A computational model for the transit of a cancer cell through a constricted microchannel.

We propose a three-dimensional computational model to simulate the transient deformation of suspended cancer cells flowing through a constricted microchannel. We model the cell as a liquid droplet enclosed by a viscoelastic membrane, and its nucleus as a smaller stiffer capsule. The cell deformation and its interaction with the suspending fluid are solved through a well-tested immersed boundary lattice Boltzmann method. To identify a minimal mechanical model that can quantitatively predict the transient cell deformation in a constricted channel, we conduct extensive parametric studies of the effects of the rheology of the cell membrane, cytoplasm and nucleus and compare the results with a recent experiment conducted on human leukaemia cells. We find that excellent agreement with the experiment can be achieved by employing a viscoelastic cell membrane model with the membrane viscosity depending on its mode of deformation (shear versus elongation). The cell nucleus limits the overall deformation of the whole cell, and its effect increases with the nucleus size. The present computational model may be used to guide the design of microfluidic devices to sort cancer cells, or to inversely infer cell mechanical properties from their flow-induced deformation.

Particle trapped at the isotropic-nematic liquid crystal interface: Elastocapillary phenomena and drag forces.

We present numerical simulations of a particle trapped at the isotropic-nematic liquid crystal (Iso-N) interface. We use our recent model, based on a phase-field approach [see Qiu et al., Phys. Rev. E 103, 022706 (2021)10.1103/PhysRevE.103.022706], to couple the capillary forces acting on the interface with the elastic stresses in the nematic phase along with topological defects. A range of floating configurations are first investigated as a function of the contact angle and various anchoring conditions at the fluid interface. The results show that the response of the system is driven by the existence of an anchoring conflict at the contact line. Substantial particle displacements and/or interfacial deformations may occur in this case even for moderate anchoring strengths. These findings highlight the coupling between elastic and capillary forces. In a second part, we compute drag forces exerted on a particle that moves along the Iso-N interface for several contact angles and a moderate Ericksen number. Because of the coupling between the velocity and order parameter fields, topological defects are swept downstream of the particle by the flow and sometimes escape from the particle or merge with the interface. We also find linear force-velocity laws, with drag forces at the Iso-N interface being slightly greater than their isotropic counterparts due to director distortions. We discuss these results in light of past studies on the behavior of particles being dragged in the bulk of a liquid crystal matrix.

Particle rotation speeds up capillary interactions.

We use dynamic numerical simulations to investigate the role of particle rotation in pairwise capillary interactions of particles trapped at a fluid interface. The fluid interface is modeled with a phase-field method which is coupled to the Navier-Stokes equations to solve for the flow dynamics. Numerical solutions are found using a finite element scheme in a bounded two-dimensional geometry. The interfacial deformations are caused by the buoyant weight of the particles, which are allowed to both translate and rotate due to the capillary and viscous forces and torques at play. The results show that the capillary attraction is faster between freely rotating particles than if particle rotation is inhibited, and the higher the viscosity mismatch, the greater the effect. To explain this result, we analyze the drag force exerted on the particles and find that the translational drag force on a rotating particle is always less than its non-rotating counterpart due to attenuated velocity gradients in the vicinity of the particle. We also find that the influence of interfacial deformations on particle rotation is minute.

Large-scale preparation of Co nanoparticles as an additive in carbon fiber for microwave absorption enhancement in C band.

Recent studies have found that the core-shell structured metal nanoparticles and porous carbon nanofibers (PCNF) are combined into a microwave absorbing material through electrospinning, which exhibits excellent microwave absorption performance. In this study, the core-shell structure Co nanoparticles prepared by the self-developed HEIBE process (production rate of > 50 g/h) were combined with porous carbon fibers, and their absorbing properties were greatly improved. The morphology of Co/PCNF demonstrated that CoNPs are randomly dispersed in the porous carbon nanofibers and carbon nanofiber form complex conductive network which enhances the dielectric loss of the materials. Meanwhile, the Co/PCNF has a low graphitization and shows a significant improvement in permittivity due to the combination of CoNPs and high conductivity of carbon material. The maximum reflection loss (RL) of Co/PCNF reaches - 63.69 dB at 5.28 GHz with a thickness of 5.21 mm and the absorption bandwidth (RL ≤ - 10.0 dB) is 12.92 GHz. In terms of 5.60 mm and 6.61 mm absorber, there are two absorption peaks of - 47.64 dB and - 48.30 dB appear around 12.50 GHz and 14.10 GHz, respectively. The results presented in this paper may pave a way for promising applications of lightweight and high-efficiency microwave absorbing materials (MAMs).

[Visual outcome of cataract surgery and its influencing factors in China].

Objective: To explore the visual outcome of cataract surgery and its influencing factors in China. Methods: A case-control study. The information of 2 078 479 patients who underwent cataract extraction of 31 provinces (municipalities and autonomous regions) recorded in the National Cataract Surgery Information Reporting System during January to December, 2017 were analyzed. The postoperative visual outcomes of 3 days after surgery and 3 months after surgery were analyzed. The effects of age, gender, preoperative corrected visual acuity, past medical history, and surgical methods on the results of cataract surgery were analyzed. Surgery effect was divided into ideal effect, moderate effect and poor effect according to the best corrected visual acuity after operation. Wilcoxon rank sum test and multinomial logistic regression model were used for statistical analysis. Results: There were 1 197 942 female patients (57.64%) and 880 537 male patients (42.36%) in all 2 078 479 cases. The average age was (69±11) years old. The main type of cataract was age-related (1 928 440 cases; 92.78%). There were 1 608 385 cases, 1 126 961 cases and 389 020 cases with complete corrected visual acuity before surgery, 3 days after surgery and 3 months after surgery, respectively. The median difference of corrected visual acuity of preoperative versus three days after surgery, and preoperative versus three months after surgery were -0.48, -0.52 respectively (after logarithm of the minimum angle of resolution conversion). The interquartile ranges were 0.60 and 0.73 respectively. The differences were statistically significant (Z=551 599.30, 206 815.35; both P<0.01). Multivariate analysis showed that postoperative complications (moderate effect: OR=0.50, 95%CI: 0.46 to 0.55; ideal effect: OR=0.31, 95%CI: 0.28 to 0.33), preoperative pupil abnormal (moderate effect: OR=0.52, 95%CI: 0.44 to 0.61; ideal effect: OR=0.55, 95%CI: 0.47 to 0.63), preoperative intraocular pressure abnormalities (moderate effect: OR=0.86, 95%CI: 0.79 to 0.93; ideal effect: OR=0.45, 95%CI: 0.42 to 0.49), history of hypertension (moderate effect: OR=0.90, 95%CI: 0.85 to 0.95; ideal effect: OR=0.88, 95%CI: 0.83 to 0.93) and history of diabetes (moderate effect: OR=0.86, 95%CI: 0.80 to 0.93; ideal effect: OR=0.92, 95%CI: 0.86 to 0.99) were predictors of worse outcome. Good preoperative corrected visual acuity (0.2 to 0.4 for moderate effect: OR=2.20, 95%CI: 2.06 to 2.34; for ideal effect: OR=5.25, 95%CI: 4.94 to 5.59; 0.5 to 0.7 for moderate effect: OR=1.08, 95%CI: 0.96 to 1.21; for ideal effect: OR=6.35, 95%CI: 5.69 to 7.08; above 0.8 for moderate effect: OR=0.73, 95%CI: 0.60 to 0.89; for ideal effect: OR=6.58, 95%CI: 5.51 to 7.86), small incision extracapsular extraction (moderate effect: OR=3.19, 95%CI: 2.35 to 4.33; ideal effect: OR=6.79, 95%CI: 5.13 to 8.97) and phacoemulsification (moderate effect: OR=2.12, 95%CI: 1.60 to 2.81; ideal effect: OR=3.34, 95%CI: 2.59 to 4.32) were predictors of better outcome. Conclusions: Visual acuity of patients in China improve significantly after cataract surgery. However, some patients still suffer moderate visual impairment. The effect of surgery can be affected by many factors, such as preoperative corrected visual acuity, preoperative intraocular pressure, preoperative pupil status, surgical approach and postoperative complications, etc. (Chin J Ophthalmol, 2021, 57: 63-70).

Drag force on a particle straddling a fluid interface: Influence of interfacial deformations.

We numerically investigate the influence of interfacial deformations on the drag force exerted on a particle straddling a fluid interface. We perform finite element simulations of the two-phase flow system in a bounded two-dimensional geometry. The fluid interface is modeled with a phase-field method which is coupled to the Navier-Stokes equations to solve for the flow dynamics. The interfacial deformations are caused by the buoyant weight of the particle, which results in curved menisci. We compute drag coefficients as a function of the three-phase contact angle, the viscosity ratio of the two fluids, and the particle density. Our results show that, for some parameter values, large drag forces are not necessarily correlated with large interfacial distortions and that a lower drag may actually be achieved with non-flat interfaces rather than with unperturbed ones.

[Analysis on ophthalmic human resource allocation and service delivery at county level in Mainland China in 2014].

Objective: To master the status of ophthalmic human resource allocation and service delivery at county level in Mainland China, and to provide the basis for strengthening the construction of grassroots ophthalmic personnel team and formulating feasible medium and long-term eye health plans. Methods: All the medical institutions that provided ophthalmic service at county level or above were investigated by online reporting. This study only included medical institutions at county level. Descriptive statistics were used. Results: Three thousand three hundred and fifty-nine medical institutions were included, of which 1 463 hospitals had independent departments of ophthalmology (43.55%). Each medical institution has 3.93 ophthalmologists, 4.59 ophthalmic nurses, 0.30 full-time optometrist and 0.21 full-time optician. Ophthalmologists are mainly undergraduate, and the ratio of senior, intermediate and junior titles is 1.0∶1.7∶1.9. The ophthalmic nurses are mainly graduated from junior colleges or secondary schools, and the ratio of senior, intermediate and junior titles is 1.0∶7.3∶22.3. There were statistically differences in the distribution of job titles of ophthalmologists (χ(2)=106.21, P<0.01) and nurses (χ(2)=128.54, P<0.01) in the eastern, central and western regions. Of each ophthalmologist, the annual number of outpatient, outpatient surgery, inpatient and inpatient operation was 2 377.62, 109.79, 124.03, and 85.97 respectively. Four thousand one hundred and sixty ophthalmologists were able to carry out cataract surgeries independently, accounting for 31.50% of all ophthalmologists. The quantity for annual per capita cataract operation among ophthalmologists who can perform cataract surgery independently was 181.81 per capita. The average beds rate of utilization was 68.91%, and that was less than 60% in 52.99% of medical institutions. Conclusions: Compared with 1998, ophthalmic health personnel at county level in Mainland China has expanded rapidly. But cataract ability of ophthalmologists and the number of cataract surgeries still need to be improved. The structure of ophthalmic nursing staff is irrational. The full-time optometrists and opticians are extremely scarce. It is necessary to cultivate high-quality ophthalmic health personnel and improve beds rate of utilization at county level. (Chin J Ophthalmol, 2018, 54:929-934).

[Predictive value of typical cataplexy+ DQB1*0602 positive to hypocretin-1 reduction in cerebrospinal fluid in patients with narcolepsy].

Objective: To discusses the predictive value of typical cataplexy+ HLA-DQB1*0602 positive to hypocretin-1 (HCRT-1) reduction in cerebrospinal fluid (CSF) in patients with narcolepsy. Methods: A total of 165 narcoleptic patients, who were diagnosed at the Sleep Center of Peking University People's Hospital and Peking University International Hospital from March 2003 to March 2017, were recruited. The CSF HCRT-1 level and DQB1*0602 were measured in all the subjects. The narcoleptic patients were divided into two groups: typical cataplexy+ DQB1*0602 positive were CH group, and others who were not typical cataplexy and DQB1*0602 positive simultaneously were NCH group. The HCRT-1 level in CSF was declared to have a serious reduction when HCRT-1≤110 ng/L. According to this standard, the CH group and NCH group were subdivided into sub-groups and the data was analyzed to investigate the predictive value of typical cataplexy+ HLA-DQB1*0602 positive to HCRT-1 reduction. Results: There were 142 patients in CH group, including 137 patients with HCRT-1 reduction and 5 patients without. There were 23 patients in NCH group, including 15 patients with HCRT-1 reduction and 8 patients without. The positive predictive value of typical cataplexy+ DQB1*0602 positive for the reduction of HCRT-1 in CSF was 96.5%. Typical cataplexy+ DQB1*0602 positive had a good consistency with the HCRT-1 reduction in CSF (χ(2)=26.7, P<0.001). Conclusion: Typical cataplexy+ DQB1*0602 positive has a good predictive value to the HCRT-1 reduction in CSF in patients with narcolepsy.

[Human umbilical cord mesenchymal stem cell transplantation for the treatment of two noncontinuous segments spinal cord compression injury in rabbits].

Objective: In order to explore the effects of human umbilical cord mesenchymal stem cells (UCMSC) transplantation on the treatment of two noncontinuous segments spinal cord compression injury and to investigate whether repeated intravenous injection UCMSC was more beneficial for the recovery of spinal cord function. Methods: A total of 30 adult rabbits were randomly divided into three groups: control group (received PBS), single injection group, repeated injection group with 3 days intervals. A noncontinuous two segments SCI model was established by using the 2F Fogarty balloon catheter. Rabbits were infused with either a single total dose or three divided doses of 2×10(6) UCMSC (3 intervals) at first day post-decompreesion. Behavioral scores, somatosensory evoked potentials (SSEP) and histopathological were used to evaluate therapeutic effects. The rates of stem cell homing were studied by immunofluorescence test and the apoptosis of the spinal cord was evaluated by TUNEL test. Results: Behavior alanalyses showed that the rabbits in the UCMSC injection groups showed better motor performance than those in the control group (P<0.01), and the motor performance in the repeated transplantation group was better than that in the single transplantation group (P<0.01). The SSEP latencies were (22.53±0.75) ms, (24.52±0.45) ms and (26.31±0.69) ms in the repeated injection group, single injection group and control group (all P<0.01), respectively. Treatment with UCMSC increased ventral horn motor neurons preservation and decreased the number of TUNEL-positive cells compared with control group (P<0.01). The rates of stem cell homing in the repeated injection group was significantly higher than that in single injection group (P<0.01). Conclusion: Transplantation of UCMSC after spinal cord compression injury of two noncontinuous segments can promote functional recovery through enhancement anti-apoptotic and neuroprotective effects, and the recovery was more pronounced in the rabbits repeatedly injected at 3-day intervals.

Phylogenetic analysis of the pathogenic genus Aeromonas spp. isolated from diseased eels in China.

Analyses of 16S rRNA and housekeeping genes (HKGs) were valuated as identification markers for pathogenic Aeromonas isolated from diseased eels. The interrelationships of 32 Aeromonas strains which had been verified as pathogens to eels were studied using phylogenetic analysis with 16S rRNA and HKG sequences (cpn60, gyrB, rpoB and dnaJ) and identified by Biolog automatic microbiology analysis system (gene III). From the analysis of 5 genes, the mean gene divergences of 16S rRNA, cpn60, gyrB, rpoB and dnaJ in 32 isolates were 1.4 ± 0.2%, 7.1 ± 0.7%, 5.2 ± 0.5%, 2.2 ± 0.4% and 6.8 ± 0.5%, respectively. The results of comparative phylogeny between nucleotide based analyses (excluding the third codon position) of four HKGs with the sequences from 55 strains of Aeromonas (including 23 referenced strains of Aeromonas) showed cpn60 and dnaJ have higher discriminate power than gyrB and rpoB comparing with the taxonomical identification by Biolog system. In addition, amino acid sequences of concatenated cpn60-rpoB-gyrB is a good method for Aeromonas pathogens identification. This study showed analysis of HKG sequences can be used as an alternative method for sound identification of bacterial pathogens isolated from diseased eels in China.

[Effects of prenatal maternal seizure on hippocampal damage and cognitive deficits in offspring rats].

Objective: To observe hippocampal damage and cognitive impairment of offspring exposed to prenatal maternal seizure induced by amygdala kindling, and to explore the underlying mechanism by the detection of pathological changes of placenta. Method: Adult female SD rats were randomly divided into three groups: control group(8 rats), kindling group(12 rats) and sham group(8 rats). All the rats were allowed to mate after one week's fully kindling. The pregnant rats in kindling group received electric stimulation every 48 h. Dams were allowed to deliver naturally. Effects of maternal seizure on the number of offspring, the survival rate and body weight of pups were observed. HE staining was used to visualize histopathological changes of placenta. Morris water maze test was used to assess the cognitive function and Nissal's staining to detect hippocampal morphology of the offspring. One-way ANOVA analysis and χ2 test were used. Result: Compared with the sham group (95%(78/82)) and the control group (95%(82/86)), the survival rate of pups in kindling group(81%(66/82))was much lower (χ2=13.817, P=0.001). There were no significant differences in the number of pups per litter and pups birth-weight between kindling group and sham group or control group(F=0.312 and 0.257, P=0.736 and 0.776). HE staining showed that placental tissues from control and sham groups were normal whereas the histologic abnormalities of placentas from kindling group were characterized by thickening of the villus vascular walls, luminal stenosis, trophoblasts hyperplasia, abnormalities of trophoblasts with nuclear pyknosis and karyorrhexis and accumulation of inflammatory lymphocytes in labyrinthine zone. Nissl staining showed that neurons in hippocampus of P0(0 d after birth) and P84(84 d after birth) offspring from control and sham groups were normal, but neuronal damages were obvious in hippocampus of P0 and P84 offspring from kindling groups, and the damages in P0 pups were severe with a marked loss of neuron, shrinkage of cells and nuclear pyknosis and karyorrhexis. In the Morris water maze, compared with the sham group ((29±8), (19±9), (10±4)s) and the control group ((25±6), (17±5), (14±4)s) rats in the kindling group ((36±8), (29±8), (30±11)s) exhibited significantly longer escape latency from the 3rd, 4th, and 5th days (F=6.276, 7.518, 18.422, P=0.030, 0.003, 0.000), significant less time in the target quadrant ((27±8) vs.(58±11)and(68±13)s, F=35.993, P=0.000) and reduced number of crossing the platform ((4.4±1.7) vs. (7.2±1.6) and (8.5±1.3)times, F=18.377, P=0.000). In addition, there was no significant difference between control and sham groups(P all >0.05). Conclusion: The prenatal maternal seizures induced significant pathological damages to hippocampus and cognitive impairment of offspring. Hypoxia-ischemia of placenta might play an important role in this process.

Enteric-coated mycophenolate sodium given in combination with tacrolimus has a lower incidence of serious infections in Asian renal-transplant recipients compared with mycophenolate mofetil.

AIMS: To compare the characteristics of the enteric-coated formulation of mycophenolate sodium (EC-MPS, myfortic) and mycophenolate mofetil (MMF, CellCept) given in combination with tacrolimus in Asian renal-transplant recipients. METHODS: In a 24-month, single-centre, randomized, open-label, prospective study, 101 live-donor kidney transplant recipients were randomized to the EC-MPS (n = 50) or MMF (n = 51) group. The incidence of infection, therapeutic effect and adverse events were monitored. RESULTS: The incidences of infection were 40% and 49% for the EC-MPS and MMF groups, respectively (p = 0.362). However, serious infection was only observed in the MMF group (11.8%; p = 0.027). The incidences of gastro-intestinal adverse events (GI AEs) were 24% and 41.2% for EC-MPS and MMF, respectively (p = 0.066). However, serious diarrhoea only occurred in the MMF group (9.8%; p = 0.056). The trough level of FK 506 at the time of diarrhoea (13.22 ± 3.66 ng/ml) was significantly higher than the level within 1 month before (9.18 ± 1.12 ng/ml; p < 0.05) and 1 month after diarrhoea (9.13 ± 0.85 ng/ml; p < 0.05). The infection rate of patients with diarrhoea was significantly higher than those without diarrhoea (68%, 39%, p = 0.024). The serum creatinine level was 698 ± 60 µmol/l for EC-MPS and 673 ± 68 µmol/l for MMF from baseline (p > 0.05), and it decreased to 66 ± 6 µmol/l for EC-MPS and 69 ± 8 µmol/l for MMF at 24 months (p > 0.05). The incidences of biopsy proven acute rejection (BPAR) were 20% and 25.5% for EC-MPS and MMF, respectively (p = 0.511). CONCLUSIONS: Enteric-coated formulation of mycophenolate sodium, given in combination with tacrolimus, has a lower incidence of serious infection in Asian renal-transplant recipients compared with MMF, and the therapeutic effect of EC-MPS is similar to MMF. The clinical trial registration number is ChiCTR-IPR-14005509. The registry name is 'Effect of Enteric-coated mycophenolate sodium on posttransplant infection rate after renal transplantation compared with Mycophenolate mofetil'.

Studies on expression of p14ARF and MDM2 in human thyroid neoplasms.

AIM: We sought to evaluate the expression and clinical significance of p14ARF and MDM2 proteins in thyroid neoplasm. METHODS: Immunohistochemical streptavidin-peroxidase (S-P) method was used to detect the expression of p14ARF and MDM2 proteins in 78 cases of papillary thyroid carcinoma (PTC), 34 cases of papillary thyroid microcarcinoma (PTMC) and 45 cases of thyroid adenoma. RESULTS: The expression of p14ARF and MDM2 protein differed significantly (P<0.01) among three group. The positivity rate of p14ARF protein in PTC was significantly lower than that in thyroid adenoma (P=0.002) and PTMC (P=0.008). While the positivity rate of MDM2 protein in PTC was significantly higher than that in thyroid adenoma (P=0.000) and PTMC (P=0.009). There was a significant correlation found between the expressions of p14ARF and MDM2 proteins in PTC (P=0.013) and PTMC (P=0.012). Also, a significant correlation was found between p14ARF protein expression and lymph node metastasis in PTC (P=0.011). CONCLUSION: It was concluded that p14ARF and MDM2 proteins might be involved in the induction and development of PTC and PTMC whereas p14ARF also had diagnostic value in determining the biological behavior of PTC.

Branch Blight of Loquat Caused by Pestalotiopsis sydowiana in China.

Loquat (Eriobotrya japonica) is a subtropical tree with sour and sweet fruit and its leaf derivatives are often used to treat cough and asthma with phlegm. In 2011, a severe stem and leaf disease, with 30∼60% incidence, was observed in a local loquat cultivar "Ninghaibai" in Ninghai, Zhejiang Province, China. Infected plants exhibited brown spots on the stem and leaves, which became blackish brown to grayish white with some little sporadic black acervuli (137.9 to 189.3 µm in diameter). Leaf symptoms showed large necrotic lesions (more than 20 mm) that frequently, but not exclusively, appeared along the leaf margin or dorsal surface. Necrotic spots were water-soaked, irregularly shaped, and bordered by a tan halo. Fungal isolates were obtained by placing sterilized symptomatic tissue onto acidified potato sucrose agar (PSA) medium and consistently yielded white fungal colonies that produced acervuli (385.6 to 485.4 µm in diameter) containing black, slimy spore masses at 25°C for 7 days. Conidia (20.9 to 29.8 × 7.1 to 14.5 µm) were 5-celled and spindle shaped, and basal cells of the conidia were hyaline, while the other three middle cells were heterochrome. The upper two middle cells were darker than the lower one. The apical cell typically had 2 to 3 apical appendages, was 12.0 to 33.1 µm in length, and the basal appendage was 3.3 to 7.8 µm long. Based on these morphological features, the fungus was identified as Pestalotiopsis sydowiana (2). This characterization was further confirmed by PCR amplification and sequencing of internal transcribed spacer (ITS) of the ribosomal DNA of fungus with primers ITS1: 5'-TCCGTAGGTGAACCTGCGG-3' and ITS4: 5'-TCCTCCGCTTATTGATATGC-3' (3). A representative sequence was deposited in NCBI GenBank (Accession No. JX478272). This sequence showed 99% homology with previously deposited sequences of P. sydowiana (HQ248207.1 and FJ478105.1) from Colombia and China. Pathogenicity tests were conducted by inoculating 1-year-old seedlings and detached stems from healthy field trees of cv. Ninghaibai loquat with sclertium (20 × 5 mm) or conidial suspension (106 conidia ml-1). Control seedlings were only encircled the PSA blocks or sprayed with water. Both inoculated and control plants were covered with plastic bags at about 80% relative humidity and kept in a greenhouse at 20 to 30°C for 48 h. Detached stems were incubated to prevent desiccation in a humid chamber at 100% relative humidity and 25°C for 10 days. Four days after inoculation, lesions appeared on sclertium-inoculated seedlings or detached stems, approximately 10 days earlier than those on conidial suspension-inoculated seedlings or detached stems. Symptom observed on artificially inoculated seedlings or detached stems were similar to that observed in naturally infected plants. The control plants remained healthy. P. sydowiana was reisolated from the lesions of the infected stems and leaves but not from control leaves. It had been reported that other species of Pestalotiopsis, such as P. eriobotrifolia and P. eriobotryae-japonica, can only infect leaves of loquat (1); however, to our knowledge, this is the first report that P. sydowiana cause branch blight disease on loquat in China. References: (1) G. G. Chen et al. Acta Agric. Univ. Zhejiangensis 16:153, 1990. (2) Q. X. Ge et al. Flora Fungorum Sinicorum: Pestalotiopsis, p. 185, Science Press, Beijing, 2009. (3) T. J. White, et al. PCR Protocols: A Guide to Methods and Applications, p. 315, Academic Press, San Diego, 1990.

First Report of a Soft Rot of Philodendron 'Con-go' in China Caused by Dickeya dieffenbachiae.

Philodendron is a popular foliage plant cultivated in interiorscapes of homes, offices, and malls throughout China. A severe outbreak of a soft rot of Philodendron 'Con-go' occurred in Guangzhou, China from 2010 to 2011. The disease was characterized by leaf infections starting as pinpoint spots that are water soaked and yellow to pale brown. The lesions are sometimes surrounded by a diffuse yellow halo. When the humidity is high and temperatures are warm to hot, the spots expand rapidly, becoming slimy, irregular, and sunken with light tan centers, darker brown borders, and diffused yellow margins and may involve the entire leaf in a few days. An invasion of the midrib and larger veins by the causal bacterium often results in advancement into the petiole and stem. A survey of three areas of production of Philodendron 'Con-go' (5 ha) in Guangzhou revealed that 91% of the fields were affected at an incidence ranging from 15 to 30%. Of 41 bacterial isolates obtained from lesions, three were selected randomly for further characterization. All strains were gram negative, negative for oxidase and positive for catalase and tryptophanase (indole production), and utilized citrate, tartrate, malonate, glucose, sucrose, fructose, and maltose but not glucopyranoside, trehalose, or palatinose. Biolog analysis (version 4.20.05, Hayward, CA) identified the isolates as Pectobacterium chrysanthemi (SIM 0.804 to 0.914). According to Samson et al. (1), it was renamed as a Dickeya sp. PCR was performed on the 16S rDNA gene with primers 27f and 1495r (3) and 1,423 bp of the 16S rDNA gene (GenBank No. JN709491) showed 99% identity to P. chrysanthemi (GenBank No. AF373202), and 98% to Dickeya dieffenbachiae (GenBank No. JF311644). Additionally, the gyrB gene was amplified with primers gyrB-f1 (5'-atgtcgaattcttatgactcctc-3') and gyrB-r1 (5'-tcaratatcratattcgcygctttc-3') designed based on all the submitted gyrB gene sequences of Dickeya spp. The dnaX gene was amplified with primers dnaXf and dnaXr (2). The products were sequenced and phylogeny analyses were performed by means of MEGA 5.05. Results showed that the gyrB and the dnaX genes of the strains were 98% homologous to those of D. dieffenbachiae (GenBank Nos. JF311652 and GQ904757). Therefore, on the basis of phylogenetic trees of the 16S rDNA, gyrB, and dnaX gene sequences, the bacterial isolate named PC1 is related to D. dieffenbachiae (100% bootstrap values). Pathogenicity of each of the three strains on Philodendron 'Con-go' was confirmed by injecting 60 50-day-old seedlings each with 0.1 ml of the isolate suspension (108 CFU/ml) into the leaves. Another 60 were injected with sterile water to serve as the control treatment. Plants were enclosed in plastic bags and returned to the greenhouse under 50% shade at 32°C day and 28°C night temperatures with high humidity. After 72 h, all the injected plants started to show symptoms similar to those observed on field plants, but no symptoms appeared on the control plants. The reisolates were identical to the inoculated strains in biochemical characteristics. Bacteria characteristic of the inoculated strains were not reisolated from the control plants. To our knowledge, this is the first report of D. dieffenbachiae causing soft rot of Philodendron 'Con-go' in China. References: (1) R. Samson et al. Evol. Microbiol. 55:1415, 2005. (2) M. Slawiak et al. Eur. J. Plant Pathol. 125:245, 2009. (3) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China.

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (106 CFU/ml) on the potato slices of cultivar 'Favorita' and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China. References: (1) Y. X. Fei et al. J. Hexi Univ. 26:51, 2010.(2) B. Ma et al. Phytobacteriology 97:1150, 2007. (3) S. Nabhan et al. Plant Pathol. 61:498, 2012. (4) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

First Report of a Soft Rot of Phalaenopsis aphrodita Caused by Dickeya dieffenbachiae in China.

Phalaenopsis orchids, originally from tropical Asia, are mainly planted in Thailand, Singapore, Malaysia, the Philippines, and Taiwan and have gained popularity from consumers all over the world. The cultivation area of Phalaenopsis orchids has been rising and large-scale bases have been established in mainland China, especially South China because of suitable environmental conditions. In September 2011, a soft rot of Phalaenopsis aphrodita was found in a Phalaenopsis planting base in Guangzhou with an incidence of ~15%. Infected plants initially showed water-soaked, pale-to-dark brown pinpoint spots on leaves that were sometimes surrounded by a yellow halo. Spots expanded rapidly with rising humidity and temperatures, and in a few days, severely extended over the blade with a light tan color and darker brown border. Lesions decayed with odorous fumes and tissues collapsed with inclusions exuding. The bacterium advanced to the stem and pedicle. Finally, leaves became papery dry and the pedicles lodged. Six diseased samples were collected, and bacteria were isolated from the edge of symptomatic tissues after sterilization in 0.3% NaOCl for 10 min, rinsing in sterile water three times, and placing on nutrient agar for culture. Twelve representative isolates were selected for further characterization. All strains were gram negative, grew at 37°C, were positive for indole production, and utilized malonate, glucose, and sucrose but not glucopyranoside, trehalose, or palatinose. Biolog identification (version 4.20.05, Hayward, CA) was performed and Pectobacterium chrysanthemi (SIM 0.868) was confirmed for the tested isolates (transfer to genus Dickeya). PCR was used to amplify the 16S rDNAgene with primers 27f and 1492r, dnaX gene with primers dnaXf and dnaXr (3), and gyrB gene with primers gyrBf (5'-GAAGGYAAAVTKCATCGTCAGG-3') and gyrB-r1 (5'-TCARATATCRATATTCGCYGCTTTC-3') designed on the basis of the published gyrB gene sequences of genus Dickeya. BLASTn was performed online, and phylogeny trees (100% bootstrap values) were created by means of MEGA 5.05 for these gene sequences, respectively. Results commonly showed that the representative tested strain, PA1, was most homologous to Dickeya dieffenbachiae with 98% identity for 16S rDNA(JN940859), 97% for dnaX (JN989971), and 96% for gyrB (JN971031). Thus, we recommend calling this isolate D. dieffenbachiae PA1. Pathogenicity tests were conducted by injecting 10 P. aphrodita seedlings with 100 µl of the bacterial suspension (1 × 108 CFU/ml) and another 10 were injected with 100 µl of sterile water as controls. Plants were inoculated in a greenhouse at 28 to 32°C and 90% relative humidity. Soft rot symptoms were observed after 2 days on the inoculated plants, but not on the control ones. The bacterium was isolated from the lesions and demonstrated identity to the inoculated plant by the 16S rDNA sequence comparison. Previously, similar diseases of P. amabilis were reported in Tangshan, Jiangsu, Zhejiang, and Wuhan and causal agents were identified as Erwinia spp. (2), Pseudomonas grimontii (1), E. chrysanthemi, and E. carotovora subsp. carovora (4). To our knowledge, this is the first report of D. dieffenbachiae causing soft rot disease on P. aphrodita in China. References: (1) X. L. Chu and B. Yang. Acta Phytopathol. Sin. 40:90, 2010. (2) Y. M. Li et al. J. Beijing Agric. Coll. 19:41, 2004. (3) M. Slawiak et al. Eur. J. Plant Pathol. 125:245, 2009. (4) Z. Y. Wu et al. J. Zhejiang For. Coll. 27:635, 2010.

Nanoparticles and 3D sponge-like porous networks of manganese oxides and their microwave absorption properties.

Hydrohausmannite nanoparticles (approximately 10 nm) were prepared by the hydrothermal method at 100 degrees C for 72 h. Subsequent annealing was done in air at 400 degrees C and 800 degrees C for 10 h, Mn(3)O(4) nanoparticles (approximately 25 nm) and 3D Mn(2)O(3) porous networks were obtained, respectively. The products were characterized by XRD, TEM, SAED and FESEM. Time-dependent experiments were carried out to exhibit the formation process of the Mn(2)O(3) networks. Their microwave absorption properties were investigated by mixing the product and paraffin wax with 50 vol%. The Mn(3)O(4) nanoparticles possess excellent microwave absorbing properties with the minimum reflection loss of -27.1 dB at 3.1 GHz. In contrast, the Mn(2)O(3) networks show the weakest absorption of all samples. The absorption becomes weaker with the annealing time increasing at 800 degrees C. The attenuation of microwave can be attributed to dielectric loss and their absorption mechanism was discussed in detail.

Numerical analysis of mixing by electrothermal induced flow in microfluidic systems.

An electrothermal flow induced chaotic mixing in microfluidic systems is studied analytically and numerically. The flow is induced due to the Coulombic and dielectric forces arising from the variation of the dielectric properties with respect to the temperature in the presence of an electric field. The numerical model is validated using an analytical solution derived for basic flow patterns in a simplified geometry. The computational model has been used to illustrate the mixing in microcavity and T-sensor constructs. The simulations predict the chaotic nature of the mixing process, where the material interface evolution shows exponential growth.

Effect of standard vs extended Roux limb length on weight loss outcomes after laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Increasing the length of the Roux limb in open Roux-en-Y gastric bypass (RYGB) effectively increases excess weight loss in superobese patients with a body mass index (BMI) >50 kg/m2. Extending the RYGB limb length for obese patients with a BMI < 50 could produce similar results. The purpose of this study was to compare the outcomes of superobese patients undergoing laparoscopic RYGB with standard (< or =100-cm) with those undergoing the procedure with an extended (150-cm) Roux limb length over 1-year period of follow-up. METHODS: Retrospective data over 2.5 years were reviewed to identify patients with a BMI < 50 who underwent primary laparoscopic RYGB with 1-year follow-up ( n = 58). Forty-five patients (sRYGB group) received limb lengths < or = 100 cm, including 45 cm ( n = 1), 50 cm ( n = 2), 60 cm ( n = 6), 65 cm ( n = 1), 70 cm ( n = 1), 75 cm ( n = 3), and 100 cm ( n = 31). Thirteen patients (eRYGB group) received 150-cm limbs. Postoperative weight loss was compared at 3 weeks, 3 months, 6 months, and 1 year. RESULTS: Comparing the sRYGB vs the eRYGB group (average +/- SD), respectively: There were no significant differences in age (41.5 +/- 11.0 vs 38.0 +/- 11.9 years), preoperative weight (119.2 +/- 11.9 vs 127.8 +/- 12.5 kg), BMI (43.7 +/- 3.0 vs 45.2 +/- 3.5 kg/m2), operative time (167.1 +/- 72.7 vs 156.5 +/- 62.4 min), estimated blood loss (129.9 +/- 101.1 vs 166.8 +/- 127.3 cc), or length of stay (median, 3 vs 3 days; range, 2-18 vs 3-19). Body weight decreased over time in both groups, except in the sRYGB group between 3 and 6 months and 6 and 12 months after surgery and in the eRYGB group between 6 and 12 months. BMI also decreased over time, except in the eRYGB group between 6 and 12 months. Absolute weight loss leveled out between 6 and 12 months in both groups, with no increase after 6 months. Percent of excess weight loss did not increase in the eRYGB group after 6 months. An extended Roux limb did not significantly affect body weight, BMI, absolute weight loss, or precent of excess weight loss at any time point when the two groups were compared. A trend toward an increased proportion of patients with >50% excess weight loss ( p = 0.07) was observed in the extended Roux limb group. CONCLUSIONS: In this series, no difference in weight loss outcome variables were observed up to 1 year after laparoscopic RYGB. Thus, extending Roux limb length from < or =100 cm to 150 cm did not significantly improve weight loss outcome in patients with a BMI < 50 kg/m2.