The purpose of this study is to identify clinicopathologic factors and/or preoperative MRI vascular patterns in the prediction of ischemia necrosis of the nipple-areola complex (NAC) or skin flap ...post nipple-sparing mastectomy (NSM).
We performed a retrospective analysis of 441 NSM procedures from January 2011 to September 2021 from the breast cancer database at our institution. The ischemia necrosis of NAC or skin flap was evaluated in correlation with clinicopathologic factors and types of skin incision. Patients who received NSM with preoperative MRI evaluation were further evaluated for the relationship between vascular pattern and the impact on ischemia necrosis of NAC or skin flap.
A total of 441 cases with NSM were enrolled in the current study, and the mean age of the cases was 49.1 ± 9.8 years old. A total of 41 (9.3%) NSM procedures were found to have NAC ischemia/necrosis. Risk factors were evaluated of which old age, large mastectomy specimen weight (> 450 g), and peri-areola incision were identified as predictors of NAC necrosis. Two-hundred seventy NSM procedures also received preoperative MRI, and the blood supply pattern was 18% single-vessel type and 82% double-vessel pattern. There were no correlations between MRI blood supply patterns or types of skin flap incisions with ischemia necrosis of NAC. There were also no correlations between blood loss and the pattern or size of the blood vessel.
Factors such as the type of skin incision, age, and size of mastectomy weight played an important role in determining ischemia necrosis of NAC; however, MRI vascular (single or dual vessel supply) pattern was not a significant predictive factor.
The near-surface mounted (NSM) FRP strengthening technique has attracted worldwide attention as an effective alternative to the externally bonded (EB) FRP strengthening technique. In the NSM FRP ...strengthening method, grooves are first cut in the concrete cover of a concrete member for the FRP reinforcement to be inserted and embedded using an adhesive. The NSM FRP method has many advantages over the EB FRP method, including a higher bonding efficiency and a better protection of the FRP reinforcement. Existing experimental studies have shown that FRP strips owned a better bond efficiency compared with other section shapes (e.g. round bars and square bars), due to the fact that they had a larger perimeter-to-cross-sectional area ratio. This paper presents a state-of-the-art review, particularly on the flexural strengthening of RC beams with NSM CFRP strips. The observed failure modes in laboratory experiments of such FRP-strengthened RC beams are classified and the existing strength models are examined along with the failure mechanisms behind. The main knowledge gaps to be bridged in future studies are also identified. This review partially formed the basis of the development of design provisions on the NSM strengthening technique in the relevant Hong Kong design guideline.
This paper deals with strengthening statically indeterminate reinforced concrete (RC) beams with carbon and glass Fiber Reinforced Polymers (FRP) rods by using the Near Surface Mounted (NSM) ...technique. The test program consisted of six two-span beams; one control beam, which had exploited for comparison purposes, and five others initially strengthened in flexure with NSM-FRP rods in both hogging and sagging regions. The main test parameters were type, ratio and length of the FRP bars as well as characteristics of the filling material. The study presents and discusses their impacts on the global flexural behavior of continuous RC beam that mainly includes investigating the overall capacity, failure mode, moment redistribution and ductility state.
All NSM-FRP strengthened beams displayed higher overall capacity than the control beam; the test results showed that implementing the NSM technique in an appropriate way could significantly improve the yielding capacity and load-carrying capacity of RC beams without large decrease in the ductility index or the moment redistribution degree despite the non-conventional failure mode. The beam failure was primary affected by the strengthening length; terminating the FRP bars before the zero moment point caused to change the failure mode from pull out of the FRP bars to premature peeling off of the concrete cover. On the other hand, moment redistribution and ductility of the NSM-FRP beams were negatively affected by: (I) Increasing the FRP reinforcement, (II) Decreasing the FRP length or (III) Using mortar as a filling material instead of epoxy-resin. Adopting a nonlinear analysis of the cross-sections could accurately quantify the moment–curvature and the ultimate load of the NSM-FRP continuous beams.
This paper introduced a novel Artificial Neural Networks (ANN)-based bond–slip model for the Near-surface mounted (NSM) FRP system using cement-based adhesives, as an alternative to epoxy adhesives ...due to their high-temperature resistance and moisture-durability problems, employing experimental data. Therefore, closed-form formulas were presented for key components of the bond-slip law, including maximum bond stress, corresponding slip, fracture energy, and post-peak branch, while taking important factors into account. Compared to available bond-slip laws, this innovative model demonstrates promising potential in predicting the bond behaviour, thereby enabling more efficient and reliable designs for the NSM FRP strengthening applications using cement-based adhesives.
•A novel ANN-based bond–slip model for NSM FRP systems with cement-based adhesives.•Closed-formed formulas for key bond-slip components.•An efficient solution to address inadequacies in current bond-slip laws.•Reliable predictions for the NSM FRP bond behaviour with cement-based adhesives.
The preliminary experience and learning curve of robotic nipple sparing mastectomy (R-NSM) in the management of breast cancer were analyzed and reported.
The medical records of patients who underwent ...R-NSM for breast cancer during the period of March 2017 to June 2018 were collected from the same surgeon in a single institute. Data on clinicopathologic characteristics, type of surgery, method of breast reconstruction, and operation time were prospective collected. Learning curve of R-NSM was evaluated and analyzed by the cumulative sum (CUSUM) plot method.
A total of 39 consecutive R-NSM procedures from 35 patients were analyzed. The time needed for “docking”, “R-NSM”, and “R-NSM and immediate prosthesis breast reconstruction (IPBR)” decreased after cases experience accumulated, and in mature phase procedures could finished within 10 min, 100mins, and 240 min, separately. In CUSUM plots analysis of learning curve, the cases needed to decrease operation time for “docking”, “R-NSM”, and “total time for R-NSM and IPBR” were 13th, 13th, and 12th procedures separately. Mastectomy weight and lymph node metastasis were factors related to operation time. The rate of total nipple areolar complex necrosis for R-NSM was 0%. One (2.9%, 1/35) R-NSM procedure was found to have positive margin involved in the final pathologic check-up. No implant loss, or local recurrence was observed during a mean follow-up of 8.6 ± 4.5 (1.3–16.7) months.
From our preliminary experience, R-NSM and IPBR (or R-NSM alone) is a safe procedure, and the operation time needed significantly decrease after cases experience accumulated.
The learning curve of robotic nipple sparing mastectomy in the management of breast cancer were evaluated with cumulative sum plots, and factors affecting the operation time were discussed. We revealed that time for R-NSM fluctuated with mastectomy weight, and this fluctuation could be reduced after cases experience accumulated. From our preliminary experience, R-NSM and IPBR (or R-NSM alone) is a safe procedure, and could be a promising new technique for breast cancer patients indicated for mastectomy. Current study provides some valuable information for the development and patient selection for robotic surgery in total skin and nipple preserving type mastectomy.
Strengthening of concrete structures using Fiber Reinforced Polymer (FRP) composites has gained prominence in the recent years due to its various advantages. Reinforced Concrete (RC) columns are ...predominantly subjected to compression loading and often need strengthening to increase their strength and ductility. This paper explores an innovative hybrid strengthening technique where short RC square column elements are strengthened using both Near Surface Mounted (NSM) CFRP laminates and Externally Bonded (EB) CFRP fabrics for confinement. Ten square column elements of cross sectional dimension 230mm and height of 450mm were cast, strengthened and tested under pure axial compression to investigate the efficiency of different combinations of strengthening techniques. Existing constitutive models available from past literature were used to predict the behavior of FRP strengthened RC column elements. A close correlation was observed between the peak strength obtained from experimental and analytical values. Hybrid strengthening technique was found to be more efficient leading to higher increase in strength, stiffness and ductility as compared to only NSM strengthened or only CFRP confined RC columns.
In the developmental stage of minimal-accessed nipple-sparing mastectomy (MA-NSM), selecting patients with small to medium-sized breasts was common for better cosmetic outcomes and oncological ...safety. However, the suitability of MA-NSM for large, ptotic breasts remained uncertain. This retrospective study aim to assess MA-NSM outcomes in patients with large breasts.
This retrospective study included patients receiving conventional NSM (C-NSM) and MA-NSM from January 2011 to September 2022, at a single institution. We analyzed perioperative parameters and clinical outcomes based on breast specimen size, classified as small (≤300 g), medium (>300–450 g), large (>450–600 g), and very large (>600 g).
A total of 728 patients was enrolled. C-NSM was performed in 51% (371/728) of cases, while MA-NSM was done in 49% (357/728). The overall complication rate of MA-NSM was comparable to C-NSM (p = 0.573), but severe complications (Clavien-Dindo, CD III) was significantly reported more following C-NSM, regardless of breast size. During a median follow-up of 52 months, no significant difference in oncological outcomes was observed. Comparing MA-NSM and C-NSM outcomes in large-very large breasts (>450 g), MA-NSM demonstrated significantly less blood loss (p = 0.036) and lower incidence of severe complications (CD ≥ III) compared to C-NSM (p = 0.002).
MA-NSM is feasible for large breasts and offers benefits by reducing blood loss and decreasing the incidence of severe complications (CD ≥ III) in this patient group.
Synopsis: MA-NSM is feasible to perform in large breasts and also offers benefits by reducing blood loss and lowering the incidence of severe complications (CD ≥ III) in this patient group.
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•Fire tests on RC slabs strengthened with prestressed (0 %–50 %) CFRP-NSM systems.•Fire resistance of prestressed NSM systems decreased with prestress level increase.•Fire resistance ...of prestressed NSM systems increased with fire protection.•Critical temperatures at CFRP anchorages ranged between 1.6 × Tg and 3.4 × Tg.
Carbon fibre reinforced polymer (CFRP) composites are now widely used to strengthen reinforced concrete (RC) structures. Among the strengthening systems available, near-surface mounted (NSM)-prestressed CFRP laminates offer several advantages, as they significantly increase the load carrying capacity and also the serviceability performance of RC structures. However, as for other CFRP systems, there is a concern about their behaviour at elevated temperature and under fire exposure due to the glass transition process undergone by their polymeric components. Nevertheless, the fire performance of NSM-prestressed-CFRP strengthening systems has not yet been investigated. This paper presents an experimental study about the fire resistance behaviour of RC slab strips strengthened with prestressed NSM-CFRP laminates; the slabs were simultaneously subjected to a mechanical (fire) load and the ISO 834 fire curve, and the influence of the following parameters on their fire resistance behaviour was assessed: (i) the prestress level (0 %, 25 % and 50 % of the CFRP tensile strength), and (ii) the presence of passive fire protection, comprising up to 48 mm thick calcium silicate (CS) boards. The results obtained showed that: (i) without fire protection, the strengthening system remained effective during a very low period of fire exposure, which significantly decreased with the prestress level, from 16 min (0 %) to less than 5 min (50 %); (ii) with fire protection, even with 50 % of prestress, the strengthening system remained effective for more than 120 min; and (iii) the “critical” temperatures in the anchorages of the strengthening systems were found to be about 2.5Tg, 2.0Tg and 1.5Tg, for the prestress levels of 0 %, 25 % and 50 %, respectively, with Tg being the glass transition temperature of the adhesive.
This investigation aims to study the flexural behaviour of reinforced concrete (RC) beams strengthened with near-surface mounted (NSM) carbon fibre reinforced polymer prestressed concreteprisms ...(CFRP-PCPs). Eight RC beams were tested under monotonic loading until the failure load was reached. One beam was un-strengthened to act as a control beam. The other seven beams were strengthened with non-prestressed or prestressed NSM CFRP-PCPs. The effects of bond length, prestress level, and concrete type of the CFRP-PCPs on the flexural capacity, flexural crack and deflection are discussed in this paper. The results indicate that the flexural capacity of RC beams strengthened with NSM CFRP-PCPs was greater than the control beam. An obvious improvement was discovered in the crackresistance when the RC beams were strengthened with prestressed NSM CFRP-PCPs. The strengthened beams showed a higher first-cracking, yielding, and ultimate load as the bond length and prestress level of CFRP-PCPs increased up to a critical level. The beams strengthened with CFRP-PCPs, which were cast with ultra-high performance concrete (UHPC), exhibited greater load capacity than the corresponding beams with epoxyresin mortar. The analytical model of flexural response for the NSM CFRP-PCPs strengthening beams is presented. The analytical results are in good agreement with the experimental results, which revealed the NSM CFRP-PCPs is an effective technique for flexural strengthening of the RC beams.
Abstract
The nonstructural protein NSm of tomato spotted wilt virus (TSWV) has been identified as the avirulence determinant of the tomato single dominant
Sw‐5
resistance gene. Although
Sw‐5
...effectiveness has been shown for most TSWV isolates, the emergence of resistance‐breaking (RB) isolates has been observed. It is strongly associated with two point mutations (C118Y or T120N) in the NSm viral protein. TSWV‐like symptoms were observed in tomato crop cultivars (+
Sw‐5
) in the Baja California peninsula, Mexico, and molecular methods confirmed the presence of TSWV. Sequence analysis of the NSm 118–120 motif and three‐dimensional protein modelling exhibited a noncanonical C118F substitution in seven isolates, suggesting that this substitution could emulate the C118Y‐related RB phenotype. Furthermore, phylogenetic and molecular analysis of the full‐length genome (TSWV‐MX) revealed its reassortment‐related evolution and confirmed that putative RB‐related features are restricted to the NSm protein. Biological and mutational NSm 118 residue assays in tomato (+
Sw‐5
) confirmed the RB nature of TSWV‐MX isolate, and the F118 residue plays a critical role in the RB phenotype. The discovery of a novel TSWV‐RB Mexican isolate with the presence of C118F substitution highlights a not previously described viral adaptation in the genus
Orthotospovirus
, and hence, the necessity of further crop monitoring to alert the establishment of novel RB isolates in cultivated tomatoes.
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