Excitation of electronic states in tetrahydrofuran by electron impact

We report on differential and integral cross section measurements for the electron impact excitation of the three lowest lying Rydberg bands of electronic states in tetrahydrofuran. The energy range of the present experiments was 15–50 eV with the angular range of the differential cross section measurements being 15°–90°. The important effects of the long-range target dipole moment and the target dipole polarizability, on the scattering dynamics of this system, are evident from the present results. To the best of our knowledge, there are no other theoretical or experimental data against which we can compare the cross section results from this study

Primary melanoma of the prostate: case report and review of the literature

Background: Primary melanoma of the prostate has an extremely rare incidence. Only five cases have been reported in the literature and prognosis is poor. The most likely origin of prostatic melanoma is the transitional epithelium of the prostatic urethra. Surgical care for primary melanoma of mucosal sites is less well established than for primary cutaneous melanoma, but excision of the primary is recommended if the patient has no systemic disease. Case presentation: Here, we describe a case of primary malignant melanoma of the prostate. A 37-year-old male patient with history of both chemo- and radiation therapy for Hodgkin’s disease was admitted to the University Hospital Heidelberg on suspicion of pleomorphic sarcoma of the bladder. In-house diagnostic work-up revealed a malignant melanoma of the prostate. We then performed radical prostatectomy with extended lymphadenectomy. Despite presumably curative surgery, the patient suffered from early relapse of disease with pulmonary metastasis. Systemic chemotherapy and subsequent immuno-oncologic treatment was thereafter initiated. Conclusion: Since prostatic melanoma is a rare disease and a melanoma metastasis of unknown primary is the differential diagnosis, a multidisciplinary approach including early imaging to rule out possible metastases and to search for another potentially existing primary is advisable. To prevent complications related to local tumor progression and to receive tissue for mutational analysis, we recommend complete surgical resection to reduce the tumor mass. Novel immune and targeted oncologic therapies can lead to an improved survival in some cases and support of clinical trials is needed

Fluorescent D-amino-acids reveal bi-cellular cell wall modifications important for Bdellovibrio bacteriovorous predation

Modification of essential bacterial peptidoglycan (PG) containing cell walls can lead to antibiotic resistance, for example β-lactam resistance by L,D-transpeptidase activities. Predatory Bdellovibrio bacteriovorus are naturally antibacterial and combat infections by traversing, modifying and finally destroying walls of Gram-negative prey bacteria, modifying their own PG as they grow inside prey. Historically, these multi-enzymatic processes on two similar PG walls have proved challenging to elucidate. Here, with a PG labelling approach utilizing timed pulses of multiple fluorescent D-amino acids (FDAAs), we illuminate dynamic changes that predator and prey walls go through during the different phases of bacteria:bacteria invasion. We show formation of a reinforced circular port-hole in the prey wall; L,D-transpeptidaseBd mediated D-amino acid modifications strengthening prey PG during Bdellovibrio invasion and a zonal mode of predator-elongation. This process is followed by unconventional, multi-point and synchronous septation of the intracellular Bdellovibrio, accommodating odd- and even-numbered progeny formation by non-binary division

Localization of Dirac-like excitations in graphene in the presence of smooth inhomogeneous magnetic fields

The present article discusses magnetic confinement of the Dirac excitations in graphene in presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to $1/r$ is chosen. In the next case we choose a more realistic magnetic field which does not blow up at the origin and gradually fades away from the origin. The magnetic fields chosen do not have any finite/infinite discontinuity for finite values of the radial coordinate. The novelty of the two magnetic fields is related to the equations which are used to find the excited spectra of the excitations. It turns out that the bound state solutions of the two-dimensional hydrogen atom problem are related to the spectra of graphene excitations in presence of the $1/r$ (inverse-radial) magnetic field. For the other magnetic field profile one can use the knowledge of the bound state spectrum of a two-dimensional cut-off Coulomb potential to dictate the excitation spectra of the states of graphene. The spectrum of the graphene excitations in presence of the inverse-radial magnetic field can be exactly solved while the other case cannot be. In the later case we give the localized solutions of the zero-energy states in graphene.Comment: 9 pages, 6 figures, to appear in Journal of Physics: Condensed Matte