Synchronous gastric and duodenal metastases from head and neck squamous cell carcinoma: a unique presentation of upper gastrointestinal bleeding.

Metastatic disease to the stomach or duodenum is an infrequent diagnosis, and head and neck squamous cell carcinoma (HNSCC) is one of the least common primary malignancies that lead to gastric or duodenal metastases. We report the case of a 65-year-old man with human immunodeficiency virus infection and previously diagnosed HNSCC who presented with melena. The patient had a percutaneous endoscopic gastrostomy tube placed 3 months prior to his presentation. Laboratory testing was significant for normocytic anemia and a digital rectal examination was positive for melena. Esophagogastroduodenoscopy revealed numerous cratered nodules with contact bleeding in the stomach as well as the duodenum that appeared malignant. Biopsies of the gastric and duodenal nodules were positive for p40 and CK 5/6, consistent with metastatic squamous cell carcinoma

Distinct phase-amplitude couplings distinguish cognitive processes in human attention

Abstract Spatial attention is the cognitive function that coordinates the selection of visual stimuli with appropriate behavioral responses. Recent studies have reported that phase-amplitude coupling (PAC) of low and high frequencies covaries with spatial attention, but differ on the direction of covariation and the frequency ranges involved. We hypothesized that distinct phase-amplitude frequency pairs have differentiable contributions during tasks that manipulate spatial attention. We investigated this hypothesis with electrocorticography (ECoG) recordings from participants who engaged in a cued spatial attention task. To understand the contribution of PAC to spatial attention we classified cortical sites by their relationship to spatial variables or behavioral performance. Local neural activity in spatial sites was sensitive to spatial variables in the task, while local neural activity in behavioral sites correlated with reaction time. We found two PAC frequency clusters that covaried with different aspects of the task. During a period of cued attention, delta-phase/high-gamma (DH) PAC was sensitive to cue direction in spatial sites. In contrast, theta-alpha-phase/beta-low-gamma-amplitude (TABL) PAC robustly correlated with future reaction times in behavioral sites. Finally, we investigated the origins of TABL PAC and found it corresponded to behaviorally relevant, sharp waveforms, which were also coupled to a low frequency rhythm. We conclude that TABL and DH PAC correspond to distinct mechanisms during spatial attention tasks and that sharp waveforms are elements of a coupled dynamical process

Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition

Brain areas within the lateral parietal cortex (LPC) and ventral temporal cortex (VTC) have been shown to code for abstract quantity representations and for symbolic numerical representations, respectively. To explore the fast dynamics of activity within each region and the interaction between them, we used electrocorticography recordings from 16 neurosurgical subjects implanted with grids of electrodes over these two regions and tracked the activity within and between the regions as subjects performed three different numerical tasks. Although our results reconfirm the presence of math-selective hubs within the VTC and LPC, we report here a remarkable heterogeneity of neural responses within each region at both millimeter and millisecond scales. Moreover, we show that the heterogeneity of response profiles within each hub mirrors the distinct patterns of functional coupling between them. Our results support the existence of multiple bidirectional functional loops operating between discrete populations of neurons within the VTC and LPC during the visual processing of numerals and the performance of arithmetic functions. These findings reveal information about the dynamics of numerical processing in the brain and also provide insight into the fine-grained functional architecture and connectivity within the human brain

Lithium extraction from oilfield brine

Lithium production through atmospheric evaporation of saline brine is generally the most economically efficient method of extraction. As global demand for lithium increases, production technology has evolved to reduce processing time of lithium from brine. The resulting technology invites the opportunity to consider lithium production from lower concentration petroleum brines, a long-overlooked lithium-rich resource. Capitalizing on advanced filtration technology and petroleum well infrastructure, the petroleum-producing geologic formations in the U.S. were evaluated for their lithium production potential. The U.S. Geological Survey National Produced Waters Geochemical Database was utilized to identify lithium-rich brine from wells across the U.S. The volume and concentration potential of the most promising lithium-enriched geologic formation were calculated. Historical and current well production data were compiled and used to estimate the expected lithium production for the geologic formation. This data was then applied to a financial model to determine the method of brine production under which extracting lithium from oilfield brine would be profitable. Advanced technology offers the advantage of recovering Li from concentrations as low as 70 mg/L. Of the produced water samples, only 344 samples had Li concentrations greater than or equal to 70 mg/L. The majority of the high Li concentration samples were identified in the Smackover Formation. The Smackover was selected to analyze for lithium extraction and production. Lithium-enriched brine can be gathered from the Smackover by collecting produced water from active wells in the formation or by drilling a purpose-designed well to access brine. Despite the ability to recover low-concentration lithium in brines, Results from the financial analysis indicate that the profitability of lithium extraction from Smackover oilfield brine is dependent on the lithium concentration of brine that is processed by the facility. Profit can be further enhanced by using economies of scale to increase the brine processing capacity of the facility. In this analysis, drilling a purpose-designed well resulted in the only profitable endeavor. When utilizing existing infrastructure to collect brine, the profitability is highly dependent on the number of active wells that produce from the Smackover Formation. This analysis indicates that a standalone lithium extraction company is best positioned to capitalize on lithium extraction from oilfield brine.Energy and Earth ResourcesBusiness Administratio

Parent involvement in educational decision-making.

EducationDoctor of Education (Ed.D.

Six family factors and their relationships to patients' performance in group therapy

Thesis (M.S.)--Boston Universit

Analyzing Tool Dynamics and Surface Roughness Variation for Low Depths of Cut when Milling 6061-T6 Aluminum

This study explores the relationship between endmill tool dynamics and cutting parameters, emphasizing the impact of these factors on machining dynamics, surface finish, and dimensional control. It introduces a novel approach to analyze and optimize the overall performance of a solid carbide endmill, with a specific focus on machining Aluminum 6066-T6. By using stability lobes diagrams (SLD), stable conditions for cutting were chosen, and then surface roughness and tool and workpiece vibration analyses were performed to assess machining performance. This work aims to understand the effects of operating below the peaks and valleys, inherent in the shape of the SLD, using different RPMs. The study's methodology involves tap tests using CutPro - Tap Test Module and milling tests on a horizontal machining center. The surface roughness measurement was performed using an Alicona Infinite Focus confocal microscope and accelerometers were positioned on the spindle bearing housing and workpiece. The findings suggest that within the stable range below the stability lobe diagram's boundary, there is a significant difference in vibration resulting in variation in surface roughness corresponding to the peaks and valleys of the SLD. The variation of acceleration, and consequently vibration, was considerably higher when operating below valleys which negatively affected the surface roughness of the workpiece. The surface roughness plays a pivotal role in tool performance and subsequently influences metal removal rate and tool and spindle life. For conditions closer to instability, this is even more important. In conclusion, this research lays the foundation for a holistic approach to solid carbide endmill design and cutting parameter selection, showing that the machining process can be optimized in terms of the SLDs, even in regions far below the stability limitThesisMaster of Applied Science (MASc