Temecula Valley Unified School District

SUMMARY & CONCLUSIONSAs part of the effort to decarbonize California’s energy infrastructure, there is ongoing research on the effects of hydrogen on the safety and performance of existing natural gas transmission, distribution, and end-use equipment. This paper presents an approach to system modeling for a distribution line and connected central power station based on a real system being tested for hydrogen compatibility. In total, this system covers about two miles of distribution pipe that connects to a central turbine which is expected to be blended with hydrogen. The system model examines the risk of loss-of-containment as well as the potential reduction or loss of functionality that could result from adverse effects of hydrogen on each component. This model is built using the hybrid causal logic method, which allows Bayesian networks to be mathematically related to fault trees and event sequence diagrams.For pipe segments, the increased risk of fatigue and fracture failures is modeled according to the API 579 Level 2 Assessment for crack acceptability. The initial flaw size is taken as an uncertain variable, allowing the probability of failure to be assessed according to the expected distribution of flaw size. The effect of hydrogen on the fracture resistance of the pipe was evaluated using a regression model based on historical experimental testing of commonly used pipeline steels in hydrogen environments. For discrete components, such as valves, the expected failure modes and the baseline failure rates for each mode are determined by published historical failure data. The change in each failure mode is modeled as a relative change in the underlying physical failure mechanisms that are most likely to cause that failure mode. These mechanisms are modeled using data driven or physics-based models, such as the one developed for the reduction in steel fracture toughness, where available. Where such models are not available, expert opinion is used to estimate the relative change in risk. The combination of differing information sources is accomplished using a Bayesian network where the operating conditions of individual components can be set as evidence to obtain the risk of all failure modes for that component.The distribution lines and central plant are each considered as a separate phase of the model, where a failure in the distribution line will result in a loss of functionality for the central plant.

Conformational entropy associated with thermal vibrations plays fundamental roles in protein function, from ligand binding and catalysis to allosteric regulation. Cooper and Dryden first proposed entropy-driven allostery as an example of these effects. However, measuring the underlying thermal motions remains technically challenging. Here, we introduce LSP-MD, a computational method that builds on the Local Spatial Pattern (LSP) alignment to track side-chain stability in molecular dynamics (MD) simulations. LSP-MD uses graph-based Protein Residue Networks (PRNs) with edge weights derived from fast, local geometric fluctuations. Applied to protein kinase A (PKA), the method captures picosecond-time scale vibrations with amplitudes in the 0-2 Å range and frequencies below 100 cm-1─within the range implicated in entropy-mediated signaling. Centrality measures derived from LSP-MD networks remain stable across different simulation lengths, vector definitions, and force fields, confirming robustness. Importantly, LSP-MD reproduces key findings from traditional LSP analysis, while offering a clearer physical basis and greater computational efficiency. This method opens new opportunities for exploring entropy-driven allosteric behavior in diverse macromolecular systems.

Thrombotic thrombocytopenic purpura is a hematologic disease with a high mortality rate that affects multiple organ systems. It is caused by a deficiency of a metalloprotease known as the ADAMTS-13 enzyme. Patients can present with fever, hemolytic anemia, thrombocytopenia, kidney injury, and neurological symptoms. Here we present a case of a female with TTP who was initially diagnosed with benign paroxysmal positional vertigo (BPPV). Her initial symptoms were vertigo, blurry vision, and gait imbalance, which were accompanied by elevated total bilirubin, acute kidney injury, thrombocytopenia, and normal hemoglobin. When the patient followed up in her primary care clinic, she was found to have worsening renal function, hemolytic anemia, and severe thrombocytopenia. She was subsequently diagnosed with TTPand referred to the emergency department (ED) where she received emergent treatment with therapeutic plasma exchange (TPE) and later rituximab. This case stresses the importance of considering TTP in patients presenting with symptoms and laboratory values suggestive of the disease, even when anemia is not present.

Neutropenic enterocolitis (NEC), also referred to as typhlitis, is a condition associated with a high mortality risk and primarily manifests in immunocompromised patients. It is characterized by ulceration, edema, and hemorrhage affecting the bowel wall. The underlying cause of NEC is postulated as an immunocompromised condition that facilitates bacterial infiltration through compromised bowel mucosa. The high mortality rate is attributable to bowel necrosis, culminating in perforation and sepsis. This report describes a case involving a patient with metastatic seminoma who exhibited seizure-like activity, fever, Streptococcus gallolyticus bacteremia, and NEC. The patient underwent treatment involving broad-spectrum antibiotics and filgrastim. The patient's neutropenia resolved leading to discharge on oral antibiotics. The case reported is unique, as it links NEC toStreptococcus gallolyticus and seminoma.Streptococcus gallolyticushas not been previously associated with NEC.