Comment on Naef, R.; Acree, W.E., Jr. Calculation of the Three Partition Coefficients logPow, logKoa and logKaw of Organic Molecules at Standard Conditions at Once by Means of a Generally Applicable Group Additivity Method. Preprints2023, 2023120275.

Next to the paper referred to in the title [...].

Comment on Naef, R.; Acree, W.E., Jr. Revision and Extension of a Generally Applicable Group-Additivity Method for the Calculation of the Standard Heat of Combustion and Formation of Organic Molecules. Molecules 2021, 26, 6101.

Next to the paper referred to in the title [...].

Imaging of pH and pO2 gives insight in molecular processes of irradiated cells.

One of the major challenges in radiation therapy is the interference with tissue repair processes due to hypoxic characteristics and pH dysregulation. In this study, we present dual imaging of pH and oxygenation in vitro based on luminescent biocompatible sensor foils that allow studying the effects of irradiation on different cell types in culture. Different sensitivities of fibroblast and oral squamous carcinoma cells were observed by complementing oxygen and pH differences with proliferation assays. This study highlights especially the distinct role of oxygen after irradiation and the difference in proliferation processes of irradiated normal dermal cells in contrast to irradiated tumor cells.

Dynamics of oxygen and carbon dioxide in rhizospheres of Lobelia dortmanna - a planar optode study of belowground gas exchange between plants and sediment.

Root-mediated CO2 uptake, O2 release and their effects on O2 and CO2 dynamics in the rhizosphere of Lobelia dortmanna were investigated. Novel planar optode technology, imaging CO2 and O2 distribution around single roots, provided insights into the spatiotemporal patterns of gas exchange between roots, sediment and microbial community. In light, O2 release and CO2 uptake were pronounced, resulting in a distinct oxygenated zone (radius: c. 3 mm) and a CO2 -depleted zone (radius: c. 2 mm) around roots. Simultaneously, however, microbial CO2 production was stimulated within a larger zone around the roots (radius: c. 10 mm). This gave rise to a distinct pattern with a CO2 minimum at the root surface and a CO2 maximum c. 2 mm away from the root. In darkness, CO2 uptake ceased, and the CO2 -depleted zone disappeared within 2 h. By contrast, the oxygenated root zone remained even after 8 h, but diminished markedly over time. A tight coupling between photosynthetic processes and the spatiotemporal dynamics of O2 and CO2 in the rhizosphere of Lobelia was demonstrated, and we suggest that O2 -induced stimulation of the microbial community in the sediment increases the supply of inorganic carbon for photosynthesis by building up a CO2 reservoir in the rhizosphere.

Background-free referenced luminescence sensing and imaging of pH using upconverting phosphors and color camera read-out.

Fluorescence background and problems with proper signal referencing severely disrupt the read-out of luminescence sensors and images. We present a pH sensor film in combination with a simple read-out technique that overcomes issues of background signals and autofluorescence. It consists of micrometer-sized upconversion phosphors (UCPs) and a pH indicator (Neutral Red) that absorbs their green emission. Both are embedded in a proton permeable hydrogel matrix. The UCPs generate green and red luminescence upon excitation with IR light of 980 nm wavelength. Solely the green light of the UCPs is affected by the pH indicator, while the red emission acts as inert reference signal for ratiometric measurements. The emission peaks of the UCPs match the red and green color channels of standard digital cameras. Thereby, the devised sensor film can be used for referenced ratiometric sensing and 2D imaging of pH using a color camera read-out. The sensor setup using common and hand-held devices is cheap and straightforward and allows for point-of-care measurements. Finally, pH measurements in human serum samples show the potential of this sensor for imaging free of interfering background signals.

2D luminescence imaging of pH in vivo.

Luminescence imaging of biological parameters is an emerging field in biomedical sciences. Tools to study 2D pH distribution are needed to gain new insights into complex disease processes, such as wound healing and tumor metabolism. In recent years, luminescence-based methods for pH measurement have been developed. However, for in vivo applications, especially for studies on humans, biocompatibility and reliability under varying conditions have to be ensured. Here, we present a referenced luminescent sensor for 2D high-resolution imaging of pH in vivo. The ratiometric sensing scheme is based on time-domain luminescence imaging of FITC and ruthenium(II)tris-(4,7-diphenyl-1,10-phenanthroline). To create a biocompatible 2D sensor, these dyes were bound to or incorporated into microparticles (aminocellulose and polyacrylonitrile), and particles were immobilized in polyurethane hydrogel on transparent foils. We show sensor precision and validity by conducting in vitro and in vivo experiments, and we show the versatility in imaging pH during physiological and chronic cutaneous wound healing in humans. Implementation of this technique may open vistas in wound healing, tumor biology, and other biomedical fields.

Luminescent probes and sensors for temperature.

Temperature (T) is probably the most fundamental parameter in all kinds of science. Respective sensors are widely used in daily life. Besides conventional thermometers, optical sensors are considered to be attractive alternatives for sensing and on-line monitoring of T. This Review article focuses on all kinds of luminescent probes and sensors for measurement of T, and summarizes the recent progress in their design and application formats. The introduction covers the importance of optical probes for T, the origin of their T-dependent spectra, and the various detection modes. This is followed by a survey on (a) molecular probes, (b) nanomaterials, and (c) bulk materials for sensing T. This section will be completed by a discussion of (d) polymeric matrices for immobilizing T-sensitive probes and (e) an overview of the various application formats of T-sensors. The review ends with a discussion on the prospects, challenges, and new directions in the design of optical T-sensitive probes and sensors.

Quantification of oxygen consumption in head and neck cancer using fluorescent sensor foil technology.

Introduction: Head and neck squamous cell carcinoma (HNSCC) patients suffer from frequent local recurrences that negatively impact on prognosis. Hence, distinguishing tumor and normal tissue is of clinical importance as it may improve the detection of residual tumor tissue in surgical resection margins and during imaging-based surgery planning. Differences in O2 consumption (OC) can be used to this aim, as they provide options for improved surgical, image-guided approaches. Methods: In the present study, the potential of a fluorescent sensor foil-based technology to quantify OC in HNSCC was evaluated in an in vitro 3D model and in situ in patients. Results: In vitro measurements of OC using hypopharyngeal and esophageal cell lines allowed a specific detection of tumor cell spheroids embedded together with cancer-associated fibroblasts in type I collagen extracellular matrix down to a diameter of 440 µm. Pre-surgery in situ measurements were conducted with a handheld recording device and sensor foils with an oxygen permeable membrane and immobilized O2-reactive fluorescent dyes. Lateral tongue carcinoma and carcinoma of the floor of the mouth were chosen for analysis owing to their facilitated accessibility. OC was evaluated over a time span of 60 seconds and was significantly higher in tumor tissue compared to healthy mucosa in the vicinity of the tumor. Discussion: Hence, OC quantification using fluorescent sensor foil-based technology is a relevant parameter for the differentiation of tumor tissue of the head and neck region and may support surgery planning.

Unveiling photodeactivation pathways for a new iridium(III) cyclometalated complex.

We report the synthesis and characterization of a neutral heteroleptic Ir(III) complex bearing 6-fluoro-2-phenylbenzo[d]thiazole as cyclometalating ligand and (Z)-6-(9H-carbazol-9-yl)-5-hydroxy-2,2-dimethylhex-4-en-3-one as ancillary ligand. The photodeactivation mechanisms have been elucidated through extensive density functional theory (DFT) calculations. The active role of metal-centered ((3) MC) triplet excited states in the nonradiative deactivation pathways is, for first time, confirmed in such complexes.

Cobalt nanoparticles growth on a block copolymer thin film: a time-resolved GISAXS study.

Cobalt sputter deposition on a nanostructured polystyrene-block-poly(ethylene oxide), P(S-b-EO), template is followed in real time with grazing incidence small-angle X-ray scattering (GISAXS). The polymer template consists of highly oriented parallel crystalline poly(ethylene oxide) (PEO) domains that are sandwiched between two polystyrene (PS) domains. In-situ GISAXS shows that cobalt atoms selectively decorate the PS domains of the microphase-separated polymer film and then aggregate to form surface metal nanopatterns. The polymer template is acting as a directing agent where cobalt metal nanowires are formed. At high metal load, the characteristic selectivity of the template is lost, and a uniform metal layer forms on the polymer surface. During the early stage of cobalt metal deposition, a highly asymmetric nanoparticles agglomeration is dominating structure formation. The cobalt nanoparticles mobility in combination with the high tendency of the nanoparticles to coalescence and to form immobile large-sized particles at the PS domains are discussed as mechanisms of structure formation.

Fluorescent pH-sensitive nanoparticles in an agarose matrix for imaging of bacterial growth and metabolism.

Living color: fluorescent pH-sensitive nanoparticles 12 nm in diameter were prepared and incorporated into agarose gel in a Petri dish to image pH changes during bacterial growth and metabolism.

The Ionospheric Connection Explorer - Prime Mission Review.

The two-year prime mission of the NASA Ionospheric Connection Explorer (ICON) is complete. The baseline operational and scientific objectives have been met and exceeded, as detailed in this report. In October of 2019, ICON was launched into an orbit that provides its instruments the capability to deliver near-continuous measurements of the densest plasma in Earth's space environment. Through collection of a key set of in-situ and remote sensing measurements that are, by virtue of a detailed mission design, uniquely synergistic, ICON enables completely new investigations of the mechanisms that control the behavior of the ionosphere-thermosphere system under both geomagnetically quiet and active conditions. In a two-year period that included a deep solar minimum, ICON has elucidated a number of remarkable effects in the ionosphere attributable to energetic inputs from the lower and middle atmosphere, and shown how these are transmitted from the edge of space to the peak of plasma density above. The observatory operated in a period of low activity for 2 years and then for a year with increasing solar activity, observing the changing balance of the impacts of lower and upper atmospheric drivers on the ionosphere.

Ultra-small, highly stable, and sensitive dual nanosensors for imaging intracellular oxygen and pH in cytosol.

We report on the first dual nanosensors for imaging of pH values and oxygen partial pressure in cells. The sensors have a unique nanostructure in that a soft core structure is rigidized with a silane reagent, while poly(ethylene glycol) chains form an outer shell. Lipophilic oxygen-sensitive probes and reference dyes are encapsulated inside the hydrophobic core, while a pH-sensitive probe is covalently attached to the poly(ethylene glycol) end-group on the shell. The core/shell structure renders the nanosensors well dispersed and highly stable in various kinds of aqueous media. Their average size is 12 nm, and they respond to both pH and oxygen in the physiological range. They do not pass cell membranes, but can be internalized into the cellular cytosol by electroporation, upon which they enable sensing and imaging of pH values and oxygen with high spatial resolution. The nanosensor strategy shown here is expected to be applicable to the development of various other kinds of multiple nanosensors for in vivo studies.

A sprayable luminescent pH sensor and its use for wound imaging in vivo.

Non-invasive luminescence imaging is of great interest for studying biological parameters in wound healing, tumors and other biomedical fields. Recently, we developed the first method for 2D luminescence imaging of pH in vivo on humans, and a novel method for one-stop-shop visualization of oxygen and pH using the RGB read-out of digital cameras. Both methods make use of semitransparent sensor foils. Here, we describe a sprayable ratiometric luminescent pH sensor, which combines properties of both these methods. Additionally, a major advantage is that the sensor spray is applicable to very uneven tissue surfaces due to its consistency. A digital RGB image of the spray on tissue is taken. The signal of the pH indicator (fluorescein isothiocyanate) is stored in the green channel (G), while that of the reference dye [ruthenium(II)-tris-(4,7-diphenyl-1,10-phenanthroline)] is stored in the red channel (R). Images are processed by rationing luminescence intensities (G/R) to result in pseudocolor pH maps of tissues, e.g. wounds.

Referenced dual pressure- and temperature-sensitive paint for digital color camera read out.

The first fluorescent material for the referenced simultaneous RGB (red green blue) imaging of barometric pressure (oxygen partial pressure) and temperature is presented. This sensitive coating consists of two platinum(II) complexes as indicators and a reference dye, each of which is incorporated in appropriate polymer nanoparticles. These particles are dispersed in a polyurethane hydrogel and spread onto a solid support. The emission of the (oxygen) pressure indicator, PtTFPP, matches the red channel of a RGB color camera, whilst the emission of the temperature indicator [Pt(II) (Br-thq)(acac)] matches the green channel. The reference dye, 9,10-diphenylanthracene, emits in the blue channel. In contrast to other dual-sensitive materials, this new coating allows for the simultaneous imaging of both indicator signals, as well as the reference signal, in one RGB color picture without having to separate the signals with additional optical filters. All of these dyes are excitable with a 405 nm light-emitting diode (LED). With this new composite material, barometric pressure can be determined with a resolution of 22 mbar; the temperature can be determined with a resolution of 4.3 °C.

Influence of nanoparticle surface functionalization on the thermal stability of colloidal polystyrene films.

The installation of large scale colloidal nanoparticle thin films is of great interest in sensor technology or data storage. Often, such devices are operated at elevated temperatures. In the present study, we investigate the effect of heat treatment on the structure of colloidal thin films of polystyrene (PS) nanoparticles in situ by using the combination of grazing incidence small-angle X-ray scattering (GISAXS) and optical ellipsometry. In addition, the samples are investigated with optical microscopy, atomic force microscopy (AFM), and field emission scanning electron microscopy (FESEM). To install large scale coatings on silicon wafers, spin-coating of colloidal pure PS nanoparticles and carboxylated PS nanoparticles is used. Our results indicate that thermal annealing in the vicinity of the glass transition temperature T(g) of pure PS leads to a rapid loss in the ordering of the nanoparticles in spin-coated films. For carboxylated particles, this loss of order is shifted to a higher temperature, which can be useful for applications at elevated temperatures. Our model assumes a softening of the boundaries between the individual colloidal spheres, leading to strong changes in the nanostructure morphology. While the nanostructure changes drastically, the macroscopic morphology remains unaffected by annealing near T(g).

Efficiency-improved organic solar cells based on plasticizer assisted soft embossed PEDOT:PSS layers.

Organic solar cells (OSCs) have attracted extensive attention as a promising approach for cost-effective photovoltaic devices. This study demonstrates a novel imprinting approach based on additional plasticizing, which is suited for thin polyethylenedioxythiophene:polystyrenesulphonate (PEDOT:PSS) layers. Such films are widely used as electron blocking and hole collecting intermediate layers in OSCs. Master molds with nano-scale channels are used for the temperature and pressure assisted imprinting routine and the shape of the imprinted structures is easily tunable via the plasticizer concentration. Depending on the surface topology of the PEDOT:PSS films structured poly(3-hexylthiophene) (P3HT):phenyl-C(61)-butyric acid methyl ester (PCBM) bulk heterojunction solar cells have improved power conversion efficiencies in comparison to their planar references. This effect results from enhanced optical absorption due to the resulting textured aluminum electrode and improved charge carrier extraction at the artificially structured electrodes. In addition, OSCs based on low aspect ratio PEDOT:PSS imprints show increased relative performance under oblique light incidence.

Impact of age and body site on adult female skin surface pH.

BACKGROUND: pH is known as an important parameter in epidermal barrier function and homeostasis. AIM: The impact of age and body site on skin surface pH (pH(SS)) of women was evaluated in vivo. METHODS: Time domain dual lifetime referencing with luminescent sensor foils was used for pH(SS) measurements. pH(SS) was measured on the forehead, the temple, and the volar forearm of adult females (n = 97, 52.87 ± 18.58 years, 20-97 years). Every single measurement contained 2,500 pH values due to the luminescence imaging technique used. RESULTS: pH(SS) slightly increases with age on all three investigated body sites. There are no significant differences in pH(SS) between the three investigated body sites. CONCLUSION: Adult pH(SS) on the forehead, the temple and the volar forearm increases slightly with age. This knowledge is crucial for adapting medical skin care products.

A critique of race-based and genomic medicine.

Now that a composite human genome has been sequenced (HGP), research has accelerated to discover precise genetic bases of several chronic health issues, particularly in the realms of cancer and cardiovascular disease. It is anticipated that in the future it will be possible and cost effective to regularly sequence individual genomes, and thereby produce a DNA profile that potentially can be used to assess the health risks for each person with respect to certain genetically predisposed conditions. Coupled with that enormous diagnostic power, it will then depend upon equally rapid research efforts to develop personalized courses of treatment, including that of pharmaceutical therapy. Initial treatment attempts have been made to match drug efficacy and safety to individuals of assigned or self-identified groups according to their genetic ancestry or presumed race. A prime example is that of BiDil, which was the first drug approved by the US FDA for the explicit treatment of heart patients of African American ancestry. This race-based approach to medicine has been met with justifiable criticism, notably on ethical grounds that have long plagued historical applications and misuses of human race classification, and also on questionable science. This paper will assess race-based medical research and practice in light of a more thorough understanding of human genetic variability. Additional concerns will be expressed with regard to the rapidly developing area of pharmacogenomics, promoted to be the future of personalized medicine. Genomic epidemiology will be discussed with several examples of on-going research that hopefully will provide a solid scientific grounding for personalized medicine to build upon.

Comment on Tagliaferro et al. Introducing the Novel Mixed Gaussian-Lorentzian Lineshape in the Analysis of the Raman Signal of Biochar. Nanomaterials 2020, 10, 1748.

Despite the fact that this comment deals with a paper that was published two years ago [...].