Efficacy and safety of enteral supplementation with high-dose vitamin D in critically ill patients with vitamin D deficiency

BACKGROUND

Vitamin D deficiency is associated with mortality and morbidity in critically ill patients. This study investigated the safety and effectiveness of enteral high-dose vitamin D supplementation in intensive care unit (ICU) patients in Asia.

METHODS

This was a multicenter, prospective, randomized-controlled study. Eligible participants with vitamin D deficiency were randomly assigned to the control or vitamin D supplementation group. In the vitamin D supplementation group, the patients received 569,600 IU vitamin D. The primary outcome was the serum 25(OH)D level on day 7.

RESULTS

41 and 20 patients were included in the vitamin D supplementation and control groups, respectively. On day 7, the serum 25(OH)D level was significantly higher in the vitamin D supplementation group compared to the control group (28.5 [IQR: 20.2-52.6] ng/mL and 13.9 [IQR: 11.6-18.8] ng/mL, p < 0.001). Only 41.5% of the patients achieved serum 25(OH)D levels higher than 30 ng/mL in the supplementation group. This increased level was sustained in the supplementation group on both day 14 and day 28. There were no significant adverse effects noted in the supplementation group. Patients who reached a serum 25(OH)D level of >30 ng/mL on day 7 had a significantly lower 30-day mortality rate than did those who did not (5.9% vs 37.5%, p < 0.05).

CONCLUSIONS

In our study, less than half of the patients reached adequate vitamin D levels after the enteral administration of high-dose vitamin D. A reduction in 30-day mortality was noted in the patients who achieved adequate vitamin D levels. TRIAL REGISTRATION CLINICALTRIALS.

GOV ID

NCT04292873, Registered, March 1, 2020.

Optimal Timing of Targeted Temperature Management for Post-Cardiac Arrest Syndrome: Is Sooner Better?

Targeted temperature management (TTM) is often considered to improve post-cardiac arrest patients’ outcomes. However, the optimal timing to initiate cooling remained uncertain. This retrospective analysis enrolled all non-traumatic post-cardiac arrest adult patients with either out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrest (IHCA) who received TTM from July 2015 to July 2021 at our hospital. The values of time delay before TTM and time to target temperature were divided into three periods according to optimal cut-off values identified using receiver operating characteristic curve analysis. A total of 177 patients were enrolled. A shorter time delay before TTM (pre-induction time) was associated with a lower survival chance at 28 days (32.00% vs. 54.00%, p = 0.0279). Patients with a longer cooling induction time (>440 minis) had better neurological outcomes (1.58% vs. 1.05%; p = 0.001) and survival at 28 days (58.06% vs. 29.25%; p = 0.006). After COX regression analysis, the influence of pre-induction time on survival became insignificant, but patients who cooled slowest still had a better chance of survival at 28 days. In conclusion, a shorter delay before TTM was not associated with better clinical outcomes. However, patients who took longer to reach the target temperature had better hospital survival and neurological outcomes than those who were cooled more rapidly. A further prospective study was warranted to evaluate the appropriate time window of TTM.

Duration of varenicline prescription and efficacy of smoking cessation treatment: an observational study in Taiwan

Although varenicline has had a significant effect on smoking cessation in randomized clinical trials, the dose-effect of varenicline treatment for smoking cessation in real-world settings remains unclear. This study aimed to evaluate the association between the duration of varenicline prescription and smoking cessation in Taiwan after adjusting for potential confounding effects and endogeneity bias. A total of 5106 Taiwanese participants received varenicline monotherapy for smoking cessation between March 2012 and September 2016. Multinomial logistic regression (MLR) was used to analyze the association between varenicline prescription duration and smoking cessation, stratified by the frequency of smoking clinic visits and propensity scores of early stopping of smoking cessation treatment. Compared to the reference of nonquitting, longer durations of varenicline prescription were associated with the greater likelihood of immediate and complete quitting (OR = 1.08, 95% CI = 1.02-1.14) and late quitting (OR = 1.14, 95% CI = 1.07-1.20). Among those who were more likely to continue visiting smoking clinics, longer use of varenicline was significantly associated with an increase in immediate-and-complete quitting (OR = 1.19, 95% CI = 1.15-1.23) and late quitting (OR = 1.24, 95% CI = 1.20-1.28). Varenicline prescription duration was not associated with smoking cessation among smokers who visited smoking clinics once. The relationship between varenicline prescription duration and smoking cessation was modified by the frequency of smoking clinic visits and was dependent on quitting process patterns. Encouraging smokers to continue visiting the smoking cessation clinic and use medication will help smoking cessation efforts in Taiwan.

Voltage–Time Transformation Model for Threshold Switching Spiking Neuron Based on Nucleation Theory

In this study, we constructed a voltage–time transformation model (V–t Model) to predict and simulate the spiking behavior of threshold-switching selector-based neurons (TS neurons). The V–t Model combines the physical nucleation theory and the resistor–capacitor (RC) equivalent circuit and successfully depicts the history-dependent threshold voltage of TS selectors, which has not yet been modeled in TS neurons. Moreover, based on our model, we analyzed the currently reported TS devices, including ovonic threshold switching (OTS), insulator-metal transition, and silver- (Ag-) based selectors, and compared the behaviors of the predicted neurons. The results suggest that the OTS neuron is the most promising and potentially achieves the highest spike frequency of GHz and the lowest operating voltage and area overhead. The proposed V–t Model provides an engineering pathway toward the future development of TS neurons for neuromorphic computing applications.

Prevalence of Vitamin D Deficiency and Associated Factors in Critically Ill Patients: A Multicenter Observational Study

Background: Vitamin D deficiency is common in the general population worldwide, and the prevalence and severity of vitamin D deficiency increase in critically ill patients. The prevalence of vitamin D deficiency in a community-based cohort in Northern Taiwan was 22.4%. This multicenter cohort study investigated the prevalence of vitamin D deficiency and associated factors in critically ill patients in Northern Taiwan. Methods: Critically ill patients were enrolled and divided into five groups according to their length of stay at intensive care units (ICUs) during enrolment as follows: group 1, <2 days with expected short ICU stay; group 2, <2 days with expected long ICU stay; group 3, 3-7 days; group 4, 8-14 days; and group 5, 15-28 days. Vitamin D deficiency was defined as a serum 25-hydroxyvitamin D (25(OH)D) level < 20 ng/ml, and severe vitamin D deficiency was defined as a 25(OH)D level < 12 ng/ml. The primary analysis was the prevalence of vitamin D deficiency. The exploratory analyses were serial follow-up vitamin D levels in group 2, associated factors for vitamin D deficiency, and the effect of vitamin D deficiency on clinical outcomes in critically ill patients. Results: The prevalence of vitamin D deficiency was 59% [95% confidence interval (CI) 55-62%], and the prevalence of severe vitamin D deficiency was 18% (95% CI 15-21%). The median vitamin D level for all enrolled critically ill patients was 18.3 (13.7-23.9) ng/ml. In group 2, the median vitamin D levels were <20 ng/ml during the serial follow-up. According to the multivariable analysis, young age, female gender, low albumin level, high parathyroid hormone (PTH) level, and high sequential organ failure assessment (SOFA) score were significantly associated risk factors for vitamin D deficiency. Patients with vitamin D deficiency had longer ventilator use duration and length of ICU stay. However, the 28- and 90-day mortality rate were not associated with vitamin D deficiency. Conclusions: This study demonstrated that the prevalence of vitamin D deficiency is high in critically ill patients. Age, gender, albumin level, PTH level, and SOFA score were significantly associated with vitamin D deficiency in these patients.

Maxacalcitol Pharmacokinetic-Pharmacodynamic Modeling and Simulation for Secondary Hyperparathyroidism in Patients Receiving Maintenance Hemodialysis

BACKGROUND

Maxacalcitol was approved in Taiwan in 2018 as the first active vitamin D3 injection for secondary hyperparathyroidism (SHPT) in patients on maintenance hemodialysis. However, no data from any clinical study with maxacalcitol in Taiwanese patients is available.

OBJECTIVES

This analysis aimed to evaluate the profiles of parathyroid hormone (PTH) and calcium (Ca) concentrations in Taiwanese SHPT patients on hemodialysis and maxacalcitol.

METHODS

We developed population pharmacokinetic (PK) and pharmacodynamic (PD) models using a modeling and simulation approach. The data for these analyses were obtained from two studies: a clinical pharmacology study in Japanese patients and an ethnic comparison study in healthy Japanese and -Taiwanese volunteers. We then conducted a simulation study with a PK-PD model comprising the PK and PD models developed here.

RESULTS

Serum maxacalcitol concentration profile was modeled using a two-compartment model that took into consideration the distribution of concentrations below the lower limit of quantification. An ethnic difference in clearance was included in the PK model as a covariate. A PD model that used a PTH/Ca feedback loop best described the observed data. There were no significant differences in Ca or PTH concentrations between Taiwanese and Japanese based on the simulation results from our PK-PD model, even though maxacalcitol exposure was approximately 40% higher in Taiwanese than in Japanese.

CONCLUSIONS

On the basis of these population PK and PD analyses and the clinical study conducted in Japan, there is no clinically relevant difference between Taiwanese and Japanese in terms of serum Ca or PTH levels.

[Using Teamwork to Reduce the Incidence of Incontinence-Associated Dermatitis]

BACKGROUND & PROBLEMS

Dermatitis associated with incontinence was the cause of 55% of the total of 386 skin lesion cases in our unit between July and December 2016 and 40.3% of the skin lesion cases in our unit during March and April 2017, indicating the importance of this issue. Our survey showed that the nurses in our unit scored an average of 78.9% on knowledge related to the prevention of incontinence-associated dermatitis and only 58.2% on knowledge related to incontinence-associated dermatitis care. The main reasons for the high incidence of incontinence-associated dermatitis included: incorrect implementation of care, no discussion with the medical team, no incontinence care standards, no continue education, lack of related equipment for preventing incontinence-associated dermatitis, unit patient characteristics, and drugs used.

PURPOSE

To reduce the incidence of incontinence-associated dermatitis from 40.3% to 32.0%.

RESOLUTION

A care-bundle in treating incontinence-associated dermatitis was implemented by designing an assessment flow chart for evaluating incontinence-associated dermatitis, by setting standard guidelines for incontinence-associated dermatitis care, by distributing reminder cards, special toolboxes, and by changing how the little diapers were wrapped. In-service education lessons, inter-professional collaborative practice, and regular internal audit were also executed.

RESULTS

After project implementation, the knowledge score of nurses increased from 78.9% to 95.7%; the correctness of care score, as retested in November 2017, increased from 58.2% to 91.5%; and the incidence of incontinence-associated dermatitis dropped to 18.5%. These improvements achieved the goals of this project. Furthermore, the sustained effect of the project measures was confirmed, with the incidence of incontinence-associated dermatitis determined as 17.9% at three months after completion of the project.

CONCLUSIONS

Formulating care procedures and cooperating with medical team personnel to provide creative care measures were shown to effectively decrease the incidence of incontinence-associated dermatitis and improve overall quality of care. The findings of this project support the revision by hospitals of regulations and procedures related to adult incontinence-associated dermatitis to provide caregivers with basis-of-care standards and uniform care procedures and standards in support of effective patient skin care regimens.

Metabolic tumor volume predicts overall survival in patients with primary pulmonary lymphoepithelioma-like carcinoma

Pretreatment tumor metabolic burden, measured using fluorine-18 fluorodeoxyglucose positron emission tomography/computerized tomography (¹⁸F-FDG PET/CT), has been demonstrated to predict outcomes in various types of malignancies. Additionally, Epstein-Barr virus (EBV) serum titer is associated with stages of pulmonary lymphoepithelioma-like carcinoma (LELC). The present study aimed to investigate the prognostic value of the functional parameters of ¹⁸F-FDG PET/CT in pulmonary LELC and their association with serum EBV DNA. The present retrospective study analyzed data from 71 patients with pulmonary LELC; among these, 32 patients with pulmonary LELC underwent pretreatment ¹⁸F-FDG PET/CT staging between January 2008 and December 2016. EBV viral load and functional parameters of ¹⁸F-FDG PET/CT were used for survival analysis. Multivariate analysis identified tumor stage IV as a significant predictor of poor progression-free survival [hazard ratio (HR), 4.85; P=0.049], whereas elevated total metabolic tumor volume (MTV ≥72.6 ml) independently predicted worse overall survival (OS; HR, 12.59; P=0.024). Pretreatment serum EBV DNA titer was significantly positively associated with total MTV (P=0.0337) and total lesion glycolysis (TLG; P=0.0093), but could not predict outcomes. Total MTV was an independent predictor of OS, and may guide clinical management for pulmonary LELC.

Factors Associated With Recommendations for Assistive Technology Devices for Persons With Mobility Limitations Using Workplace Accommodation Services

The objective of this study was to identify the interactions between impairment-related and work-related factors associated with recommendations for specific assistive technology devices (ATDs) for persons with mobility limitations who used workplace accommodation (WA) services. A retrospective and secondary data analysis was conducted on 132 WA service users with mobility limitations in Taipei City from 2008 to 2012 using chi-square automatic interaction detector (CHAID). The CHAID analyses revealed interactions between impairment-related factors (difficulty walking and upper extremity pain) and work-related factors (frequent moving around outdoors), which were significantly associated with the recommendation of powered wheelchairs ( p < .05). Interactions between the impairment-related factor (difficulty walking) and the work-related factor (frequent sitting for long periods of time) were associated with the recommendation of ergonomic chairs ( p < .001) for persons with mobility limitations. By identifying the interactions between impairment-related and work-related factors in recommending workplace ATDs for persons with mobility limitations, this study provides evidence-based ATDs recommendations for persons with mobility limitations.

Increased risk of avascular necrosis in patients with psoriatic disease: A nationwide population-based matched cohort study

BACKGROUND

Avascular necrosis (AVN) and psoriasis have some pathogenic mechanisms and associated conditions in common.

OBJECTIVE

To examine the association between psoriasis and AVN.

METHODS

This study used data from the Taiwan National Health Insurance Research Database for the period 2004-2006 and identified 28,268 patients with psoriasis, who were then matched for age and sex with 113,072 controls without psoriasis from the Taiwan Longitudinal Health Insurance Database 2000. Multivariate Cox proportional hazards models were used for the analysis.

RESULTS

The unadjusted risk of AVN was significantly higher for patients with psoriasis than for controls (hazard ratio [HR] 2.29) and remained significant after adjustment for other risk factors (adjusted HR 1.96; 95% confidence interval 1.62-2.38). The risk for AVN increased in relation to psoriasis severity and was higher for patients with psoriasis and arthritis than for patients without arthritis. The adjusted HRs were higher for male patients than for female patients and for patients younger than 30 years compared with older patients.

LIMITATIONS

We lacked information on daily tobacco use, alcohol consumption, and physical activity.

CONCLUSION

The risk for AVN increased with the disease severity of psoriasis.

3D Ta/TaO x /TiO2/Ti synaptic array and linearity tuning of weight update for hardware neural network applications

The implementation of highly anticipated hardware neural networks (HNNs) hinges largely on the successful development of a low-power, high-density, and reliable analog electronic synaptic array. In this study, we demonstrate a two-layer Ta/TaO x /TiO2/Ti cross-point synaptic array that emulates the high-density three-dimensional network architecture of human brains. Excellent uniformity and reproducibility among intralayer and interlayer cells were realized. Moreover, at least 50 analog synaptic weight states could be precisely controlled with minimal drifting during a cycling endurance test of 5000 training pulses at an operating voltage of 3 V. We also propose a new state-independent bipolar-pulse-training scheme to improve the linearity of weight updates. The improved linearity considerably enhances the fault tolerance of HNNs, thus improving the training accuracy.

Fully parallel write/read in resistive synaptic array for accelerating on-chip learning

A neuro-inspired computing paradigm beyond the von Neumann architecture is emerging and it generally takes advantage of massive parallelism and is aimed at complex tasks that involve intelligence and learning. The cross-point array architecture with synaptic devices has been proposed for on-chip implementation of the weighted sum and weight update in the learning algorithms. In this work, forming-free, silicon-process-compatible Ta/TaOx/TiO2/Ti synaptic devices are fabricated, in which >200 levels of conductance states could be continuously tuned by identical programming pulses. In order to demonstrate the advantages of parallelism of the cross-point array architecture, a novel fully parallel write scheme is designed and experimentally demonstrated in a small-scale crossbar array to accelerate the weight update in the training process, at a speed that is independent of the array size. Compared to the conventional row-by-row write scheme, it achieves >30× speed-up and >30× improvement in energy efficiency as projected in a large-scale array. If realistic synaptic device characteristics such as device variations are taken into an array-level simulation, the proposed array architecture is able to achieve ∼95% recognition accuracy of MNIST handwritten digits, which is close to the accuracy achieved by software using the ideal sparse coding algorithm.

Characterization and Modeling of Nonfilamentary Ta/TaOx/TiO2/Ti Analog Synaptic Device

A two-terminal analog synaptic device that precisely emulates biological synaptic features is expected to be a critical component for future hardware-based neuromorphic computing. Typical synaptic devices based on filamentary resistive switching face severe limitations on the implementation of concurrent inhibitory and excitatory synapses with low conductance and state fluctuation. For overcoming these limitations, we propose a Ta/TaOx/TiO2/Ti device with superior analog synaptic features. A physical simulation based on the homogeneous (nonfilamentary) barrier modulation induced by oxygen ion migration accurately reproduces various DC and AC evolutions of synaptic states, including the spike-timing-dependent plasticity and paired-pulse facilitation. Furthermore, a physics-based compact model for facilitating circuit-level design is proposed on the basis of the general definition of memristor devices. This comprehensive experimental and theoretical study of the promising electronic synapse can facilitate realizing large-scale neuromorphic systems.

Perceived environmental and personal factors associated with walking and cycling for transportation in Taiwanese adults

This study examined perceived environmental and personal factors associated with walking and cycling as means of transportation for Taiwanese adults. A random-digit-dialing telephone-based cross-sectional survey was conducted with Taiwanese adults aged 20 to 64 years. Data on time spent walking and cycling for transportation and perceptions of neighborhood environment and personal characteristics were obtained from 1065 adults by using the International Physical Activity Questionnaire-long version and its environmental module. Adjusted binary logistic regression was performed. The results showed that, after adjusting potential confounders, common and different personal and perceived environmental factors were associated with walking and cycling for transportation. For common personal factors, adults who had employment were less likely to engage in 150 min of walking per week (odds ratio [OR] = 0.41; 95% confidence interval (CI): 0.27-0.62) and to use cycling as a means of transportation (OR = 0.51; 95% CI: 0.32-0.79). For common perceived environmental factors, adults who perceived good connectivity of streets were more likely to walk (OR = 1.95; 95% CI: 1.20-3.16) and cycle (OR = 2.02; 95% CI: 1.16-3.54) for transportation. Targeting employed adults and improving the connectivity of streets should be a priority for developing transport policies and intervention strategies to promote active transportation.

Homogeneous barrier modulation of TaOx/TiO2 bilayers for ultra-high endurance three-dimensional storage-class memory

Three-dimensional vertical resistive-switching random access memory (VRRAM) is the most anticipated candidate for fulfilling the strict requirements of the disruptive storage-class memory technology, including low bit cost, fast access time, low-power nonvolatile storage,and excellent endurance. However, an essential self-selecting resistive-switching cell that satisfies these requirements has yet to be developed. In this study, we developed a TaOx/TiO2 double-layer V-RRAM containing numerous highly desired features, including: (1) a self-rectifying ratio of up to 10³ with a sub-μA operating current, (2) little cycle-to-cycle and layer-to-layer variation, (3) a steep vertical sidewall profile for high-density integration, (4) forming-free and self-compliance characteristics for a simple peripheral circuit design, and (5) an extrapolated endurance of over 10¹⁵ cycles at 100 °C. Furthermore, the switching and self-rectifying mechanisms were successfully modeled using oxygen ion migration and homogeneous barrier modulation. We also suggest the new possibility of monolithically integrating working and storage memory by exploiting a unique tradeoff between retention time and endurance.

Abstract 4442: Activity participation and quality of life for persons with breast cancer: A longitudinal study

Breast cancer is recognized as one of the most common cancers in women. The prevalence rate of breast cancer in Taiwan is 53/100,000 in 2007. Although the survival rate for the breast cancer was enhanced in recent years, the consequences of the illness, including its impact on the quality of life are in need of attention and treatment. The purpose of the study is to investigate factors related to the quality of life for persons with breast cancer from longitudinal view. The model of the study includes predictors from categories of illness related, psychosocial, contextual and activity participation. The outcome variables are 26 items of the World Health Organization Quality of Life Brief Taiwan version (WHOQOL-BREFTW). The study was approved by the IRB board. One hundred subjects diagnosed as breast cancer were recruited to participate in the study. They were from an outpatient treatment center in a teaching hospital in northern Taiwan. Seventy-six subjects were followed up after three months. The mean age of the subjects was 49.6 (SD=8.6); 77% of them were married; 55% of them had college degree; the average onset duration was 254.7 days (SD=337.7). Seventy percent of the subjects were receiving chemotherapy; 30% of the subjects were receiving targeted therapy. Sixty percent of the subjects were diagnosed as 2nd stage cancer. The study was longitudinal in nature. The average follow up duration was 104 days (SD=15.9 days). The independent variables of the model included: disease stage; number of comorbidity; medication side effect; sense of mastery; sense of competence; level of depression and anxiety; social support; satisfaction with daily occupation; time spent in certain activity and role perofrmance etc. The linear mixed effect model was used to analyze the dataset which offers benefits to overcome missing data, repeated measurement and small sample size. The results of the study showed that overall QOL was predicted by the number of comorbidity, satisfaction with daily occupations, time spent at leisure activity, time at rest and number of roles. Overall health was predicted by side effects, level of depression, level of social support and time spent at leisure activity. Satisfaction with daily occupations was the most important factor to predict QOL, followed by sense of competence, level of depression, level of anxiety, and educational level. “The meaningfulness of life” was predicted only by social support; “Enjoying life” was predicted by educational level, stage of cancer and time spent at leisure activity. “The satisfaction with sex life” was predicted only by “social support”. The results support the importance of participation in daily occupation as a way to improve the QOL of persons with breast cancer. Furthermore, levels of depression, level of anxiety as well as sense of competence are significant factors to be addressed. Finally, social support provides essential buffering effect on the aspect of QOL.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4442. doi:1538-7445.AM2012-4442

Activator-independent transcription of Snf1-dependent genes in mutants lacking histone tails

Transcriptional regulation of Snf1-dependent genes occurs in part by histone-acetylation-dependent binding of the transcription factor Adr1. Analysis of previously published microarray data indicated unscheduled transcription of a large number of Snf1- and Adr1-dependent genes when either the histone H3 or H4 tail was deleted. Quantitative real-time PCR confirmed that the tails were important to preserve stringent transcriptional repression of Snf1-dependent genes when glucose was present. The absence of the tails allowed Adr1 and RNA Polymerase II to bind promoters in normally inhibitory conditions. The promoters escaped glucose repression to a limited extent and the weak constitutive ADH2 transcription induced by deletion of the histone tails was transcription factor- and Snf1-independent. These effects were apparently due to a permissive chromatin structure that allowed transcription in the absence of repression mediated by the histone tails. Deleting REG1, and thus activating Snf1 in the H3 tail mutant enhanced transcription in repressing conditions, indicating that Snf1 and the H3 tail influence transcription independently. Deleting REG1 in the histone H4 tail mutant appeared to be lethal, even in the absence of Snf1, suggesting that Reg1 and the H4 tail have redundant functions that are important for cell viability.

Lasiodiplodia theobromae as a Causal Agent of Kumquat Dieback in Taiwan

Kumquat (Fortunella margarita (Lour.) Swingle) is an important citrus fruit crop of Iland County in northeastern Taiwan. Fruit produced in this area are mainly for making preserves, which is a well-known product in Taiwan. Decline of kumquat was first noticed in 1990. Since 1995, it has become an important problem affecting ≈80% of kumquat orchards. The problem was especially serious after the passage of a typhoon. Some orchards were abandoned due to death of many declining trees. Initial symptoms were yellowing and browning of leaves on some branches of affected trees. Abscission of leaves and fruits occurred, subsequently resulting in the appearance of dieback of affected branches. Disease symptoms could progress to other branches of the same tree, gummosis on the trunk, and eventually death of the tree. Previously, Phytophthora citrophthora (Smith & Smith) Leonian was reported to be a causal organism of kumquat decline (1). Recently, isolations from declining kumquat trees in several orchards failed to recover P. citrophthora and instead we isolated Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (syn. Botryodiplodia theobromae Pat.) from tissue taken from the margin of discolored bark and wood on symptomatic branches. The fungus produced grayish black colonies on V8 agar and black ostiolate pycnidia (125 to 650 μm in diameter) with ovoid to elongate conidia (20 to 32 × 12 to 16 μm) on autoclaved whole wheat grains that were placed on V8 agar. Young conidia were hyaline and nonseptate, whereas mature conidia were brown, one septate, and striate. Pathogenicity tests were carried out on healthy kumquat trees located at the Taiwan Agricultural Research Institute experimental farm. Three isolates of L. theobromae were cultured on wheat-oat medium. Colonized grains (≈5 g) were held against a wound made by lightly scrapping a branch (5 to 7 mm in diameter) 200 to 250 cm above the ground by wrapping a sheet of clear plastic around the branch (2). Eighteen branches were used for each isolate, and the same number of branches similarly inoculated with sterile grains as a control. Healthy branches inoculated with L. theobromae showed disease symptoms similar to those observed on naturally infected plants. Discoloration of leaves on inoculated branches occurred within 1 week. Subsequently, all the leaves fell and infected branches died. The numbers of inoculated branches killed by the three isolates of L. theobromae tested were 18, 9, and 14 after 1 month. All control branches remained disease free. L. theobromae was reisolated from symptomatic tissues, completing Koch's postulates. The same isolates were used to inoculate trunks of kumquat trees with the method described above. Six trunks were inoculated with each isolate, and the same number of trunks similarly inoculated with sterile grains was used as the control. Gummosis on inoculated trunks occurred in 1 week. The numbers of inoculated trunks showing gummosis induced by the three isolates of L. theobromae tested were 6, 5, and 6 after 1 month. L. theobromae was reisolated from symptomatic tissue. All control trunks remained free of gummosis. Our results show that in addition to P. citrophthora, L. theobromae can also cause a dieback on kumquat. To our knowledge, this is the first report of disease caused by L. theobromae on kumquat or on any species in the Rutaceae family in Taiwan. References: (1) P. J. Ann et al. Plant Pathol. Bull. (Taiwan) 6:198, 1997. (2) W. H. Ko et al. Plant Pathol. 35:254, 1986.

Development, Evaluation, and Application of a Primary Aerosol Model

The Segmented-Plume Primary Aerosol Model (SPPAM) has been developed over the past several years. The earlier model development goals were simply to generalize the widely used Industrial Source Complex Short-Term (ISCST) model to simulate plume transport and dispersion under light wind conditions and to handle a large number of roadway or line sources. The goals have been expanded to include development of improved algorithm for effective plume transport velocity, more accurate and efficient line and area source dispersion algorithms, and recently, a more realistic and computationally efficient algorithm for plume depletion due to particle dry deposition. A performance evaluation of the SPPAM has been carried out using the 1983 PNL dual tracer experimental data. The results show the model predictions to be in good agreement with observations in both plume advection-dispersion and particulate matter (PM) depletion by dry deposition. For PM_2.5 impact analysis, the SPPAM has been applied to the Rubidoux area of California. Emission sources included in the modeling analysis are: paved road dust, diesel vehicular exhaust, gasoline vehicular exhaust, and tire wear particles from a large number of roadways in Rubidoux and surrounding areas. For the selected modeling periods, the predicted primary PM_2.5 to primary PM10 concentration ratios for the Rubidoux sampling station are in the range of 0.39-0.46. The organic fractions of the primary PM_2.5 impacts are estimated to be at least 34-41%. Detailed modeling results indicate that the relatively high organic fractions are primarily due to the proximity of heavily traveled roadways north of the sampling station. The predictions are influenced by a number of factors; principal among them are the receptor locations relative to major roadways, the volume and composition of traffic on these roadways, and the prevailing meteorological conditions.