The first realization of a biomolecular OR gate function with double-sigmoid response (sigmoid in both inputs) is reported. Two chemical inputs activate the enzymatic gate processes, resulting in the output signal: chromogen oxidation, which occurs when either one of the inputs or both are present (corresponding to the OR binary function), and can be optically detected. High-quality gate functi...

Colorectal cancer exfoliates cancer cells into the lumen of the bowel, and possibly, raw bowel mucosa should provide a good medium for the exfoliated cancer cells. We report an extremely rare case of a sigmoid carcinoma metastasizing to a low fistula in ano. The patient was operated on for a fistula in ano. Biopsy demonstrated a moderate differentiated adenocarcinoma. Thereafter, sigmoidoscopy ...

We will be examining the Sigmoid Beverton-Holt difference equation. It has been shown that when the Sigmoid Beverton-Holt has a p-periodically-varying growth rate, there exists a p-periodic globally asymptotically stable solution {xn}. In this paper we extend this result to include a more general class of Sigmoid Beverton-Holt functions. Furthermore, we consider the case in which the variables ...

Causes of colonic and recto-sigmoid hematomas are multifactorial. Patients can present with a combination of dropping hemoglobin, bowel obstruction and perforation. Computed tomography imaging can provide clues to a diagnosis of intramural hematoma. We present a case of rectal hematoma and a review of current management literature. A 72-year-old male on therapeutic anticoagulation for a pulmona...

This paper presents a Gaussian noise filter that uses a sigmoid shaped membership function to model image information in the spatial domain. This function acts as a tunable smoothing intensification operator. With a proper choice of two sigmoid parameters ‘t’ and ‘a’, the filter strength can be tuned for removal of Gaussian noise in intensity images. An image information measure, Total Compatib...

The case of a patient with surgically proven internal herniation of a loop of ileum through the sigmoid mesocolon is described. This 66-year-old man presented clinically with acute lower abdominal pain and an elevated white blood cell count. A computed tomography (CT) scan showed a thickened bowel loop with "bird-beak" appearance in the pelvis, centered towards the medial side and lying aside t...

Sigmoid volvulus is a rare, but serious, complication that can occur during pregnancy. We present a case of a 33-year-old pregnant female in the third trimester with a sigmoid volvulus. Detorsion of the volvulus was performed during colonoscopy. The patient underwent an elective sigmoidectomy at a later date. Prompt diagnosis of the volvulus sigmoid is critical to minimize fetal and maternal mo...

Dural arteriovenous fistulae of the transverse and sigmoid sinuses are highly variable in symptomatology and prognosis. However, we have identified a subgroup of patients who have a high risk of hemorrhage and dementia due to severe venous overload caused by high arterial flow into the fistulae and by occlusive changes of the transverse and sigmoid sinuses. Three representative cases selected f...

While the exponential learning equation, indicating a gradually diminishing improvement, is one of the standard equations to describe learning, a sigmoid behavior with initially increasing then decreasing improvement has also been suggested. Herewe show that the sigmoid behavior ismathematically derived from the standard exponential equation when the independent variable of the equation is rest...

Volvulus is an unusual condition in Western countries, generally isolated to elderly patients with multiple comorbidities. This report describes an unusual case of a very large gangrenous sigmoid volvulus in a young, otherwise healthy 25-year-old female. A review of the diagnosis and management is subsequently described. Without a consideration of the atypical demographics for sigmoid volvulus,...