In the ground state of the highly conjugated green fluorescent protein (GFP), the chromophore should be planar. However, numerous crystal structures of GFP and GFP-like proteins have been reported with slightly twisted chromophores. We have previously shown that the protein cavity surrounding the chromophore in wild-type GFP is not complementary with a planar chromophore. This study shows that the crystal structure of wild-type GFP is not an anomaly: most of the GFP and GFP-like proteins in the protein databank have a protein matrix that is not complementary with a planar chromophore. When the pi-conjugation across the ethylenic bridge of the chromophore is removed the protein matrix will significantly twist the freely rotating chromophore from the relatively planar structures found in the crystal structures. The possible consequences of this nonplanar deformation on the photophysics of GFP are discussed. A volume analysis of the cis-trans-isomerization of HBDI, a GFP chromophore model compound, reveals that its hula-twist motion is volume conserving. This means that, if the GFP chromophore or GFP chromophore model compounds undergo a cis-trans-isomerization in a volume-constricting medium, such as a protein matrix or viscous liquid, it will probably isomerize by means of a HT-type motion.

Green fluorescent protein (GFP) and GFP-like fluorescent proteins owe their photophysical properties to an autocatalytically formed intrinsic chromophore. According to quantum mechanical calculations, the excited state of chromophore model systems has significant dihedral freedom, which may lead to fluorescence quenching intersystem crossing. Molecular dynamics simulations with freely rotating chromophoric dihedrals were performed on green, yellow, and blue fluorescent proteins in order to model the dihedral freedom available to the chromophore in the excited state. Most current theories suggest that a restriction in the rotational freedom of the fluorescent protein chromophore will lead to an increase in fluorescence brightness and/or quantum yield. According to our calculations, the dihedral freedom of the systems studied (BFP > A5 > YFP > GFP) increases in the inverse order to the quantum yield. In all simulations, the chromophore undergoes a negatively correlated hula twist (also known as a bottom hula twist mechanism).

The development of surgical techniques required to successfully care for patients with pathology of the aortic root has evolved considerably since Cooley and De Bakey's original report. Although it is common to hear aortic root replacement referred to as a "Bentall," the methods currently employed have gone through considerable evolution, such that the techniques of today should not be referred to as a Bentall.

To develop the next generation of translational investigators, New York University School of Medicine (NYUSOM) and the NYU-NYC Health and Hospitals Corporation Clinical and Translational Science Institute (NYU-HHC CTSI) developed the Masters of Science in Clinical Investigation dual-degree (MD/MSCI) program. This five-year program dedicates one year to coursework and biomedical research, followed by a medical school/research overlap year, to prepare students for academic research careers. This article details the MD/MSCI program's curriculum and approach to mentorship, describes the research/professional interests of students, and reports student productivity. In the first four years of the program (2010-2014) 20 students were matriculated; 7 (35%) were women, and 12 (60%) research projects were in surgical specialties. To date, 14 students have applied to residency, and half pursued surgical residency programs. Our students have produced 68 accepted abstracts, 15 abstracts in submission, 38 accepted papers and 24 papers in submission. Despite the time-limited nature of this program, additional training in research design and implementation has promoted a high level of productivity. We conclude that dual-degree training in medicine and translational research is feasible for medical students and allows for meaningful participation in valuable projects. Follow-up is warranted to evaluate the academic trajectory of these students.

Primary cardiac tumors are rare, with an autopsy incidence of 0.001-0.030% [1]. Of these, approximately 25% are malignant, with sarcomas comprising the majority of this group [2]. Distribution among the cardiac chambers varies, but those arising from the atria are more common. We report the case of a 57-year-old woman with a large right ventricular undifferentiated pleomorphic sarcoma that was thought to be a myxoma on preoperative imaging. Case report A 57-year-old woman presented with several weeks of dyspnea, lower extremity edema, fatigue, and influenza-like symptoms. Transaminases were mildly elevated (aspartate transaminase