Postoperative electrocardiography changes: To worry or not to worry.

Abnormal postoperative electrocardiograms are not uncommon, oftentimes leading to further cardiac workup especially when the findings are new and not easily explainable. A forty-year-old woman, with a history of left breast cancer status post bilateral mastectomies and reconstructions, presented for robot-assisted low-anterior resection secondary to rectal cancer. Postoperative electrocardiogram showed poor R wave progression, biphasic T waves in V2-4, and possible anterior wall ischemia. Her electrocardiogram from 6 years ago was normal. No recent electrocardiogram was available for comparison. Initially, the abnormal postoperative electrocardiogram appeared worrisome. However, the patient was completely asymptomatic, and all vital signs were normal. Cardiac point-of-care ultrasound showed normal parasternal long and short axis views. The biphasic T waves in V2-4 were suggestive of Wellens syndrome, but the accompanying poor R wave progression was not consistent with the diagnostic criteria. The anesthesiologist then remembered the patient's history of the presence of a left breast implant and suspected it might have caused the changes on the electrocardiogram. A literature search did find one publication that shows approximately 45% of patients with breast implants present with electrocardiogram changes, including poor R wave progression and negative T waves. Therefore, no further cardiac workup was ordered for our patient. She was discharged home 3 days later. Breast implants and electrocardiogram changes are a lesser-known topic. Obtaining a pre-operative electrocardiogram should be considered in patients with previous breast implants, to serve as a baseline for comparison if the patient were to need another electrocardiogram in the future.

The theory of oxygen hemoglobin association.

We develop a theory of oxygen hemoglobin association and derive the oxygen hemoglobin association equation and determine the values of the four association constants by curve fitting four commonly accepted data points that relate oxygen saturation and oxygen partial pressure (PO2) in the blood using mathematical reasoning and chemical kinetics. The four association constants come from the progression of oxygen binding to each of the four subunits on the hemoglobin molecule in a cooperative manner. The binding of oxygen alters the affinity of subsequent binding of additional oxygen molecules, which is reflected in changing magnitudes of the association constants. We also demonstrate rather surprisingly that the value of the third association constant is significantly smaller than all other association constants and offer some conjecture about this puzzling finding. With our equation, we can compute the distributions of all five oxyhemoglobin species at various PO2 levels that are published for the first time in the history of hemoglobin research. After examining the distributions, we find the triply bound oxyhemoglobin exists in very low concentration, consistent with the small third association constant. In addition, we present the oxygen levels where maximal concentrations of various oxyhemoglobin species occur, another unexpected finding that was never published before. Finally, we determine the inflection point of the hemoglobin association curve, a defining property to a specific sigmoid curve, representing the steepest portion of the curve.

Electrographic lead I and V5 monitoring could have detected a missed left-side pneumothorax intraoperatively.

We present an EKG monitoring strategy to detect pneumothorax during high-risk surgery. In the literature, EKG changes and pneumothorax are well-described. However, anesthesiologists only monitor lead II on a three-lead EKG system in the operating room. In our case, there was only a subtle change in lead II for a left-sided pneumothorax, which could have been easily missed. On the contrary, there was a marked QRS amplitude reduction and T wave flattening/inversion in lead I and V5 . We recommend lead V5 be added to the continuous monitoring and lead I be periodically checked for surgeries known to potentially cause pneumothorax.

Toward a Unified Theory of Customer Continuance Model for Financial Technology Chatbots.

With the popularity of financial technology (fintech) chatbots equipped with artificial intelligence, understanding the user's response mechanism can help bankers formulate precise marketing strategies, which is a crucial issue in the social science field. Nevertheless, the user's response mechanism towards financial technology chatbots has been relatively under-investigated. To fill these literature gaps, latent growth curve modeling was adopted by the present research to survey Taiwanese users of fintech chatbots. The present study proposed a customer continuance model to predict continuance intention for fintech chatbots and that cognitive and emotional dimensions positively influence the growth in a user's attitude toward fintech chatbots, which in turn, positively influences continuance intention over time. In total, 401 customers of fintech chatbots were surveyed through three time points to examine the relationship between these variables over six months. The results support the theoretical model of this research and can advance the literature of fintech chatbots and the information technology adoption model.

Differential regulation of Arabidopsis plastid gene expression and RNA editing in non-photosynthetic tissues.

RNA editing is one of the post-transcriptional processes that commonly occur in plant plastids and mitochondria. In Arabidopsis, 34 C-to-U RNA editing events, affecting transcripts of 18 plastid genes, have been identified. Here, we examined the editing and expression of these transcripts in different organs, and in green and non-green seedlings (etiolated, cia5-2, ispF and ispG albino mutants, lincomycin-, and norflurazon-treated). The editing efficiency of Arabidopsis plastid transcripts varies from site to site, and may be specifically regulated in different tissues. Steady state levels of plastid transcripts are low or undetectable in etiolated seedlings, but most editing sites are edited with efficiencies similar to those observed in green seedlings. By contrast, the editing of some sites is completely lost or significantly reduced in other non-green tissues; for instance, the editing of ndhB-149, ndhB-1255, and ndhD-2 is completely lost in roots and in lincomycin-treated seedlings. The editing of ndhD-2 is also completely lost in albino mutants and norflurazon-treated seedlings. However, matK-640 is completely edited, and accD-794, atpF-92, psbE-214, psbF-77, psbZ-50, and rps14-50 are completely or highly edited in both green and non-green tissues. In addition, the expression of nucleus-encoded RNA polymerase dependent transcripts is specifically induced by lincomycin, and the splicing of ndhB transcripts is significantly reduced in the albino mutants and inhibitor-treated seedlings. Our results indicate that plastid gene expression, and the splicing and editing of plastid transcripts are specifically and differentially regulated in various types of non-green tissues.