Study on a one-dimensional defective photonic crystal suitable for organic compound sensing applications

Organic-compound-based sensors have important applications, such as applications in geothermal power stations, the shoe industry, the extraction of vegetable oil, azeotropic calibration and medical science. Herein, a 1D photonic crystal (PC) with a defect has been used to develop a photonic-technology-based organic compound sensor with optimum performance. The structure of the proposed organic compound sensor consists of a water cavity sandwiched between two symmetric sub-PCs, which are composed of alternate layers of SiO₂ and ZnO. The proposed air/(SiO₂/ZnO)⁵/cavity/(SiO₂/ZnO)⁵/glass structure with the optimized structural parameters achieves a quality factor that varies between a minimum value of 4968.2 and a maximum value of 6418.5. The FOM and sensitivity values of the proposed sensing design are on the order of 10² and 10³, respectively. The LOD value of the proposed sensor is on the order of 10⁻⁵, which is very low, as is always expected for chemical sensing designs. Thus, the simple design and excellent performance make our design highly efficient and suitable for sensing applications in the industrial and biomedical fields.

Organic-compound-based sensors have important applications, such as applications in geothermal power stations, the shoe industry, the extraction of vegetable oil, azeotropic calibration and medical science.     

Restriction of bacterial growth under commercial catheter dressings

The effect on the normal cutaneous flora after iodine and alcohol disinfection of the skin of three commercially available moisture-permeable polyurethane dressings was compared with that of a gauze-and-tape dressing. Dressings also were evaluated clinically for membrane adhesion and skin erythema, pruritis, hyperpigmentation, vesiculitis, and tenderness. Each of 50 healthy volunteers and 49 long-term inpatients, 25 of whom were receiving antibiotic therapy, received simultaneously on their volar forearm patches of Op-Site, Tegaderm, Uniflex, and gauze dressings. Controls consisted of one exposed skin site and one covered with moisture-retaining vinylidene film (Saran Wrap). Although after 3 days of adhesion, commercial dressings prevented indigenous flora from returning to normal population densities, no significant quantitative differences were found between them and the gauze-and-tape dressing. Generally, all clinical dressings maintained normal flora at one tenth the population of the uncovered site; the Saran Wrap control supported 100-fold more bacteria than the exposed site. No differences were discovered in the levels of gram-negative bacteria, or among patient groups and between patients and healthy subjects, except for the lower incidence of erythema and itching among patients compared with healthy subjects.     

Comparative antibacterial efficacy of a 2-minute surgical scrub with chlorhexidine gluconate, povidone-iodine, and chloroxylenol sponge-brushes

Chlorhexidine gluconate (Hibiclens), povidone-iodine (E-Z Scrub 201), and chloroxylenol (ParaSoft) sponge-brushes were compared for antibacterial efficacy in 2-minute surgical scrubs. Thirty-nine volunteers completed a 7-day baseline period and a 5-day treatment period. Thirteen participants were assigned to a chlorhexidine group, 12 to a povidone-iodine group, and 14 to a chloroxylenol group. Subjects followed a standardized protocol, performing 11 scrubs during the treatment period. Bacterial counts were taken by the glove-juice procedure immediately after scrubbing and at 3 and 6 hours later on days 1, 2, and 5. The use of chlorhexidine achieved significantly (p less than 0.01) greater adjusted mean log10 bacterial count reductions than did povidone-iodine and chloroxylenol at all sampling times, with greater reductions as the study progressed.     

Preoperative biliary drainage before resection in obstructive jaundice

BACKGROUND: Surgery for patients with malignant obstructive jaundice carries high morbidity and mortality rates. Preoperative biliary drainage (PBD) has been used in an attempt to improve the outcome in these patients. AIM: To review the evidence in the literature on whether PBD improves postoperative morbidity and mortality in obstructive jaundice patients. MEHOD: Using Medline a literature search was performed for papers published in English from January 1980 to October 2000, using the text words 'obstructive jaundice', 'preoperative', 'drainage' and 'stent'. All retrieved papers which reported experimental or clinical observations relevant to the study aim were carefully analysed and the findings are summarised in this review. RESULTS AND CONCLUSION: There is no evidence in the literature to support the view that routine PBD improves postoperative morbidity and mortality in patients with obstructive jaundice undergoing resection. PBD has its own complications that cancel out its benefits. However, PBD could be beneficial in patients presenting with sepsis, coagulation abnormalities or malnutrition.     

An Antireflux Anastomosis Following Esophagectomy: A Randomized Controlled Trial

Background  

Reflux of duodeno-gastric fluid is a significant problem after esophagectomy with gastric conduit reconstruction. Symptoms may be severe and impact considerably upon the quality of life. Previous studies have suggested that a fundoplication type anastomosis may limit post-esophagectomy reflux.     

Detection of haptenated proteins in organotypic human skin explant cultures exposed to dapsone.

Bioactivation of parent drug to reactive metabolite(s) followed by protein haptenation has been suggested to be a critical step in the elicitation of cutaneous drug reactions. Although liver is believed to be the primary organ of drug bioactivation quantitatively, other organs including skin may also metabolize drugs. Cultured human epidermal keratinocytes and dermal fibroblasts have been shown to be capable of bioactivating sulfonamides and sulfones, giving rise to haptenated proteins. It is, however, unclear whether metabolic events in these isolated cells reflect bioactivation in vivo. Hence, split-thickness human skin explants were exposed to dapsone (DDS) or its arylhydroxylamine metabolite (dapsone hydroxylamine, D-NOH) and probed for protein haptenation. DDS and D-NOH were applied either epicutaneously or mixed in the medium (to mimic its entry into skin from the systemic circulation). DDS-protein adducts were readily detected in skin explants exposed to either DDS or D-NOH. Adducts were detected mainly in the upper epidermal region in response to epicutaneous application, whereas adducts were formed all over the explants when DDS/D-NOH were mixed in the culture medium. In addition, adducts were visible in HLA-DR+ cells, indicating their presence in the dendritic cell population in the skin. Our results demonstrate the ability of intact human skin to bioactivate DDS leading to protein haptenation.     

Four-week administration of nimesulide, a cyclooxygenase-2 inhibitor, improves endothelial dysfunction in the hindlimb vasculature of streptozotocin-induced diabetic rats

The aim of this study was to examine the effect of chronic administration of nimesulide, a cyclooxygenase-2 inhibitor, on endothelial dysfunction in streptozotocin-induced diabetic rats. Three groups of Sprague-Dawley rats (300–350 g, n = 6) were used. The first group served as normoglycemic control and the second and third groups were rendered diabetic by an intraperitoneal injection of streptozotocin (60 mg/kg). The third group received the selective COX-2 inhibitor, nimesulide (20 mg/kg/day), orally by gavage for 4 weeks while the second group received only drinking water and served as diabetic control. At the end of the treatment period, the rats were anesthetized with urethane (1.2 g/kg) and mean arterial pressure, heart rate and hindlimb blood flow were monitored. This was followed by the injection of acetylcholine (endothelium-dependent vasodilator, 0.1–0.8 μg/kg) and sodium nitroprusside (endothelium-independent vasodilator 1–4 μg/kg). Mean arterial pressure was significantly reduced and hindlimb vascular conductance was not significantly affected in the control diabetic group when compared to the normoglycemic control group. Nimesulide treatment did not cause any significant change in any of the measured hemodynamic parameters. Acetylcholine and sodium nitroprusside induced dose-dependent increases in hindlimb vascular conductance in control normoglycemic rats which were attenuated in diabetic control rats. Nimesulide reversed the attenuation of acetylcholine-induced increase in hindlimb vascular conductance. In conclusion, chronic administration of the selective COX-2 inhibitor, nimesulide improved endothelial dysfunction in the hindlimb vasculature of streptozotocin induced diabetic rats. This suggests that COX-2 products might be involved in the pathogenesis of endothelial dysfunction in streptozotocin-induced diabetic rats.     

Latissimus dorsi pedicled flap for upper extremity soft-tissue reconstruction

The latissimus dorsi often is used as a functional muscle transfer to restore elbow and shoulder motion. Although less common, its use as a pedicled muscle flap with a split-thickness skin graft provides excellent soft-tissue coverage of large upper extremity wounds. Seven male patients ranging in age from 6-71 years were treated with a pedicled latissimus dorsi muscle flap and split-thickness skin graft for coverage of open wounds of the shoulder, arm, or elbow with exposed vital structures (mean wound size: 15x10 cm). The flap also was used as a functional muscle transfer in one patient to replace destroyed anterior and middle portions of the deltoid. Wounds resulted from trauma in three patients, infection following trauma in two, and sarcoma excision in two. All flaps healed well, and donor site morbidity was minimal. At mean 16-month follow-up (range: 3-41 months), all muscle flaps had contoured well, producing satisfactory cosmesis. Functional results were good, and all patients were satisfied with their outcome. The tendinous insertion is left intact to guard against excessive traction on the pedicle when the flap is used for soft-tissue coverage only.     

Anterior versus posterior approach in reconstruction of infected nonunion of the tibia using the vascularized fibular graft: potentialities and limitations

The potentialities, limitations, and technical pitfalls of the vascularized fibular grafting in infected nonunions of the tibia are outlined on the basis of 14 patients approached anteriorly or posteriorly. An infected nonunion of the tibia together with a large exposed area over the shin of the tibia is better approached anteriorly. The anastomosis is placed in an end-to-end or end-to-side fashion onto the anterior tibial vessels. To locate the site of the nonunion, the tibialis anterior muscle should be retracted laterally and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. All the scarred skin over the anterior tibia should be excised, because it becomes devitalized as a result of the exposure. To cover the exposed area, the fibula has to be harvested with a large skin paddle, incorporating the first septocutaneous branch originating from the peroneal vessels before they gain the upper end of the flexor hallucis longus muscle. A disadvantage of harvesting the free fibula together with a skin paddle is that its pedicle is short. The skin paddle lies at the antimesenteric border of the graft, the site of incising and stripping the periosteum. In addition, it has to be sutured to the skin at the recipient site, so the soft tissues (together with the peroneal vessels), cannot be stripped off the graft to prolong its pedicle. Vein grafts should be resorted to, if the pedicle does not reach a healthy segment of the anterior tibial vessels. Defects with limited exposed areas of skin, especially in questionable patency of the vessels of the leg, require primarily a fibula with a long pedicle that could easily reach the popliteal vessels and are thus better approached posteriorly. In this approach, the site of the nonunion is exposed medial to the flexor digitorum muscle and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. No attempt should be made to strip the scarred skin off the anterior aspect of the bone lest it should become devitalized. Any exposed bone on the anterior aspect should be left to granulate alone. This occurs readily when stability has been regained at the fracture site after transfer of the free fibula. The popliteal and posterior tibial vessels are exposed, and the microvascular anastomosis placed in an end-to-side fashion onto either of them, depending on the length of the pedicle and the condition of the vessels themselves. To obtain the maximal length of the pedicle of the graft, the proximal osteotomy is placed at the neck of the fibula after decompressing the peroneal nerve. The distal osteotomy is placed as distally as possible. After detaching the fibula from the donor site, the proximal part of the graft is stripped subperiosteally, osteotomized, and discarded. Thus, a relatively long pedicle could be obtained. To facilitate subperiosteal stripping, the free fibula is harvested without a skin paddle. In this way, the use of a vein graft could be avoided. Patients presenting with infected nonunions of the tibia with extensive scarring of the lower extremity, excessively large areas of skin loss, and with questionable patency of the anterior and posterior tibial vessels are not suitable candidates for the free vascularized fibular graft. Although a vein graft could be used between the recipient popliteal and the donor peroneal vessels, its use decreases flow to the graft considerably. These patients are better candidates for the Ilizarov bone transport method with or without free latissimus dorsi transfer.