bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of precipitation on soil respiration and its temperature/moisture sensitivity in three subtropical forests in Southern China
Authors: Jiang H. , Deng Q. , Zhou G. , Hui D. , Zhang D. , Liu S. , Chu G. , Li J.
Published: November 2012

Abstract. Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in Southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation (Abbr. EP, DP and AP, respectively) – in three subtropical forests in Southern China. The three forests include Masson pine forest (PF), coniferous and broadleaved mixed forest (MF) and monsoon evergreen broadleaved forest (BF). Our observations showed that altered precipitation can strongly influence soil respiration, not only through the well-known direct effects of soil moisture, but also by modification on both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity in the three forests showed rising trends with precipitation increase, and its moisture sensitivity showed an opposite trend. In the wet season, the EP treatment also decreased soil respiration and its temperature sensitivity, and enhanced moisture sensitivity in all three forests. Soil respiration under the DP treatment increased significantly in the PF only, and no significant change was found for either moisture or temperature sensitivity. However, the DP treatment in the MF and BF reduced temperature sensitivity significantly. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF.
On the origin of multi-decadal to centennial Greenland temperature anomalies over the past 800 yr
Authors: Kobashi T. , Shindell D. T. , Kodera K. , Box J. E. , Nakaegawa T. , Kawamura K.
Published: November 2012

Abstract. The surface temperature of the Greenland ice sheet is among the most important climate variables for assessing how climate change may impact human societies associated with accelerating sea level rise. However, the causes of multi-decadal-to-centennial temperature changes in Greenland are not well understood, largely owing to short observational records. To examine the causes of the Greenland temperature variability, we calculated the Greenland temperature anomalies (GTA(G-NH)) over the past 800 yr by subtracting the standardised NH temperature from the standardised Greenland temperature. It decomposes the Greenland temperature variation into background climate (NH); Polar amplification; and Regional variability (GTA(G-NH)). The Central Greenland polar amplification factor as expressed by the variance ratio = Greenland/NH is 2.6 over the past 161 yr, and 3.3–4.2 over the past 800 yr. The GTA explains 31–35% of the variation of Greenland temperature in the multi-decadal-to-centennial time scale over the past 800 yr. Another orthogonal component of the Greenland and NH temperatures, GTP(G+NH) (Greenland temperature plus = standardized Greenland temperature + standardized NH temperature) exhibited the multi-decadal variations that were likely induced by large volcanic eruptions, increasing greenhouse gasses, and internal variation of climate. We found that the GTA(G-NH) has been influenced by solar-induced changes in atmospheric circulation patterns such as those produced by North Atlantic Oscillation/Arctic Oscillation (NAO/AO). Climate modelling indicates that the anomaly is also likely linked to solar-paced changes in the Atlantic meridional overturning circulation (AMOC) and to associated changes in northward oceanic heat transport.
Reconnection current sheet structure in a turbulent medium
Authors: Vishniac E. T. , Pillsworth S. , Eyink G. , Kowal G. , Lazarian A. , Murray S.
Published: November 2012

Abstract. In the presence of turbulence, magnetic field lines lose their dynamical identity and particles entrained on field lines diffuse through space at a rate determined by the amplitude of the turbulence. In previous work (Lazarian and Vishniac, 1999; Kowal et al., 2009; Eyink et al., 2011) we showed that this leads to reconnection speeds which are independent of resistivity. In particular, in Kowal et al. (2009) we showed that numerical simulations were consistent with the predictions of this model. Here we examine the structure of the current sheet in simulations of turbulent reconnection. Laminar flows consistent with the Sweet-Parker reconnection model produce very thin and well ordered currents sheets. On the other hand, the simulations of Kowal et al. (2009) show a strongly disordered state even for relatively low levels of turbulence. Comparing data cubes with and without reconnection, we find that large scale field reversals are the cumulative effect of many individual eddies, each of which has magnetic properties which are not very different from turbulent eddies in a homogeneous background. This implies that the properties of stationary and homogeneous MHD turbulence are a reasonable guide to understanding turbulence during large scale magnetic reconnection events. In addition, dissipation and high energy particle acceleration during reconnection events take place over a macroscopic volume, rather than being confined to a narrow zone whose properties depend on microscopic transport coefficients.
Cataracts and Dupuytren Disease: A Case Report and Review of the Literature
Authors: Cutolo Carlo A. , Lombardo Sara , Vercellin Alice C. Verticchio , Bertone Chiara , De Amici Mara , Antoniazzi Elena , Milano Giovanni
Published: November 2012

Purpose.

Dupuytren disease is an inherited proliferative and progressive connective disease. Ectopic disease may, however, be located distant from the palmar fascia.

Methods.

Case report and review of the literature.

Results.

We describe a case of symmetric bilateral posterior subcapsular cataracts associated with symmetric bilateral Dupuytren disease and symmetric bilateral Ledderhose disease in a 56-year-old Caucasian man. His medical history was negative for glucocorticoids intake, diabetes, and exposure to radiation. Serum transforming growth factor β (TGF-β)1 concentration has been evaluated and was found to be almost double compared to the controls.

Conclusions.

We speculate that the TGF-β plays an important role for ocular and connective tissue disorders.
Mixture of Ether and Silicone Oil for the Treatment of Inferior Complicated Retinal Detachment
Authors: Romano Mario R. , Zenoni Stefano , Arpa Paolo , Mariotti Cesare
Published: November 2012

Purpose.

To report the efficacy and ocular tolerance of a new tamponade made with ether and silicone oil (HeavySil [HSIL]) for the treatment of retinal detachment (RD) complicated by inferior proliferative vitreous retinopathy (PVR).

Methods.

Prospective noncomparative interventional study on 31 consecutive eyes that underwent pars plana vitrectomy and were treated with HSIL as an intraocular tamponade. All patients presented with at least one retinal break and grade B–C PVR located between 4 and 8 o'clock. The main endpoint criteria were retinal reattachment after the removal of HSIL and complications arisen from the use of this tamponade.

Results.

Primary anatomic success was achieved in 27 out of 31 cases. Mean visual acuity improved from logMAR 1.4 (SD 0.7) to logMAR 1.1 (SD 0.6) (p=0.02). The main complications reported were cataract formation (5 out of 7 phakic eyes cases), clinically visible emulsification (6 cases), and difficulty of oil removal in 3 cases. Severe intraocular inflammation with HSIL in situ was found in only one case.

Conclusions.

HeavySil, a saturated solution of ether with silicone oil, is a safe and effective tamponade agent for the treatment of complicated RD. The most common complications are cataract formation and oil emulsification.
Performance Analysis of a Neuro-PID Controller Applied to a Robot Manipulator
Authors: Pezeshki Saeed , Badalkhani Sajad , Javadi Ali
Published: November 2012

The performance of robot manipulators with nonadaptive controllers might degrade significantly due to the open loop unstable system and the effect of some uncertainties on the robot model or environment. A novel Neural Network PID controller (NNP) is proposed in order to improve the system performance and its robustness. The Neural Network (NN) technique is applied to compensate for the effect of the uncertainties of the robot model. With the NN compensator introduced, the system errors and the NN weights with large dispersion are guaranteed to be bounded in the Lyapunov sense. The weights of the NN compensator are adaptively tuned.

The simulation results show the effectiveness of the model validation approach and its efficiency to guarantee a stable and accurate trajectory tracking process in the presence of uncertainties.
An Evolutionary Computational Approach to Humanoid Motion Planning
Authors: Hettiarachchi Dhammika Suresh , Iba Hitoshi
Published: November 2012

The theme of our work is centred on humanoid motion planning and balancing using evolutionary computational techniques. Evolutionary techniques, inspired by the Darwinian evolution of biological systems, make use of the concept of the iterative progress of a population of solutions with the aim of finding an optimally fit solution to a given problem. The problem we address here is that of asymmetric motion generation for humanoids, with the aim of automatically developing a series of motions to resemble certain predefined postures. An acceptable trajectory and stability is of the utmost concern in our work. In developing these motions, we are utilizing genetic algorithms coupled with heuristic knowledge of the problem domain. Unlike other types of robots, humanoids are complex in both construction and operation due to their myriad degrees of freedom and the difficulty of balancing on one or more limbs. The work presented in this paper includes the adopted methodology, experimental setup, results and an analysis of the outcome of a series of evolutionary experiments conducted for generating the said asymmetric motions.
Power Saving MAC Protocols for WSNs and Optimization of S-MAC Protocol
Authors: Kaur Simarpreet , Mahajan Leena
Published: November 2012

Low power MAC protocols have received a lot of consideration in the last few years because of their influence on the lifetime of wireless sensor networks. Since, sensors typically operate on batteries, replacement of which is often difficult. A lot of work has been done to minimize the energy expenditure and prolong the sensor lifetime through energy efficient designs, across layers. Meanwhile, the sensor network should be able to maintain a certain throughput in order to fulfill the QoS requirements of the end user, and to ensure the constancy of the network. This paper introduces different types of MAC protocols used for WSNs and proposes S-MAC, a Medium-Access Control protocol designed for Wireless Sensor Networks. S-MAC uses a few innovative techniques to reduce energy consumption and support self-configuration. A new protocol is suggested to improve the energy efficiency, latency and throughput of existing MAC protocol for WSNs. A modification of the protocol is then proposed to eliminate the need for some nodes to stay awake longer than the other nodes which improves the energy efficiency, latency and throughput and hence increases the life span of a wireless sensor network.
UHF RFID Antenna: Printed Dipole Antenna with a CPS Matching Circuit and Inductively Coupled Feed
Authors: Popović Nenad
Published: November 2012

This paper presents simulated (WIPL-D pro) and measured results of a UHF RFID antenna realized with a dipole matched to a CPS (Coplanar Stripline) and inductively coupled with a small rectangular loop. Such a design enables achieving and controlling high values of the inductive reactance that is necessary for obtaining good match of the antenna to an Application Specific Integrated Circuit (ASIC) chip. The antenna is characterized by a simple and robust design, which results in low-cost realization.
Octafilar Helical Antenna for Portable UHF-RFID Reader
Authors: Zainud-Deen Saber H. , Malhat Hend A. , Awadalla Kamal H.
Published: November 2012

Octafilar helical antenna (OFHA) is proposed for handheld ultra-high-frequency (UHF) radio frequency identification (RFID) reader. The investigated antenna configuration consists of OFHA placed on reader device in the presence of human hand model. The antenna is designed at UHF band centered at 915 MHz. The antenna return loss, axial ratio, gain, co-polarized and cross-polarized field components are calculated using the finite element method (FEM) and compared with that calculated by finite integration technique (FIT) for verification of the simulated results. A comparison between the performance of the quadrifilar helical antenna (QFHA) and the octafiliar helical antenna (OFHA) designed at 915 MHz in the presence of the reader device and human hand model is investigated. The OFHA introduces high gain, high front to back ratio, good axial ratio and omnidirectional coverage.
The Design and Cost Analysis of DCP Algorithm based on Directional Circle
Authors: Qian-Mu Li , Hai-Yan Mao , Hong Zhang
Published: November 2012

This paper proposed a theoretical analysis model of the DCP cost and its assumption. Repatrolling the regular network topologies of Grid and Hexagonal, it reasoned the relationship of DCP cost, the DCP parameter (start TTL a, the fixed increment value b, and the patrol threshold L), network size, and the node density out. In order to validate the conclusion, this paper simulated it with a lot of AODV-DCP experiments in the JiST/SWANS simulation platform. It provides a necessary theoretical basis for setting the DCP parameter.
Atomistic Investigation of Load Transfer Between DWNT Bundles “Crosslinked” by PMMA Oligomers
Authors: Naraghi Mohammad , Bratzel Graham H. , Filleter Tobin , An Zhi , Wei Xiaoding , Nguyen SonBinh T. , Buehler Markus J. , Espinosa Horacio D.
Published: November 2012

The production of carbon nanotube (CNT) yarns possessing high strength and toughness remains a major challenge due to the intrinsically weak interactions between “bare” CNTs. To this end, nanomechanical shear experiments between functionalized bundles of CNTs are combined with multiscale simulations to reveal the mechanistic and quantitative role of nanotube surface functionalization on CNT‐CNT interactions. Notably, the in situ chemical vapor deposition (CVD) functionalization of CNT bundles by poly(methyl methacrylate) (PMMA)‐like oligomers is found to enhance the shear strength of bundle junctions by about an order of magnitude compared with “bare” van der Waals interactions between pristine CNTs. Through multiscale simulations, the enhancement of the shear strength can be attributed to an interlocking mechanism of polymer chains in the bundles, dominated by van der Waals interactions, and stretching and alignment of chains during shearing. Unlike covalent bonds, such synergistic weak interactions can re‐form upon failure, resulting in strong, yet robust fibers. This work establishes the significance of engineered weak interactions with appropriate structural distribution to design CNT yarns with high strength and toughness, similar to the design paradigm found in many biological materials.
Polyhedral Oligosilsesquioxane‐Modified Boron Nitride Nanotube Based Epoxy Nanocomposites: An Ideal Dielectric Material with High Thermal Conductivity
Authors: Huang Xingyi , Zhi Chunyi , Jiang Pingkai , Golberg Dmitri , Bando Yoshio , Tanaka Toshikatsu
Published: November 2012

Dielectric polymer composites with high thermal conductivity are very promising for microelectronic packaging and thermal management application in new energy systems such as solar cells and light emitting diodes (LEDs). However, a well‐known paradox is that conventional composites with high thermal conductivity usually suffer from the high dielectric constant and high dielectric loss, while on the other hand, composite materials with excellent dielectric properties usually possess low thermal conductivity. In this work, an ideal dielectric thermally conductive epoxy nanocomposite is successfully fabricated using polyhedral oligosilsesquioxane (POSS) functionalized boron nitride nanotubes (BNNTs) as fillers. The nanocomposites with 30 wt% fraction of POSS modified BNNTs exhibit much lower dielectric constant, dielectric loss tangent, and coefficient of thermal expansion in comparison with the pure epoxy resin. As an example, below 100 Hz, the dielectric loss of the nanocomposites with 20 and 30 wt% BNNTs is reduced by one order of magnitude in comparison with the pure epoxy resin. Moreover, the nanocomposites show a dramatic thermal conductivity enhancement of 1360% in comparison with the pristine epoxy resin at a BNNT loading fraction of 30 wt%. The merits of the designed composites are suggested to originate from the excellent intrinsic properties of embedded BNNTs, effective surface modification by POSS molecules, and carefully developed composite preparation methods.
Word smithing in medical genetics. Part II
Authors: Cohen Jr. M. Michael
Published: November 2012

Terminology discussed here is subsumed under “common misused terms in medical genetics articles” (depressed nasal bridge; anophthalmia; rotated ears; low‐set ears; heterotopia; ASD as an abbreviation for autism spectrum disorders; mental retardation; “radiographs revealed something”; and new syndrome) and also subsumed under “erroneous terminology that persists at the editorial and publishing level” (failure to understand the possessive case of names ending in “s”; failure to understand that a comma should not be used before Jr; problematic use of numbers in reference sections; failure to italicize Latin phrases; failure to honor book titles that begin words with upper case letters; omitting the corresponding author; and inadequate citation of foreign languages). © 2012 Wiley Periodicals, Inc.
Synthese aromatischer Nitrile mithilfe nichtmetallischer CN‐Quellen
Authors: Kim Jinho , Kim Hyun Jin , Chang Sukbok
Published: November 2012

Aromatische Nitrile werden effizient durch die übergangsmetallkatalysierte Cyanierung von Aryl(pseudo)halogeniden mit metallischen CN‐Quellen wie CuCN, KCN, NaCN, Zn(CN)2, TMSCN oder K4[Fe(CN)6] synthetisiert. Nachteilig an diesen Verfahren sind jedoch die stöchiometrischen Mengen von Metallabfall, die Vergiftung des Metallkatalysators oder die Bildung von toxischem HCN‐Gas. Für die Cyanierung von Aryl‐Halogen‐ und Aryl‐H‐Bindungen wird daher seit einiger Zeit auch eine Reihe von “nichtmetallischen” organischen CN‐Quellen erkundet. Dieser Kurzaufsatz stellt verschiedene nichtmetallische CN‐Quellen und ihre Anwendung für die Synthese von Arylnitrilen vor.
Biocomposites based on lignin and plasticized poly(L‐lactic acid)
Authors: Rahman Mohammed Arifur , De Santis Diego , Spagnoli Gloria , Ramorino Giorgio , Penco Maurizio , Phuong Vu Thanh , Lazzeri Andrea
Published: November 2012

In this research work, biocomposites based on a ternary system containing softwood Kraft lignin (Indulin AT), poly‐L‐lactic acid (PLLA) and polyethylene glycol (PEG) have been developed. Two binary systems based on PLLA/PEG and PLLA/lignin have also been studied to understand the role of plasticizer (i.e., PEG) and filler (i.e., lignin) on the overall physicomechanical behavior of PLLA. All samples have been prepared by melt‐blending. A novel approach has also been introduced to improve the compatibility between PLLA and PEG by using a transesterification catalyst under reactive‐mixing conditions. In PEG plasticized PLLA flexibility increases with increasing content of PEG and no significant effect of the molecular weight of PEG on the flexibility of PLLA has been observed. Differential scanning calorimetry and size‐exclusion chromatography along with FTIR analysis show the formation of PLLA‐b‐PEG copolymer for high temperature processed PLLA/PEG systems. On the other hand, binary systems containing lignin show higher stiffness than PLLA/PEG system and good adhesion between the particles and the matrix has been observed by scanning electron microscopy. However, a concomitant good balance in stiffness introduced by the lignin particles and flexibility introduced by PEG has been observed in the ternary systems. This study also showed that high temperature reactive melt‐blending of PLLA/PEG leads to the formation of a segmented PLLA‐b‐PEG block copolymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of core‐shell morphology evolution on the rheology, crystallization, and mechanical properties of PA6/EPDM‐g‐MA/HDPE ternary blend
Authors: Dou Rui , Wang Wei , Zhou Yan , Li Lan‐peng , Gong Lei , Yin Bo , Yang Ming‐bo
Published: November 2012

In this article, polyamide 6 (PA6), maleic anhydride grafted ethylene‐propylene‐diene monomer (EPDM‐g‐MA), high‐density polyethylene (HDPE) were simultaneously added into an internal mixer to melt‐mixing for different periods. The relationship between morphology and rheological behaviors, crystallization, mechanical properties of PA6/EPDM‐g‐MA/HDPE blends were studied. The phase morphology observation revealed that PA6/EPDM‐g‐MA/HDPE (70/15/15 wt %) blend is constituted from PA6 matrix in which is dispersed core‐shell droplets of HDPE core encapsulated by EPDM‐g‐MA phase and indicated that the mixing time played a crucial role on the evolution of the core‐shell morphology. Rheological measurement manifested that the complex viscosity and storage modulus of ternary blends were notable higher than the pure polymer blends and binary blends which ascribed different phase morphology. Moreover, the maximum notched impact strength of PA6/EPDM‐g‐MA/HDPE blend was 80.7 KJ/m2 and this value was 10–11 times higher than that of pure PA6. Particularly, differential scanning calorimetry results indicated that the bulk crystallization temperature of HDPE (114.6°C) was partly weakened and a new crystallization peak appeared at a lower temperature of around 102.2°C as a result of co‐crystal of HDPE and EPDM‐g‐MA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Comparative study of anal acoustic reflectometry and anal manometry in the assessment of faecal incontinence
Authors: Hornung B R , Mitchell P J , Carlson G L , Klarskov N , Lose G , Kiff E S
Published: November 2012

Background

Anal acoustic reflectometry (AAR) is a reproducible technique providing a novel physiological assessment of anal sphincter function. It may have advantages over conventional anal manometry. The aims of this study were to determine the ability of AAR and anal manometry to identify changes in anal sphincter function in patients with faecal incontinence (FI) and to relate these changes to the severity of FI.

Methods

Women with FI underwent assessment with AAR and anal manometry. All patients completed the Vaizey FI questionnaire and were classified according to symptom type (urge, passive or mixed) and integrity of the anal sphincters. The ability of AAR and anal manometry to correlate with symptom severity was evaluated. AAR was compared with anal manometry in detecting differences in anal sphincter function between symptomatic subgroups, and patients with and without a sphincter defect.

Results

One hundred women with FI were included in the study. The AAR variables opening pressure, opening elastance, closing elastance and squeeze opening pressure correlated with symptom severity, whereas the manometric measurements maximum resting pressure and maximum squeeze pressure did not. Unlike anal manometry, AAR was able to detect differences in anal sphincter function between different symptomatic subgroups, whereas anal manometry was not. An anal sphincter defect was not associated with a significant change in anal sphincter function determined by either AAR or anal manometry.

Conclusion

In the assessment of women with FI, AAR variables correlated with symptom severity and could distinguish between different symptomatic subgroups. AAR may help to guide management in these patients.
Long-term follow-up of the Medical Research Council CLASICC trial of conventional versus laparoscopically assisted resection in colorectal cancer
Authors: Green B L , Marshall H C , Collinson F , Quirke P , Guillou P , Jayne D G , Brown J M
Published: November 2012

Background

Laparoscopic resection is used widely in the management of colorectal cancer; however, the data on long-term outcomes, particularly those related to rectal cancer, are limited. The results of long-term follow-up of the UK Medical Research Council trial of laparoscopically assisted versus open surgery for colorectal cancer are presented.

Methods

A total of 794 patients from 27 UK centres were randomized to laparoscopic or open surgery in a 2:1 ratio between 1996 and 2002. Long-term follow-up data were analysed to determine differences in survival outcomes and recurrences for intention-to-treat and actual treatment groups.

Results

Median follow-up of all patients was 62·9 (interquartile range 22·9 − 92·8) months. There were no statistically significant differences between open and laparoscopic groups in overall survival (78·3 (95 per cent confidence interval (c.i.) 65·8 to 106·6) versus 82·7 (69·1 to 94·8) months respectively; P = 0·780) and disease-free survival (DFS) (89·5 (67·1 to 121·7) versus 77·0 (63·3 to 94·0) months; P = 0·589). In colonic cancer intraoperative conversions to open surgery were associated with worse overall survival (hazard ratio (HR) 2·28, 95 per cent c.i. 1·47 to 3·53; P < 0·001) and DFS (HR 2·20, 1·31 to 3·67; P = 0·007). In terms of recurrence, no significant differences were observed by randomized procedure. However, at 10 years, right colonic cancers showed an increased propensity for local recurrence compared with left colonic cancers: 14·7 versus 5·2 per cent (difference 9·5 (95 per cent c.i. 2·3 to 16·6) per cent; P = 0·019).

Conclusion

Long-term results continue to support the use of laparoscopic surgery for both colonic and rectal cancer.
Severity of portal hypertension and prediction of postoperative liver failure after liver resection in patients with Child–Pugh grade A cirrhosis
Authors: Chen X , Zhai J , Cai X , Zhang Y , Wei L , Shi L , Wu D , Shen F , Lau W-Y , Wu M
Published: November 2012

Background

Patients with Child–Pugh grade A cirrhosis and clinical evidence of portal hypertension are likely to develop posthepatectomy liver failure (PHLF). Whether such patients are suitable candidates for partial hepatectomy is controversial. This study explored the impact of portal venous pressure (PVP) on PHLF and the possibility of stratifying patients with Child–Pugh grade A cirrhosis for risk of PHLF using clinical data alone.

Methods

Between April 2009 and May 2011, consecutive patients who underwent partial hepatectomy for hepatocellular carcinoma and intraoperative measurement of PVP were included in this prospective study. Using signs of clinically significant portal hypertension (CSPH), patients with Child–Pugh grade A cirrhosis were subclassified into three groups: no, mild and severe CSPH. Risk factors for PHLF were subjected to univariable and multivariable analysis, and receiver operating characteristic (ROC) curve analysis.

Results

Sixty-seven (35·3 per cent) of 190 patients developed PHLF, which was persistent in 12 patients (6·3 per cent). Four patients (2·1 per cent) died from PHLF within 3 months of surgery. Multivariable analysis showed both PVP and CSPH to be independent predictors of PHLF (P < 0·001). PVP values, incidence of PHLF and persistent PHLF were significantly higher in the severe CSPH group than in the other two groups (P < 0·001). Severe CSPH (odds ratio 27·68, P = 0·005) and a preoperative neutrophil : lymphocyte ratio (NLR) of 2·8 or above (odds ratio 49·75, P = 0·002) were independent factors affecting the incidence of persistent PHLF.

Conclusion

The severity of CSPH, corresponding to different PVP levels, could be used to stratify patients with Child-Pugh grade A cirrhosis and to predict the incidence of PHLF. Patients with severe CSPH or a NLR of 2·8 or above were more likely to develop persistent PHLF after partial hepatectomy.
Effects of hydrogen sulphide in an experimental model of renal ischaemia–reperfusion injury
Authors: Hunter J P , Hosgood S A , Patel M , Rose R , Read K , Nicholson M L
Published: November 2012

Background

Renal ischaemia–reperfusion injury (IRI) is a major cause of acute renal failure and renal transplant dysfunction. The aim of this study was to investigate the efficacy of the endogenous gaseous signalling molecule hydrogen sulphide in protecting against renal IRI.

Methods

Large White female pigs underwent laparotomy and cross-clamping of the left renal pedicle for 60 min. Animals were allocated randomly to treatment with either intravenous hydrogen sulphide (n = 6) or saline control (n = 6) 10 min before clamp release, and then underwent a right nephrectomy. Staff were blinded to treatment allocation and animals were recovered for 7 days.

Results

Hydrogen sulphide therapy resulted in a marked reduction in kidney injury with reduced serum creatinine levels on days 1–5, in a reduced area under the creatinine–time curve, and a halving of the time to achieve a creatinine level of less than 250 µmol/l, compared with the control. Hydrogen sulphide also preserved glomerular function, as shown by the urinary protein/creatinine ratio, which, compared with baseline, increased on days 1 and 3 in the control group (mean(s.e.m.) 3·22(1·43), P = 0·016 and 2·59(1·27), P = 0·031), but not in the treatment group (0·99(0·23), P = 0·190 and 1·06(0·44), P = 0·110, respectively). Mean(s.e.m.) tumour necrosis factor α levels at 6 h postreperfusion increased in the control animals (56(6) versus 115(21) pg/ml; P = 0·026), but not in the hydrogen sulphide-treated animals (61(7) versus 74(11) pg/ml; P = 0·460). Renal neutrophil infiltration at 30 min (myeloperoxidase staining) was also significantly reduced by treatment with hydrogen sulphide (P = 0·016).

Conclusion

Hydrogen sulphide offers a promising new approach to ameliorating renal IRI with potential translation into a number of clinical settings, including renal transplantation.
Liver resection for hepatocellular carcinoma in patients without cirrhosis
Authors: Thelen A , Benckert C , Tautenhahn H-M , Hau H-M , Bartels M , Linnemann J , Bertolini J , Moche M , Wittekind C , Jonas S
Published: November 2012

Background

Data on liver resection for hepatocellular carcinoma (HCC) without cirrhosis are sparse. The present study was conducted to evaluate the indications and results of liver resection for HCC with regard to safety and efficacy.

Methods

Data for patients who had liver resection for HCC without cirrhosis between January 1996 and March 2011 were retrieved retrospectively using a prospective database containing information on all patients who underwent hepatectomy for HCC. Patient and tumour characteristics were analysed for influence on overall and disease-free survival to identify prognostic factors by univariable and multivariable analysis.

Results

The 1-, 3- and 5-year overall survival rates after resection with curative intent for HCC without cirrhosis were 84, 66 and 50 per cent respectively. Disease-free survival rates were 69, 53 and 42 per cent respectively. The 90-day mortality rate was 4·5 per cent (5 of 110 patients). Surgical radicality and growth pattern of the tumour were independent prognostic factors for overall survival. Disease-free survival after resection with curative intent was independently affected by growth pattern and by the number and size of tumour nodules.

Conclusion

Liver resection for HCC without cirrhosis carries a low perioperative risk and excellent long-term outcome if radical resection is achieved.
Non-operative management of acute cholecystitis in the elderly (Br J Surg 2012; 99: 1254–1261)
Authors: Bass G , Walsh T N
Published: November 2012

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.
Deactivation and Regeneration of H‐USY Zeolite during Lignin Catalytic Fast Pyrolysis
Authors: Ma Zhiqiang , van Bokhoven Jeroen A.
Published: November 2012

Catalytic fast pyrolysis of alkaline lignin over H‐USY zeolites uniquely yields a high fraction of aromatics but only very small amounts of tar and char. This study focused on the deactivation and regeneration of the H‐USY zeolite. N2 physisorption, thermogravimetric analysis (TGA), temperature‐programmed desorption of NH3, and 27Al MAS NMR analysis were used to determine coking, pore topology, and the number of acid sites of the deactivated and regenerated H‐USY catalyst. Deactivation occurred mainly owing to coke deposition on the catalyst. Both pore blockage and active site poisoning were observed during deactivation. The coke was removed through calcination of the deactivated catalysts in air at high temperature. Calcination restored the high porosity and the acid sites to a large extent. Even better catalytic performance was obtained after the reintroduction of protons through an ion‐exchange step. Recovery of catalytic properties was high but incomplete, because of structural changes in the catalyst during the reaction–regeneration process.
Synthesis of Dimethyl Carbonate from Methyl Carbamate and Methanol Using a Fixed‐Bed Reactor
Authors: Wang D. , Zhang X. , Wei W. , Sun Y.
Published: November 2012

Several mixed oxide catalysts were prepared by coprecipitation for dimethyl carbonate (DMC) synthesis from methyl carbamate and methanol. During the batch process, the DMC yield was below 35 %. In order to minimize the unfavorable thermodynamic equilibrium and side reactions for the DMC synthesis, a fixed‐bed reactor was designed. A maximum DMC yield of ∼ 73 % could be realized over a ZnO‐Al2O3 catalyst. The effects of reaction conditions for this type of reactor were investigated in detail.
Measurement and Simulation of Axial Velocity in a Filter Bag
Authors: Saleem M. , Tahir M. S. , Krammer G.
Published: November 2012

The axial velocity in two different tests with pulse‐jet bag filters made of needle felts on a pilot‐scale test facility separating limestone dust from air under ambient conditions is measured and simulated at different cake area loads. Results reveal that the axial velocity profiles are not truly linear along the whole length of the bag. A nonuniform gas flow prevails when the bags are differently dust‐loaded. The same behaviors are observed even at the end of filtration cycles at different upper pressure drop limits. At the higher upper limit, the nonuniformity is stronger. Radial velocity profiles are nearly symmetric along the length of the bag.
Mechanistic Origin of the Vibrational Coherence Accompanying the Photoreaction of Biomimetic Molecular Switches
Authors: Léonard Jérémie , Schapiro Igor , Briand Julien , Fusi Stefania , Paccani Riccardo Rossi , Olivucci Massimo , Haacke Stefan
Published: November 2012

The coherent photoisomerization of a chromophore in condensed phase is a rare process in which light energy is funneled into specific molecular vibrations during electronic relaxation from the excited to the ground state. In this work, we employed ultrafast spectroscopy and computational methods to investigate the molecular origin of the coherent motion accompanying the photoisomerization of indanylidene–pyrroline (IP) molecular switches. UV/Vis femtosecond transient absorption gave evidence for an excited‐ and ground‐state vibrational wave packet, which appears as a general feature of the IP compounds investigated. In close resemblance to the coherent photoisomerization of rhodopsin, the sudden onset of a far‐red‐detuned and rapidly blue‐shifting photoproduct signature indicated that the population arriving on the electronic ground state after nonadiabatic decay through the conical intersection (CI) is still very focused in the form of a vibrational wave packet. Semiclassical trajectories were employed to investigate the reaction mechanism. Their analysis showed that coupled double‐bond twisting and ring inversions, already populated during the excited‐state reactive motion, induced periodic changes in π‐conjugation that modulate the ground‐state absorption after the non‐adiabatic decay. This prediction further supports that the observed ground‐state oscillation results from the reactive motion, which is in line with a biomimetic, coherent photoisomerization scenario. The IP compounds thus appear as a model system to investigate the mechanism of mode‐selective photomechanical energy transduction. The presented mechanism opens new perspectives for energy transduction at the molecular level, with applications to the design of efficient molecular devices.
Solid‐Phase Synthesis of Structurally Diverse Heterocycles by an Amide–Ketone Condensation/N‐Acyliminium Pictet–Spengler Sequence
Authors: Komnatnyy Vitaly V. , Givskov Michael , Nielsen Thomas E.
Published: November 2012

An efficient approach for the solid‐phase synthesis of structurally diverse heterocyclic compounds is presented. Under acidic reaction conditions, peptidic levulinamides undergo intramolecular ketone–amide condensation reactions to form cyclic N‐acyliminium intermediates. In the presence of a tethered nucleophile, a second cyclization reaction results in the formation of a fused bicyclic ring system. The scope of the methodology was demonstrated by several combinations of substituted ketones and nucleophiles, the latter conveniently originating from amino acids with functionalized side chains, such as tryptophan, substituted phenylalanines, and cysteine. The cyclization sequence provides diastereomerically pure products in high yields. In one extension of the methodology, the resulting relative stereochemistry of the products enables the formation of bridged ring systems by a unique cyclative release mechanism.
Impact of Lesion Length on Functional Significance in Intermediate Coronary Lesions
Authors: Iguchi Tomokazu , Hasegawa Takao , Nishimura Satoshi , Nakata Shinji , Kataoka Toru , Ehara Shoichi , Hanatani Akihisa , Shimada Kenei , Yoshiyama Minoru
Published: November 2012

Background:

Myocardial fractional flow reserve (FFR) is useful in the evaluation of coronary lesion ischemia. However, the impact of lesion length on FFR has not been adequately assessed.

Hypothesis:

We hypothesized that lesion length would influence functional significance in intermediate coronary lesions.

Methods:

FFR measurements were assessed in 136 patients (163 lesions) with stable angina who had >40% stenotic coronary lesion by quantitative coronary angiography (QCA). One hundred sixty‐three lesions were classified as intermediate (40%–70% stenosis; n=107; group I) or significant (≥70%; n=56; group S) by QCA. We assessed the relationships between lesion length, coronary stenosis, and FFR in these 163 lesions.

Results:

Regression analysis revealed an inverse correlation between the percentage of diameter stenosis (%DS) and FFR in group S (r = −0.83, P < 0.0001). In group I, no significant correlation was found between %DS and FFR (r = −0.06, P = 0.55), whereas lesion length was significantly inversely correlated with FFR (r = −0.79, P < 0.0001). Receiver operating characteristic curve analysis demonstrated that the best cutoff value for predicting an FFR value <0.80 was a lesion length >16.1 mm in group I (sensitivity, 86%; specificity, 94%).

Conclusions:

These study findings suggest that lesion length has a physiologically significant impact on intermediate‐grade coronary lesions. Clin. Cardiol. 2011 DOI: 10.1002/clc.22076

The authors have no funding, financial relationships, or conflicts of interest to disclose.
Epigenetic silencing of Id4 identifies a glioblastoma subgroup with a better prognosis as a consequence of an inhibition of angiogenesis
Authors: Martini Maurizio , Cenci Tonia , D'Alessandris Giorgio Quintino , Cesarini Valeriana , Cocomazzi Alessandra , Ricci‐Vitiani Lucia , De Maria Ruggero , Pallini Roberto , Larocca Luigi Maria
Published: November 2012

BACKGROUND:

Inhibitors of DNA binding/differentiation (Id1 to Id4) are a family of helix‐loop‐helix transcription factors, which are highly expressed during embryogenesis and at lower levels in mature tissues. Id4 plays an important role in neuronal stem cell differentiation, and its deregulation has been implicated in glial neoplasia.

METHODS:

The methylation status of Id4 was analyzed by methylation‐specific polymerase chain reaction (PCR) in 62 glioblastoma (GBM) cases and in 20 normal brain tissues. Methylation status of Id4 was confirmed by sequencing after subcloning and messenger RNA (mRNA) and protein expression. We also evaluated the mRNA expression of MGP (matrix GLA protein), TGF‐β1 (transforming growth factor beta 1), and VEGF (vascular endothelial growth factor) by real‐time PCR analysis. Clinical and histological assessment of tumor angiogenesis was performed by evaluating the relative enhancing tumor ratio on magnetic resonance imaging and microvessel density on von Willebrand factor–stained sections, respectively.

RESULTS:

The promoter of Id4 was methylated in 23 of 62 (37%) GBMs. In methylated GBMs, Id4 mRNA was significantly reduced, compared with unmethylated GBMs (P = .0002). A significant reduction of protein expression was detected in all hypermethylated cases. GBMs with methylated Id4 showed a significant reduction of MGP, TGF‐β1, and VEGF mRNA expression and had significantly lower relative enhancing tumor ratio (P = .0108) and microvessel density (P = .0241) values with respect to unmethylated GBMs. Finally, Id4 methylation was significantly associated with a favorable clinical outcome (P = .0006).

CONCLUSIONS:

These data suggest that methylation of Id4 may be involved in the pathogenesis of GBM and in the resistance of this neoplasm to conventional treatment throughout MGP‐mediated neoangiogenesis. Cancer 2013. © 2012 American Cancer Society
Time to adjuvant chemotherapy and survival in non–small cell lung cancer
Authors: Booth Christopher M. , Shepherd Frances A. , Peng Yingwei , Darling Gail , Li Gavin , Kong Weidong , Biagi James J. , Mackillop William J.
Published: November 2012

BACKGROUND:

The time interval between surgery and initiation of adjuvant chemotherapy (ACT) may impact survival in colorectal and breast cancers. This is the first report describing the association between time to adjuvant chemotherapy (TTAC) and survival in non–small cell lung cancer (NSCLC).

METHODS:

All cases of NSCLC diagnosed in Ontario, Canada, from 2004 to 2006 who underwent surgical resection (n = 3354) were identified using the Ontario Cancer Registry. TTAC was defined as the interval between dates of surgery and initiation of ACT. Factors associated with TTAC greater than 10 weeks were evaluated by logistic regression. The Cox proportional hazards model was used to describe the effect of delayed TTAC (analyzed as a continuous variable) on overall survival.

RESULTS:

Among the 1032 cases treated with ACT, the median TTAC was 8 weeks (range, 1‐16 weeks); 35% of cases initiated ACT more than 10 weeks after surgery. Rates of TTAC greater than 10 weeks varied widely across regions (11%‐50%, P = .001). There was no significant association between increased comorbidity and delayed TTAC; there was a trend toward greater delay in TTAC with longer postoperative hospital stay (P = .054) and postoperative readmission to hospital (P = .056). Male sex, higher stage of disease, greater comorbidity, and more extensive surgery were independently associated with inferior survival. TTAC was not associated with overall survival (odds ratio = 1.00, 95% confidence interval = 0.99‐1.00).

CONCLUSIONS:

One‐third of NSCLC patients treated with ACT in the general population start ACT beyond 10 weeks after surgery. Delayed TTAC does not appear to be associated with inferior survival in NSCLC. Cancer 2013. © 2012 American Cancer Society.
Attrition rates, reasons, and predictive factors in supportive care and palliative oncology clinical trials
Authors: Hui David , Glitza Isabella , Chisholm Gary , Yennu Sriram , Bruera Eduardo
Published: November 2012

BACKGROUND:

Attrition is common among supportive care/palliative oncology clinical trials. However, to the authors' knowledge, few studies to date have documented the reasons and predictors for dropout. In the current study, the authors' objective was to determine the rate, reasons, and factors associated with attrition both before reaching the primary endpoint and at the end of the study.

METHODS:

A review of all prospective interventional supportive care/palliative oncology trials conducted in the Department of Palliative Care and Rehabilitation Medicine at The University of Texas MD Anderson Cancer Center in Houston between 1999 and 2011 was performed. Patient and study characteristics and attrition data were extracted.

RESULTS:

A total of 1214 patients were included in 18 clinical trials. The median age of the patients was 60 years. Approximately 41% had an Eastern Cooperative Oncology Group performance status of ≥ 3, a median Edmonton Symptom Assessment Scale (ESAS) for fatigue of 7 of 10, and a median ESAS for dyspnea of 2 of 10. The attrition rate was 26% (95% confidence interval [95% CI], 23%‐28%) for the primary endpoint and 44% (95% CI, 41%‐47%) for the end of the study. Common reasons for primary endpoint dropout were symptom burden (21%), patient preference (15%), hospitalization (10%), and death (6%). Primary endpoint attrition was associated with a higher baseline intensity of fatigue (odds ratio [OR], 1.10 per point; P = .01) and a longer study duration (P = .04). End‐of‐study attrition was associated with higher baseline levels of dyspnea (OR, 1.06; P = .01), fatigue (OR, 1.08; P = .01), Hispanic race (OR, 1.87; P = .002), higher level of education (P = .02), longer study duration (P = .01), and outpatient studies (P = 0.05).

CONCLUSIONS:

The attrition rate was high in supportive care/palliative oncology clinical trials, and was associated with various patient characteristics and a high baseline symptom burden. These findings have implications for future clinical trial design including eligibility criteria and sample size calculation. Cancer 2013. © 2012 American Cancer Society.