Journal articles: 'Vrram'

1

Sun, Wookyung, Sujin Choi, Bokyung Kim, and Hyungsoon Shin. "Effect of Initial Synaptic State on Pattern Classification Accuracy of 3D Vertical Resistive Random Access Memory (VRRAM) Synapses." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 4730–34. http://dx.doi.org/10.1166/jnn.2020.17798.

Full text

Abstract:

Amidst the considerable attention artificial intelligence (AI) has attracted in recent years, a neuromorphic chip that mimics the biological neuron has emerged as a promising technology. Memristor or Resistive random-access memory (RRAM) is widely used to implement a synaptic device. Recently, 3D vertical RRAM (VRRAM) has become a promising candidate to reducing resistive memory bit cost. This study investigates the operation principle of synapse in 3D VRRAM architecture. In these devices, the classification response current through a vertical pillar is set by applying a training algorithm to the memristors. The accuracy of neural networks with 3D VRRAM synapses was verified by using the HSPICE simulator to classify the alphabet in 7×7 character images. This simulation demonstrated that 3D VRRAMs are usable as synapses in a neural network system and that a 3D VRRAM synapse should be designed to consider the initial value of the memristor to prepare the training conditions for high classification accuracy. These results mean that a synaptic circuit using 3D VRRAM will become a key technology for implementing neural computing hardware.

APA, Harvard, Vancouver, ISO, and other styles

2

Chen, Zhisheng, Renjun Song, Qiang Huo, Qirui Ren, Chenrui Zhang, Linan Li, and Feng Zhang. "Analysis of Leakage Current of HfO2/TaOx-Based 3-D Vertical Resistive Random Access Memory Array." Micromachines 12, no. 6 (May 26, 2021): 614. http://dx.doi.org/10.3390/mi12060614.

Full text

Abstract:

Three-dimensional vertical resistive random access memory (VRRAM) is proposed as a promising candidate for increasing resistive memory storage density, but the performance evaluation mechanism of 3-D VRRAM arrays is still not mature enough. The previous approach to evaluating the performance of 3-D VRRAM was based on the write and read margin. However, the leakage current (LC) of the 3-D VRRAM array is a concern as well. Excess leakage currents not only reduce the read/write tolerance and liability of the memory cell but also increase the power consumption of the entire array. In this article, a 3-D circuit HSPICE simulation is used to analyze the impact of the array size and operation voltage on the leakage current in the 3-D VRRAM architecture. The simulation results show that rapidly increasing leakage currents significantly affect the size of 3-D layers. A high read voltage is profitable for enhancing the read margin. However, the leakage current also increases. Alleviating this conflict requires a trade-off when setting the input voltage. A method to improve the array read/write efficiency is proposed by analyzing the influence of the multi-bit operations on the overall leakage current. Finally, this paper explores different methods to reduce the leakage current in the 3-D VRRAM array. The leakage current model proposed in this paper provides an efficient performance prediction solution for the initial design of 3-D VRRAM arrays.

APA, Harvard, Vancouver, ISO, and other styles

3

Sun, Wookyung, Sujin Choi, Bokyung Kim, and Junhee Park. "Three-Dimensional (3D) Vertical Resistive Random-Access Memory (VRRAM) Synapses for Neural Network Systems." Materials 12, no. 20 (October 22, 2019): 3451. http://dx.doi.org/10.3390/ma12203451.

Full text

Abstract:

Memristor devices are generally suitable for incorporation in neuromorphic systems as synapses because they can be integrated into crossbar array circuits with high area efficiency. In the case of a two-dimensional (2D) crossbar array, however, the size of the array is proportional to the neural network’s depth and the number of its input and output nodes. This means that a 2D crossbar array is not suitable for a deep neural network. On the other hand, synapses that use a memristor with a 3D structure are suitable for implementing a neuromorphic chip for a multi-layered neural network. In this study, we propose a new optimization method for machine learning weight changes that considers the structural characteristics of a 3D vertical resistive random-access memory (VRRAM) structure for the first time. The newly proposed synapse operating principle of the 3D VRRAM structure can simplify the complexity of a neuron circuit. This study investigates the operating principle of 3D VRRAM synapses with comb-shaped word lines and demonstrates that the proposed 3D VRRAM structure will be a promising solution for a high-density neural network hardware system.

APA, Harvard, Vancouver, ISO, and other styles

4

Alimkhanuly, Batyrbek, Sanghoek Kim, Lok-won Kim, and Seunghyun Lee. "Electromagnetic Analysis of Vertical Resistive Memory with a Sub-nm Thick Electrode." Nanomaterials 10, no. 9 (August 20, 2020): 1634. http://dx.doi.org/10.3390/nano10091634.

Full text

Abstract:

Resistive random access memories (RRAMs) are a type of resistive memory with two metal electrodes and a semi-insulating switching material in-between. As the persistent technology node downscaling continues in transistor technologies, RRAM designers also face similar device scaling challenges in simple cross-point arrays. For this reason, a cost-effective 3D vertical RRAM (VRRAM) structure which requires a single pivotal lithography step is attracting significant attention from both the scientific community and the industry. Integrating an extremely thin plane electrode to such a structure is a difficult but necessary step to enable high memory density. In addition, experimentally verifying and modeling such devices is an important step to designing RRAM arrays with a high noise margin, low resistive-capacitive (RC) delays, and stable switching characteristics. In this work, we conducted an electromagnetic analysis on a 3D vertical RRAM with atomically thin graphene electrodes and compared it with the conventional metal electrode. Based on the experimental device measurement results, we derived a theoretical basis and models for each VRRAM design that can be further utilized in the estimation of graphene-based 3D memory at the circuit and architecture levels. We concluded that a 71% increase in electromagnetic field strength was observed in a 0.3 nm thick graphene electrode when compared to a 5 nm thick metal electrode. Such an increase in the field led to much lower energy consumption and fluctuation range during RRAM switching. Due to unique graphene properties resulting in improved programming behavior, the graphene-based VRRAM can be a strong candidate for stacked storage devices in new memory computing platforms.

APA, Harvard, Vancouver, ISO, and other styles

5

Choi, Sujin, Wookyung Sun, and Hyungsoon Shin. "Analysis of Read Margin and Write Power Consumption of a 3-D Vertical RRAM (VRRAM) Crossbar Array." IEEE Journal of the Electron Devices Society 6 (2018): 1192–96. http://dx.doi.org/10.1109/jeds.2018.2873016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Wu, Min‐Ci, Yi‐Hsin Ting, Jui‐Yuan Chen, and Wen‐Wei Wu. "Low Power Consumption Nanofilamentary ECM and VCM Cells in a Single Sidewall of High‐Density VRRAM Arrays." Advanced Science 6, no. 24 (October 7, 2019): 1902363. http://dx.doi.org/10.1002/advs.201902363.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Choi, Sujin, Wookyung Sun, and Hyungsoon Shin. "Analysis of Cell Variability Impact on a 3-D Vertical RRAM (VRRAM) Crossbar Array Using a Modified Lumping Method." IEEE Transactions on Electron Devices 66, no. 1 (January 2019): 759–65. http://dx.doi.org/10.1109/ted.2018.2878440.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Yu, Jie, Woyu Zhang, Danian Dong, Wenxuan Sun, Jinru Lai, Xu Zheng, Tiancheng Gong, et al. "Long-Term Accuracy Enhancement of Binary Neural Networks Based on Optimized Three-Dimensional Memristor Array." Micromachines 13, no. 2 (February 17, 2022): 308. http://dx.doi.org/10.3390/mi13020308.

Full text

Abstract:

In embedded neuromorphic Internet of Things (IoT) systems, it is critical to improve the efficiency of neural network (NN) edge devices in inferring a pretrained NN. Meanwhile, in the paradigm of edge computing, device integration, data retention characteristics and power consumption are particularly important. In this paper, the self-selected device (SSD), which is the base cell for building the densest three-dimensional (3D) architecture, is used to store non-volatile weights in binary neural networks (BNN) for embedded NN applications. Considering that the prevailing issues in written data retention on the device can affect the energy efficiency of the system’s operation, the data loss mechanism of the self-selected cell is elucidated. On this basis, we introduce an optimized method to retain oxygen ions and prevent their diffusion toward the switching layer by introducing a titanium interfacial layer. By using this optimization, the recombination probability of Vo and oxygen ions is reduced, effectively improving the retention characteristics of the device. The optimization effect is verified using a simulation after mapping the BNN weights to the 3D VRRAM array constructed by the SSD before and after optimization. The simulation results showed that the long-term recognition accuracy (greater than 105 s) of the pre-trained BNN was improved by 24% and that the energy consumption of the system during training can be reduced 25,000-fold while ensuring the same accuracy. This work provides high storage density and a non-volatile solution to meet the low power consumption and miniaturization requirements of embedded neuromorphic applications.

APA, Harvard, Vancouver, ISO, and other styles

9

Lo, Shih-Che, and Hung-Hsu Tsai. "Design of 3D Virtual Reality in the Metaverse for Environmental Conservation Education Based on Cognitive Theory." Sensors 22, no. 21 (October 30, 2022): 8329. http://dx.doi.org/10.3390/s22218329.

Full text

Abstract:

Background: Climate change causes devastating impacts with extreme weather conditions, such as flooding, polar ice caps melting, sea level rise, and droughts. Environmental conservation education is an important and ongoing project nowadays for all governments in the world. In this paper, a novel 3D virtual reality architecture in the metaverse (VRAM) is proposed to foster water resources education using modern information technology. Methods: A quasi-experimental study was performed to observe a comparison between learning involving VRAM and learning without VRAM. The 3D VRAM multimedia content comes from a picture book for learning environmental conservation concepts, based on the cognitive theory of multimedia learning to enhance human cognition. Learners wear VRAM helmets to run VRAM Android apps by entering the immersive environment for playing and/or interacting with 3D VRAM multimedia content in the metaverse. They shake their head to move the interaction sign to initiate interactive actions, such as replaying, going to consecutive video clips, displaying text annotations, and replying to questions when learning soil-and-water conservation course materials. Interactive portfolios of triggering actions are transferred to the cloud computing database immediately by the app. Results: Experimental results showed that participants who received instruction involving VRAM had significant improvement in their flow experience, learning motivation, learning interaction, self-efficacy, and presence in learning environmental conservation concepts. Conclusions: The novel VRAM is highly suitable for multimedia educational systems. Moreover, learners’ interactive VRAM portfolios can be analyzed by big-data analytics to understand behaviors for using VRAM in the future to improve the quality of environmental conservation education.

APA, Harvard, Vancouver, ISO, and other styles

10

Chaudhry, Arif, Jeremie D. Oliver, Krishna S. Vyas, Nho V. Tran, Jorys Martinez-Jorge, David Larson, Eric Dozois, Heidi Nelson, and Oscar J. Manrique. "Comparison of Outcomes in Oncoplastic Pelvic Reconstruction with VRAM versus Omental Flaps: A Large Cohort Analysis." Journal of Reconstructive Microsurgery 35, no. 06 (January 18, 2019): 425–29. http://dx.doi.org/10.1055/s-0038-1677524.

Full text

Abstract:

Background The purpose of this study is to describe our experience and outcomes in oncoplastic pelvic reconstruction for patients who underwent either vertical rectus abdominis musculocutaneous (VRAM) or omental flap following abdominoperineal resection (APR) at a single tertiary care institution. Methods All patients who underwent pelvic reconstruction following APR with either VRAM or omental flaps from January 1992 to January 2017 were retrospectively reviewed. Patient demographics and relevant comorbidities including chemotherapy and radiation therapy data were collected and analyzed. In addition, margin status at the time of oncologic resection was analyzed. Flap-specific data were collected for each approach. Oncologic data collected included cancer type, stage at time of APR, and rate of tumor recurrence within the flap. Results A total of 562 patients were identified who underwent pelvic reconstruction with either VRAM or omental pedicle flaps. Of these, 274 (48.8%) underwent VRAM reconstruction and 288 (51.2%) underwent omental flap reconstruction. All margins were negative at time of cancer ablation surgery. Complications data included: seroma (VRAM = 2 [0.36%]; omentum = 32 [5.69%], p < 0.0001), wound dehiscence (VRAM = 31 [5.52%]; omentum = 17 [3.02%], p = 0.022), abscess (VRAM = 4 [0.71%]; omentum = 27 [4.8%], p < 0.0001), cellulitis (VRAM = 2 [0.36%]; omentum = 10 [1.78%], p = 0.025). Statistical comparison of tumor recurrence between these two reconstructive approaches showed a significantly higher recurrence rate in omental flaps compared with VRAM flaps (p = 0.000127). Conclusion The results of this study suggest a significantly higher tumor recurrence rate in omental flap pelvic reconstruction compared with VRAM flaps. This knowledge has the potential to influence surgical planning and flap selection in pelvic reconstruction.

APA, Harvard, Vancouver, ISO, and other styles

11

Preetha Rani, K., J. Satish Kumar, V. Singaravelu, and Fernandes Deyonna. "Gracilis Myocutaneous Flap: Adding to the Armamentarium of Complex Sacrococcygeal Defect Reconstruction." Indian Journal of Plastic Surgery 52, no. 02 (May 2019): 246–49. http://dx.doi.org/10.1055/s-0039-1696078.

Full text

Abstract:

Abstract Background With increasing radicality of rectal cancer surgeries, the postoperative defects are becoming more complex. This demands an ideal reconstructive option with minimal morbidity to the patient. Although vertical rectus abdominis myocutaneous (VRAM) flap is the commonly used flap, gracilis myocutaneous flap is increasingly being performed to avoid morbidity associated with VRAM flap. Results We share our experience about two of our patients treated for rectal malignancy with pelvic exenteration who were reconstructed immediately with pedicled gracilis myocutaneous flap. Both the patients had an uneventful postoperative recovery period and were discharged on postoperative day 10. During follow-up period both patients had a healthy flap with no evidence of recurrence. No perineal hernias or gross dehiscence of skin closure occurred. Conclusion Gracilis myocutaneous flap has its own place with unique advantages adding to the armamentarium of reconstructive options for complex perineal defects, thereby avoiding the morbidity associated with VRAM flap. It stands as a reliable alternative in patients where VRAM cannot be used.

APA, Harvard, Vancouver, ISO, and other styles

12

Stein, Michael, and Moein Momtazi. "Bladder Outlet Obstruction as a Cause for Late Total Flap Failure in Pelvic Reconstruction with a VRAM." Journal of Reconstructive Microsurgery Open 03, no. 02 (July 2018): e55-e57. http://dx.doi.org/10.1055/s-0038-1669453.

Full text

Abstract:

Background A 67-year-old man presented with abrupt failure of a pedicled vertical rectus abdominus myocutaneous (VRAM) flap 13 days postoperatively. Methods The patient underwent pelvic reconstruction with a pedicled VRAM flap following sacral chordoma and abdominoperineal resection. The flap remained well perfused and viable until postoperative day 13, at which point the patient was noted to become systemically unwell with fever, chills, and abdominal pain. This clinically coincided with prompt arterial and venous insufficiency of the VRAM flap. Results Computed tomography of the abdomen was ordered to rule out a pelvic collection and revealed an inflated Foley catheter in the bulbar urethra. This was associated with marked distention of the bladder and bilateral hydronephrosis. Direct compression of the deep inferior epigastric pedicle by the bladder neck was noted. Conclusion The case highlights the importance of considering bladder outlet obstruction and subsequent distention as a cause of pedicle compression and VRAM flap failure following pelvic reconstruction.

APA, Harvard, Vancouver, ISO, and other styles

13

Hinojosa, Marcelo W., Dhavan A. Parikh, Raman Menon, Garrett A. Wirth, Michael J. Stamos, and Steven Mills. "Recent Experience with Abdominal Perineal Resection with Vertical Rectus Abdominis Myocutaneous Flap Reconstruction after Preoperative Pelvic Radiation." American Surgeon 75, no. 10 (October 2009): 995–99. http://dx.doi.org/10.1177/000313480907501029.

Full text

Abstract:

Abdominoperineal resection (APR) after pelvic radiation can be complicated by an increased rate of difficult to treat perineal wound complications. In an effort to improve postoperative morbidity after APR, myocutaneous flap reconstructions have been used. We review our recent experience with APR with vertical rectus abdominis myocutaneous flap reconstruction (VRAM) after preoperative pelvic radiation. A retrospective review of patients who underwent APR with VRAM reconstruction after pelvic radiation from December 2004 to July 2008 was conducted. Outcome measures included demographics, comorbidities, length of stay, wound complications, and morbidity and mortality. Fifteen patients with a mean age of 61 ± 9 years underwent APR with VRAM reconstruction. Five patients also required posterior vaginectomy with the APR. Indications for APR were rectal cancer (n = 14, 93%) and anal canal cancer (n = 1, 7%). There were no intraoperative complications. Mean estimated blood loss was 635 ± 446 mL and mean intraoperative blood transfusion requirements were 1 ± 2 units. Mean length of hospital stay was 11 ± 4 days. Six (40%) patients had minor perineal wound complications. One (7%) patient had a perineal wound infection requiring reoperation with washout and reapproximation. There was no 30-day or in-hospital mortality. All VRAM flaps remained viable through follow-up. APR with VRAM flap reconstruction after preoperative pelvic radiation can be performed safely with limited wound complications and no mortality.

APA, Harvard, Vancouver, ISO, and other styles

14

Tóth, Bence, János Vad, and Gábor Kotán. "Comparison of the Rotating Source Identifier and the Virtual Rotating Array Method." Periodica Polytechnica Mechanical Engineering 62, no. 4 (July 16, 2018): 261–68. http://dx.doi.org/10.3311/ppme.11194.

Full text

Abstract:

The aim of this paper is to present two acoustic beamforming methods developed for rotating sources, namely the Rotating Source Identifier (ROSI) and the Virtual Rotating Array method (VRAM). These were applied onto a series of simulated test cases, and their behaviour was analysed. Both methods were able to localise the source reliably. However, the source strength was found to depend on the number or microphones when VRAM was applied. This phenomenon was quantified and an approximate formula was given providing the minimum number of microphones required to reach a certain amplitude error. Beamwidth and side lobe suppression were found to agree between the two methods, meaning that the way rotation is handled does not significantly affect the point spread functions. The computational cost of ROSI was two to three orders of magnitude higher than that of VRAM. The results show that both methods are applicable for the beamforming analysis of rotating sound sources. However, in case of VRAM, the number of microphones has to be chosen carefully to obtain reliable amplitude results.

APA, Harvard, Vancouver, ISO, and other styles

15

Khalil, Haitham H., Ahmed El-Ghoneimy, Yasser Farid, Walid Ebeid, Ahmed Afifi, Ahmed Elaffandi, and Tarek Mahboub. "Modified Vertical Rectus Abdominis Musculocutaneous Flap for Limb Salvage Procedures in Proximal Lower Limb Musculoskeletal Sarcomas." Sarcoma 2008 (2008): 1–6. http://dx.doi.org/10.1155/2008/781408.

Full text

Abstract:

Introduction and aim. Management of complicated wounds after tumor extipiration of pelvic and proximal lower limb musculoskeletal sarcoma represents an essential component in the outcome of these patients. The authors present modified vertical rectus abdominis musculocutaneous (VRAM) flap techniques to reconstruct extensive defects after debridment of these complicated wounds.Material and Methods. Over a period of 4 years (2002–2005), 5 men and 2 women were managed. Median age was 21 years (range 15–49). The patients were managed for complicated lower trunk, groin, and upper thigh wounds after resection of three pelvic chondrosarcomas as well as two pelvic and two proximal femur osteosarcomas. The modifications included a VRAM flap with lateral and tongue-like extension design of the skin paddle (5 cases) or a delayed extended VRAM flap (2 cases).Results. All flaps showed complete survival and healing with no ischemic events providing stable coverage. All patients were ambulant with good limb functions in terms of walking and gait after adequate rehabilitation, 2 needed support with crutches.Conclusion. The modified VRAM flaps offer reliable reconstructive tools for coverage of complex groin and thigh defects by providing larger well-vascularized soft tissue with acceptable donor site.

APA, Harvard, Vancouver, ISO, and other styles

16

Ainge, David J. "Upper Primary Students Constructing and Exploring Three Dimensional Shapes: A Comparison of Virtual Reality with Card Nets." Journal of Educational Computing Research 14, no. 4 (June 1996): 345–69. http://dx.doi.org/10.2190/kr4e-tunn-gyvd-jr9u.

Full text

Abstract:

A grade six/seven class which constructed and explored 3D shapes worlds with the VREAM program was compared with a grade five/six/seven control group which constructed and examined shapes from card nets. Students were tested on visualizing appearance of shapes from alternative viewpoints, recognition of shapes in the environment, and writing shape names, before and after the learning phase. Ease of using Virtual Reality (VR), and student engagement with VR were observed informally. VR had little impact on shape visualization and name writing, but strongly enhanced recognition. Students had no major difficulty in using the VREAM program, and enthusiasm for VR was unanimous and sustained.

APA, Harvard, Vancouver, ISO, and other styles

17

Eseme, Ebai A., Matteo Scampa, Juan A. Viscardi, Myriam Ebai, Daniel F. Kalbermatten, and Carlo M. Oranges. "Surgical Outcomes of VRAM vs. Gracilis Flaps in Vulvo-Perineal Reconstruction following Oncologic Resection: A Proportional Meta-Analysis." Cancers 14, no. 17 (September 1, 2022): 4300. http://dx.doi.org/10.3390/cancers14174300.

Full text

Abstract:

Pelvic exenteration and abdominoperineal resection are radical techniques commonly used for locally advanced or recurrent pelvic malignancy with high morbidity due to large pelvic defects. Flaps can help provide healthy, well-vascularized, non-irradiated tissues to fill pelvic dead space. We conducted a proportional meta-analysis to compare surgical outcomes of vertical rectus abdominus myocutaneous flap (VRAM) vs. gracilis flap for vulvo-perineal reconstruction following oncologic resection. A comprehensive literature search was conducted in the MEDLINE, PubMed, Embase, Google Scholar, and Cochrane Library databases. Proportional meta-analysis was performed to compare the surgical outcomes of using VRAM or gracilis flaps. Our review yielded 16 eligible studies. The pooled resolution rate of overall donor site complications for VRAM flap (pooled proportion = 0.576 [95% CI 0.387, 0.754]) was significantly higher than the pooled rate of overall donor site complications of gracilis flap (pooled proportion = 0.160 [95% CI 0.058, 0.295]). Partial and total flap necrosis were similar in both groups. There was no statistically significant difference between minor and major complications for both flaps. Both flaps can be used safely for vulvo-perineal reconstruction following oncologic resection with similar recipient site outcomes, although the VRAM flap will have more donor site complications than the gracilis flap.

APA, Harvard, Vancouver, ISO, and other styles

18

Soper, J. T., L. J. Havrilesky, A. A. Secord, A. Berchuck, and D. L. Clarke-Pearson. "Rectus abdominis myocutaneous flaps for neovaginal reconstruction after radical pelvic surgery." International Journal of Gynecologic Cancer 15, no. 3 (2005): 542–48. http://dx.doi.org/10.1136/ijgc-00009577-200505000-00021.

Full text

Abstract:

The objective of this article is to compare the flap-specific complications associated with vertical (VRAM) and transverse (TRAM) rectus abdominis myocutaneous flap vaginal reconstructions performed during radical pelvic procedures. A retrospective chart review was performed to identify all patients who underwent VRAM and TRAM neovaginal reconstructions performed on the Gynecologic Oncology Service at Duke University Medical Center. Flap-specific complications were compared between the two techniques. From 1988 to 2003, 14 VRAM and 18 TRAM flap neovaginal reconstructions were performed on 32 women during the course of 22 (68%) total pelvic exenterations, 8 (25%) partial exenterations, and 2 (6%) radical vulvovaginectomies. Twenty-eight (88%) patients had been previously treated with radiation therapy or concurrent chemoradiation. Associated procedures included continent urinary conduit in 21 (66%), rectosigmoid reanastomosis in 8 (25%), and intraoperative or postoperative sidewall radiation therapy in 7 (22%) of patients. Overall median survival was 14 months (range: 2-week postoperative death to 65 months), with two (6%) acute postoperative mortalities. Fifteen flap-specific complications occurred in 12 (38%) patients, with no significant differences in flap type. Abdominal wound complications included four (12%) superficial wound separations, while one (3%) patient had a fascial dehiscence associated with complex fistulas that contributed to her death, but no patient developed incisional hernia. One patient each developed >50% flap loss after TRAM and <50% flap loss after VRAM flap, respectively. Four (12%) patients developed vaginal stricture or stenosis, two (6%) required percutaneous drainage of pelvic abscess or hematoma, and two (6%) developed rectovaginal fistula. Univariate analysis revealed a trend for increasing flap loss with body mass index >35 (P = 0.056, Fisher exact two-tailed test), but there were no significant associations with other patient characteristics or flap-specific complications. Thirteen (62%) of 21 patients who survived >12 months reported coitus. Both VRAM and TRAM are reliable techniques for neovaginal reconstructions after radical pelvic surgery and have a similar distribution of flap-specific complications involving the donor and recipient sites.

APA, Harvard, Vancouver, ISO, and other styles

19

Alfadz Kholifah Akbar, Muhammad Pratama Mandala Putra, and Denny Irwansyah. "The Vertical Rectus Abdominis Myocutaneous Flap for Complex Abdominal Wall Reconstruction on a Relapse Case of Monophasic Synovial Sarcoma." Asian Journal of Health Research 2, no. 1 (March 8, 2023): 56–60. http://dx.doi.org/10.55561/ajhr.v2i1.70.

Full text

Abstract:

Introduction: Vertical Rectus Abdominis Myocutaneous (VRAM) flap is a chosen method for a large wound closure instead of Anterolateral Thigh (ALT) flap. Both versatile and highly vascularized flaps share almost similar advantages for large wound closure. In our case, the site and size of the wound are the points of consideration. Case Presentation: A 16-year-old girl with a chief complaint of a large progressive lower abdominal mass enlarged since January 2021 that has grown back from the same site. Abdominal CT-Scan shows a tumor in the right lower abdomen infiltrated to the pelvic cavity and spanning from the lower abdominal area all the way to the groin area. Histopathology interpretation suggests a Monophasic Synovial Sarcoma. The patient underwent a second tumor resection with VRAM flap as the wound closure. The benefits of this versatile flap are excellent dead space obliteration and low Surgical Site Occurrence (SSO’s). Conclusion: As postulated in many studies VRAM flap is an excellent flap for a CAWR procedure. The expected SSO’s is non-existence during the postoperative follow-up

APA, Harvard, Vancouver, ISO, and other styles

20

Baruah, Upasana, Apoorva Tak, Debabrata Barmon, and Dimpy Begum. "Vulvar reconstruction in post-RT case using the versatile VRAM flap: reporting the rare extrapelvic approach." BMJ Case Reports 16, no. 4 (April 2023): e254773. http://dx.doi.org/10.1136/bcr-2023-254773.

Full text

Abstract:

Although primary vulvovaginal reconstruction following vulvectomy has a significant chance of improving patient outcomes, flap reconstruction is not a recognised component of the accepted standard of care for vulvar cancer. We provide a case of a patient who underwent successful vulvar reconstruction using the extrapelvic vertical rectus abdominis myocutaneous (VRAM) flap. This musculocutaneous flap offers adequate coverage and bulk to the perineal defect after excision in post-irradiated vulvar cancer.To proceed with sphincter-saving surgery, she was scheduled for neoadjuvant chemoradiation, as the lesion involved the urethra and perineal body. However, she experienced severe grade IV dermatitis after receiving 37 Gy of radiation. Though the lesion had reduced in size, it was still large enough to cause significant perineal deformity.We performed a vulvar reconstructive surgery using the uncommon but reliable extrapelvic VRAM flap. This well-vascularised VRAM flap is particularly useful in irradiated areas prone to poor healing. Postoperatively, the wound healed well and the patient underwent adjuvant therapy 6 weeks later. We emphasise the advantages of well-perfused muscle for the primary repair of prior irradiated perineal lesions.

APA, Harvard, Vancouver, ISO, and other styles

21

Yeo, Hyun-Dong, Jae-Ho Chung, Seung-Ha Park, Byung-Il Lee, and Eul-Sik Yoon. "Vertical Rectus Abdominis Myocutaneous-Pedicled Island Flap for Covering Defect of the Suprapubic Area: A Case Report." Journal of Wound Management and Research 17, no. 2 (June 30, 2021): 154–57. http://dx.doi.org/10.22467/jwmr.2021.01564.

Full text

Abstract:

Immediate reconstruction of defects in the lower abdomen is challenging. We present a successful reconstruction case using a vertical rectus abdominis myocutaneous (VRAM) flap for a radiation ulcer on the suprapubic area following radiation therapy for recurred malignant melanoma. Before flap elevation, we conducted sufficient debridement until pliable healthy tissue was revealed. Afterwards, a 15×9 cm VRAM flap was elevated. We then inserted the flap through a suprafascial tunnel. At 6 months postoperatively, a completely healed aesthetic flap was achieved. This case is meaningful in that it involves a successful reconstruction of a sizable abdominal wall defect of the suprapubic area with unhealthy and unviable adjacent tissue following repeated surgery and chemoradiotherapy.

APA, Harvard, Vancouver, ISO, and other styles

22

Horch, Raymund E., Ingo Ludolph, Andreas Arkudas, and Aijia Cai. "Personalized Reconstruction of Genital Defects in Complicated Wounds with Vertical Rectus Abdominis Myocutaneous Flaps including Urethral Neo-Orifice." Journal of Personalized Medicine 11, no. 11 (October 24, 2021): 1076. http://dx.doi.org/10.3390/jpm11111076.

Full text

Abstract:

Non-healing extensive wounds in the perineal region can lead to severe soft tissue infections and disastrous complications, which are not manageable with conservative measures. Specifically in recurrent or advanced pelvic malignancies, irradiation often leads to extensive scarring and wound breakdown, resulting in significant soft tissue defects during surgical tumor excision. Among several surgical options to reconstruct the perineum, the transpelvic vertical rectus abdominis myocutaneous (VRAM) flap has proven to be one of the most reliable methods. Specific modifications of this flap allow an individualized procedure depending on the patient’s needs. We modified this technique to include the urethral orifice into the skin paddle of VRAM flaps in three patients as a novel option to circumvent urinary diversion and maintain an acceptable quality of life.

APA, Harvard, Vancouver, ISO, and other styles

23

Nakagawa, Tsuyoshi, Goshi Oda, Hiroki Mori, Noriko Uemura, Kimio Wakana, Noriko Oshima, Masanori Tokunaga, et al. "Laparoscopic Abdominal Surgery after Primary Breast Reconstruction Using an Abdominal Flap." Medicina 57, no. 9 (September 10, 2021): 952. http://dx.doi.org/10.3390/medicina57090952.

Full text

Abstract:

Background and objectives: Our department has been performing primary breast reconstruction for breast cancer surgery, incorporating a transverse rectus abdominis myocutaneous flap (TRAM)/vertical rectus abdominis myocutaneous flap (VRAM) since 1998 and a deep inferior epigastric artery perforator flap (DIEP) since 2008. Currently, most gastrointestinal operations in abdominal surgery are performed laparoscopically or are robot-assisted. Cases in which abdominal surgery was performed after breast reconstruction using an abdominal flap were reviewed. Method: A total of 119 cases of primary breast reconstruction using an abdominal flap performed in our department were reviewed. Result: The reconstructive techniques were DIEP in 69 cases and TRAM/VRAM in 50 cases. After breast surgery, seven abdominal operations were performed in six cases. In DIEP cases, one robotic surgery was performed for uterine cancer, and one laparoscopic surgery was performed for ovarian tumor. In TRAM/VRAM cases, two laparoscopic cholecystectomies, one laparoscopic total gastrectomy, one laparoscopic ileus reduction, and one open total hysterectomy oophorectomy were performed. Six surgeries were completed by laparoscopy or robotic assistance. Conclusion: The survival rate after breast cancer surgery is improving, and the choice of breast reconstruction procedure should take into account the possibility of performing a prophylactic resection of the ovaries due to the genetic background and possibly postoperative abdominal surgery due to other diseases. However, in cases in which laparoscopic surgery was attempted after breast reconstruction using an abdominal flap, the laparoscopic surgery could be completed in all cases.

APA, Harvard, Vancouver, ISO, and other styles

24

Schellerer, Vera S., Lenka Bartholomé, Melanie C. Langheinrich, Robert Grützmann, Raymund E. Horch, Susanne Merkel, and Klaus Weber. "Donor Site Morbidity of Patients Receiving Vertical Rectus Abdominis Myocutaneous Flap for Perineal, Vaginal or Inguinal Reconstruction." World Journal of Surgery 45, no. 1 (September 29, 2020): 132–40. http://dx.doi.org/10.1007/s00268-020-05788-5.

Full text

Abstract:

Abstract Background Management of donor site closure after harvesting a vertical rectus abdominis myocutaneous (VRAM) flap is discussed heterogeneously in the literature. We aim to analyze the postoperative complications of the donor site depending on the closure technique. Methods During a 12-year period (2003–2015), 192 patients in our department received transpelvic VRAM flap reconstruction. Prospectively collected data were analyzed retrospectively. Results 182 patients received a VRAM flap reconstruction for malignant, 10 patients for benign disease. The median age of patients was 62 years. 117 patients (61%) received a reconstruction of donor site by Vypro® mesh, 46 patients (24%) by Vicryl® mesh, 23 patients (12%) by direct closure and 6 patients (3%) by combination of different meshes. 32 patients (17%) developed in total 34 postoperative complications at the donor site. 22 complications (11%) were treated conservatively, 12 (6%) surgically. 17 patients (9%) developed incisional hernia during follow-up, with highest incidence in the Vicryl® group (n = 8; 17%) and lowest in the Vypro® group (n = 7; 6%). Postoperative parastomal hernias were found in 30 patients (16%) including three patients with simultaneous hernia around an urostomy and a colostomy. The highest incidence of parastomal hernia was found in patients receiving primary closure of the donor site (n = 6; 26%), the lowest incidence in the Vypro® group (n = 16; 14%). Conclusion The use of Vypro® mesh for donor site closure appears to be associated with a low postoperative incidence of complications and can therefore be recommended as a preferred technique.

APA, Harvard, Vancouver, ISO, and other styles

25

Wamalwa, A. O., and S. O. Khainga. "VRAM flap for an above knee amputation stump." JPRAS Open 23 (March 2020): 11–18. http://dx.doi.org/10.1016/j.jpra.2019.11.002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Mir, Mushtaq, Muddassir Shahdhar, Khurshid Ganaie, and Quibtiya Syed. "Oncological safety of immediate rectus abdominis myocutaneous breast reconstruction in patients with locally advanced disease (stage IIb and III)." South Asian Journal of Cancer 02, no. 04 (October 2013): 239–42. http://dx.doi.org/10.4103/2278-330x.119921.

Full text

Abstract:

Abstract Background: The management of locally advanced (Stage IIb and III) breast cancer is challenging. It often includes multimodal treatment with systemic therapy and/or radiation therapy and surgery. Immediate breast reconstruction has not traditionally been performed in these patients. We review the results of immediate rectus abdominis musculo-cutaneous (TRAM/VRAM) flap in 60 patients treated for Stage IIb and III breast cancer. Materials and Methods: Data were collected prospectively on 60 patients diagnosed with Stage IIb (32 patients) and Stage III (28 patients) breast cancer between May 2008 and May 2012. All patients had mastectomy and immediate rectus abdominis myocutaneous reconstruction (TRAM in 40 patients and VRAM in 20 patients). All patients received primary systemic therapy, and all patients received postoperative radiotherapy to the operative site. Results: Mean age was 40.13 (range 28-53) years, mean hospital stay was 8.86 days and mean follow-up for the group was 28 months. Neither of them developed local disease recurrence in the operative site till the last follow-up. Eight (13.3%) patients had some delay in chemo-radiation therapy due to flap-related complications. Flap-related complications were present in eight patients (partial flap failure in four and superficial skin necrosis in four). There was no adverse effect of chemo-radiation therapy on reconstructed breast. Conclusion: Immediate TRAM/VRAM breast reconstruction for locally advanced breast cancer is not associated with a significant delay in adjuvant therapy or an increased risk of local relapse. Radiation therapy can be delivered to the reconstructed breast when indicated without difficulty. Breast reconstruction facilitates surgical resection of locally advanced breast cancer with primary closure and should be considered if the patient desires immediate breast reconstruction.

APA, Harvard, Vancouver, ISO, and other styles

27

Tokmakov, I. V., L. V. Moskaleva, and M. C. Lin. "Quantum chemical/vRRKM study on the thermal decomposition of cyclopentadiene." International Journal of Chemical Kinetics 36, no. 3 (January 6, 2004): 139–51. http://dx.doi.org/10.1002/kin.10180.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Adrian, Yosef, Rachel Caroline Lesmana, and Sudimanto. "Analisis Performa pada Video Graphic Array (VGA) Nvidia GTX 950M DDR3 dan Nvidia GTX 950M GDDR5." Media Informatika 20, no. 2 (July 31, 2021): 91–96. http://dx.doi.org/10.37595/mediainfo.v20i2.74.

Full text

Abstract:

Video Graphic Array card (VGA) berfungsi untuk memproses data grafik atau sinyal digital pada komputer lalu kemudian sinyal grafik tersebut ditransfer ke layar monitor. VGA card yang dipakai untuk benchmark adalah NVIDIA GTX 950M GDDR5 dan NVIDIA GTX 950M DDR3. VGA card ini cukup diminati karena harga yang terjangkau serta performa yang tinggi dimana kartu grafis ini sudah mempunyai lebar jalur data (bus width) sebesar 128 bit serta terdiri dari varian DDR3 dan GDDR5. Pengambilan data spesifikasi dan performa diambil dari situs Jagat Review Gatot Tri [9] dan Notebookcheck Otshoff [8] yang mana dari data tersebut akan dilakukan analisa terhadap hasil benchmark yang didapat. Berdasarkan data dari spesifikasi dan benchmarking VGA card yang diperoleh, diketahui bahwa perbedaan Double-Data-Rate (DDR) pada Video Random Access Memory (VRAM) berpengaruh besar pada proses merender dan menampilkan gambar. VGA card memiliki komponen-komponen yang saling bekerja sama secara sederhana yaitu chip GPU, besar VRAM, dan tipe DDR. Oleh karena itu, perbedaan tipe DDR pada sebuah VGA card merupakan hal penting dalam performansi sebuah kartu grafis.

APA, Harvard, Vancouver, ISO, and other styles

29

Young, S., N. Pantelide, and S. Iyer. "VRAM steal syndrome – a unique cause of flap necrosis in chest wall reconstruction." Annals of The Royal College of Surgeons of England 100, no. 3 (March 2018): e64-e65. http://dx.doi.org/10.1308/rcsann.2017.0228.

Full text

Abstract:

The pedicled vertical rectus abdominis myocutaneous (VRAM) flap is a robust flap, which is considered to be a ‘workhorse’ regional option for chest wall reconstruction. We describe a previously unreported complication of partial flap loss due to ‘steal syndrome’, whereby arterial supply was diverted away from the flap due to dialysis from an ipsilateral arteriovenous fistula.

APA, Harvard, Vancouver, ISO, and other styles

30

Kim, Bum Sik, Dowon Kim, Soo A. Lim, Su Rak Eo, Yea Sik Han, and Jung Soo Yoon. "Successful Reconstruction of a Lower Chest Wall Defect with Delayed Fungal Deep Sternal Wound Infection following a Blast Injury in South Korea: A Case Report." Journal of Wound Management and Research 18, no. 1 (February 28, 2022): 62–66. http://dx.doi.org/10.22467/jwmr.2021.01879.

Full text

Abstract:

Although blast injuries have been considered a problem unique to military practice or warfare, accidental civilian blast-related injuries due to misplaced landmines have been reported in South Korea. A 71-year-old man was admitted to the emergency room due to multiple severe blast injuries after the detonation of an unknown explosive device. After shrapnel that penetrated the pericardium was removed via median sternotomy in an emergency operation, an extensive defect remained on the lower third of the anterior chest wall. After debriding the contaminated wound several times, chest wall reconstruction with a skin-paddled vertical rectus abdominis muscle (VRAM) flap was successfully performed. However, the patient presented a delayed fungal infection of the deep sternal wound 28 days postoperatively. To salvage the previous flap, antifungal agents were administered and negative-pressure wound therapy was performed between serial radical debridement. The previous flap was successfully salvaged with infection control, and the final defect was covered by re-rotating the previous flap. This case presents the successful reconstruction of a chest wall defect using a skin-paddled VRAM flap notwithstanding a delayed sternal wound infection from a rare civilian blast injury in South Korea.

APA, Harvard, Vancouver, ISO, and other styles

31

Haddock, Nicholas T., Mark D. DeLacure, and Pierre B. Saadeh. "Less Is More: VRAM Inset Modification in Glossectomy Reconstruction." Plastic and Reconstructive Surgery 122, no. 2 (August 2008): 70e—72e. http://dx.doi.org/10.1097/prs.0b013e31817d5f12.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Boccara, David, Kevin Serror, Samuel Levy, Maurice Mimoun, and Marc Chaouat. "Post-operative care of VRAM flaps for perineal reconstruction." Journal of Plastic, Reconstructive & Aesthetic Surgery 71, no. 3 (March 2018): 446–47. http://dx.doi.org/10.1016/j.bjps.2017.11.009.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Kim, Jennifer E., John Pang, Joani M. Christensen, Devin Coon, Patricia L. Zadnik, Jean-Paul Wolinsky, Ziya L. Gokaslan, et al. "Soft-tissue reconstruction after total en bloc sacrectomy." Journal of Neurosurgery: Spine 22, no. 6 (June 2015): 571–81. http://dx.doi.org/10.3171/2014.10.spine14114.

Full text

Abstract:

OBJECT Total en bloc sacrectomy is a dramatic procedure that results in extensive sacral defects. The authors present a series of patients who underwent flap reconstruction after total sacrectomy, report clinical outcomes, and provide a treatment algorithm to guide surgical care of this unique patient population. METHODS After institutional review board approval, data were collected for all patients who underwent total sacrectomy between 2002 and 2012 at The Johns Hopkins Hospital. Variables included demographic data, medical history, tumor characteristics, surgical details, postoperative complications, and clinical outcomes. All subtotal sacrectomies were excluded. RESULTS Between 2002 and 2012, 9 patients underwent total sacrectomy with flap reconstruction. Diagnoses included chordoma (n = 5), osteoblastoma (n = 1), sarcoma (n = 2), and metastatic colon cancer (n = 1). Six patients received gluteus maximus (GM) flaps with a prosthetic rectal sling following a single-stage, posterior sacrectomy. Four required additional paraspinous muscle (PSM) or pedicled latissimus dorsi (LD) fasciocutaneous flaps. Three patients underwent multistage sacrectomy with an anterior-posterior approach, 2 of whom received pedicled vertical rectus abdominis myocutaneous (VRAM) flaps, and 1 of whom received local GM, LD, and PSM flaps. Flap complications included dehiscence (n = 4) and infection (n = 1). During the 1st year of follow-up, 2 of 9 patients (22%) were able to ambulate with an assistive device by the 1st postoperative month, and 6 of 9 (67%) were ambulatory with a walker by the 3rd postoperative month. By postoperative Month 12, 5 of 9 patients (56%)—or 5 of 5 patients not lost to follow-up (100%)—were able to able to ambulate independently. CONCLUSIONS The authors' experience suggests that the GM and pedicled VRAM flaps are reliable options for softtissue reconstruction of total sacrectomy defects. For posterior-only operations, GM flaps with or without a prosthetic rectal sling are generally used. For multistage operations including a laparotomy, the authors consider the pedicled VRAM flap to be the gold standard for simultaneous reconstruction of the pelvic diaphragm and obliteration of dead space.

APA, Harvard, Vancouver, ISO, and other styles

34

Korotkov, V. A., L. O. Petrov, M. R. Kasymov, V. V. Pasov, V. Yu Skoropad, L. V. Tivkova, A. S. Yamshchikova, et al. "Surgical treatment of vulvar cancer with perineal defect reconstruction using a VRAM flap. Clinical case." Andrology and Genital Surgery 23, no. 4 (January 9, 2023): 103–9. http://dx.doi.org/10.17650/2070-9781-2022-23-4-103-109.

Full text

Abstract:

The article presents a clinical case of perineal defect reconstruction using a VRAM flap in a patient with vulvar cancer. Stepwise surgical treatment method is described. A multidisciplinary meeting allows to realize a plan of surgical help for such patients with the goal of treating oncological process and its complications.We have proposed a variant of perineal defect reconstruction through transfer of a vertical rectus abdominis musculocutaneous flap with a vascular pedicle.

APA, Harvard, Vancouver, ISO, and other styles

35

Lee, Dawoon, and Wookeen Chung. "Improving the memory efficiency of RTM using both Nyquist sampling and DCT based on GPU." Journal of Geophysics and Engineering 19, no. 4 (July 29, 2022): 706–23. http://dx.doi.org/10.1093/jge/gxac045.

Full text

Abstract:

Abstract Reverse time migration (RTM) is used to obtain complex structural images of subsurface media. The RTM can be expressed as a zero-lag cross-correlation between the source and receiver wave fields. As imaging conditions can be calculated based on the pre-stored source wavefield and the received wavefield generated during backward modelling, only the source wavefield must be stored in the memory (or disc). Therefore, reducing source-wavefield storage requirements can improve memory efficiency. High-performance computing based on graphic processing units (GPUs) is being developed to reduce the computational time in wave-propagation modelling. Accordingly, GPU-based RTM technology has the potential to improve the computational efficiency of RTM. Storage of the source wavefield wholly in GPU video random-access memory (VRAM) may further improve computational efficiency. In this paper, we present a new algorithm for a three-dimensional (3D) GPU-based RTM that can enable efficient storage of the source wavefield in VRAM using both Nyquist sampling and discrete cosine transform (DCT) compression. A numerical example employing a modified SEG/EAGE 3D overthrust model presented in this study verifies that the proposed algorithm requires only 2% of the memory usage of conventional RTM while producing similar results.

APA, Harvard, Vancouver, ISO, and other styles

36

Tran, Nho V., Franklin H. Sim, David G. Lewallen, and Stephen W. Carmichael. "Case Reports: Transsciatic Foramen Pedicle VRAM Coverage of Gluteal Defects." Clinical Orthopaedics and Related Research 452 (November 2006): 270–73. http://dx.doi.org/10.1097/01.blo.0000229303.59771.6d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Zimman, Oscar A., Pedro H. Bistoletti, Teresita Cravino, and Arturo Figueroa. "P86: The Use of the VRAM Flap in Thoracic Reconstruction." Plastic and Reconstructive Surgery 118, Supplement (September 2006): 166–67. http://dx.doi.org/10.1097/00006534-200609151-00183.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Ruppert, R. "100 Patienten mit VRAM-Flap zur Beckenbodenrekonstruktion nach Becken-Exenteration." coloproctology 37, no. 3 (June 2015): 213–14. http://dx.doi.org/10.1007/s00053-015-0012-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Touny, Ahmed, Haitham Othman, Sherif Maamoon, Samy Ramzy, and Hamdy Elmarakby. "Perineal reconstruction using pedicled vertical rectus abdominis myocutaneous flap (VRAM)." Journal of Surgical Oncology 110, no. 6 (June 24, 2014): 752–57. http://dx.doi.org/10.1002/jso.23692.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Kramer, Erik J., James Dodington, Ava Hunt, Terrell Henderson, Adaobi Nwabuo, Rochelle Dicker, and Catherine Juillard. "Violent reinjury risk assessment instrument (VRRAI) for hospital-based violence intervention programs." Journal of Surgical Research 217 (September 2017): 177–86. http://dx.doi.org/10.1016/j.jss.2017.05.023.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Rouzbehani, Behnam, Luis M. Correia, and Luísa Caeiro. "A Service-Oriented Approach for Radio Resource Management in Virtual RANs." Wireless Communications and Mobile Computing 2018 (July 10, 2018): 1–13. http://dx.doi.org/10.1155/2018/4163612.

Full text

Abstract:

Virtualisation, as a key role player of future mobile communications, promotes the idea of service-oriented architectures. This paper proposes a model of Radio Resource Management (RRM) for emerging Virtual Radio Access Networks, based on the interaction between two separated management entities: Common-RRM (CRRM) to coordinate the radio resources among the Radio Access Technologies (RATs) and a centralised virtualisation platform on top of it, called Virtual-RRM (VRRM), which is responsible for service orchestration among Virtual Network Operators, enabling the definition of various services and policies, separately from vendors and underlying RATs. The main objective of VRRM is to satisfy the Service Level Agreements associated with different service classes to the highest possible level, within the framework of proportional fairness. On the other hand, CRRM is in charge of mapping the demanded capacity of each service onto the most suitable RATs. The model is further extended to deal with extreme situations of resource shortage, resulting from high traffic loads, by introducing delay to lower priority services. The performance of the proposed model is evaluated in a practical multi-RAT scenario. Results confirm that the isolation of service classes is consistent with the introduced serving weights, while all the demanded capacities from different services are responded by the most suitable RATs. Finally, independent of the variation of traffic load, 100% of the aggregated capacity is used.

APA, Harvard, Vancouver, ISO, and other styles

42

Krautz, Christian, Klaus Weber, Roland Croner, Axel Denz, Matthias Maak, Raymund Horch, and Robert Grützmann. "Zylindrische abdominoperineale Rektumexstirpation mit partieller Vulva- und Vaginaresektion sowie perinealer und vaginaler Defektrekonstruktion durch einen vertikalen Rectus-abdominis-Muskel-Haut-Lappen (VRAM-Lappen)." Zentralblatt für Chirurgie - Zeitschrift für Allgemeine, Viszeral-, Thorax- und Gefäßchirurgie 142, no. 06 (December 2017): 543–47. http://dx.doi.org/10.1055/s-0043-117172.

Full text

Abstract:

Zusammenfassung Einleitung Patienten mit sehr tief sitzenden Rektum- oder Analkarzinomen, bei denen eine abdominoperineale Rektumexstirpation (APE) durchgeführt werden muss, profitieren von einer Erweiterung der Resektion und der damit verbundenen Vermeidung des sog. „Coning“ im Levatorenbereich. Diese von T. Holm entwickelte Technik der zylindrischen APE hat zu einer deutlichen Reduktion der Rate an intraoperativen Tumorperforationen sowie der positiven zirkumferenziellen Resektionsränder und konsekutiv zu einer erniedrigten Lokalrezidivrate geführt. Aufgrund des Auftretens von Wundheilungsstörungen in bis zu 60% aller Fälle hat sich die Verwendung myokutaner Lappenplastiken vor allem nach neoadjuvanter Radiotherapie bewährt. Derartige Lappenplastiken liefern ausreichend Füllsubstanz für Hohlräume, ergänzen vaskularisiertes Gewebe in vorbestrahlten Regionen, erleichtern den Wundverschluss und ermöglichen vaginale und perineale Rekonstruktionen. In diesem Video wird das Prinzip der zylindrischen APE mit Erweiterung durch eine partielle Vulva- und Vaginaresektion sowie nachfolgender Rekonstruktion der vaginalen Hinterwand und des vulvoperianalen Defekts mit einem vertikalen Rectus-abdominis-Muskel-Haut-Lappen (VRAM-Lappen) dargestellt. Indikation Lokal fortgeschrittenes Analkarzinom mit Infiltration und Fistel zur posterioren Vagina ohne Hinweis auf eine Fernmetastasierung bei Zustand nach neoadjuvanter Radiochemotherapie. Operation Erweiterte zylindrische abdominoperineale Rektumexstirpation mit partieller Vulva- und Vaginaresektion, Anlage eines endständigen Descendostomas mit parastomaler, intraperitonealer Onlay-Mesh-Augmentation (IPOM), vaginale und perineale Rekonstruktionen mit einem VRAM-Lappen rechts und Inlay-Netzaugmentation des vorderen Rektusscheidenblatts rechts. Zusammenfassung Die extralevatorische APE ist aus onkologischer Sicht der herkömmlichen Technik überlegen. Die Verwendung myokutaner Lappenplastiken verbessert die postoperative Wundheilung und Lebensqualität.

APA, Harvard, Vancouver, ISO, and other styles

43

Bognár, Gábor, András Novák, Gábor István, Zoltán Lóderer, György Ledniczky, and Pál Ondrejka. "Kiterjesztett abdominoperinealis rectumexstirpatiót követő gáttájéki rekonstrukció verticalis rectus abdominis myocutan (VRAM) lebennyel." Magyar Sebészet 65, no. 5 (October 1, 2012): 388–95. http://dx.doi.org/10.1556/maseb.65.2012.5.10.

Full text

Abstract:

Absztrakt Az anorectalis régió daganatai miatt végzett abdominoperinealis exstirpatiót (APE) követő perinealis sebgyógyulási zavarok komoly kihívást jelentenek a sebész számára. A sebgyógyulás körüli szövődmények csökkentését célzó sebészi lehetőségek közé tartozik a myocutan lebennyel való perinealis rekonstrukció is. Cikkünk irodalmi áttekintést nyújt az abdominoperinealis exstripatiót követő verticalis rectus abdominis myocutan (VRAM) lebennyel végzett perinealis rekonstrukciók eredményeiről. A kombinált neoadjuváns radio-kemoterápia elterjedése és a sebészi radikalitás kiterjesztésének lehetősége olyan kettős kockázattal jár, melynek csökkentésére hasznos lehetőség a colorectalis és a plasztikai sebész együttműködése.

APA, Harvard, Vancouver, ISO, and other styles

44

Hasen, Kent V., Jerome D. Chao, and Neil A. Fine. "USE OF THE VRAM AFTER ABDOMINOPLASTY— CAN IT BE DONE SAFELY?" Plastic and Reconstructive Surgery 110, no. 2 (August 2002): 706. http://dx.doi.org/10.1097/00006534-200208000-00064.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Ribuffo, Diego, Massimiliano Marcellino, Geoffrey R. Barnett, Nicholas D. Houseman, and Nicolò Scuderi. "USE OF THE VRAM AFTER ABDOMINOPLASTY— CAN IT BE DONE SAFELY?" Plastic and Reconstructive Surgery 110, no. 2 (August 2002): 706–7. http://dx.doi.org/10.1097/00006534-200208000-00065.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Suzman, Michael S. "The ???Sideways??? VRAM Flap for Broad Soft-Tissue Chest Wall Coverage." Plastic and Reconstructive Surgery 117, no. 7 (June 2006): 2526–27. http://dx.doi.org/10.1097/01.prs.0000220018.96254.38.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Song, Tianyan, Dharmesh Sabharwal, and Sun Nyunt Wai. "VrrA Mediates Hfq-Dependent Regulation of OmpT Synthesis in Vibrio cholerae." Journal of Molecular Biology 400, no. 4 (July 2010): 682–88. http://dx.doi.org/10.1016/j.jmb.2010.05.061.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Ghadimi, Mehdi, Alireza Sirousmehr, Mohammad Hossein Ansari, and Ahmad Ghanbari. "Organic soil amendments using vermicomposts under inoculation of N2-fixing bacteria for sustainable rice production." PeerJ 9 (September 2, 2021): e10833. http://dx.doi.org/10.7717/peerj.10833.

Full text

Abstract:

Organic and biological fertilizers are considered as a very important source of plant nutrients. A field experiment was conducted during 2017−2018 in paddy soil to investigate the effect of vermicomposting of cattle manure mixture with Azolla and rice straw on soil microbial activity, nutrient uptake, and grain yield under inoculation of N2-fixing bacteria. Experimental factors consisted of organic amendments at six levels (vermicomposts prepared from manure (VM); manure + rice straw (VRM); manure + Azolla mixture (VAM); manure + rice straw + Azolla mixture (VRAM); raw manure without vermicomposting (M), and a control) and N2-fixing bacteria at three levels (Azotobacter chroococcum, Azospirillum brasilence, and non−inoculation). The results showed that, vermicompost treatments compared to control and raw manure significantly increased the number and biomass−C of soil microorganisms, urease activity, number of tillers hill−1, phosphorus (P) and potassium (K) uptake, and grain and protein yield. Inoculation of plants with N2-fixing bacteria, especially Azotobacter increased the efficiency of organic amendments, so that the maximum urease activity, soil microbial activity, P and N uptake, and grain yield (4,667 (2017) and 5,081 (2018) kg/h) were observed in vermicompost treatments containing Azolla (VAM and VRAM) under inoculation with Azotobacter. The results of the study suggested that, using an organic source along with inoculation with appropriate N2-fixing bacteria for vermicompost has a great effect on enzyme activity, soil biology, nutrient uptake and grain yield has a synergistic interaction on agronomic traits under flooded conditions. Therefore, this nutrient method can be used as one of the nutrient management strategies in the sustainable rice production.

APA, Harvard, Vancouver, ISO, and other styles

49

Fischlin, Claudia, Zacharia Mbaidjol, Radu Olariu, Mihai Constantinescu, and Jonathan Leckenby. "Focused Arterial Anastomotic Assessment in a Novel Univariate Design of a Vertical Rectus Abdominis Muscle Flap in a Pig Model." Journal of Reconstructive Microsurgery Open 02, no. 01 (January 2017): e52-e57. http://dx.doi.org/10.1055/s-0037-1602817.

Full text

Abstract:

Background Microsurgical anastomosis is the basis for free tissue transfer. The goal of this study was to create an animal model that mimics free tissue transfer but would focus on the arterial anastomotic assessment alone, without additional bias of a venous anastomosis. Methods A vertical rectus abdominis musculocutaneous (VRAM) flap based on the left deep superior epigastric artery (DSEA) was raised in six large white pigs. The right DSEA was raised and used as the donor vessel. An arterial end-to-end microsurgical anastomosis was then performed between the right and the left SEA artery. The lateral deep epigastric vein (DIEV) was left intact to drain the flap. Perfusion of the flap was confirmed clinically by laser Doppler and by flowmetry. Results One flap failure was observed in this study that occurred on postoperative day (POD) 5 as a consequence of venous occlusion due to hematoma. There was a significant initial drop in arterial flow across the anastomosis in comparison to preanastomotic flow measurements (p < 0.05); however, this was normalized by the seventh POD (p > 0.05). Flow measurements in the vein significantly increased after the arterial anastomosis was completed and the seventh POD (p < 0.05). Laser Doppler assessment demonstrated adequate tissue perfusion of the skin island flap. Conclusion This modified VRAM flap is a viable procedure to simulate a free flap transfer and assess the arterial anastomosis alone, while maintaining the flap's innate venous drainage. This method can allow the investigation of new arterial anastomosis techniques and devices.

APA, Harvard, Vancouver, ISO, and other styles

50

Kozan, Andrei A., Adrian M. Smith, David W. Ilsley, and Nicholas Rhodes. "First case of penile metastasis following abdominoperineal resection with VRAM flap reconstruction." Journal of Surgical Case Reports 2016, no. 11 (November 2016): rjw182. http://dx.doi.org/10.1093/jscr/rjw182.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Vrram'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles