Unravelling the object-based nature of visual working memory: insight from pointers.

Visual working memory (VWM) plays a crucial role in temporarily storing and processing visual information, but the nature of stored representations and their interaction with new inputs has long been unclear. The pointer system refers to how VWM links new sensory inputs to stored information using specific cues. This study aimed to investigate whether the pointer system is based on spatial, feature-based, or object-based cues by employing the repetition benefit effect, where memory performance improves with repeated memory items. Across three experiments, we manipulated spatial positions, shapes, and colors as pointer cues to determine how these features affect VWM consolidation and updating. The results showed that while spatial location serves as a strong pointer cue, shape and color features can also effectively reestablish object correspondence in VWM. These findings support the view that the pointer system in VWM is flexible and object-based, utilizing various feature cues to maintain memory continuity. This study provides new insights into how VWM connects new inputs with stored information through the pointer system.

A Robotic Solution for Precision Smoothing and Roughening of Precast Concrete Surfaces: Design and Experimental Validation.

Prefabricated construction has pioneered a new model in the construction industry, where prefabricated component modules are produced in factories and assembled on-site by construction workers, resulting in a highly efficient and convenient production process. Within the construction industry value chain, the smoothing and roughening of precast concrete components are critical processes. Currently, these tasks are predominantly performed manually, often failing to achieve the desired level of precision. This paper designs and develops a robotic system for smoothing and roughening precast concrete surfaces, along with a multi-degree-of-freedom integrated intelligent end-effector for smoothing and roughening. Point-to-point path planning methods are employed to achieve comprehensive path planning for both smoothing and roughening, enhancing the diversity of textural patterns using B-spline curves. In the presence of embedded obstacles, a biologically inspired neural network method is introduced for precise smoothing operation planning, and the A* algorithm is incorporated to enable the robot's escape from dead zones. Experimental validation further confirms the feasibility of the entire system and the accuracy of the machining path planning methods. The experimental results demonstrate that the proposed system meets the precision requirements for smoothing and offers diversity in roughening, affirming its practicality in the precast concrete process and expanding the automation level and application scenarios of robots in the field of prefabricated construction.

Luteolin-7-O-ß-d-Glucuronide Attenuated Cerebral Ischemia/Reperfusion Injury: Involvement of the Blood-Brain Barrier.

Ischemic stroke is a common cerebrovascular disease with high mortality, high morbidity, and high disability. Cerebral ischemia/reperfusion injury seriously affects the quality of life of patients. Luteolin-7-O-ß-d-glucuronide (LGU) is a major active flavonoid compound extracted from Ixeris sonchifolia (Bge.) Hance, a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the protective effect of LGU on cerebral ischemia/reperfusion injury was investigated in an oxygen-glucose deprivation/reoxygenation (OGD/R) neuronal model and a transient middle cerebral artery occlusion (tMCAO) rat model. In in vitro experiments, LGU was found to improve the OGD/R-induced decrease in neuronal viability effectively by the MTT assay. In in vivo experiments, neurological deficit scores, infarction volume rates, and brain water content rates were improved after a single intravenous administration of LGU. These findings suggest that LGU has significant protective effects on cerebral ischemia/reperfusion injury in vitro and in vivo. To further explore the potential mechanism of LGU on cerebral ischemia/reperfusion injury, we performed a series of tests. The results showed that a single administration of LGU decreased the content of EB and S100B and ameliorated the abnormal expression of tight junction proteins ZO-1 and occludin and metalloproteinase MMP-9 in the ischemic cerebral cortex of the tMCAO 24-h injury model. In addition, LGU also improved the tight junction structure between endothelial cells and the degree of basement membrane degradation and reduced the content of TNF-α and IL-1ß in the brain tissue. Thereby, LGU attenuated cerebral ischemia/reperfusion injury by improving the permeability of the blood-brain barrier. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

Luteolin-7-O-ß-d-glucuronide Ameliorates Cerebral Ischemic Injury: Involvement of RIP3/MLKL Signaling Pathway.

Luteolin-7-O-ß-d-glucuronide (LGU) is a major active flavonoid glycoside compound that is extracted from Ixeris sonchifolia (Bge.) Hance, and it is a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the neuroprotective effect of LGU was investigated in an oxygen glucose deprivation (OGD) model and a middle cerebral artery occlusion (MCAO) rat model. In vitro, LGU was found to effectively improve the OGD-induced decrease in neuronal viability and increase in neuronal death by a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) leakage rate assay, respectively. LGU was also found to inhibit OGD-induced intracellular Ca2+ overload, adenosine triphosphate (ATP) depletion, and mitochondrial membrane potential (MMP) decrease. By Western blotting analysis, LGU significantly inhibited the OGD-induced increase in expressions of receptor-interacting serine/threonine-protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). Moreover, molecular docking analysis showed that LGU might bind to RIP3 more stably and firmly than the RIP3 inhibitor GSK872. Immunofluorescence combined with confocal laser analyses disclosed that LGU inhibited the aggregation of MLKL to the nucleus. Our results suggest that LGU ameliorates OGD-induced rat primary cortical neuronal injury via the regulation of the RIP3/MLKL signaling pathway in vitro. In vivo, LGU was proven, for the first time, to protect the cerebral ischemia in a rat middle cerebral artery occlusion (MCAO) model, as shown by improved neurological deficit scores, infarction volume rate, and brain water content rate. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

In situ preparation and properties of polyvinyl alcohol/synthetic ribbon-like nanocellulose composites.

This study presents a novel approach in which a dual network (DN) composite, comprising polyvinyl alcohol (PVA) and ribbon-like nanocellulose (RC), was synthesized in one step using the volume exclusion effect involved in enzyme-catalyzed cellulose synthesis. Additionally, the impact of PVA as a crowding reagent during enzymatic catalysis on the in situ formation of nanocellulose and its resulting aspect ratio was explored. In contrast, the other two composites were created by incorporating enzyme-catalyzed synthetic block cellulose (BC) and its acid-hydrolyzed regenerated disc-shaped cellulose (DC) into the PVA. Subsequently, the mechanism by which three distinct types of nanocellulose, varying in morphology and size, was explored to elucidate their contributions to enhancing the properties of PVA. The results demonstrated that PVA/RC outperformed PVA/BC and PVA/DC. The elevated aspect ratio and intricate network structure of RCs not only significantly bolster the mechanical robustness of PVA/RC, leading in an 86.40 % surge in tensile strength and a remarkable 277.03 % rise in tensile modulus in comparison to pure PVA, but also induce a slight enhancement in elongation at break. Moreover, the thermal stability and biodegradability of PVA/RC was enhanced. Collectively, this study introduces an innovative strategy for the efficient fabrication of biodegradable composites with enhanced properties.

Research on economic and social impact of carbon emissions in the construction industry at a regional scale: a case of Shandong, China.

To identify the impact of carbon emissions in the construction industry on the society and economy at a regional scale is of great significance for the sustainable development of the construction industry. Taking Shandong, China, as an example, this study uses a process-based carbon emission assessment method to calculate the carbon emissions of the construction industry in Shandong from 2010 to 2020. Based on specific situations at different phases, ten major factors affecting the society and economy have been analyzed and identified. Then, the Seemingly Uncorrelated Regression (SUR) model was used to analyze carbon emissions and economic and social factors at each stage. The results show the following: (1) The overall carbon emissions of the construction industry in Shandong are on an increasing trend, the carbon emission intensity is on a decreasing trend, and the material production and operation stages are the main source of carbon emissions; (2) There is a significant relationship between carbon emissions in the construction phase and all influencing factors, so it should be the main phase for macro-regulation; (3) Unlike in the Ordinary Least Square (OLS) model, the error terms of the gross output value of the construction industry and the total turnover of the main building materials equations are independent; however, there is an interaction between the error terms of the remaining equations. The results provide a theoretical reference for governmental departments to set up environmental targets and make policy regulations.

Dam Safety Evaluation Method after Extreme Load Condition Based on Health Monitoring and Deep Learning.

The safety operation of dams after extreme load is an important frontier research topic in the field of dam engineering. The dam health monitoring provides a reliable data basis for a safety evaluation after extreme loads. This study proposes a novel data-driven fusion model for a dam safety evaluation after extreme load based on monitoring data derived by sensors. First, the relationship between dam environmental quantity and effect quantity is deeply excavated based on bidirectional long short-term memory (BiLSTM) network, which is a deeply improved LSTM model. Aiming at the parameter optimization problem of BiLSTM model, sparrow search algorithm (SSA), which is an advanced optimization algorithm, is integrated. Second, conducting the constructed SSA-BiLSTM model to estimate the change law of dam effect quantity after the extreme load. Finally, the Mann-Whitney U-test theory is introduced to establish the evaluation criterion of the dam safety state. Project case shows that the multiple quantitative prediction accuracy evaluation indicators of the proposed method are significantly superior to the comparison method, with mean absolute percentage error (MAPE) and mean absolute error (MAE) values decreasing by 30.5% and 27.8%, respectively, on average. The proposed model can accurately diagnose the dam safety state after the extreme load compared with on-site inspection results of the engineering department, which provides a new method for dam safety evaluation.

Electrophysiological and behavioral evidence for the attention capture and suppression failure of irrelevant singleton in test anxiety.

Attention bias (ABs) and inhibition deficits play crucial roles in the development, maintenance, and recurrence of test anxiety. However, whether test-anxious individuals will show ABs and inhibition deficits of general task-irrelevant stimuli in a complex visual display is unclear. Thus, we used the additional singleton task (AST) and recorded event-related potentials (ERPs) indices of attentional selection (the N2 posterior contralateral, N2pc), suppression (distractor positivity, PD), and maintenance of working memory (the sustained posterior contralateral negativity, SPCN) to explore this issue. Twenty-eight participants in the high test-anxious (HTA) group and twenty-eight participants in the low test-anxious (LTA) group attended the experiment and were required to search for a target and synchronously ignore a singleton distractor on some trials. Consequently, HTA and LTA individuals had poorer accuracies and longer response times in the distractor-present condition than in the distractor-absent condition. The HTA group got larger interferences from singleton distractors than the LTA group. Electrophysiological results revealed a distractor N2pc and SPCN in the HTA group. Moreover, target N2pc and SPCN in the HTA group were larger when the singleton distractor and target were on the same side than on the opposite side. These results indicated that HTA individuals were captured attention by singleton distractors and failed to expel them from working memory. Accordingly, the present findings extended previous work by providing direct evidence that test anxiety could increase the effects of stimulus-driven attention systems and impair the function of goal-directed attention systems.

Iterative deep neural networks based on proximal gradient descent for image restoration.

The algorithm unfolding networks with explainability of algorithms and higher efficiency of Deep Neural Networks (DNN) have received considerable attention in solving ill-posed inverse problems. Under the algorithm unfolding network framework, we propose a novel end-to-end iterative deep neural network and its fast network for image restoration. The first one is designed making use of proximal gradient descent algorithm of variational models, which consists of denoiser and reconstruction sub-networks. The second one is its accelerated version with momentum factors. For sub-network of denoiser, we embed the Convolutional Block Attention Module (CBAM) in previous U-Net for adaptive feature refinement. Experiments on image denoising and deblurring demonstrate that competitive performances in quality and efficiency are gained by compared with several state-of-the-art networks for image restoration. Proposed unfolding DNN can be easily extended to solve other similar image restoration tasks, such as image super-resolution, image demosaicking, etc.

Characteristics of Seed Vigor in Rice Varieties with Different Globulin Accumulations.

Seed vigor of rice is an important trait for direct seeding. The objective of this study was to reveal the relationship between globulin and seed vigor, and then to explore a method for evaluating seed vigor. Several rice varieties with different levels of 52 kDa globulin accumulation were used to compare seed vigor under normal and aged conditions. Results showed that varieties with high globulin accumulation obtained significantly higher seed vigor, measured by germination percentage and germination index, compared with those varieties with low globulin accumulation under normal and aged conditions. Meanwhile, a significantly higher accumulation of reactive oxygen species (ROS) was observed in the early germinating seeds of varieties with high globulin accumulation compared to those varieties with low globulin accumulation under normal and aged conditions. Collectively, the globulin content could be applied in the evaluation of seed vigor, which contributes to the selection of rice varieties for direct seeding.

Neurophysiological correlates for dynamic variability between vigilance and avoidance in test anxiety.

Attention bias (ABs) to threat is essential in the etiology and maintenance of test anxiety. However, little is known about the attention pattern of ABs in test anxiety. The stimulus duration affects the attention pattern in anxiety. Thus, the present research combined the dot-probe paradigm and event-related potentials (ERPs) and varied the stimulus duration (100 ms or 500 ms) to test the ABs in test anxiety. Consequently, both groups showed a threat N2pc in 100 ms and 500 ms duration, suggesting that both groups allocated attention to the test-related threat. However, in the 100 ms duration, the high test-anxious (HTA) group had smaller target-elicited P1 and greater target-elicited N2 in the threat-congruent condition than in the neutral condition. In the 500 ms duration, an earlier threat N2pc and a threat PD followed a greater target P1, and smaller target N2 were pronounced in the HTA group. The current results provided electrophysiological evidence that the HTA group kept a dynamic attention pattern that fluctuated shift between vigilance and avoidance in the 100 ms and 500 ms duration. The HTA group was more vigilant than the LTA group in the 500 ms duration when strategic attention was concerned, proposing that vigilance in test anxiety was not an automatic process.

New dual method for elastica regularization.

The Euler's elastica energy regularizer has been widely used in image processing and computer vision tasks. However, finding a fast and simple solver for the term remains challenging. In this paper, we propose a new dual method to simplify the solution. Classical fast solutions transform the complex optimization problem into simpler subproblems, but introduce many parameters and split operators in the process. Hence, we propose a new dual algorithm to maintain the constraint exactly, while using only one dual parameter to transform the problem into its alternate optimization form. The proposed dual method can be easily applied to level-set-based segmentation models that contain the Euler's elastic term. Lastly, we demonstrate the performance of the proposed method on both synthetic and real images in tasks image processing tasks, i.e. denoising, inpainting, and segmentation, as well as compare to the Augmented Lagrangian method (ALM) on the aforementioned tasks.

Effect of test anxiety on visual working memory capacity using evidence from event-related potentials.

This study examined the effects of test anxiety on working memory capacity. Studies have demonstrated that individuals with trait social anxiety disorder exhibit increased visual working memory capacity and that those with trait anxiety exhibit decreased working memory capacity. Test anxiety may also induce unique effects on individuals' working memory capacity, and we thus employed the change detection task to explore such effects. Participants were divided into high- and low-test anxiety groups. We used K score and contralateral delay activity (CDA) amplitude to measure working memory capacity, focusing on processing effectiveness and efficiency. The study results revealed that deficits in the working memory capacity of individuals in the high test anxiety group manifested in the CDA amplitude rather than in the K score. The CDA amplitude of the high test anxiety group did not increase after load 3, and that of the low test anxiety group did not increase after load 4. No difference was observed in the K scores of the two groups. The study concluded that test anxiety impairs processing efficiency but not processing effectiveness.

Test anxiety impairs filtering ability in visual working memory: Evidence from event-related potentials.

Attentional control theory regards individuals with high anxiety as having deficits of inhibitory control when faced with distractors, especially under high-load conditions and with threatening distractors. Research on test anxiety has a long history, but the working memory (WM) characteristics of individuals with high test anxiety (HTA) remain unclear. We used two experiments to test the WM filtering ability of individuals with HTA, and the salient results were those of the contralateral delay activity amplitude rather than K score. The first experiment employed neutral distractors. HTA participants filtered distractors under low-load conditions but not under high-load conditions. Participants with low test anxiety (LTA) filtered distractors under high-load conditions but not under low-load conditions. The second experiment utilized threatening distractors. The participants with HTA exhibited deficits in their ability to filter neutral and threatening distractors, whereas the participants with LTA filtered both types of distractor.

Electrochemically Stable Cobalt⁻Zinc Mixed Oxide/Hydroxide Hierarchical Porous Film Electrode for High-Performance Asymmetric Supercapacitor.

Construction of electrochemically stable positive materials is still a key challenge to accomplish high rate performance and long cycling life of asymmetric supercapacitors (ASCs). Herein, a novel cobalt⁻zinc mixed oxide/hydroxide (CoZn-MOH) hierarchical porous film electrode was facilely fabricated based on a cobalt⁻zinc-based metal⁻organic framework for excellent utilization in ASC. The as-constructed hierarchical porous film supported on conductive Ni foam possesses a rough surface and abundant macropores and mesopores, which allow fast electron transport, better exposure of electrochemically active sites, and facile electrolyte access and ion diffusion. Owing to these structural merits in collaboration, the CoZn-MOH electrode prepared with a zinc feeding ratio up to 45% at 110 min of heating time (CoZn-MOH-45-110) exhibited a high specific capacitance of 380.4 F·g-1, remarkable rate capability (83.6% retention after 20-fold current increase), and outstanding cycling performances (96.5% retention after 10,000 cycles), which exceed the performances of similar active electrodes. Moreover, an ASC based on this CoZn-MOH-45-110 electrode exhibited a high specific capacitance of 158.8 F·g-1, an impressive energy density of 45.8 Wh·kg-1, superior rate capability (83.1% retention after 50-fold current increase), and satisfactory cycling stability (87.9% capacitance retention after 12,000 cycles).

Publisher Correction: Global characterization of T cells in non-small-cell lung cancer by single-cell sequencing.

In the version of this article originally published, the P statistic described in Fig. 3d was incorrect. It was described as "P < 22 × 10-16". It should have been "P < 2.2 × 10-16". Also, the "CD8+ Treg" label in Fig. 4f was incorrect. It should have been "CD4+ Treg". The errors have been corrected in the HTML and PDF versions of this article.

Global characterization of T cells in non-small-cell lung cancer by single-cell sequencing.

Cancer immunotherapies have shown sustained clinical responses in treating non-small-cell lung cancer1-3, but efficacy varies and depends in part on the amount and properties of tumor infiltrating lymphocytes4-6. To depict the baseline landscape of the composition, lineage and functional states of tumor infiltrating lymphocytes, here we performed deep single-cell RNA sequencing for 12,346 T cells from 14 treatment-naïve non-small-cell lung cancer patients. Combined expression and T cell antigen receptor based lineage tracking revealed a significant proportion of inter-tissue effector T cells with a highly migratory nature. As well as tumor-infiltrating CD8+ T cells undergoing exhaustion, we observed two clusters of cells exhibiting states preceding exhaustion, and a high ratio of "pre-exhausted" to exhausted T cells was associated with better prognosis of lung adenocarcinoma. Additionally, we observed further heterogeneity within the tumor regulatory T cells (Tregs), characterized by the bimodal distribution of TNFRSF9, an activation marker for antigen-specific Tregs. The gene signature of those activated tumor Tregs, which included IL1R2, correlated with poor prognosis in lung adenocarcinoma. Our study provides a new approach for patient stratification and will help further understand the functional states and dynamics of T cells in lung cancer.

[The Initial Experience of Video-assisted Thoracic Surgery Segmentectomy for Early Stage Lung Cancer].

BACKGROUND: Segmentectomy can retains more healthy lung tissue than lobectomy, but it remains controversial in oncology for early stage lung cancer. The aim of this study is to discuss the problems of video-assisted thoracic surgery (VATS) segmentectomy in early stage lung cancer, by analyzing the clinical and pathological data of 35 cases and reviewing the literature. METHODS: There were 35 patients who received segmentectomy by complete video-assisted thoracic surgery, from May 2013 to July 2017, in single operation group in the Third Hospital of Peking University. We analyzed the patient's clinical and pathological data, intraoperative and postoperative complications, lymph node number and metastasis its situation, and compared postoperative pathology and preoperative computed tomography (CT) imaging type. In 35 cases of segmentectomy, there were 11 males and 24 females, with an average age of 57.7 years old. The lesions located in the right upper lobe were 8 cases, in the right lower lobe were 8 cases, in the left upper lobe were 13 cases, in the left lower lobe were 6 cases. The mean maximum diameter of CT imaging was 12.7 mm, and the largest diameter of hilar and mediastinal lymph nodes was less than 10 mm. 23 of them were ground glass predominating and 12 were solid components predominating. RESULTS: All 35 cases were successfully completed VATS anatomical segmentectomy. The average operation time was 153 minutes, the amount of bleeding was 51 mL. There were 10 cases of air leakage after operation, all of which were not more than 3 days. There was contralateral atelectasis in 1 case, chylothorax in 1 case. The average length of hospitalization was 6.1 days. There was no other complications outpatient related to surgery, in 30 days after discharge. The pathological changes were as follow, 2 cases of metastatic tumor, 8 cases of benign lung disease and 25 cases of primary lung cancer. In the 25 cases of primary lung cancer, there were 14 cases of invasive lung adenocarcinoma (7 cases were groundglassopacity (GGO) predominating in CT imaging), 4 cases of micro-invasive adenocarcinoma (3 cases were GGO predominating in CT imaging), 6 cases of adenocarcinoma in situ (all were pure GGO in CT imaging), 1 case of lung squamous cell carcinoma (mainly composed of solid in CT imaging). An average of 7.2 lymph nodes were removed in 25 cases of lung cancer, and all lymph nodes had no metastasis. CONCLUSIONS: VATS anatomical segmentectomy is technically safe and reliable, and the indications for lung cancer need to be strictly controlled. Its advantages still need to be confirmed by prospective randomized controlled trials.

Neoadjuvant chemotherapy followed by minimally invasive esophagectomy is safe and feasible for treatment of esophageal squamous cell carcinoma.

BACKGROUND: The advantage of neoadjuvant chemotherapy (NAC) followed by open esophagectomy for treatment of esophageal squamous cell carcinoma has been widely recognized. However, the safety and feasibility of NAC for patients receiving minimally invasive esophagectomy (MIE) remain controversial. The purpose of this study was to evaluate the potential impact of prior neoadjuvant chemotherapy on the clinical outcome of MIE by comparing two groups of patients, MIE alone and NAC plus MIE. METHODS: From May 2013 to July 2017, 124 patients with esophageal squamous cell carcinoma underwent MIE in our department, with 57 cases receiving NAC plus MIE and 67 cases receiving MIE alone. Perioperative parameters and short-term postoperative survival were compared between these two groups to evaluate the safety and feasibility of NAC given before MIE. RESULTS: The group with NAC plus MIE had slightly longer operating time, more blood loss, higher morbidity, increased chance of surgical intensive care unit stay, and longer surgical intensive care unit stay time than the group with MIE alone. However, there was no statistically significant difference between these two groups (P > 0.05). The number of lymph nodes harvested was similar in the two groups without significant difference (P > 0.05). The overall survival was not significantly different between these two groups either (P > 0.05), although before surgery the clinical stage of the group with NAC plus MIE was more advanced than the group with MIE alone. CONCLUSIONS: NAC followed by MIE is safe and feasible for treatment of esophageal squamous cell carcinoma. NAC does not negatively impact the therapeutic outcome of MIE.

Minimally invasive esophagectomy in the lateral-prone position: Experience of 124 cases in a single center.

BACKGROUND: Minimally invasive esophagectomy was first introduced as a new technique for esophageal cancer treatment 20 years ago. Performing this procedure in the lateral-prone position is the most appropriate method. Since May 2013, our center has performed 124 esophageal cancer operations using this procedure. Herein, we share our experience. METHODS: We retrospectively reviewed 124 consecutive patients who had received minimally invasive esophagectomy in the lateral-prone position from May 2013 to June 2017. The procedure, operative variables, postoperative complications, and oncology outcomes were assessed. RESULTS: The surgery was successful in all 124 patients; three cases converted to an abdominal opening procedure during surgery. The mean total lymph node harvest was 19.2: 12.9 in the thoracic cavity and 6.0 in the abdominal cavity. The average total operation duration was 376 minutes and blood loss was 156 mL. No mortality occurred within 30 postoperative days. Forty-three cases of postoperative morbidity occurred in 38 patients (30.6%), including 11 anastomotic leakages (8.9%), 1 chyle leak (0.8%), 12 lateral recurrent nerve palsies (9.7%), 11 pulmonary complications (8.9%), and 8 other complications (6.5%). A learning curve indicated that blood loss, operation duration, and the number of lymph nodes harvested would improve with time. CONCLUSIONS: Surgical and oncological outcomes following minimally invasive esophagectomy for esophageal cancer were acceptable. There are some advantages to this technique compared to previous reports of opening procedures.