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- Almquist, Martin, et al.
(författare)
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A prospective study on an innovative online forum for peer reviewing of surgical science
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Background Peer review is important to the scientific process. However, the present system has been criticised and accused of bias, lack of transparency, failure to detect significant breakthrough and error. At the British Journal of Surgery (BJS), after surveying authors' and reviewers' opinions on peer review, we piloted an open online forum with the aim of improving the peer review process. Methods In December 2014, a web-based survey assessing attitudes towards open online review was sent to reviewers with a BJS account in Scholar One. From April to June 2015, authors were invited to allow their manuscripts to undergo online peer review in addition to the standard peer review process. The quality of each review was evaluated by editors and editorial assistants using a validated instrument based on a Likert scale. Results The survey was sent to 6635 reviewers. In all, 1454 (21.9%) responded. Support for online peer review was strong, with only 10% stating that they would not subject their manuscripts to online peer review. The most prevalent concern was about intellectual property, being highlighted in 118 of 284 comments (41.5%). Out of 265 eligible manuscripts, 110 were included in the online peer review trial. Around 7000 potential reviewers were invited to review each manuscript. In all, 44 of 110 manuscripts (40%) received 100 reviews from 59 reviewers, alongside 115 conventional reviews. The quality of the open forum reviews was lower than for conventional reviews (2.13 (± 0.75) versus 2.84 (± 0.71), P<0.001). Conclusion Open online peer review is feasible in this setting, but it attracts few reviews, of lower quality than conventional peer reviews.
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- Almquist, Martin, et al.
(författare)
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Cardiac arrest with vagal stimulation during intraoperative nerve monitoring.
- 2016
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Ingår i: Head and Neck. - : Wiley. - 1043-3074.
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Tidskriftsartikel (refereegranskat)abstract
- Intraoperative neuromonitoring (IONM) is widely used during thyroid surgery. During both intermittent and continuous IONM stimulation of the vagus nerve is performed. This has previously been reported to be safe.
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| 4. |
- Almquist, Martin, 1988-
(författare)
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Efficient Simulation of Wave Phenomena
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wave phenomena appear in many fields of science such as acoustics, geophysics, and quantum mechanics. They can often be described by partial differential equations (PDEs). As PDEs typically are too difficult to solve by hand, the only option is to compute approximate solutions by implementing numerical methods on computers. Ideally, the numerical methods should produce accurate solutions at low computational cost. For wave propagation problems, high-order finite difference methods are known to be computationally cheap, but historically it has been difficult to construct stable methods. Thus, they have not been guaranteed to produce reasonable results.In this thesis we consider finite difference methods on summation-by-parts (SBP) form. To impose boundary and interface conditions we use the simultaneous approximation term (SAT) method. The SBP-SAT technique is designed such that the numerical solution mimics the energy estimates satisfied by the true solution. Hence, SBP-SAT schemes are energy-stable by construction and guaranteed to converge to the true solution of well-posed linear PDE. The SBP-SAT framework provides a means to derive high-order methods without jeopardizing stability. Thus, they overcome most of the drawbacks historically associated with finite difference methods.This thesis consists of three parts. The first part is devoted to improving existing SBP-SAT methods. In Papers I and II, we derive schemes with improved accuracy compared to standard schemes. In Paper III, we present an embedded boundary method that makes it easier to cope with complex geometries. The second part of the thesis shows how to apply the SBP-SAT method to wave propagation problems in acoustics (Paper IV) and quantum mechanics (Papers V and VI). The third part of the thesis, consisting of Paper VII, presents an efficient, fully explicit time-integration scheme well suited for locally refined meshes.
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| 5. |
- Almquist, Martin, et al.
(författare)
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Management of the exterior branch of the superior laryngeal nerve among thyroid surgeons - Results from a nationwide survey.
- 2015
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Ingår i: International Journal of Surgery. - : Ovid Technologies (Wolters Kluwer Health). - 1743-9159 .- 1743-9191. ; 20, s. 46-51
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Tidskriftsartikel (refereegranskat)abstract
- The external branch of the superior laryngeal nerve is important for the voice. However, it is unknown how thyroid surgeons manage this nerve during operations. We hypothesised that this management is related to the surgeon's age, gender, the surgeons' annual number of thyroid operations, i.e volume, and surgical specialisation.
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| 7. |
- Almquist, Martin, et al.
(författare)
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Order-preserving interpolation for summation-by-parts operators at nonconforming grid interfaces
- 2019
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Ingår i: SIAM Journal of Scientific Computing. - : Society for Industrial and Applied Mathematics Publications. - 1064-8275 .- 1095-7197. ; 41:2, s. A1201-A1227
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Tidskriftsartikel (refereegranskat)abstract
- We study nonconforming grid interfaces for summation-by-parts finite difference methods applied to partial differential equations with second derivatives in space. To maintain energy stability, previous efforts have been forced to accept a reduction of the global convergence rate by one order, due to large truncation errors at the nonconforming interface. We avoid the order reduction by generalizing the interface treatment and introducing order-preserving interpolation operators. We prove that, given two diagonal-norm summation-by-parts schemes, order-preserving interpolation operators with the necessary properties are guaranteed to exist, regardless of the grid-point distributions along the interface. The new methods retain the stability and global accuracy properties of the underlying schemes for conforming interfaces.
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- Almquist, Martin, et al.
(författare)
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Surgical management of cytologically indeterminate thyroid nodules
- 2019
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Ingår i: Gland Surgery. - : AME Publishing Company. - 2227-684X .- 2227-8575. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Nodules in the thyroid are frequent. Preoperative investigations including fine-needle cytology and ultrasound cannot in all patients rule out malignancy. Thus, surgical excision for histopathologic examination is often needed. In this narrative review, we examine aspects of the surgical management of indeterminate thyroid nodules, using a comprehensive review of the available literature. The authors manually searched PubMed for relevant literature, including recently published guidelines. Hemithyroidectomy without lymph node dissection remains the recommended management in indeterminate thyroid nodules, i.e., the complete removal of one lobe of the thyroid, for indeterminate thyroid nodules, defined as nodules with fine-needle cytology fulfilling the criteria of Bethesda III or IV categories. At surgery, it is important to preserve the recurrent and superior laryngeal nerves, and intraoperative neuromonitoring is a useful adjunct. Recent data also suggest that parathyroid autofluorescent techniques are promising tools for parathyroid preservation. There is still lack of specific preoperative investigations to rule in or out central lymph node metastasis. Intraoperative frozen section of lymph nodes can be valuable, but prophylactic or diagnostic central lymph node dissection is not routinely recommended. Outcomes after thyroid surgery arc better with high-volume surgeons and institutions. Surgery is probably best performed by high-volume surgeons in institutions with on-site expert pathologists and with technical adjuncts available for nerve and parathyroid preservation. Day-care surgery may be an option for selected patients.
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| 9. |
- Brändstedt, Johan, et al.
(författare)
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Vitamin D, PTH, and calcium and tumor aggressiveness in prostate cancer: a prospective nested case-control study.
- 2016
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 27:1, s. 69-80
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies suggest that low levels of vitamin D (25OHD) constitute a risk factor for more aggressive prostate cancer. We examined the relationship between pre-diagnostic serum levels of vitamin D, parathyroid hormone (PTH), and calcium and risk of prostate cancer according to tumor aggressiveness.
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| 10. |
- Brändstedt, Johan, et al.
(författare)
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Vitamin D, PTH, and calcium in relation to survival following prostate cancer
- 2016
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 27:5, s. 669-677
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Epidemiological studies suggest that low levels of vitamin D constitute a risk factor for prostate cancer. However, the results are conflicting, perhaps because prostate cancer is a very heterogeneous disease. More recent studies have focused on cancer progression and mortality. Vitamin D is closely related to both calcium metabolism and parathyroid hormone (PTH) levels, and all three factors have been implicated in prostate cancer.METHODS: We examined the associations between pre-diagnostic serum levels of vitamin D (25OHD), PTH, and calcium and mortality among 943 participants within the Malmö Diet and Cancer Study, who were diagnosed with prostate cancer. The mean time from diagnosis until the end of followup was 9.1 years (SD 4.5), and the mean time from inclusion until end of follow-up was 16.6 years (SD 4.9). The analytes were divided into quartiles, and the risk of death from prostate cancer was analyzed using Cox proportional hazard analysis, yielding hazards ratios (HR) with 95 % confidence intervals. The models were adjusted for season and year of inclusion, age at baseline, age at diagnosis, body mass index (BMI), and tumor characteristics (TNM and Gleason score).RESULTS: We observed a trend toward a lower prostate-specific mortality with 25OHD >85 nmol/L in the unadjusted analysis. This became statistically significantly in the third quartile of 25OHD (85-102 nmol/L) compared to the first (<68 nmol/L), HR 0.54 (0.34-0.85) when adjusting for age, time of inclusion, and BMI. The association was further strengthened when adjusted for age at diagnosis, Gleason score, and TNM classification with a HR in Q3 0.36 (0.22-0.60). p for trend was 0.03. Regarding calcium, there was a significantly lower HR for the second quartile (2.35-2.39 mmol/L) compared to the first (≤2.34 mmol/L) with a HR of 0.54 (0.32-0.86) in the unadjusted analysis. However, this association disappeared when adjusting for tumor characteristics. There were no associations between levels of PTH and prostate cancer mortality.CONCLUSION: This study shows that levels of pre-diagnostic vitamin D above 85 nmol/L may improve survival in men with prostate cancer.
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