Biología

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Informes técnicos (25)

  • Materias primas renovables a la vanguardia

    Particularidades de la preparación de plantas
  • Análisis de sustancias nocivas en muestras biológicas

    La molienda criogénica facilita la preparación de muestras de origen animal
  • Determinación de grasas en alimentos y forrajes

    Molienda de muestras grasosas
  • La Fragmentación

    Por lo general se asocia a la noción "fragmentación", el machacamiento, de sustancias sólidas mediante fuerza mecánica. Pero también la división de líquidos en gotas o de gases en bollas representa un proceso de fragmentación.
  • La nueva generación de molinas planetarios de bolas

    Los más precisos resultados de trituración en el más breve tiempo se consiguen con los nuevos molinos planetarios de bolas, de Retsch. Con el PM100 y el PM200, Retsch presenta una nueva generación de molinos planetarios de bolas con uno o dos unidades de trituración, que establecen nuevos estándares de rendimiento en este segmento de la producción.
  • Molienda ultrarrápida y ultrafina

    El nuevo molino ultracentrífugo ZM 200 de RETSCH es un molino de rotor no sólo extremadamente rápido y cuidadoso con el material molido, sino también de uso universal gracias a su amplia gama de accesorios.
  • Kryogene Aufbereitung von Probenmaterialien

    Die Zerkleinerung als wichtiger Verfahrensschritt der Probenaufbereitung hat einen erheblichen Einfluss auf die nachfolgende Analytik. So können zu grobe Partikelfeinheiten oder auch Inhomogenitäten insbesondere dann zu unbrauchbaren oder falschen Analyseergebnissen führen, wenn es sich um kleinste Probenvolumina handelt die repräsentativ für die Gesamtprobe sind.
  • Kryogener Aufschluss von Hefezellen nach dem Rout Protokoll

    Das Michael Rout Labor, welches an der New Yorker Rockefeller Universität beheimatet ist, nahm erstmals 2006 Kontakt zu RETSCH in den USA auf, um die Möglichkeit der kryogenen Vermahlung von Hefezellen mit einer Planeten-Kugelmühle zu diskutieren. Das Ziel ihrer Untersuchungen war die Erforschung der „Bauweise“ von Komplexen, welche an den Zellwänden von Hefezellen zu finden sind. Für den Einsatz einer Planeten-Kugelmühle sprach in erster Linie, dass sehr feine Partikelgrößen erreicht werden können, was eine wichtige Voraussetzung für fundierte Analysen an den Hefezellen ist. Eine Partikelgröße im Submikron-Bereich begünstigt eine hohe Ausbeute für die nachfolgende Proteinreinigung.
  • Stabilisotopenanalyse in der Forensik – Geographische Herkunftsbestimmung von unbekannten Toten

    Die Anwendung stabilisotopenanalytischer Methoden als Werkzeug zur Aufklärung von unklaren Tatbeständen hat sich in der Forensik etabliert. Am Institut für Rechtsmedizin der Universität München gehen Anfragen zu Erstellung von Isotopengutachten aus dem In- und Ausland ein. Der Großteil der Isotopengutachten beantwortet die Frage nach der geogra-phischen Herkunft und den Aufenthaltsorten unbekannter Toter. Die Ergebnisse der Analyse der Stabilisotopenhäufigkeitsverhältnisse von Bio- und Geoelementen in Körpergeweben lie-fern Ansatzpunkte für polizeiliche Ermittlungen. Die Grundidee der geographischen Her-kunftszuordnung von Personen mittels Isotopenanalyse liegt in der Beobachtung, dass über Ernährung und Umwelt unterschiedliche Isotopenverhältnisse chemischer Elemente in den Körper eingebaut werden, die eine regionale Komponente aufweisen (Tabelle). Menschliche Gewebe zeigen dann ebenso bestimmte Isotopensignaturen, über die sich Rückschlüsse auf die Aufenthaltsorte und die Ernährungsweise des Konsumenten ziehen lassen.
  • How to minimize standard deviations by correct sample preparation

    Modern analytical methods increase precision and push detection limits to make even the smallest traces of sample components detectable. Despite this development sample preparation, which is carried out prior to the actual analysis, is frequently neglected. Errors caused by lacking accuracy in sample preparation have a much bigger impact than errors made during analysis. Just like an iceberg which is mostly hidden under water, only a small part of the sum of errors is perceived whereas the major part of potential errors is not taken into account (fig. 1). One of the reasons may be the fact that sampling and sample preparation have always been done in a traditional way which has become a routine over the years and is no longer considered as having a critical influence on the subsequent analyses.
  • White Paper: Cryogenic Preparation of Sample Materials

    A solid sample material should always be sufficiently prepared by size reduction and homogenization before it is subjected to chemical or physical analysis. Care should be taken that the analysis sample fully represents the original material and that the sample preparation process is carried out reproducibly. Only then are meaningful results guaranteed. Most sample materials can be reduced to the required analytical fineness at room temperature by choosing a mill with a suitable size reduction principle (impact, pressure, friction, shearing, cutting).
  • Ultrafine Grinding with Laboratory Ball Mills

    How are nano particles produced? The “Bottom-Up” method synthesizes particles from atoms or molecules. The “Top-Down” method involves reducing the size of larger particles to nanoscale, for example with laboratory mills. Due to their significantly enlarged surface in relation to the volume, small particles are drawn to each other by their electrostatic charges. Nano particles are produced by colloidal grinding which involves dispersion of the particles in liquid to neutralize the surface charges. Both water and alcohol can be used as dispersion medium, depending on the sample material. Factors such as energy input and size reduction principle make ball mills the best choice for the production of nanoparticles.
  • Down to the bone

    Use of laboratory grinders for size reduction of human bones and bioceramics

    Bone implants and substances for bone regeneration are used in surgery to replace degenerated bone material by implants or to “re-build” it with specific substances. The material used in implants varies from autogeneic (supplied by the patient) through allogeneic (supplied by a donor) bones to replacement materials such as hydroxylapatite (HA) and tricalcium phosphate (TCP). Bovine bones and corals are used in conjunction with synthetically produced foamed materials to form a basis for the regeneration of bone substance. Various RETSCH mills are suitable for the preliminary and fine grinding of human bones as well as bioceramic materials.
  • Representative Analysis Results Require Adequate Sample Preparation

    A faultless and comparable analysis is closely linked to an accurate sample handling. Only a sample representative of the initial material can provide meaningful analysis results. Rotating dividers and rotary tube dividers are an important means to ensure the representativeness of a sample and thus the reproducibility of the analysis. Correct sample handling consequently minimizes the probability of a production stop due to incorrect analysis results. Thus correct sample handling is the key to effective quality control.
  • CryoMill - Cryogenic grinding was never more convenient or efficient

    Some sample materials have properties which make size reduction at ambient temperature impossible. If, for example, very elastic materials need to be ground or volatile components have to be preserved for further analysis, it is essential to carry out cryogenic grinding. The use of liquid nitrogen helps to embrittle the sample, thus improving its breaking properties, and preventing volatile substances from escaping due to the frictional heat produced by the grinding process.
  • What hair reveals

    The detection of illegal drugs and pharmaceuticals is important in areas such as forensic science, traffic or competitive sports. Chemical substances can be detected in blood, saliva, urine and hair, the latter having the advantage of storing the substances for a fairly long period, depending on the hair length. In addition to the tracing of drug abuse, hair samples are also used for DNA analysis.
  • What Hair Reveals

    The detection of illegal drugs and pharmaceuticals plays a role in various fields, for example in forensic science, road traffic accidents, in competitive sports or at the workplace. Chemical substances can be detected in blood, saliva, urine and in hair. Hair has the great advantage of storing the substances for a long period, which means that detection is still possible several months after consumption of the drug. In addition to the detection of drugs, hair samples are also used for DNA analysis as well as for the analysis of heavy metals and minerals.
  • Using the CryoMill for samples with volatile substances

    For the size reduction of many materials it is more suitable to use a cryogenic mill than a laboratory mill which operates at room temperature. The sample is embrittled by liquid nitrogen which improves its breaking behavior when submitted to impact, pressure and friction; moreover, volatile components of the sample are preserved. The RETSCH CryoMill is not only the most modern and safest cryogenic mill in the market, it also provides excellent grinding results.
  • Rapid and efficient disruption of yeast cells with the Mixer Mill MM 400

    Cell disruption of bacteria, yeast, filamentous fungi or microalgae is a standard procedure in basic biological research, applied biotechnology or medical research to get access to nucleic acids (DNA, RNA) or cell proteins. For the isolation of DNA or RNA usually less than 1 ml of cell material is needed. For the extraction of proteins, however, larger amounts of cell suspension are required. A very efficient method of cell disruption is the co called “bead beating” where cells in suspension are mechanically disrupted by glass beads in single-use reaction vials.
  • Efficient Grinding at –196 °C

    RETSCH’s New CryoMill for Safe and Reproducible Grinding with Liquid Nitrogen
  • Tracking Down Fake Cashmere

    Cashmere wool is the best known precious wool. It is won from the cashmere goat which originates from the high mountain region of the same name. Due to its properties such as softness and warmth, cashmere wool gains more and more popularity in the manufacture of clothing. Genuine cashmere is won solely from the goat’s downy hair and must possess a certain hair structure with an exactly defined length and thickness.
  • Making Whole Cell Extract of Saccharomyces cerevisiae

    Preparation at the Courtesy of the Staley Lab at the University of Chicago
  • Cryogenic disruption of yeast cells

    The MM 301 can be used for cell disruption applications. In this case, yeast cells were embrittled with liquid nitrogen.
  • Representative results require adequate sample preparation

    The following situation is typical for many production plants: After a routine quality check, the production process is stopped or an already produced batch is suspended, because the analysis results were not within the relevant critical values. But does the tested product really deviate from the specifications? The quality control managers are convinced of this because modern analysis instruments provide results with very low tolerances. The sample in question was tested several times and the result was confirmed. The question is why the product does not match the specifications although the production parameters have not been changed in any way.
    The possibility that the tested product is indeed deficient cannot be excluded. However, it is often not the product itself which causes irregular analysis results but a lack of understanding of the steps which come before the analysis.

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