Generalized and wavelength-dependent temperature calibration function for multipoint regenerated fiber Bragg grating sensors.

A new calibration methodology for regenerated fiber Bragg grating (RFBG) temperature sensors up to 700 °C is proposed and demonstrated. A generalized, wavelength-dependent temperature calibration function is experimentally determined that describes the temperature-induced wavelength shifts for all RFBG sensor elements that are manufactured with the same fabrication parameters in the wavelength range from 1465 nm to 1605 nm. Using this generalized calibration function for absolute temperature measurements, each RFBG sensor element only needs to be calibrated at one reference temperature, representing a considerable simplification of the conventional calibration procedure. The new calibration methodology was validated with 7 RFBGs, and uncertainties were found to be compliant with those of Class 1 thermocouples (< ±1.5 K or < ±0.4% of the measured temperature). The proposed calibration technique overcomes difficulties with the calibration of spatially extended multipoint RFBG sensor arrays, where setting up an adequate calibration facility for large sensor fibers is challenging and costly. We assume that this calibration method can also be adapted to other types of FBG temperature sensors besides RFBGs. An accurate and practical calibration approach is essential for the acceptance and dissemination of the fiber-optic multipoint temperature sensing technology.

1-(Hex-5-en-1-yl)-4-{[3-methyl-2,3-di-hydro-1,3-benzo-thia-zol-2-yl-idene]meth-yl}quinolin-1-ium iodide monohydrate.

The title thia-zole orange derivative, bearing an alkene substituent, crystallized as a monohydrate of its iodide salt, namely, (Z)-1-(hex-5-en-1-yl)-4-{[3-methyl-2,3-di-hydro-1,3-benzo-thia-zol-2-yl-idene]meth-yl}quinolin-1-ium iodide monohydrate, C24H25N2S+·I-·H2O. The packing features aromatic π-stacking and van der Waals inter-actions. The water mol-ecule of crystallization inter-acts with the cation and anion via O-H⋯N and O-H⋯I hydrogen bonds, respectively.

Temperature and external strain sensing with metal-embedded optical fiber sensors for structural health monitoring.

An optical fiber with both temperature and strain fiber Bragg grating sensors were embedded into an aluminum cast structure during the casting process. Temperature and strain calibrations were carried out respectively for the metal-embedded sensors. Temperature and external strain decoupling was further demonstrated in a temperature range from 25 to 80 °C and an external strain range from 0 to ∼110 µÉ›. With the interpolated temperature measured by two temperature sensors at different positions, the external strain could be decoupled from temperature and thermal strain at the strain sensor. The temperature and external strain values obtained from our embedded optical fiber sensors agreed well with reference values, revealing the good performance of the metal-embedded optical fiber sensors. The difference between the measured values and the reference values are within ±5 µÉ› for external strain and ±1 °C for temperature. With only a single fiber, the in-situ temperature and external strain information in the aluminum structure can be monitored in real time, representing an important step towards fiber-optic smart casts. Our investigation demonstrates that embedded optical fiber sensors can be a promising method for structural health monitoring of metallic structures.

Fiber Bragg Sensors Embedded in Cast Aluminum Parts: Axial Strain and Temperature Response.

In this study, the response of fiber Bragg gratings (FBGs) embedded in cast aluminum parts under thermal and mechanical load were investigated. Several types of FBGs in different types of fibers were used in order to verify general applicability. To monitor a temperature-induced strain, an embedded regenerated FBG (RFBG) in a cast part was placed in a climatic chamber and heated up to 120 ∘C within several cycles. The results show good agreement with a theoretical model, which consists of a shrink-fit model and temperature-dependent material parameters. Several cast parts with different types of FBGs were machined into tensile test specimens and tensile tests were executed. For the tensile tests, a cyclic procedure was chosen, which allowed us to distinguish between the elastic and plastic deformation of the specimen. An analytical model, which described the elastic part of the tensile test, was introduced and showed good agreement with the measurements. Embedded FBGs - integrated during the casting process - showed under all mechanical and thermal load conditions no hysteresis, a reproducible sensor response, and a high reliable operation, which is very important to create metallic smart structures and packaged fiber optic sensors for harsh environments.

Incidence, Risk Factors, and Outcome of Acute Kidney Injury in Neurocritical Care.

PURPOSE: Acute kidney injury (AKI) is a severe complication in medical and surgical intensive care units accounting for a high morbidity and mortality. Incidence, risk factors, and prognostic impact of this deleterious condition are well established in this setting. Data concerning the neurocritically ill patients is scarce. Therefore, aim of this study was to determine the incidence of AKI and elucidate risk factors in this special population. METHODS: Patients admitted to a specialized neurocritical care unit between 2005 and 2011 with a length of stay above 48 hours were analyzed retrospectively for incidence, cause, and outcome of AKI (AKI Network-stage ≥2). RESULTS: The study population comprised 681 neurocritically ill patients from a mixed neurosurgical and neurological intensive care unit. The prevalence of chronic kidney disease (CKD) was 8.4% (57/681). Overall incidence of AKI was 11.6% with 36 (45.6%) patients developing dialysis-requiring AKI. Sepsis was the main cause of AKI in nearly 50% of patients. Acute kidney injury and renal replacement therapy are independent predictors of worse outcome (hazard ratio [HR]: 3.704; 95% confidence interval [CI]: 1.867-7.350; P < .001; and HR: 2.848; CI: 1.301-6.325; P = .009). Chronic kidney disease was the strongest independent risk factor (odds ratio: 12.473; CI: 5.944-26.172; P < .001), whereas surgical intervention or contrast agents were not associated with AKI. CONCLUSIONS: Acute kidney injury in neurocritical care has a high incidence and is a crucial risk factor for mortality independently of the underlying neurocritical condition. Sepsis is the main cause of AKI in this setting. Therefore, careful prevention of infectious complications and considering CKD in treatment decisions may lower the incidence of AKI and hereby improve outcome in neurocritical care.

[Endoscopic resection of a scarred rectal adenoma using EndoRotor]. / Endoskopische Abtragung eines vernarbten Adenoms im Rektum mittels EndoRotor.

INTRODUCTION: Benign colorectal neoplasia are commonly resected using snare resection or endoscopic submucosal dissection (ESD). These methods are safe, but just the piecemeal resection in flat adenomas greater than 20 mm harbor a relevant risk of recurrence. Interventional endoscopic therapy of recurrent lesions can be challenging, even in expert hands due to a high risk of complications. While smaller, scarred recurrent adenomas less than 20 mm are suitable for endoscopic full-thickness resection, hitherto larger ones have had to be removed with more laborious, time-consuming and costly endoscopic methods, or had to undergo surgery. METHOD: The EndoRotor is a novel non-diathermic resection system for benign neoplasia in the gastrointestinal tract. The tissue is aspirated into an opening at the tip of a flexible resection catheter, dissected by means of a rotating blade on the inside of the catheter and finally transported into a tissue trap. CASE REPORT: We present the case of a 79-year-old female patient with a large recurrent adenoma of a lateral-spreading tumor granular type in the rectum. Whereas a part of the adenoma could be resected with ESD, the scarred parts were not amenable to traditional endoscopic methods. By using EndoRotor, the scarred adenoma could be resected completely and without any complication. CONCLUSION: Scarred adenomas pose a challenge for interventional endoscopy. In this case study, EndoRotor proved to be a safe and viable method and a new resection option for complicated scarred rectal adenomas.

Transcriptional responses to sucrose mimic the plant-associated life style of the plant growth promoting endophyte Enterobacter sp. 638.

Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g., flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.

Heterogeneous nanoclusters assembled by PNA-templated double-stranded DNA.

Heterogeneous nanoclusters with trimeric and core-shell architectures containing nanoparticles of different size and composition have been fabricated via site-specific PNA-"invasion" of DNA double helix. This novel strategy facilitates the incorporation of double-stranded DNA into the nanoparticle assembly design.

Fluorescent DNA nanotags featuring covalently attached intercalating dyes: synthesis, antibody conjugation, and intracellular imaging.

We have synthesized fluorescent DNA duplexes featuring multiple thiazole orange (TO) intercalating dyes covalently attached to the DNA via a triazole linkage. The intercalating dyes stabilize the duplex against thermal denaturation and show bright fluorescence in the green region of the spectrum. The emission color can be changed to orange or red by addition of energy-accepting Cy3 or Cy5 dyes attached covalently to the DNA duplex. The dye-modified DNA duplexes were then attached to a secondary antibody for intracellular fluorescence imaging of centrosomes in Drosophila embryos. Bright fluorescent foci were observed at the centrosomes in both the donor (TO) and acceptor (Cy5) channels, because the energy transfer efficiency is moderate. Monitoring the Cy5 emission channel significantly minimized the background signal because of the large shift in emission wavelength allowed by energy transfer.

Site-selective binding of nanoparticles to double-stranded DNA via peptide nucleic acid "invasion".

We demonstrate a novel method for by-design placement of nano-objects along double-stranded (ds) DNA. A molecular intercalator, designed as a peptide nucleic acid (PNA)-DNA chimera, is able to invade dsDNA at the PNA-side due to the hybridization specificity between PNA and one of the duplex strands. At the same time, the single-stranded (ss) DNA tail of the chimera, allows for anchoring of nano-objects that have been functionalized with complementary ssDNA. The developed method is applied for interparticle attachment and for the fabrication of particle clusters using a dsDNA template. This method significantly broadens the molecular toolbox for constructing nanoscale systems by including the most conventional not yet utilized DNA motif, double helix DNA.

Substituent effects on the assembly of helical cyanine dye aggregates in the minor groove of a DNA template.

Double-helical DNA was used as a template for the assembly of helical cyanine dye aggregates. The aggregates consist of cofacial dimers aligned end-to-end in the minor groove of the DNA. The effect of methoxy or fluoro substituents placed on the periphery of the cyanine dye heterocycles on aggregation both in water and on the DNA template was studied by UV-vis and circular dichroism spectroscopy. Methoxy groups were found to be stronger promoters of aggregation than fluoro, and a dimethoxy dye exhibited a higher propensity to aggregate compared with an unsymmetrical methoxy/fluoro dye. Semiempirical calculations supported the experimental observation of methoxy substitution favoring aggregation. These results indicate that dispersion and hydrophobic effects contribute more to dimerization/aggregation than do electron donor-acceptor effects.

DNA-incorporating nanomaterials in biotechnological applications.

The recently developed ability to controllably connect biological and inorganic objects on a molecular scale opens a new page in biomimetic methods with potential applications in biodetection, tissue engineering, targeted therapeutics and drug/gene delivery. Particularly in the biodetection arena, a rapid development of new platforms has largely been stimulated by a spectrum of novel nanomaterials with physical properties that offer efficient, sensitive and inexpensive molecular sensing. Recently, DNA-functionalized nano-objects have emerged as a new class of nanomaterials that can be controllably assembled in predesigned structures. Such DNA-based nanoscale structures might provide a new detection paradigm due to their regulated optical, electrical and magnetic responses, chemical heterogeneity and high local biomolecular concentration. The specific biorecognition DNA and its physical-chemical characteristics allows for an exploitation of DNA-functionalized nanomaterials for sensing of nucleic acids, while a broad tunability of DNA interactions permits extending their use for detection of proteins, small molecules and ions. We discuss the progress that was achieved in the last decade in the exploration of new detection methods based on DNA-incorporating nanomaterials as well as their applications to gene delivery. The comparison between various detection platforms, their sensitivity and selectivity, and specific applications are reviewed.