Axions are well motivated particles that could make up most or all of the dark matter if they have masses below 100 µeV. Microwave cavity techniques comprised of closed resonant structures immersed in solenoid magnets are sensitive to dark matter axions with masses of a few µeV, but face difficulties scaling to higher masses. We present the a novel detector architecture consisting of an open, Fabry-Pérot resonator and a series of current-carrying wire planes, and demonstrate this technique with a search for dark matter axion-like particles called Orpheus. This search excludes dark matter axion-like particles with masses between 68.2 and 76.5 µeV and axion-photon couplings greater than 4 × 10 −7 GeV −1 . We project that the fundamental sensitivity of this technique could be extended to be sensitive to couplings below 1 × 10 −15 GeV −1 , consistent with the DFSZ model of QCD axions.
Peptides or peptide conjugates capable of assembling into one-dimensional (1D) nanostructures have been extensively investigated over the past two decades due to their implications in human diseases and also their interesting applications as biomaterials. While many of these filamentous assemblies contain a β-sheet-forming sequence as the key design element, their eventual morphology could assume a variety of shapes, such as fibrils, ribbons, belts, or cylinders. Deciphering the key factors that govern the stacking fashion of individual β-sheets will help understand the polymorphism of peptide assemblies and greatly benefit the development of functional materials from customized molecular design. Herein, we report the decisive role of electrostatic interactions in the lamination and untwisting of 1D assemblies of short peptides. We designed and synthesized three short peptides containing only six amino acids (EFFFFE, KFFFFK, and EFFFFK) to elucidate the effective control of β-sheet stacking. Our results clearly suggest that electrostatic repulsions between terminal charges reduce the pitch of the twisting β-sheet tapes, thus leading to highly twisted, intertwined fibrils or twisted ribbons, whereas reducing this repulsion, either through molecular design of peptide with opposite terminal charges or through coassembly of two peptides carrying opposite charges, results in formation of infinite assemblies such as belt-like morphologies. We believe these observations provide important insight into the generic design of β-sheet assemblies.
It is possible to achieve a CSF leak rate of 0% by using this closure protocol. With proper experience, endoscopic skull base surgery should not be considered to have a higher CSF leak rate than open transcranial or microscopic transsphenoidal surgery.
O lfactOry groove meningiomas arise from the midline anterior cranial fossa, extend from the crista galli to the planum sphenoidale, and account for 8% to 13% of meningiomas. 2,41 Frequently, these massive tumors can extend posteriorly and envelop the anterior clinoid processes and the parasellar region. Moreover, these aggressive meningiomas can infiltrate and erode the cribriform plate, invading the ethmoid and sphenoid sinus. Microsurgical approaches include bicoronal, pterional, and lateral supraorbital "keyhole" craniotomies. 2,42 In the abbreviatioNs DVT = deep venous thrombosis; EOR = extent of resection; GTR = gross-total resection; LMS = lion's mane sign; NTR = near-total resection; STR = subtotal resection. obJective Although the endonasal endoscopic approach has been applied to remove olfactory groove meningiomas, controversy exists regarding the efficacy and safety of this approach compared with more traditional transcranial approaches. The endonasal endoscopic approach was compared with the supraorbital (eyebrow) keyhole technique, as well as a combined "above-and-below" approach, to evaluate the relative merits of each approach in different situations. methods Nineteen cases were reviewed and divided according to operative technique into 3 different groups: purely endonasal (6 cases); supraorbital eyebrow (microscopic with endoscopic assistance; 7 cases); and combined endonasal endoscopic with either the bicoronal or eyebrow microscopic approach (6 cases). Resection was judged on postoperative MRI using volumetric analysis. Tumors were assessed based on the Mohr radiological classification and the presence of the lion's mane sign. results The mean age at surgery was 61.4 years. The mean tumor volume was 19.6 cm 3 in the endonasal group, 33.5 cm 3 in the supraorbital group, and 37.8 cm 3 in the combined group. Significant frontal lobe edema was identified in 10 cases (52.6%). The majority of tumors were either Mohr Grade II (moderate) (42.1%) or Grade III (large) (47.4%). Gross-total resection was achieved in 50% of the endonasal cases, 100% of the supraorbital eyebrow cases with endoscopic assistance, and 66.7% of the combined cases. The extent of resection was 87.8% for the endonasal cases, 100% for the supraorbital eyebrow cases, and 98.9% for the combined cases. Postoperative anosmia occurred in 100% of the endonasal and combined cases and only 57.1% of the supraorbital eyebrow cases. Excluding anosmia, permanent complications occurred in 83.3% of the cases in the endoscopic group, 0% of the cases in the supraorbital eyebrow group, and 16.7% of cases in the combined group (p = 0.017). There were 3 tumor recurrences: 2 in the endonasal group and 1 in the combined group. coNclusioNs The supraorbital eyebrow approach, with endoscopic assistance, leads to a higher extent of resection and lower rate of complications than the purely endonasal endoscopic approach. The endonasal endoscopic approach by itself may be suitable for a small percentage of cases. The combined above-and-below approaches are use...
Endonasal endoscopic skull base approaches are viable in the pediatric population, they are not impeded by sphenoid sinus aeration, and they have minimal risk of cerebrospinal fluid leak and meningitis. Outcomes and complications can be predicted based on specific radio anatomical skull base measurements rather than age.
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