[Analysis of the clinical predictive value of lactate on the prognosis of patients with acute-on-chronic liver failure combined with infection].

Objective: To explore the predictive value of lactic acid for the adverse prognostic outcomes in patients with acute-on-chronic liver failure combined with infection. Methods: A retrospective analysis was conducted on the clinical data of 208 cases of ACLF combined with infection who were hospitalized from January 2014 to March 2016. Patients were divided into a survival group (n = 83) and a mortality group (n = 125) according to the results of a 90-day follow-up. The clinical data were statistically analyzed between the two groups. Multivariate logistic regression with two categorical variables was used to analyze the independent risk factors for 90-day disease mortality and establish a new prediction model. The receiver operating characteristic curve (ROC curve) was used to evaluate the predictive value of lactic acid, the MELD score, the MELD-Na score, lactic acid combined with the MELD score, lactic acid combined with the MELD-Na score, and the new model. Results: The 90-day mortality rate of 208 cases of ACLF combined with infection was 60.1%. There were statistically significant differences in white blood cell count, neutrophil count, total bilirubin (TBil), serum creatinine (Cr), blood urea nitrogen (BUN), blood ammonia, the international normalized ratio (INR), lactic acid (LAC), procalcitonin, the MELD score, the MELD-Na score, hepatic encephalopathy (HE), acute kidney injury (AKI), and bleeding between the two groups. Multivariate logistic regression analysis showed that TBil, INR, LAC, HE, and bleeding were independent risk factors for 90-day mortality in patients with ACLF combined with infection. After the establishment of MELD-LAC, MELD-Na-LAC, and a new prediction model, the ROC curve revealed that the AUC (95% confidence interval) of MELD-LAC and MELD-Na LAC were 0.819 (0.759 ~ 0.870) and 0.838 (0.780 ~ 0.886), respectively, and was superior than the MELD score [0.766 (0.702 ~ 0.823)] and MELD-Na score [0.788 (0.726 ~ 0.843)], with P < 0.05, while the new model had an AUC of 0.924, the sensitivity of 83.9%, specificity of 89.9%, and accuracy of 87.8%, which was higher than LAC, MELD score, MELD-Na score, MELD-LAC, and MELD-Na-LAC (P < 0.01). Conclusion: Lactic acid is an independent risk factor for mortality in patients with ACLF combined with infection, and it improves the clinical predictive value of MELD and MELD-Na for the prognosis of mortality.

[Progress on epidemiological characteristics and interventions of pedestrian distraction].

Pedestrian distraction is one of the important risk factors of road injury. This review summarized the epidemiological characteristics, influencing factors, safety implications, and the published intervention measures. The review found that: a) the prevalence of pedestrian distraction poses a serious threat to pedestrian safety, but most epidemiological studies on pedestrian distraction focus on mobile phone use, and the incidence of pedestrian distraction varied greatly across studies using various research methods and from different countries; b) demographic characteristics, social psychology, and environment are the three main influencing factors of pedestrian distraction; c) distraction differently affected physiology, cognition, motion control, efficiency and behavior of pedestrian's street-crossing to some degrees, threatening the safety of pedestrian; d) engineering interventions and education were the most common interventions to prevent pedestrian distraction currently, but the effectiveness of most measures was not assessed rigorously. In the future, multidisciplinary and systematic epidemiological studies are recommended to design interventions purposely and evaluate the effectiveness of interventions through rigorous designs, providing scientific evidence for reducing pedestrian distraction and improving road safety of pedestrians.

[Progress in cohort studies related to injury].

Objective: To summarize the progress of injury cohort studies over the world. Methods: Relevant information of injury cohort publications published before December 2017 were retrieved from PubMed, WanFang and China National Knowledge Infrastructure (CNKI) databases, consisting of the starting year, category of injury, study population, sample size, countries, follow-up duration, main exposure variables, outcome variables and method of data collection, and statistical methods. Results: A total of 295 studies were included in the analysis. The overall number of injury cohort studies increased with a peak in 2000, and then decreased. The top three countries that most frequently published cohort studies were the United States (52), Sweden (46) and the United Kingdom (37). A total of 29 published injury cohorts were identified in China, about 3, 23 and 3 cohort studies from the mainland of China, Taiwan Province, and Hong Kong Specific Administrative Region, respectively. The majority of cohort studies involved a single injury cause (93.6%); the most common injury causes included suicide/self-harm (46.1%), falls (17.3%) and road traffic injuries (14.6%). For the published cohort studies, exposure variables and outcome events varied with injury causes, primarily being collected through data registration system, national survey data, questionnaire survey, telephone interviews, and other means. Conclusion: A number of injury cohorts have been established worldwide, and few in the mainland of China. The existed cohort studies could offer important references for the design of large-scale, multi-center and high-quality injury cohort in China in the future.

[Review on the progress regarding the intervention mapping protocol].

Along with the significant development on both theory and practice of health promotion programs, the application of behavioral and social science theories has also been advanced in the fields of design and evaluation regarding the intervention-related studies. Intervention mapping is a new planning protocol, efficiently used to develop, implement, and evaluate health promotion related intervention programs. In this article, we are briefly introducing the basic concepts, implementation steps, specific requirements, as well as reviewing the current progress in methodologies, application that are related to intervention mapping, so as to provide reference for health intervention research studies, domestically.

[Change of prognosis and pathogens in adult patients with severe community-acquired pneumonia during different periods].

Objective: To compare the change of prognosis and pathogens of adult patients with severe community-acquired pneumonia (CAP) requiring admission to Respiratory Intensive Care Unit (RICU) during different period, and estimate the risk factors of severe CAP. Methods: The clinical data of 186 patients with severe CAP admission to RICU was collected and assessed the trend in outcomes of these patients during three time periods: Period Ⅰ (January 1 2000 to October 31 2006), Period Ⅱ (November 1 2006 to December 31 2010), and Period Ⅲ (January 1 2011 to December 31 2015), analyzed the risk factors by Cox Proportional Hazards regression, and compared the pathogens detection. Results: The total mortality was 34.9%(65/186)during 16 years, three periods was 41.4%, 35.3% and 27.7% respectively.After adjustment for other variables, the mortality was significant higher for patients admitted during Period Ⅰ than that of Period Ⅲ (HR: 1.900; 95.0%CI 1.053-3.429, P=0.033), and no significant difference for Period Ⅰ compared with Period Ⅱ (HR: 1.394; 95.0%CI 0.774-2.514, P=0.269), Period Ⅱ compared with Period Ⅲ(HR: 1.379; 95.0%CI 0.800-2.375, P=0.248). Cox regression analysis showed the predicting risk factors for prognosis including BUN≥7.14 mmol/L, acute heart failure, acute renal failure, multilobar infiltrates and septic infectious shock ( P<0.05). Multi-variate Cox regression analysis showed that multilobar infiltrates(HR=3.951, 95.0%CI 2.252-6.929, P=0.001) and septic infectious shock(HR=2.044, 95.0%CI 1.131-3.692, P=0.018) were the independent risk factors for prognosis.104 (55.9%) were detected pathogens in 186 patients.The common pathogens were Staphylococcus aureus (18 isolated strains), Legionella pneumophila (16 isolated strains), Streptococcus pneumonia (13 isolated strains). There was no significant difference between bacterial isolation except virus detection(P=0.033). Conclusion: There has been an improvement in the prognosis of severe CAP.Multilobar infiltrates and septic infectious shock were the independent risk factors for prognosis.Pathogens had changed in SCAP over time, and the detection rate of virus increased gradually.

[An investigation of normal urinary manganese value in healthy adults in different places in Guangxi, China].

Objective: To investigate the normal urinary manganese value in healthy adults in Guangxi, China and its distribution characteristics. Methods: From 2015 to 2016, stratified random sampling based on age and sex was performed to select 1533 healthy adults aged 18-60 years in Nanning,Liuzhou,Guilin,Hezhou,Wuzhou,Yulin,Guigang,Beihai,Qinzhou,Laibin,Hechi Nandan,Bose Jingxi,Chongzuo Daxin,and Fangchenggang.All of them had no history of occupational manganese exposure or acute or chronic liver/renal diseases and had lived in the local area for more than one year. A total of 1417 urine samples with normal specific gravity and complete data were obtained, and graphite furnace atomic absorption spectrometry was used to measure urinary manganese.The distribution characteristics of urinary manganese level were analyzed among adults with different ages,sexes,or presence or absence of smoking habits or among those who lived or did not live in the mining area. Results: The geometric mean of urinary manganese among healthy adults in Guangxi was 0.52 µg/L,and the upper limit of normal was 5.68µg/L. There was no significant difference in urinary manganese level between the healthy adults with different ages, sexes,or presence or absence of smoking habits (P>0.05).The healthy adults who lived in the mining area of nonferrous metal mines had a significantly higher geometric mean of urinary manganese than those who did not live in such areas(1.65µg/Lvs0.34µg/L,P<0.01). Conclusion: The upper limit of normal of urinary manganese is 5.68 µg/L among healthy adults in Guangxi,and the healthy adults who live in the mining area of manganese mine or nonferrous metal mines have a significantly higher urinary manganese level than those who do not live in such areas.

[Investigation on the normal value of urinary arsenic in healthy people in different areas of Guangxi, China].

Objective: To investigate the upper limit of the normal value of arsenic in healthy adult population in different areas of Guangxi. Methods: From 2015 to 2016, 1533 subjects from 14 counties and cities in Guangxi were collected by age, gender, stratified random sampling and questionnaire survey. 1417 urine samples with satisfactory urine quality and complete information were collected.The content of arsenic in urine was determined by atomic fluorescence spectrometry. Results: The upper limit of normal arsenic in healthy adults in guangxi was 0.053 mg/L. Male urinary arsenicP(50)(0.011mg/L)was higher than that of the female(0.008mg/L), the difference was statistically significant(Z=5.352,P<0.01). Smoking urinary arsenicP(50)(0.012mg/L) was higher than that of nonsmokers(0.009mg/L), the difference was statistically significant(Z=3.404,P<0.01). GroupP(5)0 urine arsenic in coastal areas(0.012mg/L) the crowd was higher than that in non coastal areas(0.009mg/L), the difference was statistically significant(Z=-7.522,P<0.01). Conclusion: The upper limit of normal arsenic in healthy adults in Guangxi area is 0.053mg/L,and there are differences in the levels of arsenic in healthy adults, such as different genders and regions.

[Progress in research of mobile health intervention].

With the rapid development of mobile communication technology and the growing popularity of smartphones worldwide, mobile health has become an extension of e-Health and Tele-Health, and is of value in the research and practice of public health. In this paper, we systematically assessed research literature of mobile health' s application on disease prevention and control as well as health promotion. Based on the characteristics of current literature, this paper focused on the application of mobile health in maternal health promotion, chronic disease management, and communicable disease prevention and control to provide reference for the mobile health intervention research in China.

[Study of the clinical phenotype of symptomatic chronic airways disease by hierarchical cluster analysis and two-step cluster analyses].

OBJECTIVE: To study the distinct clinical phenotype of chronic airway diseases by hierarchical cluster analysis and two-step cluster analysis. METHODS: A population sample of adult patients in Donghuamen community, Dongcheng district and Qinghe community, Haidian district, Beijing from April 2012 to January 2015, who had wheeze within the last 12 months, underwent detailed investigation, including a clinical questionnaire, pulmonary function tests, total serum IgE levels, blood eosinophil level and a peak flow diary. Nine variables were chosen as evaluating parameters, including pre-salbutamol forced expired volume in one second(FEV1)/forced vital capacity(FVC) ratio, pre-salbutamol FEV1, percentage of post-salbutamol change in FEV1, residual capacity, diffusing capacity of the lung for carbon monoxide/alveolar volume adjusted for haemoglobin level, peak expiratory flow(PEF) variability, serum IgE level, cumulative tobacco cigarette consumption (pack-years) and respiratory symptoms (cough and expectoration). Subjects' different clinical phenotype by hierarchical cluster analysis and two-step cluster analysis was identified. RESULTS: (1) Four clusters were identified by hierarchical cluster analysis. Cluster 1 was chronic bronchitis in smokers with normal pulmonary function. Cluster 2 was chronic bronchitis or mild chronic obstructive pulmonary disease (COPD) patients with mild airflow limitation. Cluster 3 included COPD patients with heavy smoking, poor quality of life and severe airflow limitation. Cluster 4 recognized atopic patients with mild airflow limitation, elevated serum IgE and clinical features of asthma. Significant differences were revealed regarding pre-salbutamol FEV1/FVC%, pre-salbutamol FEV1% pred, post-salbutamol change in FEV1%, maximal mid-expiratory flow curve(MMEF)% pred, carbon monoxide diffusing capacity per liter of alveolar(DLCO)/(VA)% pred, residual volume(RV)% pred, total serum IgE level, smoking history (pack-years), St.George's respiratory questionnaire(SGRQ) score, acute exacerbation in the past one year, PEF variability and allergic dermatitis (P<0.05). (2) Four clusters were also identified by two-step cluster analysis as followings, cluster 1, COPD patients with moderate to severe airflow limitation; cluster 2, asthma and COPD patients with heavy smoking, airflow limitation and increased airways reversibility; cluster 3, patients having less smoking and normal pulmonary function with wheezing but no chronic cough; cluster 4, chronic bronchitis patients with normal pulmonary function and chronic cough. Significant differences were revealed regarding gender distribution, respiratory symptoms, pre-salbutamol FEV1/FVC%, pre-salbutamol FEV1% pred, post-salbutamol change in FEV1%, MMEF% pred, DLCO/VA% pred, RV% pred, PEF variability, total serum IgE level, cumulative tobacco cigarette consumption (pack-years), and SGRQ score (P<0.05). CONCLUSION: By different cluster analyses, distinct clinical phenotypes of chronic airway diseases are identified. Thus, individualized treatments may guide doctors to provide based on different phenotypes.

Tetrandrine induces microRNA differential expression in human hypertrophic scar fibroblasts in vitro.

MicroRNAs (miRNAs) have recently been shown to play a role in normal wound healing process. miRNAs may be linked to pathologic wound healing and closely related to the formation of hypertrophic scars. This study aimed to explore the effects of tetrandrine on the miRNA expression profile in human hypertrophic scar fibroblasts (HSFs) in vitro. HSFs were randomly divided into two groups: the tetrandrine treatment group and the control group. The experimental and control groups were collected and analyzed by miRNA array after a 48-h culture. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to confirm the array results. The targets of differentially expressed miRNA were functionally annotated using bioinformatic approaches. miRNA microarray analysis identified 193 differentially expressed miRNAs and the expression of 186 miRNAs in the experimental group decreased while that of 7 miRNAs increased compared to the control group. The most significantly downregulated miRNA was hsa-miR-1246, and hsa-miR-27b had the highest expression level. Significant differentially expressed miRNAs were predicted to be related to several important signaling pathways related to scar wound healing. The differential miRNA expression identified in this study provides the experimental basis for further understanding the anti-fibrosis effect of tetrandrine.

First Report of Leaf Spot Disease Caused by Glomerella magna on Lobelia chinensis in China.

Lobelia chinensis is a perennial herbaceous plant in the family Campanulaceae that is native to China, where it grows well in moist to wet soils. It is commonly used as a Chinese herbal medicine. In May 2012, symptoms of leaf spot were observed on leaves of L. chinensis in Nanning, Guangxi Zhuang Autonomous Region, China. The leaf lesions began as small, water-soaked, pale greenish to grayish spots, which enlarged to gray to pale yellowish spots, 4 to 6 mm in diameter. At later stages, numerous acervuli appeared on the lesions. Acervuli were mostly epiphyllous, and 40 to 196 µm in diameter. On potato dextrose agar (PDA), a fungus was consistently recovered from symptomatic leaf samples, with a 93% isolation rate from 60 leaf pieces that were surface sterilized in 75% ethanol for 30 s and then in 0.1% mercuric chloride for 45 s. Three single-spore isolates were used to evaluate cultural and morphological characteristics of the pathogen. Setae were two to three septate, dark brown at the base, acicular, and up to 90 µm long. Conidia were long oblong-elliptical, guttulate, hyaline, and 11 to 20 × 4.1 to 6.3 µm (mean 15.2 × 5.1 µm). These morphological characteristics of the fungus were consistent with the description of Colletotrichum magna (teleomorph Glomerella magna Jenkins & Winstead) (1). The rDNA internal transcribed spacer (ITS) region of one isolate, LC-1, was sequenced (GenBank Accession No. KC815123), and it showed 100% identity to G. magna, GenBank HM163187.1, an isolate from Brazil cultured from papaya (2). Although KC815123 was identified as G. magna, it shows 99% identity to GenBank sequences from isolates of C. magna, and more research is needed to elucidate the relationships between these taxa, especially with consideration to host specificity. Pathogenicity tests were performed with each of the three isolates by spraying conidial suspensions (1 × 106 conidia/ml) containing 0.1% Tween 20 onto the surfaces of leaves of 30-day-old and 6- to 8-cm-high plants. For each isolate, 30 leaves from five replicate plants were treated. Control plants were treated with sterilized water containing 0.1% Tween 20. All plants were incubated for 36 h at 25°C and 90% relative humidity in an artificial climate chamber, and then moved into a greenhouse. Seven days after inoculation, gray spots typical of field symptoms were observed on all inoculated leaves, but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of G. magna from diseased leaves. To our knowledge, this is the first report of G. magna infecting L. chinensis worldwide. References: (1) M. Z. Du et al. Mycologia 97:641, 2005. (2) R. J. Nascimento et al. Plant Dis. 94:1506, 2010.

First Report of Leaf Spot Caused by Corynespora cassiicola on Baphicacanthus cusia in China.

Baphicacanthus cusia is a perennial herbaceous plant in the family Acanthaceae that is native to China, where it grows in warm temperate mountainous or hilly regions. It is commonly used as a Chinese herbal medicine. In March 2012, symptoms of leaf spot were observed on leaves of B. cusia in Long'an County, Guangxi, China, where this plant is extensively cultivated. Symptoms were initially small brown dots which developed into irregular to circular leaf spots. These spots enlarged and overlapped, extending until the 7- to 9-cm-long and 3- to 4-cm-wide leaves withered entirely, mostly within 2 months. On potato dextrose agar (PDA), the same fungus was cultured from 92% of 75 symptomatic leaf samples that had been surface sterilized in a 45-second dip in 0.1% mercuric chloride. Fungal structures were observed on diseased leaves: conidiophores (85 to 460 × 4 to 8 µm) were erect, brown, single or in clusters, and conidia (36 to 90 × 5 to 16 µm) were single or in chains of two to four, brown, cylindrical or obclavate, straight or slightly curved, with 3 to 18 pseudosepta and a conspicuous hilum. Three single-spore isolates were identified as Corynespora cassiicola (Berk & Curt.) Wei based on morphological and cultural characteristics (1). The rDNA internal transcribed spacer (ITS) region of one isolate, ZY-1, was sequenced (GenBank Accession No. JX908713), and it showed 100% identity to C. cassiicola, GenBank FJ852716, an isolate from Micronesia cultured from Ipomoea batatas (2). Pathogenicity tests were performed with each of the three isolates by spraying conidial suspensions (5 × 104 conidia/ml) containing 0.1% Tween 20 onto the surfaces of leaves of 60-day-old, 20-cm tall plants. For each isolate, 30 leaves from five replicate plants were treated. Control plants were treated with sterilized water containing 0.1% Tween 20. All plants were incubated for 36 h at 25°C and 90% relative humidity in an artificial climate chamber, and then moved into a greenhouse. Seven days after inoculation, dark brown spots typical of field symptoms were observed on all inoculated leaves, but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of C. cassiicola from diseased leaves. To our knowledge, this is the first report of C. cassiicola infecting B. cusia worldwide. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute: Kew, Surrey, England, 1971. (2) L. J. Dixon et al. Phytopathology 99:1015, 2009.

An Outbreak of Gummosis of Mango Trees Caused by Lasiodiplodia theobromae in Guangxi, South China.

Mango (Mangifera indica L.) is an economically important fruit in southern provinces of China. In May 2012, field surveys including 2,250 mango trees were done in nine orchards of five different counties in Guangxi Province. An outbreak of gummosis was observed in the province involving over 30,000 ha with an average of 50% disease incidence (DI) and a maximum of 70% in some orchards. Until then, gummosis had been considered a common but not serious disease. In 2012, high temperatures in April and extensive rain in May favored increased disease development. Infected plants showed abundant gum secretion from branches, stems, and main trunks. Some branches died from the disease. During the early stages of infection, branches or stems turned brown followed by xylem necrosis and exudation of a milky sap. The sap turned yellow and finally formed amber gum within several days. Initially, the gum appeared as small droplets, increasing in number, and covering most of the branches and the trunk with bark cracking under severe conditions. On potato dextrose agar (PDA), isolates with similar morphology were consistently recovered from symptomatic plant tissues after surface sterilization in 75% ethanol for 30 seconds and then in 0.1% mercuric chloride for 1 min. Five single-spore isolates from five different locations in Guangxi Province were used to evaluate characteristics of the pathogen. On PDA, cultures were gray with an irregularly distributed, fast-growing, and fluffy aerial mycelium, showing a dark underside as the colony changed from greenish to black after 5 days at 28°C. After 1 month, cultures produced globose pycnidia. Conidia were elliptical and hyaline when immature, becoming dark brown and one-septate, longitudinally striate when mature, and ranged from 20.0 to 28.0 × 10.5 to 16.0 µm (average 23.3 × 13.7 µm). Paraphyses produced within the tissues of pycnidia were hyaline, cylindrical, nonseptate, and up to 61 µm long. The fungus was identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (=Botryosphaeria rhodina (Cooke) Arx) based on morphological and cultural characteristics (1,2). The rDNA internal transcribed spacer region of one isolate showed 100% identity to L. theobromae (GenBank HM346876.2) and was deposited in GenBank (JX982240). Pathogenicity of the five isolates was tested in the field on healthy tissues in June 2012. Five green twigs and five 3-year-old branches were used. Three wounds were made on each twig or branch with a sterilized needle. Mycelial plugs were placed on wounds and covered with Parafilm. Uncolonized PDA plugs were used as controls. Two weeks later, typical brown lesions were observed on inoculated branches, and gum exuded from infected wounds. No symptoms were seen on the controls. Koch's postulates were fulfilled by reisolation of L. theobromae from diseased branches. L. theobromae is well documented as a pathogen of mango. In China, the disease was observed in the 1990s in Hainan Province, and the causal agents were identified as L. theobromae and Colletotrichum gloeosporioides Penz. & Sacc based on morphological observation (3). To our knowledge, this is the most severe outbreak reported from China. References: (1) V. S. de Oliveira Costa et al. Eur. J. Plant Pathol. 127:509, 2010. (2) F. Wang et al. Plant Dis. 95:1378, 2011. (3) Q. C. Xiao et al. Tropical Crops Research (in Chinese) 2:25, 1995.

Short communication: evaluation of Brucella infection of cows by PCR detection of Brucella DNA in raw milk.

The collection of serum samples from cows is frequently difficult to implement in large-scale surveys, and may involve a high risk of occupational infection. This study assessed the potential of using raw milk sampling as a suitable method for use in a pilot survey of Brucella abortus infection status in cattle. Raw milk samples from 816 cows were examined. Polymerase chain reaction assays of raw milk, with primers derived from the IS711 element of the Brucella genome, were used. Of the cows, 55 were Brucella positive based on serum agglutination test (SAT) results. Polymerase chain reaction amplified Brucella DNA in 25 (45%) of the 55 SAT-positive cows. All of the 689 SAT-negative cows were found to be negative in PCR assays of their milk. Brucella infection status based on PCR results was then predicted for 72 cows from private h erds in which the brucellosis status was unknown. Subsequently, SAT verification of Brucella status was performed. There was no significant difference between predicted and actual SAT-positive rates in those 72 cows. This study indicates a relationship between Brucella detection levels obtained using milk-based PCR results and SAT results. The specific, rapid, and easy sampling procedure within milk-based PCR assaying for brucellosis detection makes the milk PCR method an attractive alternative for evaluation of B. abortus infection in cows, particularly if used as a routine screening and surveillance tool to reduce brucellosis outbreaks.

Compact grating interferometer for producing photoresist gratings with incoherent light.

An achromatic interferometer was developed to produce 1200-lines/mm crossed-line photoresist gratings with a mercury arc light source. It is a compact reflection system of outstanding stability. Alignment procedures are described. The most stringent requirement, coplanar alignment of two folding gratings, was accomplished with the aid of a Twyman-Green interferometer. The grating interferometer produced crossed-line photoresist gratings with first-order diffraction efficiency exceeding 20%.