Self-Trephination in Cranial Excoriation Disorder.

BACKGROUND AND IMPORTANCE: Trephination is a procedure in which a small hole is made in the skull. Rare cases of self-trephination by individuals seeking medical benefit have been reported. Excoriation disorder is a compulsive skin-picking condition in which an individual self-inflicts cutaneous lesions. Left untreated, severe excoriation disorder can pose significant health risks. CLINICAL PRESENTATION: Here, we describe 5 patients who presented with self-trephination due to a severe form of compulsive cranial excoriation at 2 neighboring academic medical centers over a 4-year period. We review the clinical presentation of self-trephination in cranial excoriation disorder and associated risk factors, surgical and nonsurgical interventions, complications of the disease, treatments, and mortality. Defining clinical characteristics include repetitive self-induced destruction of the scalp and skull with entry into the intracranial compartment, frequent psychiatric comorbidities, infection or injury of the brain with consequent neurological morbidity or mortality, and frequent treatment failures because of poor adherence. CONCLUSION: Self-trephination in cranial excoriation disorder is a severe neuropsychological disorder and neurosurgical emergency that exposes the brain and is often life-threatening. Appropriate therapy requires antibiotics, surgical debridement and repair of the wound, and concomitant effective psychiatric management of the underlying compulsion, including the use of antidepressants and behavioral therapy.

Size Control and Antioxidant Properties of Sulfur-Rich Polymer Colloids from Interfacial Polymerization.

High sulfur content polymeric materials, known for their intriguing properties such as high refractive indices and high electrochemical capacities, have garnered significant interest in recent years for their applications in optics, antifouling surfaces, triboelectrics, and electrochemistry. Despite the high interest, most high sulfur-content polymers reported to date are either bulk materials or thin films, and there is a general lack of research into sulfur-rich polymer colloids. Water-dispersed, sulfur-rich particles are anticipated to broaden the range of applications for sulfur-containing materials. In this study, the preparation and size control parameters are presented of an aqueous dispersion of sulfur-rich polymers with the sulfur content of dispersed particles exceeding 75 wt%. Employing polymeric stabilizers with varying hydrophilic-lipophilic balance (HLB), along with changing the rank of inorganic polysulfides, allow for the control of particle size in the range of 360 nm - 1.8 µm. The sulfur-rich colloid demonstrates antioxidant properties in water, demonstrating the potential for the use of sulfur-rich polymeric materials readily removable, heterogeneous radical scavengers.

Diffusely invasive supratentorial rosette-forming glioneuronal tumor: illustrative case.

BACKGROUND: Rosette-forming glioneuronal tumors (RGNTs) are rare tumors composed of mixed glial and neurocytic components. Most lesions are confined to the posterior fossa, especially in the region of the fourth ventricle, in young adults. In few instances, diffuse involvement of the supratentorial region is identified, thereby creating significant challenges in diagnosis, surgical intervention, and prognostication. OBSERVATIONS: The authors present a 23-year-old female with chronic headaches, papilledema, and hydrocephalus who underwent radiographic evaluation revealing obstructive hydrocephalus and diffuse supratentorial enhancing and nonenhancing cystic and nodular lesions. The patient underwent a right frontal craniotomy and septostomy. An exophytic nonenhancing right frontal horn lesion was resected, and an enhancing third-ventricular lesion was biopsied. Final pathology of both of the lesions sampled was consistent with RGNT. Next-generation sequencing demonstrated tumor alterations in the FGFR-1 and PIK3CA genes. Targeted therapy with the FGFR inhibitor erdafitinib demonstrated a partial remission. LESSONS: Diffuse supratentorial spread of RGNT is an extremely rare presentation of an already uncommon pathology. In some cases, gross-total resection may not be feasible. Goals of surgery include acquiring tissue for diagnosis, maximizing safe resection, and treating any associated hydrocephalus. FGFR inhibitors may be of benefit in cases of disease progression.

Mechanochemical ring-opening metathesis polymerization: development, scope, and mechano-exclusive polymer synthesis.

Ruthenium-alkylidene initiated ring-opening metathesis polymerization has been realized under solid-state conditions by employing a mechanochemical ball milling method. This method promotes greenness and broadens the scope to include mechano-exclusive products. The carbene- and pyridine-based Grubbs 3rd-generation complex outperformed other catalysts and maintained similar mechanistic features of solution-phase reactions. High-speed ball milling provides sufficient mixing and energy to the solid reaction mixture, which is composed of an initiator and monomers, to minimize or eliminate the use of solvents. Therefore, the solubility and miscibility of monomers and Ru-initiators are not limiting factors in solid-state ball milling. A wide variety of solid monomers, including ionomers, fluorous monomers, and macromonomers, were successfully polymerized under ball milling conditions. Importantly, direct copolymerization of immiscible (ionic/hydrophobic) monomers exemplifies the synthesis of mechano-exclusive polymers that are difficult to make using traditional solution procedures. Finally, the addition of a small amount of a liquid additive (i.e., liquid-assisted grinding) minimized chain-degradation, enabling high-molecular-weight polymer synthesis.

High strength, epoxy cross-linked high sulfur content polymers from one-step reactive compatibilization inverse vulcanization.

Inverse vulcanization provides a simple, solvent-free method for the preparation of high sulfur content polymers using elemental sulfur, a byproduct of refining processes, as feedstock. Despite the successful demonstration of sulfur polymers from inverse vulcanization in optical, electrochemical, and self-healing applications, the mechanical properties of these materials have remained limited. We herein report a one-step inverse vulcanization using allyl glycidyl ether, a heterobifunctional comonomer. The copolymerization, which proceeds via reactive compatibilization, gives an epoxy cross-linked sulfur polymer in a single step, as demonstrated through isothermal kinetic experiments and solid-state 13C NMR spectroscopy. The resulting high sulfur content (≥50 wt%) polymers exhibited tensile strength at break in the range of 10-60 MPa (70-50 wt% sulfur), which represents an unprecedentedly high strength for high sulfur content polymers from vulcanization. The resulting high sulfur content copolymer also exhibited extraordinary shape memory behavior along with shape reprogrammability attributed to facile polysulfide bond rearrangement.

Transparent, Ultrahigh-Refractive Index Polymer Film (n ∼1.97) with Minimal Birefringence (Δn <0.0010).

High refractive index (RI) thin films are of critical importance for advanced optical devices, and the high refractive index polymers (HRIPs) constitute an interesting class of materials for high RI thin films due to low cost, good processability, light weight, and high flexibility. However, HRIPs have yet to realize their full potential in high RI thin film applications due to their relatively low RI, strong absorption in the blue light region, and limited film formation methods such as rapid vitrification. Herein, we report a development of a new HRIP thin film generated through a one-step vapor-phase process, termed sulfur chemical vapor deposition (sCVD), using elemental sulfur and divinyl benzene. The developed poly(sulfur-co-divinyl benzene) (pSDVB-sCVD) film exhibited RI (measured at 632.8 nm) exceeding 1.97, one of the highest RIs among polymers without metallic elements reported to date. Because the sCVD utilized vaporized sulfur with a unique sulfur-cracking step, formation of long polysulfide chains was suppressed efficiently, while high sulfur content as high as 85 wt % could be achieved with no apparent phase separation. Unlike most of inorganic high RI materials, pSDVB-sCVD was highly transparent in the entire visible range and showed extremely low birefringence of 10 × 10-4. The HRIP thin film with unprecedentedly high RI, together with outstanding transparency and low birefringence, will serve as a key component in a wide range of high-end optical device applications.

Cardiovascular Risk Factors Affect Specific Segments of the Intracranial Vasculature in High-Resolution (HR) Vessel Wall Imaging (VWI).

OBJECTIVES: Luminal-based imaging have identified different risk factors for extracranial and intracranial atherosclerosis (ICAS), but these techniques are known to underestimate the true extent of the disease. High-resolution (HR) vessel wall imaging (VWI) has recently gained recognition as a valuable tool in the assessment of ICAS. The aim of this study is to determine the association between cardiovascular risk factors and specific intracranial vessel segment involvement using HR-VWI. MATERIALS AND METHODS: From January 2017 to January 2020, consecutive patients ≥ 18 years-old undergoing HR-VWI of the brain were identified. Patients with history of primary or secondary vasculitis, reversible cerebral vasoconstriction syndrome, or moya-moya were excluded. The presence of vessel wall thickening and enhancement were assessed in the perpendicular plane for each vessel segment by two neuroradiologists. Univariate and multivariate analyses were performed to assess associations between imaging findings and cardiovascular risk factors. Interrater reliability was calculated. RESULTS: Seventy-one patients (39 men; mean age: 55.9 years) were included. Vessel wall enhancement was seen in 39/71 (55%). A total number of 105 vessel segments demonstrated abnormal enhancement and 79/105 (75%) had an eccentric pattern. Eccentric vessel wall enhancement was independently associated with age >65 years-old in the ICA (OR 9.0, CI 2.1 - 38.2, p < 0.01) and proximal MCA (OR 4.0, CI 1.2 - 13.2, p = 0.02), and with hyperlipidemia in the posterior circulation (OR 44.0, CI2.9-661.0, p<0.01). CONCLUSION: There is a significant association between eccentric vessel wall enhancement of the ICA and proximal MCA in patients with age > 65; and of the proximal posterior circulation (basilar - PCA1) with hyperlipidemia.

One-step vapor-phase synthesis of transparent high refractive index sulfur-containing polymers.

High refractive index polymers (HRIPs) have recently emerged as an important class of materials for use in a variety of optoelectronic devices including image sensors, lithography, and light-emitting diodes. However, achieving polymers having refractive index exceeding 1.8 while maintaining full transparency in the visible range still remains formidably challenging. Here, we present a unique one-step vapor-phase process, termed sulfur chemical vapor deposition, to generate highly stable, ultrahigh refractive index (n > 1.9) polymers directly from elemental sulfur. The deposition process involved vapor-phase radical polymerization between elemental sulfur and vinyl monomers to provide polymer films with controlled thickness and sulfur content, along with the refractive index as high as 1.91. Notably, the HRIP thin film showed unprecedented optical transparency throughout the visible range, attributed to the absence of long polysulfide segments within the polymer, which will serve as a key component in a wide range of optical devices.

Structural Analysis of Bottlebrush Block Copolymer Micelles Using Small-Angle X-ray Scattering.

We present structural analysis of spherical diblock copolymer micelles where core blocks have bottlebrush architecture. The dependence of the core radius (Rcore) and the corona thickness (Lcorona) on the core block length (Ncore) is investigated using small-angle X-ray scattering (SAXS) and discussed in terms of the stiffness of a core-forming polymer posed by its long fluoroalkyl side chains. The conformation of the core block is strongly stretched, and the measured exponents α and ß from power-law correlations, Rcore ∼ Ncoreα and Lcorona ∼ Ncoreß, respectively, are greater than those from any scaling predictions for block copolymer micelles with a flexible, linear core-block. Such deviations are attributed to the appreciable chain stiffness of the bottlebrush core block, and a simple model is suggested to understand how the core block stiffness influences both the dimensions of core and corona.

Type-B response regulators of rice play key roles in growth, development and cytokinin signaling.

Cytokinins are plant hormones with crucial roles in growth and development. Although cytokinin signaling is well characterized in the model dicot Arabidopsis, we are only beginning to understand its role in monocots, such as rice (Oryza sativa) and other cereals of agronomic importance. Here, we used primarily a CRISPR/Cas9 gene-editing approach to characterize the roles of a key family of transcription factors, the type-B response regulators (RRs), in cytokinin signaling in rice. Results from the analysis of single rr mutants as well as higher-order rr21/22/23 mutant lines revealed functional overlap as well as subfunctionalization within members of the gene family. Mutant phenotypes associated with decreased activity of rice type-B RRs included effects on leaf and root growth, inflorescence architecture, flower development and fertilization, trichome formation and cytokinin sensitivity. Development of the stigma brush involved in pollen capture was compromised in the rr21/22/23 mutant, whereas anther development was compromised in the rr24 mutant. Novel as well as conserved roles for type-B RRs in the growth and development of a monocot compared with dicots were identified.

Controlled Phase Separation in Poly( p-phenyleneethynylene) Thin Films and Its Relationship to Vapor-Sensing Properties.

In this paper, we report the synthesis and mesoporous film formation of hydrophobic rodlike poly( p-phenyleneethynylene)s (PPEs) and present porosity-dependent quenching studies using 1,3,5-trinitrotoluene (TNT) vapors. Nonsolvent vapor-induced phase separation was used to induce pore formation during film casting, and the concentration of PPEs in the casting solution was controlled carefully to prevent excimer formation. We found that the structures of the sidechains of the PPEs strongly influence the range of relative humidity at which controlled pore generation occurs, which could be rationalized from interfacial energies calculated from contact angle measurements. Porosity of the PPE films resulted in increased efficiency of fluorescence quenching toward TNT vapors, which previously required very thin films (below 5 nm) for sensing applications. The control of the porous structure as well as film thickness constitutes a promising strategy for enhancing the efficiency of chemosensors and in more general applications requiring fine-tuned polymer-gas interactions.

Inverse Vulcanization Polymers with Enhanced Thermal Properties via Divinylbenzene Homopolymerization-Assisted Cross-Linking.

High-refractive-index sulfur-rich polymers with significantly improved thermal properties are prepared using divinylbenzene (DVB) as a comonomer in a modified, low-temperature inverse vulcanization with elemental sulfur. Differential scanning calorimetry and Fourier transform infrared studies reveal that under the modified inverse vulcanization conditions, homopolymerized DVB segments form, leading to high glass-transition temperatures (Tg > 100 °C) and thermal stability previously unattainable from the inverse vulcanization of bifunctional olefin comonomers. On the basis of the modified procedures, a three-step molding process of the inverse vulcanization product of DVB, poly(S-r-DVB), involving (1) prepolymer formation, (2) hot-press compression molding of the soft prepolymer, and (3) thermal annealing of the molded product is demonstrated. The molded high-sulfur-content poly(S-r-DVB) exhibits a high refractive index (n > 1.85), along with high midwave infrared transmittance. Combined with a high Tg, these properties render poly(S-r-DVB) with properties highly desirable in applications involving infrared optics.

Living Light-Induced Crystallization-Driven Self-Assembly for Rapid Preparation of Semiconducting Nanofibers.

Well-defined nanostructures composed of conjugated polymers have attracted significant attention due to their intriguing electronic and optical properties. However, precise control of the size and uniformity of these semiconducting nanostructures is still rare and challenging, despite recent advances in strategies to obtain self-assembled nanostructures with narrow dispersions. Herein, we demonstrate the preparation of fluorescent conjugated block copolymers by one-shot polymerization and rapid formation of nanofibers in a few minutes via light-induced crystallization-driven self-assembly, driven by facile cis-to- trans photoisomerization of its poly( p-phenylenevinylene) blocks. Furthermore, living self-assembly was possible, allowing not only nanofibers with excellent length control and narrow size distribution but also ABA triblock comicelles and gradient comicelles, to be produced by seeded growth. Lastly, the seeded growth could be activated and deactivated repeatedly by switching the light on and off, analogous to light-induced living radical polymerization.

A one-pot synthesis of polysulfane-bearing block copolymer nanoparticles with tunable size and refractive index.

A one-pot synthesis of sulfur-rich polymer nanoparticles through a ring-opening metathesis polymerization is reported. The nanoparticles are formed in situ from diblock copolymers containing a polynorbornene derivative bearing cyclic polysulfanes. The refractive indices of the resulting nanoparticles are readily controlled in the range from 1.54 to nearly 1.65.

High sulfur content polymer nanoparticles obtained from interfacial polymerization of sodium polysulfide and 1,2,3-trichloropropane in water.

Sulfur-rich materials have recently attracted keen interest for their potentials in optical, electrochemical, and pesticidal applications as well as their utility in dynamic covalent bond chemistry. Many sulfur-rich polymers, however, are insoluble and processing methods are therefore very limited. The synthesis and characterization of water-dispersible polymer nanoparticles (NPs) with the sulfur content exceeding 75% by weight, obtained from the interfacial polymerization between 1,2,3-trichloropropane and sodium polysulfide in water is reported here. The interfacial polymerization yields well-defined sulfur-rich NPs in the presence of surfactants, which are capable of serving a dual role as a phase transfer catalyst on top of emulsifiers. Such dual role allows for the control of the product NP size by varying its concentration. The surfactants can be easily removed by centrifugation and redispersion in water is also reported here. The resulting sulfur-rich NPs are characterized through elemental analysis, dynamic light scattering, ζ-potential measurements, and scanning electron microscopy.

Facile synthesis of fluorescent polymer nanoparticles by covalent modification-nanoprecipitation of amine-reactive ester polymers.

Emission wavelength control in fluorescent nanoparticles (NPs) is crucial for their applications. In the case of inorganic quantum dots or dye-impregnated silica NPs, such a control is readily achieved by changing the size of the particles or choosing appropriate fluorescent dyes, respectively. A similar modular approach for controlling the emission wavelength of fluo-rescent polymer NPs, however, is difficult. This article reports on fluorescent polymer NPs, the synthesis of which provides a platform for a modular approach towards the preparation of fluorescent NPs of desired emission wavelength. Atom-transfer radical polymerization (ATRP) is employed to synthesize reactive ester polymers, which are then easily modified with a commercially available dye and subsequently subjected to nanoprecipitation. The resulting NPs, with low size polydispersity, show an enhanced emission quantum yield when compared with the same dye molecules in solution.

Recent approaches for the direct use of elemental sulfur in the synthesis and processing of advanced materials.

Elemental sulfur is an abundant and inexpensive material obtained as a by-product of natural-gas and petroleum refining operations. Recently, the need for the development of new energy-storage systems brought into light the potential of sulfur as a high-capacity cathode material in secondary batteries. Sulfur-containing materials were also shown to have useful IR optical properties. These developments coupled with growing environmental concerns related to the global production of excess elemental sulfur have led to a keen interest in its utilization as a feedstock in materials applications. This Minireview focuses on the recent developments on physical and chemical methods for directly processing elemental sulfur to produce functional composites and polymers.

Regiospecific synthesis of Au-nanorod/SWCNT/Au-nanorod heterojunctions.

The synthesis of precisely defined nanoscale hybrid materials remains a challenge at the frontier of chemistry and material science. In particular, the assembly of diverse high-aspect ratio one-dimensional materials such as gold nanorods and carbon nanotubes into functional systems is of ever increasing interest due to their electronic and sensing applications. To meet these challenges, methods for interfacing gold nanorods with carbon materials such as single-walled carbon nanotubes (SWCNTs) in a regio-controlled manner are needed. Herein, we report a method for the regiospecific synthesis of terminally linked gold nanorod-SWCNTs based on a nanotube surface protection strategy. The key to our approach is a SWCNT surface protection procedure allowing for selective functionalization of the SWCNT termini.