Tunable Sensing Property of 1D Periodic Structure with Defect of Liquid Crystal Sandwiched by Metallic Layers

In this paper, we have investigated the optical properties of one-dimensional periodic structure of dielectric materials with defect of liquid crystal (LC) sandwiched with two silver (Ag) layers. The transmission, reflection and absorption properties of considered periodic structure have calculated theoretically using transfer matrix method (TMM). Our study reports that the tunability of absorption defect peak of the defect periodic structure is achieved by the variation in the incident angle of electromagnetic wave. The obtained result suggests that such defect periodic structure may be used as tunable sensor and filter devices.

Data sheets for various penicillins: suggested amendments

Beecham’s data sheets for Orbenin (cloxacillin) and Floxapen (flucloxacillin) state that these drugs are ‘indicated for the treatment of infections caused by Gram-positive organisms, including infections caused by penicillin-resistant staphylococci’. These drugs are indeed excellent for infections caused by penicillin-resistant staphylococci, but they are less active than benzylpenicillin (penicillin G) or penicillin V against other Gram-positive organisms.1 The statement would be accurate if it ended ‘...., especially infections caused by penicillin-resistant staphylococci’, but there is a case for listing these latter infections as the only indication. It is also misleading to list among ‘typical indications’ conditions such as pharyngitis, tonsillitis and otitis externa, which are rarely due to staphylococci and will respond better to another antibiotic if one is needed. In our view the section on uses needs to be rewritten to make these points clear. It should also be stated that cloxacillin is incompletely absorbed from the gut and that its oral use is not advisable in patients with an absorption defect, nor for seriously ill patients (e.g. septicaemia) who need a penicillinase-resistant penicillin. Such patients should be given the drug by injection.

Bile salt absorption in the irradiated rat

Measurements of radioactivity in bile secreted by bile duct-cannulated rats after intraluminal injection of the labeled bile salt indicated bile salt absorption rates in the duodenum, ileum, and large intestine in the ratio of 1:30:2. Three days after exposure of the abdomen to 1,000 or 1,500 R of X-irradiation, absorption from the ileum was decreased by 14 and 53%, respectively. Five days after exposure to 1,500 R, absorption from the ileum was decreased by 70%. The radiomimetic nitrogen mustard, HN2, also decreased absorption. This was shown to be a radiation-induced absorption defect which probably resulted in increased excretion of bile salts, rather than an impaired secretion of bile by the liver, by injecting labeled bile salts intravenously or parenterally. At 4 days after 1,500 R and 1 day after intravenous injection of C14-labeled cholic acid, the accumulation of labeled bile salt in the lower bowel was almost twice the unirradiated value. The level of radioactivity secreted in the bile at that time was one-half control value and that present in the small intestine only one-sixth the unirradiated level, suggesting a dilution of the labeled bile salt as a result of de novo synthesis and a substantial accumulation of bile salts in the lower small intestine and large bowel.