Effect of drying conditions on pyrethrins content

Windrowed pyrethrum stems were air dried under a range of storage conditions to examine whether the current commercial practice of drying crop material is conducive to pyrethrins' degradation. Crop material was stored for up to 12 days in a commercial windrow, a shed receiving indirect light or a dark, 5 degrees C cool-room. Analysis of pyrethrins extracted from flowers of all treatments demonstrated that pyrethrins were not degrading in windrowed crops, plant material stored in the shed or in the 5 degrees C cool-room. The small differences obtained in pyrethrins content among the treatments can be explained by the natural variation in pyrethrins content of pyrethrum crops. The observation that the achenes were unchanged during this drying period supported the pyrethrins analysis. These results demonstrate that pyrethrins in planta do not degrade as rapidly as extracted pyrethrins. (C) 2005 Elsevier B.V. All rights reserved.

En bloc excision in malignant tumors of the lacrimal drainage apparatus

Purpose: To describe the surgical technique and results of en bloc excision in a series of patients with extensive malignant tumors of the lacrimal drainage apparatus (LDA). Methods: This was a noncomparative, retrospective chart review of the clinical and pathologic findings of 11 patients presenting with a malignant tumor affecting the LDA who underwent en bloc excision of the lacrimal system. Results: Of the 11 patients, 7 were male. The mean age at presentation was 58 years (range, 39 to 81 years), and all cases were unilateral. Histopathology revealed 4 squamous cell carcinomas, 3 transitional cell carcinomas, 2 mucoepidermoid carcinomas, and 2 melanomas. Epiphora and a mass were the most common presentations. An external lesion could be identified in 4 cases. Irrigation of the lacrimal system revealed nasolacrimal duct obstruction in 2 cases and common canaliculus obstruction in another 2 patients. The entire LDA and surrounding bony tissues were excised through a lateral rhinotomy approach. Adjuvant radiotherapy was given in 4 cases. Nine patients remain alive and well after a mean follow-up of 2 years (range, 6 months to 7 years). Three cases showed distant disease and 2 patients died of metastatic melanoma involvement. Conclusions: The use of en bloc excision as a radical treatment to remove the complete LDA and surrounding bony structures affords good local tumor control and may provide the best opportunity for enhanced patient survival.

Drying process of microcrystalline cellulose studied by attenuated total reflection IR spectroscopy with two-dimensional correlation spectroscopy and principal component analysis

Molecular interactions between microcrystalline cellulose (MCC) and water were investigated by attenuated total reflection infrared (ATR/IR) spectroscopy. Moisture-content-dependent IR spectra during a drying process of wet MCC were measured. In order to distinguish overlapping O–H stretching bands arising from both cellulose and water, principal component analysis (PCA) and, generalized two-dimensional correlation spectroscopy (2DCOS) and second derivative analysis were applied to the obtained spectra. Four typical drying stages were clearly separated by PCA, and spectral variations in each stage were analyzed by 2DCOS. In the drying time range of 0–41 min, a decrease in the broad band around 3390 cm−1 was observed, indicating that bulk water was evaporated. In the drying time range of 49–195 min, decreases in the bands at 3412, 3344 and 3286 cm−1 assigned to the O6H6cdots, three dots, centeredO3′ interchain hydrogen bonds (H-bonds), the O3H3cdots, three dots, centeredO5 intrachain H-bonds and the H-bonds in Iβ phase in MCC, respectively, were observed. The result of the second derivative analysis suggests that water molecules mainly interact with the O6H6cdots, three dots, centeredO3′ interchain H-bonds. Thus, the H-bonding network in MCC is stabilized by H-bonds between OH groups constructing O6H6cdots, three dots, centeredO3′ interchain H-bonds and water, and the removal of the water molecules induces changes in the H-bonding network in MCC.

Thin-layer isothermal drying of fructose, maltodextrin, and their mixture solutions

Solutions of fructose, maltodextrin (DE 5), and their mixtures at the ratios of 20:80, 40:60, 50:50, 60:40, and 80:20 were gelled with 1% agar-agar and dried under convective-conductive drying conditions. The thin slabs were maintained at isothermal drying condition of 30 and 50 degrees C. Yamamoto's simplified method based on regular regime approach was used to calculate the (effective) moisture diffusivity. Both the drying rates and the moisture diffusivity exhibited strong concentration dependence. The concentration dependence was stronger in the case of fructose and fructose rich solutions. Both the moisture diffusivity and drying rates of the mixture solutions were enhanced due to plasticization of fructose on maltodextrin, which is explained through free volume theory.

Estimation of concentration-dependent diffusion coefficient in drying process from the space-averaged concentration versus time with experimental data

The estimation of a concentration-dependent diffusion coefficient in a drying process is known as an inverse coefficient problem. The solution is sought wherein the space-average concentration is known as function of time (mass loss monitoring). The problem is stated as the minimization of a functional and gradient-based algorithms are used to solve it. Many numerical and experimental examples that demonstrate the effectiveness of the proposed approach are presented. Thin slab drying was carried out in an isothermal drying chamber built in our laboratory. The diffusion coefficients of fructose obtained with the present method are compared with existing literature results.

Combined external-endonasal approach for complete excision of the lacrimal drainage apparatus

Purpose: The purpose of this study was to describe a new surgical technique for the complete excision of the lacrimal drainage apparatus (LDA) that combines external and endoscopic approaches. Methods: This study involved a noncomparative, retrospective chart review of the clinical and pathological findings of four patients presenting with LDA papillomas who underwent a combined open and endonasal excision of the lacrimal system. Results. Of the four patients, three were male. The mean age at referral was 41 years, and all cases were unilateral. Histopathology revealed two transitional cell papillomas, one squamous cell papilloma, and one combined transitional/squamous papilloma. Epiphora and an external lesion were the main complaints at presentation. Nasolacrimal duct obstruction was present in all four patients. Papilloma virus infection was suggested in two cases and was confirmed in the only patient who had recurrence. CT identified a solid enhancing mass in two cases. The surgical approach in all cases was performed with the patient under general anesthetic supplemented with infiltration of local anesthesia with vasoconstriction. The lacrimal sac was exposed as per an external dacryocystorhinostomy with biopsy collection from the lacrimal sac lumen to confirm the diagnosis prior LDA excision. The superior aspect of the LDA was isolated by using lacrimal probes in each canaliculus to stabilized parallel incisions and careful dissection toward the common canaliculus until they met the medial aspect of the lacrimal sac. The sac was then separated from the periosteum from the medial orbital wall, using sharp dissection. Finally, an endoscopic dissection of the lower end of the nasolacrimal duct released the most inferior aspect of the LDA, allowing the surgeon to pull and excise the complete system from the external wound. Conclusions: Extensive LDA papillomas required complete excision of the drainage system to prevent recurrence and/or malignant transformation. The use of a combined approach through an open excision of the superior part of the LDA in conjunction with the direct manipulation of the nasolacrimal duct guided by the nasal endoscope facilitates the complete excision of the system for extensive benign lesions.