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A labeling strategy for in vivo 19 F-MRI (magnetic resonance imaging) based on highly fluorinated, short hydrophilic peptide probes, is developed. As dual-purpose probes, they are functionalized further by a fluorophore and an alkyne moiety for bioconjugation. High fluorination is achieved by three perfluoro-tert-butyl groups, introduced into asparagine analogues by chemically stable amide bond linkages. d-amino acids and ß-alanine in the sequences endow the peptide probes with low cytotoxicity and high serum stability. This design also yielded unstructured peptides, rendering all 27 19 F substitutions chemically equivalent, giving rise to a single 19 F-NMR resonance with <10 Hz linewidth. The resulting performance in 19 F-MRI is demonstrated for six different peptide probes. Using fluorescence microscopy, these probes are found to exhibit high stability and long circulation times in living zebrafish embryos. Furthermore, the probes can be conjugated to bovine serum albumin with only amoderate increase in 19 F-NMR linewidth to ≈30 Hz. Overall, these peptide probes are hence suitable for in vivo 19 F-MRI applications.

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A novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 µL samples could be done within 3.6 min or effectively 15.3 s per sample.

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A method for the fabrication of flexible electrical circuits on polyaramid substrates is presented based on laser-induced carbonization followed by copper electroplating. Locally carbonized flexible sheets of polyaramid (Nomex), by laser radiation, create rough and highly porous microstructures that show a higher degree of graphitization than thermally carbonized Nomex sheets. The found recipe for laser-induced carbonization creates conductivities of up to ∼45 S cm-1, thereby exceeding that observed for thermally pyrolyzed materials (∼38 S cm-1) and laser carbon derived from Kapton using the same laser wavelength (∼35 S cm-1). The electrical conductivity of the carbonized tracks was further improved by electroplating with copper. To demonstrate the electrical performance, fabricated circuits were tested and improvement of the sheet resistance was determined. Copper films exhibit antimicrobial activity and were used to fabricate customized flexible antibacterial coatings. The integration of laser carbonization and electroplating technologies in a polyaramid substrate points to the development of customized circuit designs for smart textiles operating in high-temperature environments.

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Improvements to the signal-to-noise ratio of magnetic resonance detection lead to a strong reduction in measurement time, yet as a sole optimization goal for resonator design, it would be an oversimplification of the problem at hand. Multiple constraints, for example for field homogeneity and sample shape, suggest the use of numerical optimization to obtain resonator designs that deliver the intended improvement. Here we consider the 2D Lenz lens to be a sufficiently broadband flux transforming interposer between the sample and a radiofrequency (RF) circuit and to be a flexible and easily manufacturable device family with which to mediate different design requirements. We report on a method to apply topology optimization to determine the optimal layout of a Lenz lens and demonstrate realizations for both low- (45 MHz) and high-frequency (500 MHz) nuclear magnetic resonance.

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OBJECTIVE: Khat, a type of plant that grows in Yemen and some African countries like Somalia, Ethiopia and Kenya, is considered to be addictive and contains some stimulating substances that may affect different body organs. This study was conducted to identify the causes of erectile dysfunction (ED) and to investigate the effect of chewing Khat on this disease in Yemenis. MATERIALS AND METHODS: A total of 236 patients who were treated at University of Science and Technology Hospital and complained of ED were examined with penile Doppler ultrasonography (US). Biodata and health data were collected from the patients' records and via mobile interviews. RESULTS: The causes of ED were psychological causes (72%), venous leakage (19%) and arterial disease (9%). Psychological ED was most common in 15-29-year-olds, while pathological ED increased with increasing age (p=0.041). Heart diseases and diabetes showed a significant association with pathological ED (p<0.05). Although 81% of the ED patients in this study chewed Khat, there was no significant association between chewing Khat and either pathological or psychological ED (p>0.05). CONCLUSION: Psychological problems are the main causes of ED among Yemenis especially in the younger age group. It is too early to exclude Khat as a factor contributing to this health problem, and this topic warrants further case-control studies with a larger sample size.

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Pituitary apoplexy is a rare condition which may cause death of the patient in severe cases and many times leads to hypopituitarism. We report a case of apoplexy in a large prolactinoma resulting in empty sella syndrome followed by a successful pregnancy. Our patient is a 32-year-old female with a history of a macroprolactinoma for approximately 17 years who presented to our hospital with a history of severe headache, decreased level of consciousness, fever, nausea, vomiting, and diplopia of 12 hours duration. Magnetic resonance imaging done on admission showed an increase in the size of the pituitary adenoma with a subtle hemorrhage. The patient was admitted to the intensive care unit and treated conservatively. The condition of the patient improved within a few days. A few months later, she started having regular menstrual periods. A magnetic resonance imaging of the pituitary 1.5 years later was reported as empty sella syndrome, and approximately one year later she became pregnant. With the pituitary adenoma being resolved after developing pituitary apoplexy and continuing on cabergoline, the patient had a successful pregnancy with no recurrence of the adenoma after delivery and breastfeeding.