Abstract Spiders mainly feed on insects. This means that their fangs, which are used to inject venom into the prey, have to puncture the insect cuticle that is essentially made of the same material, a chitin‐protein composite, as the fangs themselves. Here a series of structural modifications in the fangs of the wandering spider Cupiennius salei are reported, including texture variation in chitin orientation and arrangement, gradients in protein composition, and selective incorporation of metal ions (Zn and Ca) and halogens (Cl). These modifications influence the mechanical properties of the fang in a graded manner from tip to base, allowing it to perform as a multi‐use injection needle that can break through insect cuticle, which is made of a chitin composite as well.
Abstract Aim The purpose of this official guideline published and coordinated by the German Society for Psychosomatic Gynecology and Obstetrics [Deutsche Gesellschaft für Psychosomatische Frauenheilkunde und Geburtshilfe (DGPFG)] is to provide a consensus-based overview of psychosomatically oriented diagnostic procedures and treatments for fertility disorders by evaluating the relevant literature. Method This S2k guideline was developed using a structured consensus process which included representative members of various professions; the guideline was commissioned by the DGPFG and is based on the 2014 version of the guideline. Recommendations The guideline provides recommendations on psychosomatically oriented diagnostic procedures and treatments for fertility disorders.
The surface shear properties of protein adsorption layers at the air/water interface have been studied at small periodic deformations by means of a modified torsion pendulum instrument. Surface shear rheological investigations of different proteins and protein/surfactant mixtures are discussed. As proteins, human albumins and gelatin are used without and in the presence of the anionic surfactant sodium dodecyl sulphate. The results are discussed in terms of adsorption layer structure and the interaction between protein molecules and of proteins with surfactants.
There are many motivations for adding simultaneously acquired MR images to PET scanning. The most straight forward are, superior registration of MR and PET images, the addition of morphological detail when there is non-rigid motion and for pre-clinical studies simultaneous imaging could lead to a significant reduction in the time that animals are required to be anesthetised. In addition simultaneous MR has the potential to provide accurate motion correction for PET image reconstruction. For functional imaging simultaneous acquisition is required to assess the subject in the same physiological state, such as acute stroke studies. The elimination of the additional radiation associated with combining CT with PET, by providing anatomic detail with MR, would be a crucial advantage for cancer screening. Combining the two instruments necessitates some engineering tradeoffs, especially associated with the use of the highly developed photomultiplier tube (PMT) used for light amplification, because of its incompatibility with strong magnetic fields. Our approach is to provide a split in the magnet and gradients to locate the magnetic sensitive components, the PMTs, in regions of low magnetic field, leaving only the essential PET components, the scintillator blocks, in the strong magnetic field region. The crystals are coupled to the PMTs by extending the optical fibres. A further advantage accrues by moving the PET electronics out of the region seen by the MR radio-frequency (RF) and gradient coils as electromagnetic interference effects between the PET and MR systems, which could cause artefacts in either modality, are eliminated. Here we describe a preliminary evaluation of the system, which is essentially a microPET Focus-120 located in a 1T split magnet, and compare its performance to previous microPET instruments.
The design of a new scanner for use in small animal PET imaging is described. The goal is to achieve 1 mm FWHM resolution in each of three orthogonal directions throughout a volume suitable for whole body mouse imaging, roughly 40 mm diameter /spl times/ 80 mm long. Simultaneously, the design should achieve a sensitivity of greater than 5% of all decays from a point source located at the center of the scanner. The scanner uses 12, plane detector banks mounted in a 160 mm diameter ring on a rotating gantry. Each detector bank consists of a 48 /spl times/ 108 array of 20 mm long LSO crystals with an array pitch of 0.87 mm. Each bank uses two Hamamatsu H8500 large-area, multi-anode photomultiplier tubes for fluorescence detection. The detector banks are divided into two sets with the respective lines of response offset by one quarter of the array pitch to give increased sampling density. Tests using a prototype crystal array demonstrate that individual crystals can be resolved. Simulations have been performed to evaluate the performance expected in the complete scanner. With F-18 point sources, the FWHM resolutions in the radial, tangential, and axial directions are less than 1 mm for source positions throughout the desired field of view (FOV). Simultaneously, the detector sensitivity is greater than 7% of all decays for a point source located at the center of the FOV. Results are also presented for simulations using different PET isotopes to investigate the effect of positron range, and for a phantom containing hot spots added to a uniform background to evaluate the scanner performance for an extended object.
MicroPET II is a second-generation microPET scanner dedicated to high resolution PET imaging of small animals. The system consists of 90 scintillation detector modules arranged in a 3-ring configuration with a radius of 16.0 cm and ail axial extent of 4.9 cm. Each detector module consists of a 14/spl times/14 array of lutetium oxyorthosilicate crystals coupled to a multi-channel photomultiplier tube (Hamamatsu H7546) through a coherent optical fiber bundle. Printed circuit boards with a charge-division readout scheme were used to decode the 196 crystals in each array from 64 anode signals. Electronics from Concorde Microsystems. Inc. was used for signal amplification, digitization, and coincidence processing. Preliminary data showed a system with peak sensitivity of 2.26%. Energy resolution ranges from 28% to 75% with a mean of 42%. Image resolution ranges from 1.07 mm FWHM at the center of field of view (CFOV) to 1.40 mm FWHM in the radial direction and 1.14 mm FWHM in the tangential direction at 1 cm offset from CFOV. Further improvements in image and energy resolution are expected when the system geometry is fully modeled and the crystal lookup tables are improved.
We describe a method of orally administering 18F-fluoro-2-deoxyglucose (FDG) for positron emission tomography (PET) scans to determine local cerebral metabolic rates for glucose (LCMRGlc), normalized to that of whole brain, in fully conscious, non-restrained primates. Oral FDG-PET studies were performed in both non-restrained and chaired monkeys, and in one human where results could be compared with traditional intravenous FDG administration. The oral route of FDG administration gave images and whole brain-normalized PET LCMRGlc results comparable to those obtained by the intravenous route. This oral FDG-PET method may provide a useful means by which to obtain measures of LCMRGlcs for brain structures, relative to each other, in non-restrained, non-drugged primates in field and laboratory studies. This method might also have clinical applications for PET studies of children.
An intraoperative beta probe was designed, built, and tested for detection of radio‐labeled malignant tissues that has the advantage of being selectively sensitive to beta while insensitive to gamma radiation. Since beta radiation (electrons or positrons) has a short range in tissue, this probe is ideal for detecting tracers in tumors at the surface of the surgical field. This probe contains a plastic scintillation detector sensitive to beta rays and to a lesser degree some background gamma rays. A second detector counts spurious gamma rays and allows for their subtraction from the activity measured by the first detector. Sensitivity of the dual probe for I‐131 and F‐18 was measured to be 108 counts/s/kBq (4000 counts/s/μCi). The dual‐detector probe faithfully measured the 10:1 “tumor” to background ratio of radioactivity concentrations in a simulated environment of a tumor in the presence of intense background 511 keV photons. In another phantom experiment, simulating abdominal tumor deposits with various realistic I‐131 radioactive concentrations, the probe was able to accurately identify tumors of approximately 50 mg with a tumor/normal radioactivity concentration of 3/1 in 10 s.
