A Nano‐in‐Nano Vector: Merging the Best of Polymeric Nanoparticles and Drug Nanocrystals

An advanced approach that can prepare narrowly size distributed nanomaterials with ultrahigh mass fraction of therapeutics, superior colloidal stability, minimal off‐target effects, as well as precisely controlled drug‐release profiles, is strongly desirable. Here, an optimal nano‐in‐nano vector, consisting of a drug (sorafenib, SFN, or itraconazole, ICZ) nanocrystal core and a polymer (folic acid conjugated spermine‐functionalized acetalated dextran, ADS‐FA) shell on a 1:1 ratio (HSFN@ADS‐FA or ICZ@ADS‐FA) is successfully fabricated. With the help of computational fluid dynamics, the concentration and velocity field are computed in the microfluidic domain, as well as the mixing time between the solvent and nonsolvent for nanovector precursors. The favorable features of both polymer nanoparticles and drug nanocrystals are inherited by the obtained nano‐in‐nano vector, showing ultrahigh drug‐loading degree, biodegradability, pH‐responsive fast dissolution, high stability in serum, and ease of surface functionalization. Furthermore, the half‐maximal inhibitory concentration value of the nano‐in‐nano HSFN@ADS‐FA is ≈54 times lower than the conventional nanovector (LSFN@ADS‐FA) with a low drug‐loading degree. Overall, this nano‐in‐nano vector merges the best of polymeric nanoparticles and drug nanocrystals.     

Caffeine content in coffee as influenced by grinding and brewing techniques

The caffeine content of coffee as influenced by various coffee preparation methods was investigated. The variables studied included the coffee solids to water volume ratio, the volume of coffee prepared, home versus store grinding, and drip/filtered versus boiling. Caffeine contents per 177 ml (6 oz) of coffee ranged from 50 to 143 mg, depending upon the mode of preparation. As expected, more coffee solids and larger extents of grinding led to significantly higher caffeine contents in filtered coffee. Larger volumes of coffee prepared at a constant coffee solids to water ratio also yielded significantly higher caffeine contents. Homegrinding yielded caffeine contents similar to that of store-ground coffee. Boiled coffee had caffeine contents equal to or greater than filtered coffee, depending upon the length of boiling time. The variable caffeine contents in coffee resulting from the mode of preparation should be recognized and addressed by both food composition data bases and epidemiologists.     

Decorrelating detector with diversity combining for single user frequency-selective rayleigh fading multipath channels

Diversity combining techniques are applied in mobile radio communications as a means of performance improvement in a fading multipath environment. Adaptive equalizers which incorporate diversity combining were shown to combat intersymbol interference (ISI) caused by multipath provided that the fading is sufficiently slow. However, for fast fading rates, noncoherent techniques are often desirable. In this paper, we examine the performance of several coherent and noncoherent detectors that make use of diversity combining. In particular, the decorrelating filter is shown to provide reliable performance for a frequency-selective Rayleigh fading multipath channel with ISI. Numerical and simulation results are presented for a channel with two independent Rayleigh fading paths. Signal design issues which arise in the implementation of the decorrelating detector and the zero-forcing equalizer are discussed.     

Relevance vector machine for automatic detection of clustered microcalcifications

Clustered microcalcifications (MC) in mammograms can be an important early sign of breast cancer in women. Their accurate detection is important in computer-aided detection (CADe). In this paper, we propose the use of a recently developed machine-learning technique--relevance vector machine (RVM)--for detection of MCs in digital mammograms. RVM is based on Bayesian estimation theory, of which a distinctive feature is that it can yield a sparse decision function that is defined by only a very small number of so-called relevance vectors. By exploiting this sparse property of the RVM, we develop computerized detection algorithms that are not only accurate but also computationally efficient for MC detection in mammograms. We formulate MC detection as a supervised-learning problem, and apply RVM as a classifier to determine at each location in the mammogram if an MC object is present or not. To increase the computation speed further, we develop a two-stage classification network, in which a computationally much simpler linear RVM classifier is applied first to quickly eliminate the overwhelming majority, non-MC pixels in a mammogram from any further consideration. The proposed method is evaluated using a database of 141 clinical mammograms (all containing MCs), and compared with a well-tested support vector machine (SVM) classifier. The detection performance is evaluated using free-response receiver operating characteristic (FROC) curves. It is demonstrated in our experiments that the RVM classifier could greatly reduce the computational complexity of the SVM while maintaining its best detection accuracy. In particular, the two-stage RVM approach could reduce the detection time from 250 s for SVM to 7.26 s for a mammogram (nearly 35-fold reduction). Thus, the proposed RVM classifier is more advantageous for real-time processing of MC clusters in mammograms.     

Comparison of three sampling methods for the quantification of methicillin-resistant Staphylococcus aureus on the surface of pig carcases

The objective was to determine the appropriate sampling method to quantify methicillin-resistant Staphylococcus aureus (MRSA) on the surface of pig carcases. Carcases were contaminated using brain-heart infusion broth containing MRSA at 5 log and 7 log cfu/ml. Samples were collected using three methods: a wet/dry double swab (100 cm²⁾, an abrasive sponge (100 cm²) and a die cutter (2×5 cm²). Quantification of MRSA was done using decimal dilutions and cultivation in duplicate on chromogenic selective agar.The wet/dry double swab method was not sufficiently sensitive with 8 out of 10 samples being negative at low contamination levels. The abrasive sponge had reproducible results in all samples at both contamination levels. In low contamination areas 5 of the 10 die cutter samples were negative, while in the heavily contaminated areas, results of the die cutter and the abrasive sponge were comparable. It is concluded that with expected low contamination levels using the abrasive sponge is superior to the other two methods and should be used whenever contamination levels are not known.     

Fusarium mycotoxins in wheat samples harvested in Serbia: A preliminary survey

The objective of this study was to determine the occurrence of trichothecenes of both the A-type and B-type, masked mycotoxin derived from DON - deoxynivalenol-3-glucoside (DON-3-Glc), 3- and 15-acetyldeoxynivalenol (ADONs), fusarenon-X (FUS-X) and nivalenol (NIV)) as well as zearalenone (ZON) in winter wheat. Total of 54 samples were collected during the harvest of 2007 representing the most important Serbian wheat-growing regions. The samples were prepared by one-step simple method and analyzed by high performance liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The obtained recoveries proved that the used method could be successfully applied for multi-component analysis of Fusarium mycotoxins. DON, DON-3-Glc and HT-2 contents were detected approximately in 28%, 13% and 6% of the total number of samples, respectively. The amount of these toxins ranged from 17 μg/kg for DON-3-Glc to 309 μg/kg for DON. ADONs, FUS-X, NIV, T-2 toxin as well as ZON were below the limit of detection. Different susceptibility of wheat cultivars towards detected mycotoxins was observed. The results were compared to the EC Regulative and with available the literature data concerning the neighboring countries. This is first report on the simultaneous presence of 8 Fusarium mycotoxins in the wheat cultivated in the Balkan Countries region.     

Covalently Adaptable Elastin‐Like Protein–Hyaluronic Acid (ELP–HA) Hybrid Hydrogels with Secondary Thermoresponsive Crosslinking for Injectable Stem Cell Delivery

Shear‐thinning, self‐healing hydrogels are promising vehicles for therapeutic cargo delivery due to their ability to be injected using minimally invasive surgical procedures. An injectable hydrogel using a novel combination of dynamic covalent crosslinking with thermoresponsive engineered proteins is presented. Ex situ at room temperature, rapid gelation occurs through dynamic covalent hydrazone bonds by simply mixing two components: hydrazine‐modified elastin‐like protein (ELP) and aldehyde‐modified hyaluronic acid. This hydrogel provides significant mechanical protection to encapsulated human mesenchymal stem cells during syringe needle injection and rapidly recovers after injection to retain the cells homogeneously within a 3D environment. In situ, the ELP undergoes a thermal phase transition, as confirmed by coherent anti‐Stokes Raman scattering microscopy observation of dense ELP thermal aggregates. The formation of the secondary network reinforces the hydrogel and results in a tenfold slower erosion rate compared to a control hydrogel without secondary thermal crosslinking. This improved structural integrity enables cell culture for three weeks postinjection, and encapsulated cells maintain their ability to differentiate into multiple lineages, including chondrogenic, adipogenic, and osteogenic cell types. Together, these data demonstrate the promising potential of ELP–HA hydrogels for injectable stem cell transplantation and tissue regeneration.     

From White to Red: Electric‐Field Dependent Chromaticity of Light‐Emitting Electrochemical Cells based on Archetypal Porphyrins

The differences in the electroluminescence (EL) of red‐emitting free‐base ( H2TPP ) and Zn‐metalated ( ZnTPP ) archetypal porphyrins are rationalized in light‐emitting electrochemical cells by means of an electric‐field dependent effect, leading to whitish and reddish devices, respectively. Although H2TPP shows superior electrochemical and photophysical features compared to ZnTPP , devices prepared with ZnTPP surprisingly stand out with a deep‐red EL similar to its photoluminescence (PL), while H2TPP devices feature unexpected whitish EL. Standard arguments such as degradation, device architecture, device mechanism, and changes in the nature of the emitting excited states are discarded. Based on electrochemical impedance spectroscopy and first‐principles electronic structure methods, we provide evidence that the EL originates from two H2TPP regioisomers, in which the inner ring H atoms are placed in collinear and vicinal configurations. The combination of their optical features provides an explanation for both the high‐ and low‐energy EL features. Here, the emitting excited state nature is ascribed to the Q bands, since the Soret excited states remain high in energy. This contrasts to what is traditionally postulated in reports focused on H2TPP lighting devices. Hence, this work provides a new explanation for the nature of the high‐energy EL band of H2TPP that might inspire future works focused on white‐emitting molecular‐based devices.     

CsPbBr3 Nanocrystal Films: Deviations from Bulk Vibrational and Optoelectronic Properties

Metal‐halide perovskites (MHP) are highly promising semiconductors for light‐emitting and photovoltaic applications. The colloidal synthesis of nanocrystals (NCs) is an effective approach for obtaining nearly defect‐free MHP that can be processed into inks for low‐cost, high‐performance device fabrication. However, disentangling the effects of surface ligands, morphology, and boundaries on charge‐carrier transport in thin films fabricated with these high‐quality NCs is inherently difficult. To overcome this fundamental challenge, terahertz (THz) spectroscopy is employed to optically probe the photoconductivity of CsPbBr₃ NC films. The vibrational and optoelectronic properties of the NCs are compared with those of the corresponding bulk polycrystalline perovskite and significant deviations are found. Charge‐carrier mobilities and recombination rates are demonstrated to vary significantly with the NC size. Such dependences derive from the localized nature of charge carriers within NCs, with local mobilities dominating over interparticle transport. It is further shown that the colloidally synthesized NCs have distinct vibrational properties with respect to the bulk perovskite, exhibiting blue‐shifted optical phonon modes with enhanced THz absorption strength that also manifest as strong modulations in the THz photoconductivity spectra. Such fundamental insights into NC versus bulk properties will guide the optimization of nanocrystalline perovskite thin films for optoelectronic applications.