Non-detectable Levels Research Articles

Polyaniline-based electrospun polycaprolactone nanofibers: preparation and characterization

This work provides a convenient strategy for preparation of conducting polycaprolactone (PCL)/polyaniline (PAni) nanofibers, useful for development of optoelectronic sensors and devices. PCL/PAni nanofibers were obtained by electrospinning technique and characterized by SEM, FTIR, thermal analysis, and DC electrical conductivity. The influence of the experimental conditions in the electrospinning process, such as the applied voltage, on the nanofiber morphology was discussed in detail. Incorporation of PAni into PCL nanofibers significantly increased the electrical conductivity from a non-detectable level for the neat PCL to 0.032 ± 0.022 S/cm for the nanofibers containing 7.5 wt.% PAni. Therefore, electrospun PCL/PAni nanofiber mats presented optical and electrical properties, that awaken the possibility of applications for these materials as acid-base sensors and electrochromic devices.

Impaired DNA repair in mouse monocytes compared to macrophages and precursors

Previously we showed that human monocytes isolated from peripheral blood display downregulation of several DNA repair proteins, including XRCC1, ligase III, PARP-1 and DNA-PKCS, resulting in a deficiency of DNA repair, while in macrophages derived from monocytes the repair protein expression and DNA repair is restored. To see whether this is a specific phenomenon of human monocytes and macrophages, we assessed the expression of these repair genes in mice. We also addressed the question at which differentiation step in bone marrow cells downregulation of DNA repair gene expression occurs. The study revealed that mouse monocytes, similar to human, lack the expression of XRCC1, ligase III, PARP-1 and DNA-PKCS. If mice were treated with total body irradiation, they showed significant apoptosis in bone marrow monocytes, but not in peritoneal macrophages. This was also observed after treatment with the methylating anticancer drug temozolomide, resulting in high death rate of monocytes, but not macrophages. Monocytes arise from hematopoietic stem cells. Even the early stem cell fraction (LT-HSC) expressed detectable amounts of XRCC1, which was transiently upregulated, achieving the highest expression level in CMP (common myeloid progenitor) and, during the subsequent differentiation process, downregulated up to a non-detectable level in monocytes. The immediate monocyte precursor GMP also expressed ligase III, PARP-1 and DNA-PKCS. All these repair genes lacking in monocytes were upregulated again in macrophages. The sensitivity of monocytes, macrophages and precursor cells roughly correlated with their XRCC1 expression level. Monocytes, but not macrophages, also displayed strong γH2AX focal staining, indicating the presence of non-repaired DNA double-strand breaks following total body irradiation. Overall, the data revealed that murine monocytes exhibit the same DNA repair-impaired phenotype and high sensitivity compared to macrophages as observed in human. Therefore, the repair deficiency previously described for human monocytes appears to be a general property of this cell type.

Peripheral Blood Immune Profiling of Convalescent Plasma Donors Reveals Alterations in Specific Immune Subpopulations Even at 2 Months Post SARS-CoV-2 Infection.

Immune profiling of patients with COVID-19 has shown that SARS-CoV-2 causes severe lymphocyte deficiencies (e.g., lymphopenia, decreased numbers, and exhaustion of T cells) and increased levels of pro-inflammatory monocytes. Peripheral blood (PB) samples from convalescent plasma (CP) donors, COVID-19 patients, and control subjects were analyzed by multiparametric flow cytometry, allowing the identification of a wide panel of immune cells, comprising lymphocytes (T, B, natural killer (NK) and NKT cells), monocytes, granulocytes, and their subsets. Compared to active COVID-19 patients, our results revealed that the immune profile of recovered donors was restored for most subpopulations. Nevertheless, even 2 months after recovery, CP donors still had reduced levels of CD4+ T and B cells, as well as granulocytes. CP donors with non-detectable levels of anti-SARS-CoV-2-specific antibodies in their serum were characterized by higher Th9 and Th17 cells, which were possibly expanded at the expense of Th2 humoral immunity. The most noticeable alterations were identified in previously hospitalized CP donors, who presented the lowest levels of CD8+ regulatory T cells, the highest levels of CD56+CD16− NKT cells, and a promotion of a Th17-type phenotype, which might be associated with a prolonged pro-inflammatory response. A longer follow-up of CP donors will eventually reveal the time needed for full recovery of their immune system competence.

The effect of physico-chemical treatment in reducing Listeria monocytogenes biofilms on lettuce leaf surfaces

The purpose of this research was to characterize Listeria monocytogenes from several environmental and clinical sources and assess the efficacy of single and combined physico-chemical treatments in reducing biofilm on lettuce leaves. PCR analysis of L. monocytogenes isolates collected from different clinical (10 strains) and environmental sources (12 strains) was used to look for the presence of one Listeria-specific gene and five virulence genes. Biofilms of L. monocytogenes were developed on lettuce leaves over 24 h. A 5-min ultrasound and a 300-ppm sodium hypochlorite (NaOCl) wash resulted in similar reductions in cell numbers of 0.82 log CFU cm−2. For chlorine dioxide (ClO2) at 60 ppm, the cell numbers were reduced by ∼5.45 log CFU cm−2. A combined treatment of 5 min of ultrasound plus 300 ppm NaOCl or 40 ppm ClO2, provided maximal efficacy, reducing the number of L. monocytogenes on the lettuce surface to non-detectable levels. Therefore, ClO2 has the potential to replace NaOCl for the disinfection of food products in the food industry.

Relationship between imidacloprid residues and control effect on cotton aphids in arid region.

In this case, the dissipation and residues of imidacloprid as well as its control efficacy against aphids (Aphis gossypii Glover) in cotton cropping system were reported. After the final spray at the rates of 10.5-42.5g a.i. ha-1, the initial deposits were 0.59-2.25mgkg-1 with half-lives of 2.12-2.84days on leaves and 0.06-0.21mgkg-1 with half-lives of 1.51-4.20days in soil, respectively. The initial residues were significantly higher with longer persistence in the upper position of the leaf than in middle and lower positions. The different application dosages could induce a significant difference in the initial deposits, but not show consistent correlation with the dissipation rate. The repeated applications of imidacloprid could alter its residue levels and dissipation rates. The long-term residue concentrations of imidacloprid (60days after the final application) reached to the nondetectable level in soil. Combined with the control efficacy results, it was considered that the recommended dose of imidacloprid on cotton could be used effectively and safe in this arid area from the view of crop protection and environmental contamination.

Value-added switchgrass extractives for reduction of Escherichia coli O157:H7 and Salmonella Typhimurium populations on Formica coupons

Recurring outbreaks linked to Escherichia coli O157:H7-contaminated lettuce and Salmonella enterica-contaminated sprouts highlight the need for improved food safety measures. The aim of this study was to determine the ability of a bio-based antimicrobial extract prepared from switchgrass, a dedicated energy crop, to reduce E. coli O157:H7 and S. Typhimurium populations on Formica coupons, a model food-contact surface. Overnight cultures of ~7 log CFU/mL E. coli O157:H7 and S. Typhimurium, air-dried on Formica coupons were treated with 0.625% NaClO, 70% ethanol, sterile water or different batches of switchgrass extractives (SE1, SE2, and SE3) for up to 30 min. E. coli O157:H7 was reduced by 4.43 log CFU/mL after 1 min by SE3, and to non-detectable levels after 1 min by all other treatments. Populations of S. Typhimurium LT2 (15-min drying) were reduced by 3.30 log CFU/mL with 70% ethanol, 5.38 log CFU/mL with SE1, and to non-detectable levels with 0.625% NaClO after 1 min, while S. Typhimurium ATCC 23564 (1-h drying) was non-detectable after 1 min by all treatments. Under soiled conditions, 10-min treatment with SE1 and 70% ethanol reduced both bacteria to non-detectable levels. Studies with concentrated switchgrass extractives combined with various other natural disinfectants or in hurdle approaches warrant further investigation.

Sex-dependent pheromonal effects on steroid hormone levels in sea lampreys (Petromyzon marinus)

Sea lampreys (Petromyzon marinus) are basal vertebrates that exhibit reproductive control via a hypothalamic-pituitary-gonadal axis. The function and evolution of the hypothalamic and pituitary peptide hormones are well studied in this species, whereas the functions of classical sex steroid hormones have not been well established due to their low or non-detectable plasma levels. Sea lamprey pheromone 3-keto petromyzonol sulfate (3kPZS) has been shown to increase while 3-keto allocholic acid (3kACA) decreases plasma 15α-hydroxyprogesterone (15αP) levels in prespermiating males (PSM) but not in preovulatory females (POF). However, spermiating male washings that contain both 3kPZS and 3kACA facilitate spawning in both sexes. Therefore, we wondered if the effects of pheromones on POF were elicited by classical steroid hormones such as progesterone, androstenedione, testosterone and estradiol. We hypothesized that waterborne 3kACA and 3kPZS differentially alter steroid hormone levels in prespawning sea lampreys. We determined the sex differences and pheromonal effects on steroid hormone levels in prespawning sea lampreys using sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) methods. Some PSM became spermiating (SM) at the time of sample collection, and those data were treated as a separate group. We found that males contained more androstenedione and progesterone in the gonad and more estradiol and testosterone in the plasma than POF, whereas POF contained more gonadal testosterone than males (no detectable gonadal testosterone). In POF, 3kPZS decreased gonadal androstenedione but increased gonadal progesterone and plasma estradiol, whereas 3kACA only increased gonadal progesterone levels. Exposure to 3kPZS for 4 h increased plasma 15αP in POF and SM, and gonadal 15αP in POF. Interestingly, 3kACA or 3kPZS depleted gonadal or plasma 15αP in PSM at various time points. On the other hand, both pheromones had no significant effect on androstenedione, progesterone or estradiol levels in males. Plasma testosterone levels did not change after pheromone exposure in both sexes. We conclude that sea lamprey pheromones 3kACA and 3kPZS induced differential steroidal responses in POF, PSM and SM.

Subarachnoid neurocysticercosis: emerging concepts and treatment.

Subarachnoid neurocysticercosis (SUBNCC) is caused by a morphologically unique proliferative form of Taenia solium involving the subarachnoid spaces. Prolonged therapy based upon the pathophysiology of SUBNCC and long-term follow-up have shed light on the course of disease and led to highly improved outcomes. SUBNCC has a prolonged incubation period of between 10 and 25 years characterized by cyst proliferation and growth and invasion of contiguous spaces leading to mass effect (Stage 1). With induction of the host-immune responses, cysts degenerate leading to a predominately inflammatory arachnoiditis (Stage 2) causing hydrocephalus, infarcts, and other inflammatory based neurological manifestations. Inactive disease (Stage 3) may occur naturally but mostly is a result of successful treatment, which generally requires prolonged intensive anthelminthic and antiinflammatory treatments. Cerebral spinal fluid cestode antigen or cestode DNA falling to nondetectable levels predicts effective treatment. Prolonged treatment with extended follow-up has resulted in moderate disability and no mortality. Repeated short intensive 8-14-day courses of treatment are also used, but long-term outcomes and safety using this strategy are not reported. SUBNCC gives rise to a chronic arachnoiditis. Its unique ability to proliferate and induce inflammatory responses requires long-term anthelmintic and antiinflammatory medications.

Effect of thermosonication on quality attributes of hog plum (Spondias mombin L.) juice

The use of thermosonication (TS) technique to preserve the qualities of fruit juice as an alternative to conventional pasteurization has attracted research interest in recent times. In the present study, freshly prepared hog plum juice (control), and the juice samples subjected to pasteurization (90 °C for 60 s) and thermosonication (40 kHz, 400 W at 40, 50 and 60 °C each for 5, 10, 20 and 30 min) were each analyzed for physicochemical, bioactive, microbial and sensory properties. After treatment, no significant changes in pH, total soluble solids and titratable acidity were observed. Notably, TS at 40 and 50 °C significantly (p < 0.05) improved color parameters, cloudiness and browning index. Furthermore, thermosonication increased ascorbic acid (11.40–18.55%), total phenolic content (17.98–18.35%), carotenoids (2.19–4.30%), flavonoids (10–16%) and antioxidant activity (32.52–48.5%) relative to the control. Both treatments significantly reduced the microbial count to non-detectable level after processing, while sensory attributes slightly improved. However, TS treatment at 60 °C decreased most of the quality parameters. Results showed that TS can improve quality, safety and economic potential of hog plum juice as a feasible alternative to pasteurization.

SARS-CoV-2 serology and virology trends in donors and recipients of convalescent plasma

SARS-CoV-2 has infected millions worldwide. The virus is novel, and currently there is no approved treatment. Convalescent plasma may offer a treatment option. We evaluated trends of IgM/IgG antibodies/plasma viral load in donors and recipients of convalescent plasma. 114/139 (82 %) donors had positive IgG antibodies. 46/114 donors tested positive a second time by NP swab. Among those retested, the median IgG declined (p < 0.01) between tests. 25/139 donors with confirmed SARS-CoV-2 were negative for IgG antibodies. This suggests that having had the infection does not necessarily convey immunity, or there is a short duration of immunity associated with a decline in antibodies. Plasma viral load obtained on 35/39 plasma recipients showed 22 (62.9 %) had non-detectable levels on average 14.5 days from positive test versus 6.2 days in those with detectable levels (p < 0.01). There was a relationship between IgG and viral load. IgG was higher in those with non-detectable viral loads. There was no relationship between viral load and blood type (p = 0.87) or death (0.80). Recipients with detectable viral load had lower IgG levels; there was no relationship between viral load, blood type or death.

Abstract 6600: Rapid generation of TCR-engineered T lymphocytes by linking the single cell transcriptome to its corresponding T cell receptor in antigen specific T cells

Abstract Adoptive cell transfer of T-cell receptor (TCR)-engineered T cells has emerged as a powerful and potentially curative therapy for cancers and infectious diseases. However, how to rapidly identify and obtain therapeutic TCRs remains a major challenge in this field. Here, we simultaneously performed deep single-cell RNA and TCR V(D)J sequencing on 879 single T cells from in vitro stimulated CMV pp65NLV-specific CD8+ T cells. The correlation analysis of single-cell transcriptome and TCR V(D)J sequences revealed a differential distribution of T cell transcriptomic profiles among TCR clones. Two distinct cell types were identified in the T cell population. TYPE I T cell subtype, which represents the gene signatures of T cell activation and cytotoxicity, mainly includes TCR clone 1, 2 &amp; 4, while TYPE II subtype, which represents the gene signatures of naïve status, mainly includes TCR clone 3 and other low frequency clones. Based on their temporal phases of T cell activation, the selected TCR sequences from clone 1 (TCRZWX1) and clone 3 (TCRZWX3) were functionally validated by constructing TCR-engineered T cells in vitro. The two clones showed distinct cell stages corresponding to their transcriptome patterns. TCRZWX1 transgenic T cells displayed effector functions including secretion of pro-inflammatory cytokines, IFN-γ and TNF-α, and cytotoxicity in response to CMV pp65NLV peptide. However, TCRZWX3 transgenic T cells displayed non-detectable levels of IFN-γ, which might correlate with a low affinity TCR. Our results provide a novel approach using correlative analysis of the single-cell transcriptome and TCR V(D)J sequences for rapidly identifying potential therapeutic TCRs for T cell therapy. Citation Format: Linnan Zhu, Fei Wang, Qumiao Xu, Hai-Xi Sun, Ziyi Li, Yanling Liang, Zhenkun Zhuang, Ying Gu, Cheng-chi Chao. Rapid generation of TCR-engineered T lymphocytes by linking the single cell transcriptome to its corresponding T cell receptor in antigen specific T cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6600.

Optimization of Electrolysis Parameters for Green Sanitation Chemicals Production Using Response Surface Methodology

Electrolyzed water (EW) shows great potential as a green and economical sanitation solution for the food industry. However, only limited studies have investigated the optimum electrolysis parameters and the bactericidal effect of acidic electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). Here, the Box–Behnken experimental design was used to identify the optimum parameters. The tests were conducted with different types of electrodes, electrical voltages, electrolysis times, and NaCl concentrations. There were no obvious differences observed in the physico-chemical properties of EW when different electrodes were used. However, stainless steel was chosen as it meets most of the selection criteria. The best-optimized conditions for AcEW were at 11.39 V, 0.65 wt.% NaCl, and 7.23 min, while the best-optimized conditions for AlEW were at 10.32 V, 0.6 wt.% NaCl, and 7.49 min. The performance of the optimum EW (AcEW and AlEW) compared with commercial cleaning detergents for the food industry was then evaluated. The bactericidal activity of AcEW and AlEW was examined against Escherichia coli ATCC 10536 at different temperatures (30 °C and 50 °C) for 30 s. The results show that both AcEW and AlEW have the ability to reduce the Escherichia coli to non-detectable levels (less than 2 log CFU/mL).

White rot fungus Pleurotus pulmonarius enhanced bioremediation of highly PCDD/F-contaminated field soil via solid state fermentation

This study was performed to evaluate the use of white rot fungus, Pleurotus pulmonarius, to treat polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in contaminated soil using solid state fermentation (SSF). The soil was collected from a long-closed pentachlorophenol plant in southern Taiwan. The non-sterilized soil with a total PCDD/F concentration of 14,000 ± 2400 ng I-TEQ kg−1 was mixed directly with the solid fungal inocula at dry w/w ratio of 1:1.4 (ratio-adjusted test) and incubated at 26 ± 2 °C in a controlled environment. The highest PCDD/F decomposition was observed during the mycelium colonization. Pearson correlation coefficient (r) studied during this period (35 days) indicated that laccase had no significant correlation (r = −0.53), while manganese peroxidase had a strong positive correlation (r = 0.88) with PCDD/F decomposition efficiency. After 72 days, the more toxic congeners, tetra- and penta-CDD/Fs were removed to non-detectable levels. Meanwhile, the removal efficiencies of hexa-, hepta-, and octa-CDD/Fs were >80%, >97%, and >90%, respectively. The simultaneous degradation of low and high chlorinated DD/Fs suggested that overall removal was nonspecific. The overall PCDD/F removal was 96%, and the residual concentration (276 ng I-TEQ kg−1) was below the regulatory control limit (1000 ng I-TEQ kg−1). In conclusion, this study shows that P. pulmonarius via SSF can successfully remediate the PCDD/F-contaminated field soil. Furthermore, this SSF technique overcame the well-known intractability of PCDD/F biodegradation in non-sterilized soil, making it promising for actual field application.

Intake of Radionuclides in the Trees of Fukushima Forests 3. Removal of Radiocesium from Stem Wood, Cryptomeria Japonica (L.f.) D. Don.

Nuclear power plant accidents have dispersed radiocesium into the atmosphere to contaminate trees with no turnover in heartwood, as occurred in Fukushima, and as has persisted for over 30 years around Chernobyl. Here we employ the ponding method, in which radiocesium can be flushed out from the cross-cut edges of Japanese cedar, Cryptomeria japonica (L.f.) D. Don., stem with water due to xyloglucan degradation in tracheids. Furthermore, lab-scale ponding experiments have shown that a non-detectable level of radiocesium has been observed not only in the pool water used for 575 days but also in the water containing recombinant xyloglucanase. This traditional technology is now a new biotechnology.

Disease monitoring and TKI resistance mutations of EGFR mutation-positive NSCLC patients via circulating tumor DNA.

e21627 Background: 15–40% of NSCLC adenocarcinoma patients harbor EGFR sensitizing mutations. Tyrosine kinase inhibitors (TKI) provide significant clinical benefit in this population, yet all patients will develop resistance. Liquid biopsy has been demonstrated to reliably identify tumor associated somatic EGFR mutations. Quantitative assessment of mutated EGFR driven tumors could potentially be used to monitor disease progression, to assess therapeutic response, and to identify resistance mechanisms. Methods: 106 longitudinal plasma samples from 16 NSCLC patients who were treated with osimertinib as either first line or second line therapy were collected. A series of plasma samples collected during treatment and at the time of disease progression were analyzed with the AVENIO ctDNA Surveillance kit*. Mutations at each time point were identified and reported by the AVENIO software v2.0*. The mutation profile of each patient at different timepoints along with the treatment journey was examined in combination with clinical outcome data. Results: EGFR sensitizing mutations were detected in all plasma samples by sequencing except in 3 cases. Patients responsive to anti-EGFR therapy showed a rapid decrease of EGFR driver mutations to non-detectable levels. Meanwhile, patients who had stable disease or rapid disease progression had stable or slightly decreasing ctDNA levels after receiving the treatment. One patient had a MET amplification, FBXL7 SNV, and EGFR T790M detected at the time of disease progression which were not detected at baseline. One patient had both EGFR L858R and T790M mutations. This patient progressed very quickly on erlotinib. Detection of the T790M mutation decreased upon osimertinib administration, however, the L858R mutation level stayed the same. TP53 mutations were elevated in 3 patients at the time of progression, and could potentially be related to anti-EGFR resistance. Conclusions: This study clearly demonstrated that liquid biopsy could identify resistance mutations beyond EGFR prior to clinical progression. Plasma samples collected prior to or at disease progression could facilitate identification of novel resistant mutations to TKI therapy. Further studies to demonstrate the clinical utility of serial blood EGFR testing in NSCLC management are necessary. *For Research Use Only. Not for use in diagnostic procedures.

Nitro-treatment of composted poultry litter; effects on Salmonella, E. coli and nitrogen metabolism

Poultry litter is a potentially valuable crude protein feedstuff for ruminants but must be treated to kill pathogens before being fed. Composting kills pathogens but risks losses of nitrogen due to volatilization or leaching as ammonia. Treatment of poultry litter with ethyl nitroacetate, 3-nitro-1-propionate, ethyl 2-nitropropionate (at 27 µmol/g), decreased numbers of experimentally-inoculated Salmonella Typhimurium (>1.0 log10 compared to controls, 4.2 ± 0.2 log10 CFU/g) but not endogenous Escherichia coli early during simulated composting. By day 9 of simulated composting, Salmonella and E. coli were decreased to non-detectable levels regardless of treatment. Some nitro-treatments preserved uric acid and prevented ammonia accumulation, with 18% more uric acid remaining and 17–24% less ammonia accumulating in some nitro-treated litter than in untreated litter (18.1 ± 3.8 µmol/g and 3.4 ± 1.4 µmol/g, respectively). Results indicate that nitro-treatment may help preserve uric acid in composted litter while aiding Salmonella control.

Use of natural bio-sorbent in removing dye, heavy metal and antibiotic-resistant bacteria from industrial wastewater

In this study, we evaluated the ability of waste shell powder (WSP) and moringa seed powder (MSP) individually or in combination to eliminate dye, heavy metal and resistant bacteria from the industrial wastewater (IWW). The presence of dyes, heavy metals, approximately 7.0 log CFU/ml of aerobic bacteria and 3.0–4.0 log CFU/ml of other pathogens including Escherichia coli, Pseudomonas aeruginosa, Citrobacter freundii, Serratia liquefaciens and Bacillus cereus was evident in IWW of both tannery and textile industries. In addition, depending on the type of bacterial species each bacterium was resistant to as high as 50 ppm of multi-metal (Cr6+, Cd2+ and Pb2+ or its combination) and even multi-drug resistant (amoxicillin, ampicillin, cefixime, ceftazidime, and tazobactam). Combined use of MSP (0.8 gm/100 ml IWW) and WSP (0.2 gm/100 ml IWW) treatment was able to discolor the IWW within 4 h and took 24 h to eliminate heavy metals and pathogenic bacteria to non-detectable level from the IWW, simultaneously. On the other hand, individual use of MSP or WSP was not found effective enough to remove or eliminate dye, heavy metal and bacteria simultaneously from the IWW. Similar experimental results were observed in the challenge test with laboratory-prepared effluent water containing 35.0 ppm Remazol Brilliant Blue R dye and maximum 50 ppm Cr6+. Thus, the combination of these two bio-sorbents could be applicable in IWW treatment before being discharged into the environment.

Occupational Exposure and Ventilation Assessment in New York City Nail Salons.

In 2015, New York State enacted new ventilation regulations to protect employees and clients from exposure to chemicals used in nail salons. This study measured common air pollutants found in nail salons and assessed compliance with ventilation requirements. Area sampling was conducted in 12 nail salons located in New York City for three consecutive days (Thursday, Friday, and Saturday) to measure total volatile organic compounds (TVOCs), methyl methacrylate, toluene, and ethyl acetate concentrations and estimate ventilation rates. Salon characteristics were determined through a walkthrough inspection and survey administered to the manager. The average daily concentration of carbon dioxide and TVOCs across all salons was 1070 ppm [standard deviation (SD) = 440 ppm] and 29 ppm (SD = 25 ppm), respectively. Chemical-specific air sampling showed low to non-detectable levels of the three measured chemicals. Seventy-five percent of the nail salons did not meet general minimum outdoor airflow requirements. Little temporal variation was observed in day-to-day average concentrations of contaminants within salons, indicating uniform exposure during high customer count days. Salons that met the outdoor airflow requirements had twice the average daily customers (83 versus 42) and half the TVOC concentrations compared with salons that did not (33 versus 16 ppm). Nail salons not meeting ventilation requirements tended to have fewer customers and managers that did not understand the essential components of the ventilation system. Data from this study can be used as evidence of reduction in exposure due to compliance with the ventilation requirements.

Importance of Nebulizer Drying for Patients With Cystic Fibrosis.

Nebulizer therapy is an important treatment component for patients with cystic fibrosis (CF). Nebulizer manufacturers' guidelines advocate thorough nebulizer drying after washing. The aim of this study, therefore, was to examine the microbiology associated with nebulizer drying, particularly related to Pseudomonas control, and to examine microbiologically non-adherence to the recommended drying procedures. Four aspects of nebulizer drying were examined in 3 common nebulizers, including examination of the drying profile, improvement to the drying profile of assembled nebulizers, survival of Pseudomonas aeruginosa in tap water and in tap water plus 0.5% (v/v) dishwashing detergent, and the effect of drying of P. aeruginosa in tap water and tap water plus residual sputum (1%v/v, 10%v/v). Microbiologic examination was performed by using P. aeruginosa (5 clinical CF strains plus 1 National Collection of Type Cultures Reference strain). There were differences in the time to complete dryness between disassembled and fully assembled nebulizers. Vigorous repeated shaking was unable to drive off all residual water on assembled nebulizers. P. aeruginosa counts did not decrease significantly in either tap water or in tap water plus detergent after 24 h storage at ambient temperature. In contrast, all Pseudomonas organisms were killed when nebulizers were dried for 24 h, even when contaminated with 1% and 10% sputum. Dishwashing detergent did not demonstrate any antibacterial activity. This study demonstrated that nebulizer drying, if applied properly, had the ability to reduce counts of P. aeruginosa to non-detectable levels. Equally, this study showed that, if the device was not dried thoroughly and moisture remained, then the device was able to support the survival of P. aeruginosa at high numbers, which constituted an infection risk to the patient with CF. This information may help educate and inform the patient with CF about the importance of proper nebulizer drying for Pseudomonas control to improve patient awareness and safety.

Ammonium nitrogen increases Ca uptake from non-exchangeable reservoirs by eucalypt plants

Eucalypt plants can take up calcium (Ca) from soils with nondetectable levels of exchangeable Ca2+. This suggests the operation of unknown processes capable of rendering non-exchangeable forms of the nutrient available to eucalypts. An explanatory hypothesis for this phenomenon is that soil acidification by ammonium can release Ca from Ca-oxalate and soil minerals. Therefore, the objective of this work was to study the interactions between Ca-oxalate and ammonium on Ca and N nutrition of a Eucalyptus grandis × Eucalyptus urophylla hybrid (Eucalyptus urograndis) in a soil with nondetectable exchangeable Ca2+. For this, E. urograndis seedlings (clone AEC 144) were grown in pots with soil fertilized with the combination of five Ca doses (0, 0.10, 0.20, 0.40, and 0.80 cmolc/kg) as Ca-oxalate, and five N doses (0, 25, 50, 100, and 200 mg/kg) as NH4Cl. The experiment was conducted in a greenhouse for 60 days. Two additional experiments were conducted to verify the stability of Ca-oxalate at different doses in the soil along an incubation time of 60 days and at different soil pH. E. urograndis dry matter production and Ca and N uptake were highly dependent on ammonium applied to the soil, but only slightly influenced by Ca-oxalate. When no Ca-oxalate was added, Ca from a non-exchangeable source was transferred to E. urograndis. This transfer increased with increasing ammonium supply, stabilizing at the highest N dose applied. Ca-oxalate solubilization in the soil without E. urograndis plants ranged from 62 to 94% after 60 days of soil incubation and the release of Ca from Ca-oxalate did not change as a function of pH. In general, the release of Ca from Ca-oxalate presented two behaviors: pH-independent (trial without plants) and pH/NH4+-dependent (trial with plants). This is the first report demonstrating that ammonium lead to the mobilization of non-exchangeable Ca reservoirs by E. urograndis plants cultivated in a soil with no exchangeable Ca.