Shape-morphing living composites.

This work establishes a means to exploit genetic networks to create living synthetic composites that change shape in response to specific biochemical or physical stimuli. Baker's yeast embedded in a hydrogel forms a responsive material where cellular proliferation leads to a controllable increase in the composite volume of up to 400%. Genetic manipulation of the yeast enables composites where volume change on exposure to l-histidine is 14× higher than volume change when exposed to d-histidine or other amino acids. By encoding an optogenetic switch into the yeast, spatiotemporally controlled shape change is induced with pulses of dim blue light (2.7 mW/cm2). These living, shape-changing materials may enable sensors or medical devices that respond to highly specific cues found within a biological milieu.

Detection and Characteristics of Temporal Encephaloceles in Patients with Refractory Epilepsy.

BACKGROUND AND PURPOSE: Temporal encephaloceles are increasingly visualized during neuroimaging assessment of individuals with refractory temporal lobe epilepsy, and their identification could indicate an intracranial abnormality that may be related to a potential seizure focus. Careful review by an experienced neuroradiologist may yield improved detection of TEs, and other clinical, neurophysiologic, and radiologic findings may predict their presence. MATERIALS AND METHODS: Data were reviewed retrospectively in patients at our institution who were presented at a multidisciplinary conference for refractory epilepsy between January 1, 2010, and December 31, 2016. Clinical, neurophysiologic, and imaging data were collected. An expert neuroradiologist reviewed the latest MR imaging of the brain in patients for whom one was available, noting the presence or absence of temporal encephaloceles as well as other associated imaging characteristics. RESULTS: A total of 434 patients were reviewed, 16 of whom were excluded due to unavailable or poor-quality MR imaging. Seven patients had temporal encephaloceles reported on initial imaging, while 52 patients had temporal encephaloceles identified on expert review. MR imaging findings were more often initially normal in patients with temporal encephaloceles (P < .001), and detection of temporal encephaloceles was increased in patients in whom 3T MR imaging was performed (P < .001), the T2 sampling perfection with application-optimized contrasts by using different flip angle evolutions sequence was used (P < .001), or the presence of radiologic findings suggestive of idiopathic intracranial hypertension was noted. Seizure onset by scalp electroencephalogram among patients with temporal encephaloceles was significantly more likely to be temporal compared with patients without temporal encephaloceles (P < .001). A significant correlation between intracranial electroencephalogram seizure onset and patients with temporal encephaloceles compared with patients without temporal encephaloceles was not observed, though there was a trend toward temporal-onset seizures in patients with temporal encephaloceles (P = .06). CONCLUSIONS: Careful review of MR imaging in patients with refractory temporal lobe epilepsy by a board-certified neuroradiologist with special attention paid to a high-resolution T2 sequence can increase the detection of subtle temporal encephaloceles, and certain clinical and neurophysiologic findings should raise the suspicion for their presence.

Characterizing contrast-enhancing and re-enhancing lesions in multiple sclerosis.

OBJECTIVES: In multiple sclerosis (MS), contrast-enhancing lesions (CELs) in T1-weighted postcontrast MRI are considered markers of blood-brain barrier breakdown. It remains unknown if re-enhancement can be considered a radiologic indicator of different pathology in CELs. We investigated 1) the incidence of re-enhancing lesions (re-CELs) from chronic lesions; 2) differences in size, magnetization transfer ratio (MTR), and likelihood to appear as acute black holes (aBHs) between new lesions (n-CELs) and re-CELs; and 3) associations between re-CELs and features indicating more advanced disease. METHODS: In this retrospective natural history study, we examined 264 monthly MRI scans performed at month 1 (M1), month 2 (M2), and month 3 (M3) for 88 patients with MS. CELs were defined as n-CELs if not present in the M1 T2W MRI and re-CELs if present in the M1 T2W MRI. RESULTS: A total of 311 (82.7%) n-CELs and 65 (17.3%) re-CELs were identified. Of the 88 patients, 54 presented only n-CELs, 8 presented only re-CELs, and 26 presented both CEL types. Patients with both lesion types presented more CELs than those presenting only one type (p = 0.01). Re-CELs were larger (z = 2.72, p = 0.007) and had lower MTR (z = -2.80, p = 0.005) than n-CELs but the estimated proportion of aBHs from n-CELs was similar (z = -0.09, p = 0.1) from the proportion of aBHs from re-CELs. CONCLUSIONS: Nearly 20% of CELs represent the reoccurrence of enhancement in chronic plaques. Re-CELs represent larger areas of inflammation, not necessarily associated with larger areas of edema.

The implant-supported overdenture prosthesis for the edentulous maxilla.

Restoration of the edentulous maxilla with endosseous implants and a fixed prosthesis can be difficult. Problems encountered may include inadequate available bone, deficient lip support, and poor esthetics and phonetics. A palateless maxillary implant-supported overdenture has been shown to be useful in solving these problems. Four endosseous implants were placed in the anterior maxilla of a 59-year-old patient and allowed to osseointegrate for six months. After second-stage surgery was completed, a mesostructure bar incorporating ERA attachments was fabricated along with a palateless overdenture. This type of prosthesis offered a solution to the moderate to severely atrophic maxilla for a patient who was unable to tolerate a conventional prosthesis.

Interim luting agents, composite core surface hardness and retention of interim and final restorations.

This study compared the effects of ZOE interim cement on the retention of interim acrylic and final cast crowns (cemented with zinc phosphate) over cores of current conventional and hybrid composite resin formulae, and a non-eugenol interim cement (NOG) and a calcium hydroxide liner (CaOH2) on interim and final retention values over hybrid cores. Results were compared to retention of cast crowns over amalgam cores. Retention was measured with an Instron Testing Machine. Location of cement failure during separation was recorded. Surface hardness of each group was compared. Retention of cast crowns cemented with zinc phosphate over amalgam cores was significantly higher than that of any of the resin core groups (ANOVA, P less than 0.05, Sheffe Contrast). There was no significant difference in final casting retention cemented over hybrid or conventional resin cores exposed to ZOE (13.625 vs 14.125 Kg). Final casting retention differences were not significant between the three interim cement groups. Final retention of all groups exposed to an interim luting agent were significantly less than the composite control groups. The use of CaOH, as an interim luting agent for acrylic crowns over hybrid cores compared to ZOE or NOG, should afford significantly greater retention with no adverse effect on the retention of the final casting. While the surface hardness of both types of composite resin was adversely affected by exposure to interim luting agents as compared to controls, there was no correlation between final casting retention values and surface hardness of polished composite. The interim cements invariably failed at the interim acrylic crown interface while the zinc phosphate cement failed at the core interface.