Photonic clocks, Raman lasers, and Biosensors on Silicon

Micro-resonators on silicon having Q factors as high as 500 million are described, and used to demonstrate radio-frequency mechanical oscillators, micro-Raman and parametric sources with sub-100 microwatt thresholds, visible sources, as well as high-sensitivity, biological detectors

Soft lithographic fabrication of microresonators

Using ultra-high-Q toroid microcavity masters, soft lithography is applied to fabricate polymer microcavity arrays with Q factors in excess of 10^6. This technique produces resonators with material-limited quality factors

Ultra-high-Q microcavity operation in H2O and D2O

Optical microcavities provide a possible method for boosting the detection sensitivity of biomolecules. Silica-based microcavities are important because they are readily functionalized, which enables unlabeled detection. While silica resonators have been characterized in air, nearly all molecular detections are performed in solution. Therefore, it is important to determine their performance limits in an aqueous environment. In this letter, planar microtoroid resonators are used to measure the relationship between quality factor and toroid diameter at wavelengths ranging from visible to near-IR in both H2O and D2O, and results are then compared to predictions of a numerical model. Quality factors (Q) in excess of 10^8, a factor of 100 higher than previous measurements in an aqueous environment, are observed in both H2O and D2O

Simultaneous measurement of quality factor and wavelength shift by phase shift microcavity ring down spectroscopy

Optical resonant microcavities with ultra high quality factors are widely used for biosensing. Until now, the primary method of detection has been based upon tracking the resonant wavelength shift as a function of biodetection events. One of the sources of noise in all resonant-wavelength shift measurements is the noise due to intensity fluctuations of the laser source. An alternative approach is to track the change in the quality factor of the optical cavity by using phase shift cavity ring down spectroscopy, a technique which is insensitive to the intensity fluctuations of the laser source. Here, using biotinylated microtoroid resonant cavities, we show simultaneous measurement of the quality factor and the wavelength shift by using phase shift cavity ring down spectroscopy. These measurements were performed for disassociation phase of biotin-streptavidin reaction. We found that the disassociation curves are in good agreement with the previously published results. Hence, we demonstrate not only the application of phase shift cavity ring down spectroscopy to microcavities in the liquid phase but also simultaneous measurement of the quality factor and the wavelength shift for the microcavity biosensors in the application of kinetics measurements

Seafood fraud incidents control: Histological based methods as reliable tools for fresh and frozen/thawed products discrimination

Freezing is one of the commonest methods applied for seafood shelf-life extension and long-term preservation. Nevertheless, the quality decay caused by water crystallization and cellular dehydration is responsible of significant reduction of the frozen-thawed products commercial value. Therefore, according to the European Legislation on food labelling, the declaration of freezing process represents a mandatory information for the protection of consumers’ rights. In fact, the lack of such information, besides entailing a non-conformity, can favor commercial frauds. The present work aims to present the development and validation of a histological approach, based on quali-quantitative histological markers, for the discrimination between fresh and thawed-frozen fishery products. In particular, the results of the application of the histological method on Merluccius merluccius and Octopus vulgaris, respectively selected as study models for white meat fish and cephalopods species, will be presented

Species identification in petfood by using BLAST analysis of a fragment of the mitochondrial 16s ribosomal RNA gene (16srRNA).

The aim of this work was to verify the label information of pet food for cats, reporting the commercial denomination of Bianchetto among the ingredients, by sequencing and BLAST analysis of a short fragment of the mitochondrial 16SrRNA gene. Fifteen samples of petfood for cats were collected from the retail market. Three fish per samples were analyzed. After DNA extraction, performed according to Armani et al. (2011) (1), the DNA degradation pattern was assessed by electrophoretic analysis. On the basis of the 108 sequences available in GenBank belonging to the order Clupeiformes and Osmeriformes, four different primers were designed and used in combination with those reported in Armani et al. (2012) (2), for the amplification of short fragments of the mitochondrial 16SrRNA gene with a length ranging from 77 to 246 pb. Such fragments were preventively tested by BLAST analysis (http://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&BLAST_PROGRAMS=megaBlast&PAGE_TYPE=Bl astSearch&SHOW_DEFAULTS=on&LINK_LOC=blasthome) to assess their discriminatory power at inter and intra specific level. After PCR amplification, the samples associated to the expected amplicon were sequenced and the 45 sequences obtained were analyzed using the program Clustal W in Bioedit version 7.0.9.0 (3) and identified by BLAST analysis. The BLAST analysis returned an identity values of 100% with different species of the genus Encrasicholina. In particular, the most part of the samples were identified at the species level as E. heteroloba, and E. punctifer. The obtained results confirms that the molecular marker selected in this study can be used for the identification of species belonging to the Clupeiformes order, allowing a discrimination even among close species. All the 15 market pet food samples were mislabeled. In fact, while the species identification performed by molecular analysis clearly showed the presence of the juvenile form of Encrasicholina sp, also known as tropical anchovies, all the labels reported the commercial denomination of Bianchetto, which, in Italy, is allowed only for the juvenile form of Sardina pilchardus (4)

Spectrometer Scan Mechanism for Encountering Jovian Orbit Trojan Asteroids

This paper describes the design, testing, and lessons learned during the development of the Lucy Ralph (L'Ralph) Scan Mirror System (SMS), composed of the Scan Mirror Mechanism (SMM), Differential Position Sensor System (DPSS) and Mechanism Control Electronics (MCE). The L'Ralph SMS evolved from the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM), so design comparisons will be made. Lucy is scheduled to launch in October 2021, embarking upon a 12-year mission to make close range encounters in 2025 and 2033 with seven Trojan asteroids and one main belt asteroid that are within the Jovian orbit. The L'Ralph instrument is based upon the New Horizons Ralph instrument, which is a panchromatic and color visible imager and infrared spectroscopic mapper that slewed the spacecraft for imaging. The L'Ralph SMM is to provide scanning for imaging to eliminate the need to slew the spacecraft. One purpose of this paper is to gain understanding of the reasoning behind some of the design features as compared with the ATLAS BSM. We will identify similarities and differences between the ATLAS BSM and the L'Ralph SMM that resulted from the latter's unique requirements. Another purpose of this paper is to focus upon "Lessons Learned" that came about during the development of the L'Ralph SMM and its MCE, both mechanism engineering issues and solutions as well as Ground Support Equipment (GSE) issues and solutions that came about during the validation of requirements process. At the time of this writing, the L'Ralph SMM has been flight qualified and delivered to the project

An Experimental Platform for the Analysis of Polydisperse Systems Based on Light Scattering and Image Processing

In this work an experimental platform for light scattering analysis has been developed using image sensors, as CCD or CMOS. The main aim of this activity is the investigation of the feasibility of using these types of sensors for polydisperse systems analysis. The second purpose is the implementation of an experimental platform which is enough versatile to permit the observation of different phenomena in order to develop novel sensors/approach using data fusion