A radiologic determination of the different screw cutting patterns in cut and uncut orthopedic cortical screws using a novel imaging technique.

OBJECTIVE: We hypothesize that cut screws will deform in a manner that increases the core and outer diameters of the screw hole compared to uncut controls, and effects will be more pronounced in titanium screws. MATERIALS AND METHODS: We used biomechanical polyurethane foam blocks to simulate cortical bone. We organized four groups of stainless steel and titanium cut and uncut screws. Blocks were fitted with a jig to ensure perpendicular screw insertion. We imaged the blocks using digital mammography and measured them using PACS software. Power analysis determined a power of 0.95 and an alpha error of 0.05. RESULTS: Highly statistically significant differences in core diameter were found after cutting stainless steel and titanium screws. Cutting stainless steel screws increased core diameter by 0.30 mm (95% CI, 0.16 to 0.45; p < .001). Titanium screws' core diameter increased by 0.45 mm (95% CI, 0.30 to 0.61; p < .001). No significant differences were found in the outer diameters of stainless steel and titanium screws after cutting. CONCLUSION: Titanium and stainless steel screw tracts demonstrated screw core diameter and screw thread pattern deformation after cutting. Titanium screws demonstrated more significant effects.

Ultracompliant Heterogeneous Copper-Tin Nanowire Arrays Making a Supersolder.

Due to the substantial increase in power density, thermal interface resistance that can constitute more than 50% of the total thermal resistance has generally become a bottleneck for thermal management in electronics. However, conventional thermal interface materials (TIMs) such as solder, epoxy, gel, and grease cannot fulfill the requirements of electronics for high-power and long-term operation. Here, we demonstrate a high-performance TIM consisting of a heterogeneous copper-tin nanowire array, which we term "supersolder" to emulate the role of conventional solders in bonding various surfaces. The supersolder is ultracompliant with a shear modulus 2-3 orders of magnitude lower than traditional solders and can reduce the thermal resistance by two times as compared with the state-of-the-art TIMs. This supersolder also exhibits excellent long-term reliability with >1200 thermal cycles over a wide temperature range. By resolving this critical thermal bottleneck, the supersolder enables electronic systems, ranging from microelectronics and portable electronics to massive data centers, to operate at lower temperatures with higher power density and reliability.

In vitro efficacy of 2,N-bisarylated 2-ethoxyacetamides against Plasmodium falciparum.

Investigation of a series of 2,N-bisarylated 2-ethoxyacetamides resulted in the identification of four inhibitors 5, 20, 24, 29 with single-digit micromolar in vitro efficacy against two drug-resistant Plasmodium falciparum strains. These compounds are analogs of structurally-related 1,3-bisaryl-2-propen-1-ones (chalcones), the latter showing efficacy in vitro but not in a malaria-infected mouse. The 2,N-bisarylated 2-ethoxyacetamides (e.g., 2, 5, 20) were shown to possess significantly greater stability in the presence of metabolizing enzymes than the corresponding 1,3-bisaryl-2-propen-1-ones (e.g., 1, 3, 18).

An Enigmatic Case of Skeletal Fluorosis: Inhalant-Induced Toxicity.

ABSTRACT: Skeletal fluorosis is more common in the developing world, but is occasionally seen in the United States. We present radiographic, scintigraphic, CT, and clinical images of a 26-year-old woman with rapidly progressive, debilitating, polyostotic periostitis, and diffuse osteosclerosis typical of skeletal fluorosis. Laboratory analyses supported this diagnosis. The source of excess fluoride intake was elusive until a concurrent mental health workup revealed the patient's proclivity for inhaling air-duster cans containing difluoroethane. Difluoroethane inhalant abuse is an increasingly reported cause of skeletal fluorosis that astute clinicians should recognize. Discontinuation and sobriety from this toxic agent are essential for recovery.

Optimized purification methods for metallic contaminant removal from directly recycled Li-ion battery cathodes.

Metallic contaminants pose a significant challenge to the viability of directly recycling Li-ion batteries. To date, few strategies exist to selectively remove metallic impurities from mixtures of shredded end-of-life material (black mass; BM) without concurrently damaging the structure and electrochemical performance of the target active material. We herein present tailored methods to selectively ionize two major contaminants-Al and Cu-while retaining a representative cathode (LiNi0.33Mn0.33Co0.33O2; NMC-111) intact. This BM purification process is conducted at moderate temperatures in a KOH-based solution matrix. We rationally evaluate approaches to increase both the kinetic corrosion rate and the thermodynamic solubility of Al0 and Cu0, and evaluate the impact of these treatment conditions on the structure, chemistry, and electrochemical performance of NMC. Specifically, we explore the impacts of chloride-based salts, a strong chelating agent, elevated temperature, and sonication on the rate and extent of contaminant corrosion, while concurrently evaluating the effects on NMC. The reported BM purification process is then demonstrated on samples of "simulated BM" containing a practically relevant 1 wt% concentration of Al or Cu. Increasing the kinetic energy of the purifying solution matrix through elevated temperature and sonication accelerates the corrosion of metallic Al and Cu, such that ∼100% corrosion of 75 µm Al and Cu particles is achieved within 2.5 hr. Further, we determine that effective mass transport of ionized species critically impacts the efficacy of Cu corrosion, and that saturated Cl- hinders rather than accelerates Cu corrosion by increasing solution viscosity and introducing competitive pathways for Cu surface passivation. The purification conditions do not induce bulk structural damage to NMC, and electrochemical capacity is maintained in half-cell format. Testing in full cells suggests that a limited quantity of residual surface species are present after treatment, which initially disrupt electrochemical behavior at the graphite anode but are subsequently consumed. Process demonstration on simulated BM suggests that contaminated samples-which prior to treatment show catastrophic electrochemical performance-can be recovered to pristine electrochemical capacity. The reported BM purification method offers a compelling and commercially viable solution to address contamination, particularly in the "fine" fraction of BM where contaminant sizes are on the same order of magnitude as NMC and where traditional separation approaches are unfeasible. Thus, this optimized BM purification technique offers a pathway towards viable direct recycling of BM feedstocks that would otherwise be unusable.

Acute acalculous cholecystitis after gastrointestinal surgery.

Acute acalculous cholecystitis has been identified as a rare but potentially devastating entity after trauma, and burns, as well as in critically ill patients, and in the postoperative period. Gastrointestinal surgery is most frequently implicated in postoperative acute acalculous cholecystitis, especially after gastric and colorectal procedures. Review of the English literature identified 28 articles reporting 76 cases of acute acalculous cholecystitis after gastrointestinal operations, which included a case from Tulane University Medical Center of a 64-year-old man who developed postoperative acute acalculous cholecystitis after elective left hemicolectomy. A total of 52.4 per cent of the patients developed gangrenous acute acalculous cholecystitis, with a mortality rate of 21.1 per cent, much higher than that reported in postoperative calculous cholecystitis. This emphasizes the need for a high level of suspicion and early detection in the postoperative period to avoid devastating consequences.

The characteristics of patients with type 1: intraforaminal vertebral artery anomalies?

In a previous study, intraforaminal anomalies were found to occur at a rate of 7.6%. This increases the risk of injury to this vessel if the surgeon is unaware of such abnormalities preoperatively. The aim of our retrospective study was to identify patient factors that may predict anomalous intraforaminal vertebral arteries. Patient records were obtained from a previous study. In that study, the records of each consecutive patient who underwent cervical spine magnetic resonance imaging (MRI) for axial neck pain, radiculopathy, or myelopathy between January 2007 and January 2008 were reviewed. The social and medical histories of each patient were evaluated with respect to the presence or absence of an aberrant vertebral artery. We reviewed the medical records of the 250 patients whose MRIs were reviewed in the previous study. Seven patients were excluded for incomplete records. Chi-square and Fisher's exact tests were performed to compare the normal vertebral artery anatomy patients to the aberrant patients. The medical records of 19 patients with aberrant vertebral arteries and 224 patients with normal vertebral arteries were reviewed. The aberrant group was significantly older than the normal group (P=.00015). The only diagnostic condition that represented a statistically significant difference between the 2 groups was incidence of cancer. A relationship may exist between patient age, cancer, and medialization of the vertebral artery. The mechanism of this possible relationship is unclear. Although aberrant vertebral arteries are rare, a surgeon should have raised suspicion of this possibility in patients with a history of cancer.