Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection.

The precise value of the mean neutron lifetime, τn, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in situ neutron detector, the lifetime reported here [877.7 ± 0.7 (stat) +0.4/-0.2 (sys) seconds] does not require corrections larger than the quoted uncertainties.

Surgical resection of a massive primary mediastinal liposarcoma with cervical extension.

A 73-year-old man was referred for surgical excision of a massive mediastinal and cervical liposarcoma following neoadjuvant chemotherapy. Surgery was performed via a cervical incision, sternotomy and right posterolateral thoracotomy. The tumour arose from the oesophagus, which underwent extensive dissection and was oversewn with pleura after tumour resection. Histology confirmed a completely excised grade 2 de-differentiated liposarcoma with complete macroscopic excision. The patient made an excellent recovery. Oesophageal liposarcomas are rare and, unlike in this case, often extend intraluminally, necessitating oesophagectomy. To our knowledge, this is the largest such tumour found in the literature.

Isolated suprascapular nerve lesions.

This paper shows how the suprascapular nerve is liable to isolated injury and where it is most vulnerable. Lesions of the suprascapular nerve are related to disorders of the shoulder. The management of isolated suprascapular nerve lesions is discussed.