.3), 4 M urea, and a polymeric additive in a coated capillary, is useful for qualitative and quantitative analysis of proteins and peptides in milk, cheese, and whey products. The second method employs a citrate/phosphate buffer (pH 2.8) and a bare silica capillary, and is well suited for the analysis of small, casein-derived peptides in aqueous cheese extracts.     

Influence of sampling methodology on reported incidence of Salmonella in poultry

Salmonella is a major pathogen associated with poultry food products. Over the past 20 years, pressure to reduce human illness from poultry-related salmonellosis has resulted in intensive research activity as well as stronger regulatory standards in Europe, North America, and, because of international trade policies, throughout the world. In the United States, implementation of a Hazard Analysis Critical Control Point-based inspection program has been credited with reducing the incidence of Salmonella-positive carcasses from approximately 20 to 10%. Since 1998, however, the reported incidence of Salmonella in retail poultry from 12 countries implementing similar pathogen reduction programs, including the United States, has averaged 29% positive for Salmonella. Although these reports examined products at retail outlets and used a variety of sampling methodologies, these results appear to contradict the U.S. Department of Agriculture claims for Salmonella reduction. The purpose of this review is to examine this contradiction with a focus on the potential impact of sampling methodology on reported incidences of Salmonella.     

Magnetic resonance imaging of spiral patterns in crosslinked polymer gels produced via frontal polymerization

Frontal polymerization is a process in which a localized reaction zone propagates through a monomer reactant mixture, leaving a polymer product in its wake, and is the result of the coupling of the thermal transport and Arrhenius dependence of the exothermic polymerization. Under most conditions, a planar front is stable. However, for multifunctional acrylates at room temperature, fronts may propagate in a helical fashion along the axis of the reactor. This front propagation is typical of what is called a spin mode, in which the subsequent polymer sample has alternating spiral patterns of low and high monomer conversion evident on the sample surface. For the first time, we demonstrate that magnetic resonance imaging on a submillimeter scale can be used to show that the spiral patterns are not restricted to the sample surface but are distributed throughout the volume. Samples were soaked in water, and the transverse proton relaxation times were imaged. The results suggest proton mobility is smaller in the high‐conversion region in which the hot spot propagated than in the low‐conversion region. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1075–1080, 2001     

Recent Advances in Nanomaterial Probes for Optical Biothiol Sensing: A Review

The determination of biological aminothiols (mainly cysteine, homocysteine, and glutathione) is an important tool in the clinical diagnosis of many disorders and diseases. Therefore, the development of new chemical sensors and probes has attracted considerable attention. Nanomaterials have a profound role in this endeavor since they offer some unique advantages such as lower cost, faster analysis times, and ease of operation compared to classic instrumental techniques such as liquid chromatography and capillary electrophoresis. In this review, we provide a focused outline on the most recent evolvements in optical biothiol sensing using nanomaterials. The most important reaction mechanisms and detection strategies are summarized and compared in terms of their sensitivity and selectivity against various biothiol species. Critical fields for future research and challenges are discussed and elucidated.     

Solving Blue Light Riddles: New Lessons from Flavin‐binding LOV Photoreceptors

Detection of blue light (BL) via flavin‐binding photoreceptors (Fl‐Blues) has evolved throughout all three domains of life. Although the main BL players, that is light, oxygen and voltage (LOV), blue light sensing using flavins (BLUF) and Cry (cryptochrome) proteins, have been characterized in great detail with respect to structure and function, still several unresolved issues at different levels of complexity remain and novel unexpected findings were reported. Here, we review the most prevailing riddles of LOV‐based photoreceptors, for example: the relevance of water and/or small metabolites for the dynamics of the photocycle; molecular details of light‐to‐signal transduction events; the interplay of BL sensing by LOV domains with other environmental stimuli, such as BL plus oxygen‐mediating photodamage and its impact on microbial lifestyles; the importance of the cell or chromophore redox state in determining the fate of BL‐driven reactions; the evolutionary pathways of LOV‐based BL sensing and associated functions through the diverse phyla. We will discuss major novelties emerged during the last few years on these intriguing aspects of LOV proteins by presenting paradigmatic examples from prokaryotic photosensors that exhibit the largest complexity and richness in associated functions.     

Fluorescence Emission of Self-assembling Amyloid-like Peptides: Solution versus Solid State

Analysis of the intrinsic UV-visible fluorescence exhibited by self-assembling amyloid-like peptides in solution and in solid the state highlights that their physical state has a profound impact on the optical properties. In the solid state, a linear dependence of the fluorescence emission peaks as a function of excitation wavelength is detected. On the contrary, an excitation-independent emission is observed in solution. The present findings constitute a valuable benchmark for current and future explanations of the fluorescence emission by amyloids.