A Photochemical Intramolecular C-N Coupling Toward the Synthesis of Benzimidazole-Fused Phenanthridines

Herein, we report a direct photochemical dehydrogenative C-N coupling of unactivated C(sp²)-H and N(sp²)-H bonds. The catalysts or additive-free transformation of 2-([1,1'-biphenyl]-2-yl)-1H-benzo[d]imidazole to benzo[4,5]imidazo[1,2-f]phenanthridine was achieved at ∼350 nm of irradiation via ε-hydrogen abstraction. DFT calculations helped to understand that the N-H···π interaction was essential for the reaction to proceed at a lower energy than expected.

Simultaneous layer exfoliation and defect activation in g-C3N4 nanosheets with air-water interfacial plasma: spectroscopic defect probing with tailored optical properties

Defect-activated ultrathin graphitic carbon nitride nanosheets (g-C₃N₄) show an enhanced visible light absorption, better charge-separation, and facile charge transport properties. These are requisites for the designing of an active photocatalyst. Conventional methods used for layer exfoliation and defect activation require strong acids, reducing agents, or ultrasonic treatment for a sufficiently long duration. Furthermore, single-step approaches for layer exfoliation and defect incorporation have hardly been reported. Herein, we have shown atmospheric plasma enabled fabrication of g-C₃N₄ nanosheets. This approach is simple, low-cost, less time-consuming, and a green approach to exfoliate layers and activate multiple defects concurrently. The protocol involves plasma discharging at an air-water interface at 5 kV for 30-150 min. Atomic force microscopy (AFM) reveals a layer thickness of 96.27 nm in bulk g-C₃N₄. The thickness becomes 3.78 nm after 150 min of plasma treatment. The exfoliated layers emerge with nitrogen-vacancy sites and self-incorporated defects as probed by positron annihilation spectroscopy (PAS) and X-ray photoelectron spectroscopy (XPS). The defect activated layers show visible light absorption extended up to 600 nm. It is demonstrated that a non-uniform change in the band gap with the plasma treatment time results from quantum confinement in thin layers and Urbach tailing due to defects acting in opposition. Further, steady-state and time-resolved spectroscopy shows the contribution of multiple defect sites for a prolonged lifetime of photoinduced carriers. These defect-activated ultrathin nanosheets of CN serve as an active photocatalyst in the degradation of rhodamine B (RhB) under white LED illumination.

[Diagnosis, therapeutic attitude and prognostic factors of the tumors of body and tail of the pancreas--a case presentation and a review of the literature]

Neoplasms of the body and tail of the pancreas are rarer in comparison to those occurring in the head of the pancreas, representing only 10% of the total number of pancreatic malignancies. They poses even in present one of the greatest therapeutic challenge for the surgeon as their diagnosis and treatment are difficult to be done mainly due to specific anatomic position of the pancreas as well as due to the absence of any specific symptomatology belonging to the tumors of the body and tail of the pancreas having smaller dimensions. Here we are presenting two cases of neoplasms of the body and tail of the pancreas from the archives of 3rd Surgical Clinic, Cluj Napoca, hereby illustrating the experience of this clinic in the domain of high class pancreatic surgery. The two patients, having 55 and 43 years of age respectively, were diagnosed with neoplasm of the body and tail of the pancreas for which they had undergone the procedure of distal pancreatectomy along with the resection of the spleen. Out of those two cases, the first case had an invasive process of the tumor in the region of the superior mesenteric vein for what it was performed a segmental resection of the superior mesenteric vein with a termino-terminal anastomosis of the remaining two proximal and distal ends, while the second case inspite of its large dimension of the tumor (approximately 10 c.m in diameter) did not have any loco-regional invasion or any kind of distal metastasis which rendered it possible for a radical intervention. The aim of this case presentation as well as the reviews of the literatures belonging to this specialised domain is to sustain the idea that pancreatic surgery should be performed in those specialised surgical centres having profound knowledge as well as all the existing information about the diagnostic procedures, therapeutic attitude and prognostic factors of this specific pathology.

[Upper digestive hemorrhage appearing after cephalic duodeno-pancreatectomy]

The frequency of upper gastrointestinal hemorrhage as a postoperative complication of cephalic duodenopancreatectomy remained constant for decades despite the overall decrease in the incidence of mortality occuring after cephalic duodeno-pancreatomy. It is the second most common complication after anastomotic fistulas, but more frequently fatal, especially when the pancreas is anastomosed with the stomach. The case presented here is of a patient of 55 years age, diagnosed in our clinic with vaterian ampuloma for which was performed cephalic duodenopancreatectomy and gastrointestinal and hepatobiliary continuity was restored by performing terminolateral pancreato-gastric anastomosis, termino-lateral hepato-jejunal anatomosis and termino-lateral gastro-jejunal anastomosis on a jejunal loop ascended transmezocolic. Postoperative evolution of the patient was marked by appearance of two episodes of upper gastrointestinal hemorrhage, the first being solved by relaparotomy and the second benefiting from the contribution of an endoscopic intervention. From this case, we analyze risk factors for upper gastrointestinal hemorrhage appearing after cephalic duodeno-pancreatectomy and its therapeutic modalities, starting from the fact that currently there is no consensus among experts on this matter.

Acute diverticulitis--an unusual cause of liver abcesses in a young man: a case report

Liver abscess is a rare complication of sigmoid diverticulitis and must be considered within the differential diagnosis. We report a case of a male patient, age 42, admitted to our hospital with chief complaints of a dull pain in upper right abdominal quadrant, fever, weakness, diarrhoea and weight loss of approximately 3 weeks duration. Physical examination on initial work-up revealed tenderness on palpation in upper right abdomen, and left iliac fosa and a 39 degrees C fever. Biochemistry showed marked inflammatory syndrome, leukocitosis, increased level of platelets, altered liver function. Ultrasound examination revealed inhomogeneous liver nodules and the thickening of the sigmoid wall. Further CT scan examination and MRI confirmed the lesions as beeing abscesses and also revealed trombosis of right portal vein. The sigmoid wall lesions proved to be an acute diverticulitis with perisigmoiditis, stenosis and abscess. Patient underwent a surgical treatment of sigmoid resection, but the punction of the abscesses revealed no pus at aspiration, making the surgical excision of the lesions unnecessary. After the surgery, during the antibiotic treatment, the patient developed pseudomembranous colitis treated with specific antibiotics. The evolution under this treatment was positive and the aspect of the liver lesions was improuved.