Small-pore hydridic frameworks store densely packed hydrogen.

Nanoporous materials have attracted great attention for gas storage, but achieving high volumetric storage capacity remains a challenge. Here, by using neutron powder diffraction, volumetric gas adsorption, inelastic neutron scattering and first-principles calculations, we investigate a magnesium borohydride framework that has small pores and a partially negatively charged non-flat interior for hydrogen and nitrogen uptake. Hydrogen and nitrogen occupy distinctly different adsorption sites in the pores, with very different limiting capacities of 2.33 H2 and 0.66 N2 per Mg(BH4)2. Molecular hydrogen is packed extremely densely, with about twice the density of liquid hydrogen (144 g H2 per litre of pore volume). We found a penta-dihydrogen cluster where H2 molecules in one position have rotational freedom, whereas H2 molecules in another position have a well-defined orientation and a directional interaction with the framework. This study reveals that densely packed hydrogen can be stabilized in small-pore materials at ambient pressures.

A Prospective Management Strategy for Heterotaxy Syndrome with Intestinal Rotation Abnormalities: Imaging Does Not Predict Need for Surgery.

PURPOSE: Heterotaxy syndrome (HS) affects right-left anatomical development in 3% of children with congenital heart disease. Commonly, these patients have intestinal rotation abnormalities (IRA) that differ from typical malrotation. In this prospective study, we examine the development of a management pathway, imaging findings, and clinical course of patients with HS and IRA. METHODS: After literature review, a multispecialty focus group designed a pathway for HS. Participants from a single institution were prospectively enrolled from 2016 to 2019. They underwent an abdominal ultrasound and UGI, however timing was variable based on symptoms. Symptomatic IRA was defined as feeding intolerance, bilious or non-bilious vomiting, bloating, severe reflux, and intermittent pain or abdominal distention. Screening for symptoms occurred every three months for the first two years and then annually. RESULTS: 18 participants were followed for a median of 5.0 years. Three clinical categories were identified: 1) asymptomatic, not requiring intestinal surgery, 72.2%, 2) symptomatic with feeding intolerance or failure to thrive requiring gastrostomy placement and diagnostic laparoscopy with Ladd procedure, 16.7%, and 3) symptomatic requiring urgent exploration for suspicion of volvulus, 11.1%. Need for surgery did not necessarily correlate with US and/or UGI findings. CONCLUSIONS: In children with HS and IRA, postnatal imaging did not inform the need for intestinal surgery. Although rare, volvulus or other forms of proximal obstruction can be anticipated, and symptomatic patients should be offered surgical intervention. A multidisciplinary care pathway for patients with HS and IRA can coordinate care and help counsel families on the likelihood of needing intestinal surgery for IRA. LEVEL OF EVIDENCE: Level II. TYPE OF STUDY: Prospective Cohort Study.

Pseudoaneurysm of the Dorsalis Pedis Artery Following Open Reduction Internal Fixation of a Second Metatarsal Fracture: A Case Study.

Pseudoaneurysms are created by a traumatic or iatrogenic perforation of an artery, resulting in accumulation of blood between the two outermost layers of a blood vessel, the tunica media and tunica adventitia. Pedal artery pseudoaneurysms are an extremely uncommon complication of foot and ankle surgery; therefore, few cases have been reported in the literature. Early diagnosis is important to ensure timely treatment of this condition. Once clinical suspicion has been established, urgent referral to vascular surgery for prompt surgical evaluation is required to prevent potentially harmful sequalae. We present the case of a 70-year-old female who developed a pseudoaneurysm of the dorsalis pedis artery 33 days after undergoing open reduction internal fixation (ORIF) of a second metatarsal fracture. Her treatment included urgent referral to vascular surgery with subsequent surgical repair of the pseudoaneurysm via ligation of the medial dorsal branch of the dorsalis pedis artery. At 10-month follow-up, she denied any pain, sensory deficits, or functional disability and had returned to all preinjury activities with no recurrence of the pseudoaneurysm. Our case study demonstrates early diagnosis and successful treatment of a pseudoaneurysm of the dorsalis pedis artery that developed shorty after ORIF of a second metatarsal fracture.

Establishing an Online Educational Teaching File on Instagram for an Academic Radiology Department: Proof-of-Concept.

Instagram is a powerful social media platform, which can serve as the ideal educational companion app for a visually rich discipline such as Radiology. Instagram facilitates easy content creation allowing for educators to utilize this resource for easy and rapid dissemination of educational content. The authors describe their experience of creating an online publicly available radiology teaching file on Instagram as a proof-of-concept, to help other individuals and institutions in leveraging social media to create and share quality educational content for current and future trainees.

Performance of a full-scale hydrogen-storage tank based on complex hydrides.

Designing and building a full scale hydrogen storage system revealed several engineering challenges and also demonstrated the capabilities of complex hydrides. Three kg of hydrogen was stored in a four module system using modified sodium alanate as the storage media. Extensive testing of this system demonstrated the ability to follow aggressive hydrogen demand schedules that simulate actual driving. Extensive use of detailed models greatly improved the design and eventual performance of the storage system; the test data permitted further refinement of the models.

Effects of Tisseel and FloSeal on primary ischemic time in a rat fasciocutaneous free flap model.

OBJECTIVES: Free flaps are the technique of choice for reconstruction of defects resulting from extirpation of tumors of the head and neck. Advances in microsurgical technique have resulted in success rates of greater than 95%. Numerous intraoperative factors, ranging from technical issues to topically applied agents, can complicate the outcome of microsurgical free tissue transfer. Synthetic tissue adhesives and hemostatic agents are playing an ever-increasing role in reconstructive surgery. The safety of these factors in free flap surgery has not been ascertained. STUDY DESIGN: Animal Care Committee live rat model. METHODS: Male Sprague-Dawley rats were divided into three groups: group I, Control; group 2, FloSeal; group 3, Tisseel. In each group, a 3 x 6 cm ventral fasciocutaneous groin flap based on the left superficial epigastric artery was elevated and the experimental material applied beneath the flap and around the flap pedicle prior to suturing of the flap back to the wound bed. The experimental materials consisted of 0.2 mL saline in the control group, 0.5 mL FloSeal, and 0.2 mL Tisseel. In phase I of this study, the effect of each treatment on flap survival was assessed by survival at postoperative day 4. In phase II of the study, the effects of these agents on ischemic tolerance was investigated. Five rats in each treatment group were exposed to ischemic times of 6, 8, 10, and 12 hours. Survival of the flap was assessed 7 days after reversal of the ischemia. Probit curves and the critical ischemic time (CIT50) were calculated. RESULTS: All flaps survived the 2-hour period of ischemia and were viable at postoperative day 4. Flap survival from group 1 (Control), group 2 (FloSeal), and group 3 (Tisseel) at the various ischemic times was as follows: at 6 hours, 80%, 80%, and 80%, respectively; at 8 hours, 80%, 80%, 60%; at 10 hours, 60%, 33%, 40%; at 12 hours, 20%, 20%, 0%. The CIT50 for the Control, FloSeal, and Tisseel groups was 9.4, 9.0, and 7.0 hours, respectively.CONCLUSIONS FloSeal, a thrombin-based hemostatic agent, and Tisseel, a fibrin glue, displayed no adverse effect on flap survival in this model.

The effect of 2 sealants (FloSeal and Tisseel) on fasciocutaneous flap revascularization.

BACKGROUND: Fasciocutaneous tissue transfer is one of the most common procedures performed in head and neck reconstructive surgery. These composite tissues can be transferred as either a free flap or a pedicled flap. Free tissue transfer has become the reconstructive modality of choice following head and neck oncologic ablation. Synthetic tissue adhesives and hemostatic agents are rapidly gaining popularity in reconstructive surgery. Their ability to decrease bleeding and promote flap sealing and healing has led to a proliferation in their use. To our knowledge, the short-term effect of these substances on healing, as measured by flap revascularization, has not been systematically investigated. METHODS: Fifty-six male Sprague-Dawley rats were divided into 3 groups: a control group, a matrix hemostatic sealant (FloSeal) group, and a 2-component fibrin sealant (Tisseel) group. In each group, the rats had a 3 x 6-cm fasciocutaneous flap based on the inferior epigastric artery elevated and exposed to 2 hours of primary ischemia. In the control group, 0.2 mL of isotonic sodium chloride solution was placed between the flap and its bed, while in the experimental groups, 0.5 mL of FloSeal or 0.2 mL of Tisseel was applied to the wound before closure. Each group was then divided into groups of 5 rats. Each of these groups then had their pedicle divided on postischemic day 4, 5, 6, or 7. The percentage survival of the flap was measured 7 days after pedicle ligation. RESULTS: There was no statistical difference in flap survival of rats treated with isotonic sodium chloride solution, Tisseel, or FloSeal. Ligation of the flap pedicle on days 4, 5, 6, or 7 did not result in any difference in flap survival among the 3 groups. CONCLUSION: The FloSeal and Tisseel demonstrate no short-term detrimental effect on flap survival nor do they seem to affect revascularization in a fasciocutaneous free flap model.