Fluorescent Room Light Research Articles

Bio-Inspired Graphitic Carbon-Based Large-Area (10 × 10 cm2) Perovskite Solar Cells: Stability Assessments under Indoor, Outdoor, and Water-Soaked Conditions.

In the emerging photovoltaic (PV) technologies, the golden triangle rule includes higher efficiency, longevity (or stability), and low cost, which are the foremost criteria for the root of commercial feasibility. Accordingly, a unique low-cost, ecofriendly, all-solution-processed, "bio-inspired" graphitic carbon (extracted from the most invasive plant species of Eichhornia crassipes: listed as one of the 100 most dangerous species by the International Union for Conservation of Nature) and a mixed halide perovskite interface-engineered, unique single-cell large-scale (10 × 10 sq.cm with an active area of 88 cm2) carbon-based perovskite solar cell (C-PSC) are demonstrated for the first time, delivering a maximum PCE of 6.32%. Notable performance was observed under low light performance for the interface-engineered champion device fabricated using the layer-to-layer approach, which, even when tested under fluorescent room light condition (at 200 lux of about ∼0.1 SUN illumination), exhibited a significant PCE. In terms of addressing the stability issues in the fabricated PSC devices, the present work has adopted a two-step strategy: the instability toward the extrinsic factors is addressed by encapsulation, and the subsequent intrinsic instability issue is also addressed through interfacial engineering. Surprisingly, when tested under various stability conditions (STC) such as ambient air, light (continuous 1 SUN, under room light illumination (0.1 SUN) and direct sunlight), severe damp up to a depth of ∼25 mm water (cold (∼15 °C) and hot (∼65 °C)), acidic pH (∼5), and alkaline pH (∼11)) conditions, the fabricated large-scale carbon-based perovskite solar cells (C-LSPSCs) retained unexpected long-term stability in their performance for over 50 days. As to appraise the performance superiority of the fabricated C-LSPSC devices under various aforesaid testing conditions, a working model of a mini-fan has been practically powered and demonstrated.

EFFECTS OF SKIN TONE AND AMBIENT LIGHTING ON ACCURACY OF CONTACTLESS MEASUREMENT OF HEART RATE AND PULSE TRANSIT TIME: AN INVESTIGATION TOWARD IMAGE-BASED BLOOD PRESSURE ESTIMATION

Abstract Objective: Image-based photoplethysmography (iPPG) using video of the skin offers potential for contactless blood pressure (BP) estimation from the pulse transit time (PTT). Optical properties of human skin and ambient lighting are likely to affect accuracy of image-based PTT (iPPT) and are investigated here. Design and method: Twelve healthy volunteers (6 female, 27 ± 6 years) with a range of skin tones (Fitzpatrick skin scores of 5 to 27) were recruited. For each subject, the experiment was performed in standard fluorescent room lighting (100 lux) and repeated at five other levels of light intensity (40–310 lux). Two-minute videos were acquired from each subject's face and palm of the left hand; simultaneous electrocardiogram (ECG) and non-invasive finger BP were also measured. In each frame, two regions of interest (ROIs) were selected from the subject's face and hand, and the average of green colour intensity for each ROI were calculated as iPPG. The iPPG signal was band-pass filtered between 0.66–3 Hz, (corresponding to a 40–180 bpm heart rate (HR) range). HR was calculated as the dominant peak in the Fourier spectrum of filtered iPPG. Beat-to-beat values of iPTT were calculated between the corresponding feet of the iPPG pulsations. Results: The absolute error between average HR (errHR) determined from ECG and that calculated from iPPG in both ROIs was significantly correlated with room lumen (RL) and skin score (SC) (errHR = – 0.08 × RL + 0.67 × SC + 12, p < 0.05). The minimum HR error was in standard room lighting (errHR = 3.9 ± 8.9 bpm). Using average iPTT in room lighting as the reference, the percentage error (iPTT%err) between reference iPTT and iPTT in other lighting conditions significantly decreased with lower lighting conditions but was not significantly changed with skin tone score (iPTT%err = -0.09 × RL + 55, p < 0.05). Conclusions: Skin tone and ambient lighting intensity affects accuracy of contactless HR measurement. Only light intensity affects accuracy of iPTT measurement. It is likely that errors in contactless BP estimation are minimised in standard room lighting conditions but increase in dimmer conditions.

Effect of light exposure on growth rate of veterinary clinical dermatophyte isolates

Veterinary textbooks and literature suggest that exposure to light is inhibitory to growth of clinical dermatophyte isolates. We hypothesized that this idea was derived from experiments that examined the effect of high doses of ultraviolet and visible light exposure on dermatophyte growth, and that exposure to typical room lighting would not adversely affect dermatophyte growth rate. Isolates of common veterinary dermatophytes (three each of Microsporum canis, Nannizia gypsea and Trichophyton benhamiae) were exposed to typical fluorescent room lighting, incubated in a closed drawer, or exposed at close range to fluorescent wide-spectrum light. Dermatophytes were grown on Sabouraud Dextrose Agar (SAB) and Dermatophyte Test Medium (DTM). Colony diameter was measured and growth rate (expressed as colony diameter increase mm/day) calculated at the linear portion of the culture growth curve. Statistical analyses compared growth rates across the various incubation conditions and among dermatophyte isolates. There was little difference in growth rate between cultures incubated under typical fluorescent room lighting and those placed in the dark. Exposure to the close-range light increased growth rate as a consequence of the elevated incubation temperature created by the lamp. Significant differences in growth rate were noted among strains of the same dermatophyte species. Dermatophytes grew more rapidly on SAB than DTM agar. Exposure to typical lighting conditions in a clinical environment does not inhibit growth of dermatophyte colonies. Veterinary clinicians may conduct routine dermatophyte cultures without incubating them in the dark.

Stability of Ertapenem 100 mg/mL in Manufacturer's Glass Vials or Syringes at 4°C and 23°C.

Prophylactic administration of ertapenem as a single 1-g IV dose has been shown to reduce sepsis after prostate biopsy. To evaluate the stability of ertapenem after reconstitution with 0.9% sodium chloride to a final concentration of 100 mg/mL and storage in the manufacturer's original glass vials or polypropylene syringes. On study day 0, 100 mg/mL solutions of ertapenem were retained in the manufacturer's glass vials or packaged in polypropylene syringes and stored at 4°C or 23°C without protection from fluorescent room light. Samples were assayed periodically over 18 days using a validated, stability-indicating liquid chromatographic method with ultra-violet detection. A beyond-use date was determined as the time for the concentration to decline to 90% of the initial (day 0) concentration, based on the fastest degradation rate, with 95% confidence. Reconstituted solutions stored in the manufacturer's glass vials or polypropylene syringes exhibited a first-order degradation rate, such that 10% of the initial concentration was lost in the first 2.5 days when stored at 4°C or within the first 6.75 h when stored at room temperature (23°C). Analysis of variance showed differences in the percentage remaining due to temperature (p < 0.001) and study day (p < 0.001) but not type of container (p = 0.98). When a 95% CI for the degradation rate was calculated and used to determine a beyond-use date, it was established that more than 90% of the initial concentration would remain for 2.35 days at 4°C and for 0.23 day (about 5 h, 30 min) at room temperature. A 100 mg/mL ertapenem solution stored in the manufacturer's glass vial or a polypropylene syringe will retain more than 90.5% of the initial concentration when stored for 48 h at 4°C and for an additional 1 h at 23°C.

Fluorinated TiO2 as an ambient light-activated virucidal surface coating material for the control of human norovirus

We evaluated the virucidal efficacy of light-activated fluorinated TiO2 surface coatings on human norovirus and several surrogates (bacteriophage MS2, feline calcivirus (FCV), and murine norovirus (MNV)). Inactivation of viruses on surfaces exposed to a common fluorescent lamp was monitored and the effects of UVA intensity, temperature, and fluoride content were assessed. Destruction of RNA and capsid oxidation were evaluated for human norovirus inocula on the F-TiO2 surfaces, while contact with the F-TiO2 surface and exposure to residual UVA radiation of 10μWcm−2 for 60min resulted in infectivity reductions for the norovirus surrogates of 2–3 log10. Infectivity reductions on pristine TiO2 surfaces in identical conditions were over 2 orders of magnitude lower. Under realistic room lighting conditions, MS2 infectivity declined below the lower detection limit after 12h. Reductions in RNA were generally low, with the exception of GII.4, while capsid protein oxidation likely played a larger role in infectivity loss. Inactivation of norovirus surrogates occurred significantly faster on F-TiO2 compared to pristine TiO2 surfaces. The material demonstrated antiviral action against human norovirus surrogates and was shown to effectively inhibit MS2 when exposed to residual UVA present in fluorescent room lighting conditions in a laboratory setting.

Direct bromination of hydrocarbons catalyzed by Li2MnO3 under oxygen and photo-irradiation conditions

A method for the direct bromination of hydrocarbons with Br2 using a ubiquitous and inexpensive catalyst is highly desirable. Herein, we report the selective mono-bromination of hydrocarbons in good yield using Li2MnO3 as a catalyst under irradiation with a fluorescent room light. This new catalyst can be recycled. The effect of light was investigated using action spectra, which revealed that the reaction occurred on the surface of the catalyst.

Solid-state lighting for the International Space Station: Tests of visual performance and melatonin regulation

The International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts' working and living environments. Solid-state light emitting diodes (LEDs) are attractive candidates for replacing the GLAs on the ISS. The advantages of LEDs over conventional fluorescent light sources include lower up-mass, power consumption and heat generation, as well as fewer toxic materials, greater resistance to damage and long lamp life. A prototype Solid-State Lighting Assembly (SSLA) was developed and successfully installed on the ISS. The broad aim of the ongoing work is to test light emitted by prototype SSLAs for supporting astronaut vision and assessing neuroendocrine, circadian, neurobehavioral and sleep effects. Three completed ground-based studies are presented here including experiments on visual performance, color discrimination, and acute plasma melatonin suppression in cohorts of healthy, human subjects under different SSLA light exposure conditions within a high-fidelity replica of the ISS Crew Quarters (CQ). All visual tests were done under indirect daylight at 201lx, fluorescent room light at 531lx and 4870K SSLA light in the CQ at 1266lx. Visual performance was assessed with numerical verification tests (NVT). NVT data show that there are no significant differences in score (F=0.73, p=0.48) or time (F=0.14, p=0.87) for subjects performing five contrast tests (10%–100%). Color discrimination was assessed with Farnsworth-Munsell 100 Hue tests (FM-100). The FM-100 data showed no significant differences (F=0.01, p=0.99) in color discrimination for indirect daylight, fluorescent room light and 4870K SSLA light in the CQ. Plasma melatonin suppression data show that there are significant differences (F=29.61, p<0.0001) across the percent change scores of plasma melatonin for five corneal irradiances, ranging from 0 to 405μW/cm2 of 4870K SSLA light in the CQ (0–1270lx). Risk factors for the health and safety of astronauts include disturbed circadian rhythms and altered sleep–wake patterns. These studies will help determine if SSLA lighting can be used both to support astronaut vision and serve as an in-flight countermeasure for circadian desynchrony, sleep disruption and cognitive performance deficits on the ISS.

Biogenic manganese oxide: effective new catalyst for direct bromination of hydrocarbons

Nano- and micro-architectural manganese oxide produced by microorganisms catalyses the selective monobromination of hydrocarbons in excellent yield under irradiation of fluorescent room light. The knowledge gained from investigating natural materials will lead to unprecedented catalyst designing toward efficient organic reactions.

CHARACTERIZATION OF A COMMERCIALLY-AVAILABLE, OPTICALLY-STIMULATED LUMINESCENT DOSIMETRY SYSTEM FOR USE IN COMPUTED TOMOGRAPHY

Optically-stimulated luminescent (OSL) nanoDot dosimeters, commercially available from Landauer, Inc. (Glenwood, IL), were assessed for use in computed tomography (CT) for erasure and reusability, linearity and reproducibility of response, and angular and energy response in different scattering conditions. Following overnight exposure to fluorescent room light, the residual signal on the dosimeters was 2%. The response of the dosimeters to identical exposures was consistent, and reported doses were within 4% of each other. The dosimeters responded linearly with dose up to 1 Gy. The dosimeter response to the CT beams decreased with increased tube voltage, showing up to a -16% difference when compared to a 0.6-cm(3) NIST-traceable calibrated ionization chamber for a 135 kVp CT beam. The largest range in percent difference in dosimeter response to scatter at central and peripheral positions inside CTDI phantoms was 14% at 80 kVp CT tube voltage, when compared to the ionization chamber. The dosimeters responded uniformly to x-ray tube angle over the ranges of increments of 0° to 75° and 105° to 180° when exposed in air, and from 0° to 360° when exposed inside a CTDI phantom. While energy and scatter correction factors should be applied to dosimeter readings for the purpose of determining absolute doses, these corrections are straightforward but depend on the accuracy of the ionization chamber used for cross-calibration. The linearity and angular responses, combined with the ability to reuse the dosimeters, make this OSL system an excellent choice for clinical CT dose measurements.

Stability and compatibility of doxofylline with phentolamine mesilate in 0·9% sodium chloride or 5% dextrose injection for intravenous infusion

The use of extemporaneously prepared admixtures of drugs must be supported by documentation of their chemical stability. The objective was to assess the physical compatibility and the chemical stability of doxofylline with phentolamine mesilate in 0.9% sodium chloride or 5% dextrose injection for intravenous infusion. Total volumes of 20 and 1 mL of doxofylline solution and phentolamine mesilate solution, respectively, were added to 250 mL polyolefin bags containing 5% dextrose injection or 0.9% sodium chloride injection. Bags were stored for 24 h at 20-25 °C. Chemical compatibility was measures with high-performance liquid chromatography, and physical compatibility was determined visually. The samples were clear and colourless when viewed in normal fluorescent room light. The pH value and particulate content of the admixtures exhibited little change. The retentions of the initial concentration of doxofylline and phentolamine mesilate in the admixtures were within 97-105%. Doxofylline and phentolamine mesilate were stable in 5% dextrose injection or in 0.9% sodium chloride for up to 24 h at 20-25 °C. Doxofylline and phentolamine mesilate mixed in both 5% dextrose injection and 0.9% sodium chloride injection in 250 mL multilayer polyolefin bags at concentrations of 0.74 mg/mL and 36.9 μg/mL, respectively, were stable for up to 24 h at 20-25 °C.

Stability of norepinephrine solutions in normal saline and 5% dextrose in water.

Most previous stability studies for norepinephrine have reported the percentage of drug remaining in IV solutions after only 24 h. No previously published study has evaluated the effect of light on the stability of this drug. To evaluate the stability of norepinephrine (64 mg/L) in either normal saline (NS; 0.9% sodium chloride) or 5% dextrose in water (D5W) with storage at either 4°C or room temperature (23°C) in polyvinyl chloride (PVC) bags exposed to or protected from normal room lighting for 2 months. Thirty-two PVC bags were prepared, each containing norepinephrine at 64 mg/L; half of the bags had normal saline as the diluent and the other half had D5W. The bags were stored at either 4°C or room temperature (23°C), with protection from or exposure to ambient fluorescent room light. Overall, there were 4 bags for each combination of diluent, temperature, and light condition. The concentration of norepinephrine in each bag was determined by a validated, stability-indicating liquid chromatographic method on study days 0, 1, 2, 3, 4, 8, 9, 10, 11, 14, 18, 21, 23, 25, 28, 30, 36, 42, and 61. Analysis of variance revealed differences in percentage remaining as a function of study day (p < 0.001) and light conditions (p < 0.001), but not diluent (p = 0.06) or storage temperature (p > 0.99). Solutions of norepinephrine 64 mg/L in NS or D5W can be stored in PVC bags at 4°C for up to 61 days with protection from light. This expiry date allows for up to 24 h storage at 23°C. Solutions that are not protected from light will retain only 90% of the initial concentration after storage for 39 days at 4°C. This storage period could include up to 24 h at room temperature, without protection from light.

Physical and chemical stability of palonosetron hydrochloride with five common parenteral drugs during simulated Y-site administration

The physical and chemical compatibility of palonosetron hydrochloride with atropine sulfate, famotidine, heparin sodium, lidocaine hydrochloride, and potassium chloride during simulated Y-site administration were studied. Test samples were prepared in duplicate by separately mixing 7.5-mL samples of undiluted palonosetron hydrochloride 50 microg/mL with 7.5-mL samples of atropine sulfate 0.4 mg/mL, famotidine 2 mg/mL, undiluted heparin sodium 100 units/mL, lidocaine hydrochloride 10 mg/mL, and potassium chloride 0.1 meq/mL diluted in 5% dextrose in colorless 15-mL borosilicate glass screw-cap culture tubes with polypropylene caps. Physical stability of the admixtures was assessed by visual examination and by measuring turbidity and particle size and content. Chemical stability of atropine sulfate, famotidine, heparin sodium, and lidocaine hydrochloride was assessed by stability-indicating high-performance liquid chromatography. Potassium chloride concentration was determined by indirect potentiometry using a potassiumion selective electrode. All of the samples of palonosetron hydrochloride with the test drugs were initially clear and colorless in normal fluorescent room light and when viewed with a Tyndall beam. Changes in turbidity for the samples were minor throughout the study. Measured particulates of 10 mum or larger were found to be few in number in all samples and remained so throughout the observation period. The admixtures remained colorless throughout the study. No loss of palonosetron hydrochloride occurred with any of the drugs over four hours. Similarly, little or no loss of the other drugs occurred in four hours. Palonosetron hydrochloride is physically and chemically stable with atropine sulfate, famotidine, heparin sodium, lidocaine hydrochloride, and potassium chloride during simulated Y-site administration.

Application of commercial glasses for high gamma dose measurement using optical densitometric technique

Commercial glass plates have been studied for their optical density (OD) changes following 60Co gamma radiation exposure in the dose range 0.10 – 100 kGy . These glasses have responded linearly upto 15 kGy gamma doses; thereafter, the OD response became slower and reached to saturation level at 80 kGy . No further increments in the optical densities of the glasses have been observed beyond 80 kGy gamma doses. In general the glasses are found suitable for gamma radiation measurement in the dose range 0.10 – 40 kGy using optical densitometric technique. Glasses have shown OD signal fading in the range of 5.0–14.0% in first 24 h after exposure under laboratory conditions. However, the fading contributions due to various environmental conditions such as; dark and 25 ∘ C ; fluorescent room light and 25, 50, 70 ∘ C ; solar light and 35 ∘ C in first 5 h after radiation exposure have been observed as 0–5%, 0–6%, 11–32%, 31–65% and 54–68%, respectively. Optical densitometry technique using glass plates reveal reproducible dosimetric results within ± 15%. Some elements present in the glasses (K, Na, Mg, Zn and Fe) have been observed as the main contributors in the formation of colour centres in glass lattice, which change the absorption spectra of visible light. The glass with higher percentage of these elements has shown higher OD sensitivity after gamma exposure. Commercial glass plates can be used as radiation dosimeter for radiation processing facilities. It can also be used for quality assurance and absorbed dose estimation in irradiated samples for any high radiation dose facilities. The irradiated glass samples must be protected from ambient and solar light exposure during or after irradiation and should be stored in cool environment to minimize the losses of stored optical densitometric informations.

Physical and chemical stability of palonosetron hydrochloride with five opiate agonists during simulated Y-site administration

The physical and chemical compatibility of palonosetron hydrochloride with fentanyl citrate, hydromorphone hydrochloride, meperidine hydrochloride, morphine sulfate, and sufentanil citrate during simulated Y-site administration was studied. Test samples were prepared in triplicate by mixing 7.5-mL samples of undiluted palonosetron 50 microg/mL (of palonosetron) with 7.5-mL samples of fentanyl citrate 50 microg/mL, morphine sulfate 15 mg/mL, hydromorphone hydrochloride 0.5 mg/mL, meperidine hydrochloride 10 mg/mL, and sufentanil citrate 12.5 microg/mL (of sufentanil) per milliliter individually in colorless 15-mL borosilicate glass screw-cap culture tubes with polypropylene caps. Physical stability of the admixtures was assessed by visual examination and by measuring turbidity and particle size and content. Chemical stability was assessed by stability-indicating high-performance liquid chromatography. Evaluations were performed immediately and one and four hours after mixing. All of the admixtures were initially clear and colorless in normal fluorescent room light and when viewed with a high-intensity monodirectional light (Tyndall beam) and were essentially without haze. Changes in turbidity were minor throughout the study. Particulates measuring 10 microm or larger were few in all samples throughout the observation period. The admixtures remained colorless throughout the study. No loss of palonosetron hydrochloride occurred with any of the opiate agonists tested over the four-hour period. Similarly, little or no loss of the opiate agonists occurred over the four-hour period. Palonosetron hydrochloride was physically and chemically stable with fentanyl citrate, hydromorphone hydrochloride, meperidine hydrochloride, morphine sulfate, and sufentanil citrate during simulated Y-site administration.

Compatibility of palonosetron with cyclophosphamide and with ifosfamide during simulated Y-site administration

The physical and chemical compatibility of palonosetron with cyclophosphamide and with ifosfamide during simulated Y-site administration was studied. Test samples were prepared in triplicate by mixing 7.5 mL of palonosetron hydrochloride 50 microg (of palonosetron) per milliliter with 7.5 mL of cyclophosphamide 10 mg/mL and with ifosfamide 20 mg/mL. Physical stability was assessed by turbidimetry, particle sizing, and visual inspection. Chemical stability was assessed by stability-indicating high-performance liquid chromatography. Evaluations were performed immediately and one and four hours after mixing. The samples were clear and colorless when viewed in normal fluorescent room light and when viewed with a high-intensity monodirectional light. Turbidity remained unchanged, and particulate content was low and exhibited little change. Palonosetron, cyclophosphamide, and ifosfamide remained chemically stable throughout the four-hour test period. Palonosetron hydrochloride was physically compatible with cyclophosphamide or ifosfamide during simulated Y-site administration.

Photochromicity of Anabaena Sensory Rhodopsin, an Atypical Microbial Receptor with a cis-Retinal Light-adapted Form

We characterize changes in isomeric states of the retinylidene chromophore during light-dark adaptation and photochemical reactions of Anabaena (Nostoc) sp. PCC7120 sensory rhodopsin (ASR). The results show that ASR represents a new type of microbial rhodopsin with a number of unusual characteristics. The three most striking are: (i) a primarily all-trans configuration of retinal in the dark-adapted state and (ii) a primarily 13-cis light-adapted state with a blue-shifted and lower extinction absorption spectrum, opposite of the case of bacteriorhodopsin; and (iii) efficient reversible light-induced interconversion between the 13-cis and all-trans unphotolyzed states of the pigment. The relative amount of ASR with cis and trans chromophore forms depends on the wavelength of illumination, providing a mechanism for single-pigment color sensing analogous to that of phytochrome pigments. In addition ASR exhibits unusually slow formation of L-like and M-like intermediates, with a dominant accumulation of M during the photocycle. Co-expression of ASR with its putative cytoplasmic transducer protein shifts the absorption maximum and strongly decreases the rate of dark adaptation of ASR, confirming interaction between the two proteins. Thus ASR, the first non-haloarchaeal sensory rhodopsin characterized, demonstrates the diversity of photochemistry of microbial rhodopsins. Its photochromic properties and the position of its two ground state absorption maxima suggest it as a candidate for controlling differential photosynthetic light-harvesting pigment synthesis (chromatic adaptation) or other color-sensitive physiological responses in Anabaena cells.

Palonosetron HCl Compatibility and Stability with Doxorubicin HCl and Epirubicin HCl During Simulated Y-Site Administration

Palonosetron HCl is a selective 5-HT3 receptor antagonist used for the prevention of chemotherapy-induced nausea and vomiting. Palonosetron HCl may be administered with other drugs by Y-site administration, including doxorubicin HCI and epirubicin HCI. Consequently, stability and compatability information are needed to verify the acceptability of such Y-site administration. To evaluate the physical and chemical stability of undiluted palonosetron HCl 50 microg/mL with doxorubicin HCl 1 mg/mL and epirubicin HCl 0.5 mg/mL during simulated Y-site administration. Triplicate samples of palonosetron HCl with each of the anthracycline chemotherapy drugs were tested. Samples were stored and evaluated for up to 4 hours at room temperature near 23 degrees C. Physical stability was assessed using turbidimetric and particulate measurement, as well as visual inspection. Chemical stability was assessed by HPLC. All of the admixtures were clear and red-orange when viewed in normal fluorescent room light and with a Tyndall beam. Measured turbidity and particulate content were low initially and remained low throughout the study. The drug concentration was unchanged in any of the samples throughout the study. Palonosetron HCl is physically and chemically stable with doxorubicin HCl and epirubicin HCl during simulated Y-site administration of these drugs over 4 hours at ambient room temperature.

Physical and chemical stability of palonosetron HCl with cisplatin, carboplatin, and oxaliplatin during simulated Y-site administration

The objective of this study was to evaluate the physical and chemical stability of undiluted palonosetron HCl 50 mcg/mL with cisplatin 0.5 mg/mL, carboplatin 5 mg/mL, and with oxaliplatin 0.5 mg/mL in infusion solutions during simulated Y-site administration. Triplicate test samples were prepared by admixing 7.5 mL of palonosetron HCl with 7.5 mL of the cisplatin, carboplatin, and oxaliplatin dilutions. Physical stability was assessed using a multistep evaluation procedure that included both turbidimetric and particulate measurement as well as visual inspection. Chemical stability was assessed using stability-indicating HPLC analytical techniques based on the determination of drug concentrations. Evaluations were performed initially upon mixing and 1 and 4 hours after mixing. The samples were clear and colourless when viewed in normal fluorescent room light and when viewed with a Tyndall beam. Measured turbidity remained unchanged and particulate content was low and exhibited little change. HPLC analysis found palonosetron HCl, cisplatin, carboplatin, and oxaliplatin remained stable throughout the 4-hour test with no drug loss. Palonosetron HCl is physically compatible and chemically stable with cisplatin, carboplatin, and oxaliplatin during Y-site administration.

Artifactual formation of 8-oxo-2'-deoxyguanosine: role of fluorescent light and inhibitors

The pro-mutagenic oxidative DNA lesion, 8-oxo-2'-deoxyguanosine (8-oxodG) has been a subject of numerous studies. However, the absolute 8-oxodG levels in tissue DNA reported by various methods have been debated due to its artifactual production during DNA isolation and/or the DNA processing. We have investigated factors that may result in such artifacts during isolation and analysis of DNA as well as means for its prevention. 8-OxodG content was measured by a recently described TLC enrichment-mediated 32P-postlabeling. Liver DNA from 3 month-old, female Sprague-Dawley rats was isolated by a standard solvent-extraction procedure (phenol, phenol:Sevag, and Sevag; 23 degrees C), a modified solvent-extraction procedure (phenol:Sevag, and Sevag; 4 degrees C; KCl-SDS-protein precipitation) or sodium iodide extraction procedure. 8-OxodG was analyzed in the DNA by the 32P-postlabeling assay using a fluorescent light box during the workup, as well as in its absence. The 8-oxodG levels, when the fluorescent light box was used, were in similar range irrespective of the DNA isolation procedure (16.4+/-1.6 to 28.7+/-6 8-oxodG/10(6) nucleotides). However, the values were significantly lower (3.1+/-0.4 to 3.4+/-0.2 8-oxodG/10(6) nucleotides) in the absence of fluorescence light box, room fluorescent light (suspended through the ceiling) and natural room light did not alter the 8-oxodG levels. Further, the addition of 0.3 mM of PBN (N-t-butyl-alpha-phenyl nitrone) or TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl), or 6.8 mM 8-hydroxy-quinoline during the DNA isolation resulted in still lower values (0.8+/-0.1 to 1.8+/-0.5 8-oxodG/10(6) nucleotides) although this reduction was not consistently observed in different experiments. These results suggest that fluorescent light is the major 'culprit' in artifactual production and variability reported in the 8-oxodG levels.

Bromination of tri(isopropyl)boroxine and asymmetric synthesis of (2-cyano-3,3-dimethylcyclopropyl)boronic esters

Bromination of triisopropylboroxine to tris(1-bromo-1-methylethyl)boroxine is far more facile than α-bromination of sec-alkylboronic esters. Normal fluorescent room light is sufficient to initiate the free radical reaction, which can be carried out as a titration. The steric environment for replacement of the bromine by lithioacetonitrile and subsequent asymmetric insertion of a chloromethyl group into the carbonboron bond is more highly hindered than what has been studied previously, and the pinanediol ester proved to be the only useful chiral boronic ester in such circumstances. Cyclization of the cyano-substituted boronic ester to the corresponding cyclopropylboronic ester yielded a mixture of diastereomers, presumably the result of base-induced epimerization of the initially formed major isomer having the boronic ester and cyano groups trans.