New Raman measurements for H2O ice VII in the range of 300 cm-1 to 4000 cm-1 at pressures up to 120 GPa.

Raman spectroscopic measurements for H2O ice VII have been conducted to 120 GPa at 300 K in the spectroscopic range of 300-4000 cm-1. Both moissanite and diamond anvils were used for the experiments. This overcomes the problems of overlapping spectra between the diamond anvil and sample, which had prevented the observation of the stretching modes at pressures higher than ∼23 GPa in all previous measurements. The new results reveal many bands which have not been reported before. The pressure dependences of the Raman modes show anomalous changes at 13-15, ∼27, ∼44, ∼60, and 90 GPa, implying possible structural changes at these pressures. The new results demonstrate that the predicted symmetric hydrogen bond phase X transition does not occur below 120 GPa.

Complications of pediatric femoral shaft and distal physeal fractures.

Fractures of the femoral shaft comprise about 1.6% of all bony injuries in children and are the most common pediatric orthopaedic injury that requires hospitalization. The treatment of femoral fractures in children is largely dependent on the child's age and size and takes into account multiple considerations: the child's weight, associated injuries, the fracture pattern, the mechanism of injury, institutional or surgeons' preferences, and economic and social concerns. In addition, during the past two decades, there has been a dramatic change favoring surgical fixation rather than casting because of the many advantages of fixation, including more rapid mobilization. The goal of treatment should be to ultimately obtain a healed fracture and avoid associated complications, such as nonunion or delayed union, angular or rotational deformity, unequal limb lengths, infection, neurovascular injury, disruption of the growth plate, muscle weakness, and/or compartment syndrome.

Decoding the superlattice and interface structure of truncate PbS nanocrystal-assembled supercrystal and associated interaction forces.

Large scale three-dimensional supercrystals were grown by controlling evaporation of truncate PbS nanocrystal (NC) dispersed hexane suspensions. Electron microscopy analysis confirmed the nature of single supercrystal with a face-centered cubic (fcc) lattice. Synchrotron small/wide angle scattering (SAXS/WAXS) images from three typical crystallographic projections allowed ultimate reconstruction of shape orientations of NCs at different crystallographic sites. Position exchange of distinctly oriented NCs between crystallographic sites produces two nondegeneration shape-related pseudo-polymorphs of superlattice that accordingly reduce symmetry from Oh to C4h and C2h with various facet-to-facet arrangements, respectively. In situ SAXS measurements of NC-assembled supercrystal and lead oleate and oleic acid upon pressurization provide additional insights into surface ligand density and the nature of ligand-NC interactions and resulting interface structure. These results allow for feasible evaluation of both NC shape and ligand conformation enabled effects that govern the formation and stability of truncate NC assemblies with various superlattice polymorphs and associated NC-ligand interactions in solvent-mediated assembled processes.

Optical properties of PbS nanocrystal quantum dots at ambient and elevated pressure.

We investigated pressure-dependent changes in the optical properties of PbS nanocrystal quantum dots (NQD) by combining X-ray scattering and optical absorption spectroscopy in a diamond anvil cell. We discovered that the excitonic absorption peak vanishes as the NQD crystal structure reversibly undergoes the pressure-induced phase transition from rock-salt to orthorhombic structure. In the rock-salt phase, the pressure coefficient ∂E(g)/∂P of PbS NQD is negative and decreases in magnitude with decreasing NQD size. The basic theoretical model based on literature values of the PbS bulk modulus significantly overestimated the change in pressure coefficient with NQD size. We present a model that includes the size-dependence of both the pressure coefficient and bulk modulus to describe the experimentally observed optical and structural trends.

Correlating superlattice polymorphs to internanoparticle distance, packing density, and surface lattice in assemblies of PbS nanoparticles.

Assemblies of 3.5 nm PbS nanoparticles (NPs) nucleate in three dominant superlattice polymorphs: amorphous, body-centered-cubic (bcc) and face-centered-cubic (fcc) phase. This superlattice relationship can be controlled by the inter-NP distance without changing the NP size. Upon increase of inter-NP distance, the packing density decreases, and the capping molecules at NP surfaces change in structure and accordingly modify the surface energy. The driving force for NP assembly develops from an entropic maximization to a reduction of total free energy through multiple interactions between surface molecules and NPs and resulting variation of surface molecules. Upon long-term aging and additional thermal treatment, fcc undergoes a tetragonal distortion and subsequently transforms to bcc phase, and simultaneously, the NPs embedded in supercrystals reduce surface energy primarily in {200} facets. Linking molecule-NP interactions with a series of changes of packing density and surface lattice spacings of NPs allows for an interpretation of principles governing the nucleation, structure stability, and transformation of PbS NP-assembled supercrystals.

Deviatoric stress driven formation of large single-crystal PbS nanosheet from nanoparticles and in situ monitoring of oriented attachment.

Two-dimensional single-crystal PbS nanosheets were synthesized by deviatoric stress-driven orientation and attachment of nanoparticles (NPs). In situ small- and wide-angle synchrotron X-ray scattering measurements on the same spot of the sample under pressure coupled with transmission electron microscopy enable reconstruction of the nucleation route showing how enhanced deviatoric stress causes ordering NPs into single-crystal nanosheets with a lamellar mesostructure. At the same time that deviatoric stress drives SC(110) orientation in a face-centered-cubic supercrystal (SC), rocksalt (RS) NPs rotate and align their RS(200) and RS(220) planes within the SC(110) plane. When NPs approach each other along the compression axis, enhanced deviatoric stress drives soft ligands passivated at RS(200) and RS(220) surfaces to reorient from a group of SC(110) in-planes to the interspace of SC[110]-normal planes. While the internal NP structure starts a rocksalt-to-orthorhombic transition at 7.1 GPa, NPs become aligned on RS(220) and RS(200) and thus become attached at those faces. The transition-catalyzed surface atoms accelerate the inter-NP coalescing process and the formation of low-energy structure nanosheet. Above 11.6 GPa, the nucleated single-crystal nanosheets stack into a lamellar mesostructure that has a domain size comparable to the starting supercrystal.

A Two-Surgeon Approach Improves Performance for Young Surgeons in Adolescent Idiopathic Scoliosis.

Adolescent idiopathic scoliosis (AIS) is a complex 3-dimensional deformity. Previous studies have suggested a learning curve in the successful execution of this technically demanding procedure. A 2-surgeon model may be helpful for less experienced surgeons by facilitating greater consistency in surgical metrics. The objective of this study was to show no significant difference in the parameters examined for surgeries done by inexperienced primary surgeons with a 2-surgeon model compared with those done by their more experienced cohorts. All surgeries with a primary diagnosis of AIS that were performed from January 2012 to December 2015 and had a minimum of 2-year follow-up were included for analysis. Three groups were created based on surgeon experience: inexperienced surgeons (IS) group, experienced surgeons (ES) group, and a third group where the primary surgeon was in the experienced group and the assistant surgeon was in the inexperienced group (EIS). Variables included for analysis were age, Lenke classification, number of levels fused, length of surgery, length of stay, percent curve correction, ratio of estimated blood loss to levels fused, surgical blood loss, and complications. There were no significant differences between the groups in terms of operative time, blood loss, number of levels fused, lower estimated blood loss ratio to the number of levels fused, or percent curve correction (P>.05). The IS group was found to have a significant shorter length of stay (P=.004). The 2-surgeon model is an effective tool for inexperienced surgeons to achieve consistent and reproducible operative performance that is comparable with their more experienced peers. [Orthopedics. 2021;44(3):e347-e352.].

Perception Versus Reality in the Cost of Orthopedic Trauma Implants.

OBJECTIVE: Health care costs are increasing in medicine and in orthopedics. Device choice in orthopedic cases can impact the cost of the procedure and thus result in cost savings. This study aims to determine whether orthopedic attendings and residents accurately estimate device costs they are implanting in trauma cases and whether costs would influence their surgical device selection. DESIGN: Using nationally published average cost data for 13 implants, a survey was distributed at 6 US academic centers. Respondents were asked to select the correct cost from cost ranges. They also answered yes/no questions about their choices regarding published research outcomes for specific fractures. Residents' answers were compared with faculty answers using t tests for each cost estimate question, and chi-square tests for yes/no questions and frequencies. RESULTS: A total of 51 faculty members and 76 residents responded. Attending estimates were closer to the actual cost for most devices. The average total error in cost estimate for all 13 implants was $11,288.36 for residents (35.6% difference) and $10,208.33 for faculty members (32.2% difference). Significantly more faculty members estimated costs within 10% versus residents. When asked if the literature showed differences in outcome when using different implants to treat 4 common fractures, most answered these questions correctly. Further, 71.1% of residents said their choice of implant would change if costs affected physician reimbursements versus 58% for faculty members. CONCLUSIONS: Our data indicate orthopedic physicians are not aware of true implant costs and nearly half of attendings would not consider cost as a factor in deciding between equivalent implants, even if this affected their reimbursement. Most notably, participants showed a poor ability to closely estimate the cost of more expensive implants (actual device cost greater than $2000). Our results suggest that medical cost containment should be stressed to the next generation of surgeons.

Synchrotron x-ray spectroscopy of EuHNO3 aqueous solutions at high temperatures and pressures and Nb-bearing silicate melt phases coexisting with hydrothermal fluids using a modified hydrothermal diamond anvil cell and rail assembly.

A modified hydrothermal diamond anvil cell (HDAC) rail assembly has been constructed for making synchrotron x-ray absorption spectroscopy, x-ray fluorescence, and x-ray mapping measurements on fluids or solid phases in contact with hydrothermal fluids up to approximately 900 degrees C and 700 MPa. The diamond anvils of the HDAC are modified by laser milling grooves or holes, for the reduction of attenuation of incident and fluorescent x rays and sample cavities. The modified HDAC rail assembly has flexibility in design for measurement of light elements at low concentrations or heavy elements at trace levels in the sample and the capability to probe minute individual phases of a multiphase fluid-based system using focused x-ray microbeam. The supporting rail allows for uniform translation of the HDAC, rotation and tilt stages, and a focusing mirror, which is used to illuminate the sample for visual observation using a microscope, relative to the direction of the incident x-ray beam. A structure study of Eu(III) aqua ion behavior in high-temperature aqueous solutions and a study of Nb partitioning and coordination in a silicate melt in contact with a hydrothermal fluid are described as applications utilizing the modified HDAC rail assembly.

Managing atraumatic meniscal tears in middle-aged patients.

What role does arthroscopic surgery have in the treatment of patients with atraumatic meniscal tears and osteoarthritis? The authors reviewed the literature to find out.

Increased heparanase expression is caused by promoter hypomethylation and up-regulation of transcriptional factor early growth response-1 in human prostate cancer.

PURPOSE: Heparanase degrades heparan sulfate and has been implicated in tumor invasion and metastasis. The transcription factor, early growth response 1 (EGR1), is associated with the inducible transcription of the heparanase gene. We hypothesize that CpG hypomethylation in the heparanase promoter coupled with up-regulation of EGR1 levels may induce heparanase expression in human prostate cancer. EXPERIMENTAL DESIGN: Cultured prostate cancer cell lines (Du145, DuPro, LNCaP, and PC-3) with and without 5'-aza-2-deoxycytidine treatment, 177 prostate cancer samples, and 69 benign prostatic hyperplasia (BPH) samples were used. The frequency and level of heparanase promoter methylation were analyzed by methylation-specific primers which covered the core binding motif of EGR1 (GGCG) or SP1 (GGGCGG) or both. RESULTS: In cultured Du145, DuPro, LNCaP, and PC-3 cell lines, mRNA transcripts of heparanase were significantly increased after 5'-aza-2-deoxycytidine treatment, suggesting that promoter methylation was involved in the regulation of heparanase mRNA transcript. Significantly higher methylation was found in BPH samples than in prostate cancer samples (P < 0.0001), whereas mRNA transcripts of the heparanase gene were inversely lower in BPH samples than in prostate cancer samples (P < 0.01). EGR1 expression in prostate cancer tissues was significantly higher than in BPH tissues (P < 0.001) and correlated with heparanase expression (P < 0.0001). Moreover, multiple regression analysis revealed that up-regulation of EGR1 contributed significantly more to heparanase expression than did promoter CpG hypomethylation in prostate cancer samples (P < 0.0001). CONCLUSIONS: To our knowledge this is the first comprehensive study demonstrating that increased heparanase expression in prostate cancer tissues is due to promoter hypomethylation and up-regulation of transcription factor EGR1.

CpG hypermethylation of MDR1 gene contributes to the pathogenesis and progression of human prostate cancer.

Multidrug resistance 1 (MDR1) gene encodes for P-glycoprotein (P-gp), a Mr 170,000 transmembrane calcium-dependent efflux pump that is inactivated in prostate cancer. We hypothesize that inactivation of the MDR1 gene through CpG methylation contributes to the pathogenesis and progression of prostate cancer. To test this hypothesis, CpG methylation status of the MDR1 promoter and its correlation with clinicopathological findings were evaluated in 177 prostate cancer samples and 69 benign prostate hypertrophy (BPH) samples. Cellular proliferation index and apoptotic index were determined by proliferating cell nuclear antigen (PCNA) and single-strand DNA immunostaining, respectively. After 5-aza-2'-deoxycytidine treatment, increased expression of MDR1 mRNA transcript was found in prostate cancer cell lines (DU145, DuPro, and ND1). MDR1 methylation frequency was significantly higher in prostate cancer samples compared with BPH samples (54.8 versus 11.6%, respectively, P < 0.001). Logistic regression analysis revealed that PC patients are 11.5 times more likely to have MDR1 methylation than BPH patients (95% confidence interval 4.87-27.0) and that MDR1 methylation is independent of the age. Significant correlation of MDR1 methylation was observed with high pT category (P < 0.001), high Gleason sum (P = 0.008), high preoperative prostate-specific antigen (P = 0.01), and advancing pathological features. In addition, PCNA-labeling index were significantly higher in methylation-specific PCR (MSP)-positive than in MSP-negative prostate cancer samples (P = 0.048). In contrast, no significant difference in apoptotic index was found between MSP-positive and -negative prostate cancer samples. These findings suggest that CpG hypermethylation of MDR1 promoter is a frequent event in prostate cancer and is related to disease progression via increased cell proliferation in prostate cancer cells.

Late hemorrhagic pseudoseptic arthritis encountered during total knee arthroplasty due to hyaluronic acid viscosupplementation.

Osteoarthritis (OA) is the most common form of arthritis and affects approximately one-third of people in the United Sates aged 65 years and older. Since 2013, the American Academy of Orthopaedic Surgeons has not been able to recommended using hyaluronic acid for patients with symptomatic OA of the knee. Subsequent publications have also cautioned against the use of viscosupplementation based on lack of efficacy and the potential for harm. We present a case of late hemorrhagic pseudoseptic arthritis encountered during TKA due to hyaluronic acid viscosupplementation. Our triad of findings includes (1) acute and chronic inflammatory cells on frozen section, (2) synovitis with hemosiderin deposition, and (3) blackened cartilage with iron deposition on permanent histopathology. Our case is unique in that it shows a previously undescribed late complication of viscosupplementation.

Pressure Processing of Nanocube Assemblies Toward Harvesting of a Metastable PbS Phase.

This materials-by-design approach combines nanocrystal assembly with pressure processing to drive the attachment and coalescence of PbS nanocubes along directed crystallographic dimensions to form a large 3D porous architecture. This quenchable and strained mesostructure holds the storage of large internal stress, which stabilizes the high-pressure PbS phase in atmospheric conditions. Nanocube fusion enhances the structural stability; the large surface area maintains the size-dependent properties.

Collaborative graduate education: executive nurse practice and health care leadership.

Research College of Nursing and the Rockhurst University Helzberg School of Management Health Care Initiative collaborated to offer the Executive Nurse Practice: Health Care Leadership track to Research College of Nursing graduate students. This effort was not only cost effective, but also offered expert faculty in both the fields of nursing and business. The curriculum is an integration of both fields and faculties from both institutions as they communicate and collaborate each semester to successfully coordinate the track.

The Strongest Particle: Size-Dependent Elastic Strength and Debye Temperature of PbS Nanocrystals.

We investigated the elastic compressibility of PbS nanocrystals (NCs) pressurized in a diamond anvil cell and simultaneously probed the structure using synchrotron-based X-ray diffraction. The compressibility of PbS NCs exhibits bimodal size dependence. The elastic modulus of small NCs increases with increasing diameter and peaks near a particle diameter of approximately 7 nm. For large NCs the elastic modulus decreases toward the bulk value with increasing NC diameter. We explain the bimodal size-dependence of the elastic modulus in terms of a core-shell model based on distinct elasticity of the crystal near the surface and in the core of the particle. We combined insights into the size-dependent elasticity and lattice spacing to determine the Debye temperature of PbS NCs as a function of particle diameter. Understanding the size-dependent elasticity of defect-free colloidal NCs provides new insights into their crystal structure and mechanical properties.

Integrating in situ high pressure small and wide angle synchrotron x-ray scattering for exploiting new physics of nanoparticle supercrystals.

Combined small and wide angle synchrotron x-ray scattering (SAXS and WAXS) techniques have been developed for in situ high pressure samples, enabling exploration of the atomic structure and nanoscale superstructure phase relations. These studies can then be used to find connections between nanoparticle surfaces and internal atomic arrangements. We developed a four-axis control system for the detector, which we then employed for the study of two supercrystals assembled from 5 nm Fe(3)O(4) and 10 nm Au nanoparticles. We optimized the x-ray energy and the sample-to-detector distance to facilitate simultaneous collection of both SAXS and WAXS. We further performed in situ high pressure SAXS and WAXS on a cubic supercrystal assembled from 4 nm wurtzite-structure CdSe nanoparticles. While wurtzite-structure CdSe nanoparticles transform into a rocksalt structure at 6.2 GPa, the cubic superstructure develops into a lamellarlike mesostructure at 9.6 GPa. Nanoparticle coupling and interaction could be enhanced, thus reducing the compressibility of the interparticle spacing above ∼3 GPa. At ∼6.2 GPa, the wurtzite-to-rocksalt phase transformation results in a noticeable drop of interparticle spacing. Above 6.2 GPa, a combined effect from denser CdSe nanoparticle causes the interparticle spacing to expand. These findings could be related to a series of changes including the surface structure, electronic and mechanical properties, and strain distribution of CdSe under pressure. This technique opens the way for exploring the new physics of nanoparticles and self-assembled superlattices.

Chronic periglandular inflammation on prostate needle biopsy does not increase the likelihood of cancer on subsequent biopsy.

PURPOSE: Recent literature suggests a role for chronic inflammation in the development of prostate cancer. We investigated the association of chronic periglandular inflammation on prostate needle biopsy with subsequent prostate cancer development and clinical disease features at presentation. METHODS: Six hundred fifty-five patients were abstracted from a prostate/needle biopsy registry from Brigham and Women's Hospital presenting with prostate-specific antigen (PSA) > 4 ng/mL or abnormal digital rectal examination (DRE) between the years 1990 and 2004. DRE, PSA, PSA density, prostate volume, histology, and age were analyzed to identify clinical and pathologic associations with inflammation. Chronic inflammation was defined as an inflammatory cell infiltrate composed predominately of lymphocytes in a periglandular distribution. A subset of patients (n = 308) with follow-up biopsy results were used to identify if prostate inflammation predicted development of prostate cancer. RESULTS: Modeling performed based on 4 biopsy samples revealed prostate volume (P < .001) and DRE (P = .02) as significant predictors of inflammation; DRE lost significance in models accounting for volume. Kaplan-Meier analysis demonstrated inflammation does not predict subsequent prostate cancer (P = .2). Cox models with the same endpoint show inflammation at initial biopsy (P = .3), inflammation at last biopsy (P = .4), and inflammation on any previous biopsy (P = .08) are not associated with time-to-positive biopsy. CONCLUSIONS: Although inflammation on initial and subsequent biopsy does not predict prostate cancer in this cohort, we cannot dismiss its role in prostate cancer pathogenesis. Additional research is necessary to explore the relationship between prostate inflammation and prostate cancer development.

Containment of fluid samples in the hydrothermal diamond-anvil cell without the use of metal gaskets: performance and advantages for in situ analysis.

Metal gaskets (Re, Ir, Inconel, or stainless steel) normally used to contain fluid samples in the hydrothermal diamond-anvil cell (HDAC) are sometimes undesirable due to possible contamination and to gasket deformation at high pressures and temperatures resulting in nonisochoric behavior. Furthermore, in x-ray spectroscopic experiments, metal gaskets may attenuate the incident x-ray beam and emitted fluorescence x-rays, and the interaction of scattered radiation with the gasket may produce fluorescence that interferes with the x-ray spectrum of the sample. New arrangements and procedures were tested for the operation of the HDAC without using the metal gaskets. Distilled, de-ionized water was loaded into the sample chamber, a laser-milled recess 300 microm in diameter and approximately 50 microm deep centered in the 1.0 mm face of the lower diamond anvil, and sealed by pressing the top diamond anvil face directly against the lower one without a metal gasket in between. A maximum sample pressure of 202 MPa at 617 degrees C was maintained for a duration of 10 min without evidence of leakage. A small change in fluid density was observed in one experiment where the sample was held at 266 MPa at 708 degrees C for 10 min. The gasketless HDAC was also employed in x-ray absorption spectroscopy experiments, where, in addition to the sample chamber in the lower diamond, two grooves were milled at a 90 degrees angle to each other around the sample chamber to minimize the attenuation of incident and fluorescent x rays. With a minimum distance between the sample chamber and the grooves of 80 microm, a pressure of 76 MPa at 500 degrees C was maintained for 2 h with no change in the original fluid density.

Optical study of H2O ice to 120 GPa: dielectric function, molecular polarizability, and equation of state.

The refractive index of H2O ice has been measured to 120 GPa at room temperature using reflectivity methods. The refractive index increases significantly with pressure on initial compression and exhibits small changes with pressure at previously identified phase transitions. Pressure dependencies of the molecular polarizability show changing slopes in different pressure regions. A general molar refractivity analysis of this change in slope reveals features at 60 GPa due to the onset of the ice VII-X transition. Band gap closure in H2O ice is constrained by the dispersion data using a single oscillator dielectric model. Sample thickness measurements obtained from interference patterns yield pressure-volume relations in excellent agreement with those measured by x-ray diffraction.