bluuebunny/crossref_metadata_2025_split huggingface dataset:
External validation: a simulation study to compare cross-validation versus holdout or external testing to assess the performance of clinical prediction models using PET data from DLBCL patients
Authors: Eertink Jakoba J. , Heymans Martijn W. , Zwezerijnen Gerben J. C. , Zijlstra Josée M. , de Vet Henrica C. W. , Boellaard Ronald 
Published: September 2022

Abstract
Aim
Clinical prediction models need to be validated. In this study, we used simulation data to compare various internal and external validation approaches to validate models.

Methods
Data of 500 patients were simulated using distributions of metabolic tumor volume, standardized uptake value, the maximal distance between the largest lesion and another lesion, WHO performance status and age of 296 diffuse large B cell lymphoma patients. These data were used to predict progression after 2 years based on an existing logistic regression model. Using the simulated data, we applied cross-validation, bootstrapping and holdout (n = 100). We simulated new external datasets (n = 100, n = 200, n = 500) and simulated stage-specific external datasets (1), varied the cut-off for high-risk patients (2) and the false positive and false negative rates (3) and simulated a dataset with EARL2 characteristics (4). All internal and external simulations were repeated 100 times. Model performance was expressed as the cross-validated area under the curve (CV-AUC ± SD) and calibration slope.

Results
The cross-validation (0.71 ± 0.06) and holdout (0.70 ± 0.07) resulted in comparable model performances, but the model had a higher uncertainty using a holdout set. Bootstrapping resulted in a CV-AUC of 0.67 ± 0.02. The calibration slope was comparable for these internal validation approaches. Increasing the size of the test set resulted in more precise CV-AUC estimates and smaller SD for the calibration slope. For test datasets with different stages, the CV-AUC increased as Ann Arbor stages increased. As expected, changing the cut-off for high risk and false positive- and negative rates influenced the model performance, which is clearly shown by the low calibration slope. The EARL2 dataset resulted in similar model performance and precision, but calibration slope indicated overfitting.

Conclusion
In case of small datasets, it is not advisable to use a holdout or a very small external dataset with similar characteristics. A single small testing dataset suffers from a large uncertainty. Therefore, repeated CV using the full training dataset is preferred instead. Our simulations also demonstrated that it is important to consider the impact of differences in patient population between training and test data, which may ask for adjustment or stratification of relevant variables.
Selecting pseudo supervision for unsupervised domain adaptive SAR target classification
Authors: Zhao Lingjun , He Qishan , Ding Ding , Zhang Siqian , Kuang Gangyao , Liu Li 
Published: September 2022

AbstractIn recent years, deep learning has brought significant progress for the problem of synthetic aperture radar (SAR) target classification. However, SAR image characteristics are highly sensitive to the change of imaging conditions. The inconsistency of imaging parameters (especially the depression angle) leads to the distribution shift between the training and test data and severely deteriorates the classification performance. To address this problem, in this paper we propose an unsupervised domain adaptation method based on selective pseudo-labelling for SAR target classification. Our method directly trains a deep model using the data from the target domain by generating pseudo-labels in the target domain. The key idea is to iteratively select valuable samples from the target domain and optimize the classifier. In each iteration, the breaking ties (BT) criterion is adopted to select the best samples with the highest scores of relative confidence. Besides, to avoid error accumulation in the iterative process, class confusion regularization is used to improve the accuracy of pseudo-labelling. Our method is compared with state-of-the-art methods, including supervised classification and unsupervised domain adaptation methods, over the moving and stationary target acquisition and recognition (MSTAR) dataset. The experimental results demonstrate that the proposed method can achieve better classification performance, especially when the difference of depression angles of the source and target domain images is large. Besides, our method also shows its superiority under limited-sample conditions.
Distributed ranking-based resource allocation for sporadic M2M communication
Authors: Chang Yunyan , Jung Peter , Zhou Chan , Stańczak S.ławomir 
Published: September 2022

AbstractThis work proposes a novel scheme for distributed ranking-based and contention-free resource allocation in large-scale machine-to-machine (M2M) communication networks. We partition a network of N devices into disjoint clusters based on service type, and assign to each cluster a cluster-specific signature for active cluster members to indicate their active status. The devices in each cluster are totally ordered in some a priori-known manner, which gives rise to an active ranking of active cluster members. In order to tackle complexity issues in large-scale M2M networks with a massive number of devices, we propose a distributed resource allocation scheme using the framework of compressed sensing (CS), which mainly consists of three phases: (i) In a full-duplex acquisition phase, the devices transmit their cluster-specific signatures simultaneously and the network activation pattern is collected in a distributed manner. (ii) The base station detects the active clusters and the number of active devices per cluster using block sketching, and allocates resources to each active cluster accordingly. (iii) Each active device determines its active ranking in the cluster and accesses a specific resource according to the ranking position. By exploiting the sparsity in the activation pattern of the M2M devices, the proposed scheme is formulated as a CS support recovery problem for a particular binary block-sparse signal $$x\in {\mathbb{B}}^N$$

x
∈

B

N

– with block sparsity $$K_{B}$$

K
B

and in-block sparsity $$K_{I}$$

K
I

over block size d. Our analysis shows that the proposed scheme efficiently reduces the signature length to $$\mathcal {O}(\max \{K_{B}\log N, K_{B}K_{I}\log d\})$$

O
(
max

{

K
B

log
N
,

K
B

K
I

log
d
}

)

and achieves less computational complexity of $$\mathcal {O}(dK_{I}^{2}+\frac{N}{d}\log N)$$

O
(
d

K

I

2

+

N
d

log
N
)

compared with standard CS algorithms. Moreover, numerical results suggest strong robustness of the proposed scheme under noisy conditions.
Screw fixation in the treatment of displaced intra-articular calcaneus fractures: a systematic review protocol
Authors: Wilmsen Leah , Neubert Anne , Windolf Joachim , Icks Andrea , Richter Bernd , Thelen Simon 
Published: September 2022

Abstract
Background
The Calcaneus is the largest bone of the foot and the most frequent tarsal bone to be fractured. Overall, it causes round about 10 cases per 100,000 residents per year mainly in men. Especially displaced intra-articular calcaneus fractures often have early and late complications and its associated disability. There are various strategies for the treatment of displaced intra-articular calcaneus fractures, but the gold standard is still subject of a long-standing controversy. Minimally invasive procedures became more common in an attempt to reduce the high rate of complications associated with open reduction and internal fixation. With the increase in minimally invasive techniques, screw fixation also gained in significance. The current literature does not sufficiently elucidate whether the screw fixation is superior to other treatment options especially in relation to adverse events, health-related quality of life and postoperative pain. This study aims to investigate benefits and harms of treating displaced intra-articular calcaneus fractures (types II, III and IV according to Sanders) with screw fixation in adults.

Methods
A systematic review will be conducted based on the principles described in the Cochrane Handbook. We will include adults with displaced intra-articular calcaneus fractures of Sanders type II, III and IV. The surgical method of screw fixation shall be compared to other surgical interventions to stabilise calcaneus fractures. Primary outcomes are serious adverse events, health-related quality of life and postoperative pain level. MEDLINE, CENTRAL, CINAHL, Web of Science and bibnet.org, ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform (ICTR) will be searched. Screening and data extraction will be performed by two authors independently. A third author will arbitrate disputes. Risk of Bias will be assessed with the Cochrane tool. Meta-analysis will be performed if participants, interventions, comparisons and outcomes are sufficiently similar to ensure a result that is clinically meaningful.

Discussion
Due to the increasing use of minimally invasive techniques and the increasing use of screw fixation instead of open reduction and plate fixation, it is important to analyse the benefits and harms of screw fixation for calcaneus fractures. Screw fixation could, in the future, help to operate in a less invasive and tissue preserving manner while still achieving an adequate functional result for the patient

Systematic review registration
CRD42021244695
The impact of the loss of first permanent molars on the duration of treatment in patients treated with orthodontic space closure and without skeletal anchorage
Authors: Cardoso Paula Coutinho , Mecenas Paulo , Normando David 
Published: September 2022

Abstract
Background
This study aims to evaluate the impact of the loss of permanent molars on the duration of orthodontic treatment for space closure and without skeletal anchorage.

Methods
Records at the beginning (T0) and the end (T1) of orthodontic treatment were selected retrospectively. Patients were divided into two groups: loss of molar (n = 19) and control, without loss (n = 24). The impact of loss on treatment time was assessed using multiple linear regression adjusted for the number of absences, bonding failures, age, sex, PAR index at T0 and T1 at p<0.05. Treatment time was also evaluated by the number of losses and which arches were involved (upper, lower). The systematic and random errors for the PAR index were verified using the intraclass correlation coefficient (ICC) and the Dahlberg formula, respectively.

Results
A small random error (1.51) and excellent replicability (ICC = 99.6) were observed. Overall average treatment time was 22.5 months (± 7.95) for the group without loss and 44.7 months (± 17.3) with a loss. Treatment time was longer in cases where there was a higher number of missing molars and when both arches were involved. In addition to the loss (β = 4.25, p < 0.001), the number of missed appointments (β = 2.88, p < 0.001) had a significant effect and increased treatment time. Bonding failures, gender, age, and PAR index at T0 and T1 were not significantly associated with treatment time in the multivariate model (p > 0.05).

Conclusion
Loss of the first permanent molar has a negative impact on orthodontic treatment time in cases of space closure. The treatment time is longer when there are more tooth losses and arches involved. Treatment time also increases with greater numbers of missed clinical appointments.
Scoping review on diagnostic criteria and investigative approach in sepsis of unknown origin in critically ill patients
Authors: Ling Lowell , Mui Oliver Oi Yat , Laupland Kevin B. , Lefrant Jean-Yves , Roberts Jason A. , Gopalan Pragasan Dean , Lipman Jeffrey , Joynt Gavin M. ,   for the CaBoOM investigators, Stelfox Tom , Niven Daniel , Paramalingam Rameiya , Vonderhaar Derek , Freebairn Ross , Joynt Gavin M. , Ling Lowell , Leung Patricia , Gopalan Dean , Lefrant Jean Yves , Lloret Sophie , Elotmani Loubna , Roberts Jason A. , Lipman Jeffrey , Laupland Kevin B. , Fourie Cheryl , Saba Renee , Carlisle Dougal , Edwards Felicity 
Published: September 2022

Abstract
Background
Up to 11% of critically ill patients with sepsis have an unknown source, where the pathogen and site of infection are unclear. The aim of this scoping review is to document currently reported diagnostic criteria of sepsis of unknown origin (SUO) and identify the types and breadth of existing evidence supporting diagnostic processes to identify the infection source in critically ill patients with suspected SUO.

Methods
A literature search of Embase, MEDLINE and PubMed for published studies from 1910 to August 19, 2021 addressing the topic of SUO was performed. Study type, country of origin according to World Bank classification, diagnostic criteria of sepsis of unknown origin, and investigative approaches were extracted from the studies.

Results
From an initial 722 studies, 89 unique publications fulfilled the inclusion and exclusion criteria and were included for full text review. The most common publication type was case report/series 45/89 (51%). Only 10/89 (11%) of studies provided a diagnostic criteria of SUO, but a universally accepted diagnostic criterion was not identified. The included studies discussed 30/89 (34%) history, 23/89 (26%) examination, 57/89 (64%) imaging, microbiology 39/89 (44%), and special tests 32/89 (36%) as part of the diagnostic processes in patients with SUO.

Conclusions
Universally accepted diagnostic criteria for SUO was not found. Prospective studies on investigative processes in critically ill patients managed as SUO across different healthcare settings are needed to understand the epidemiology and inform the diagnostic criteria required to diagnose SUO.
Whole-liver enhanced CT radiomics analysis to predict metachronous liver metastases after rectal cancer surgery
Authors: Liang Meng , Ma Xiaohong , Wang Leyao , Li Dengfeng , Wang Sicong , Zhang Hongmei , Zhao Xinming 
Published: September 2022

Abstract
Background
To develop a radiomics model based on pretreatment whole-liver portal venous phase (PVP) contrast-enhanced CT (CE-CT) images for predicting metachronous liver metastases (MLM) within 24 months after rectal cancer (RC) surgery.

Methods
This study retrospectively analyzed 112 RC patients without preoperative liver metastases who underwent rectal surgery between January 2015 and December 2017 at our institution. Volume of interest (VOI) segmentation of the whole-liver was performed on the PVP CE-CT images. All 1316 radiomics features were extracted automatically. The maximum-relevance and minimum-redundancy and least absolute shrinkage and selection operator methods were used for features selection and radiomics signature constructing. Three models based on radiomics features (radiomics model), clinical features (clinical model), and radiomics combined with clinical features (combined model) were built by multivariable logistic regression analysis. Receiver operating characteristic (ROC) curves were used to assess the diagnostic performance of models, and calibration curve and the decision curve analysis were performed to evaluate the clinical application value.

Results
In total, 52 patients in the MLM group and 60 patients in the non-MLM group were enrolled in this study. The radscore was built using 16 selected features and the corresponding coefficients. Both the radiomics model and the combined model showed higher diagnostic performance than clinical model (AUCs of training set: radiomics model 0.84 (95% CI, 0.76–0.93), clinical model 0.65 (95% CI, 0.55–0.75), combined model 0.85 (95% CI, 0.77–0.94); AUCs of validation set: radiomics model 0.84 (95% CI, 0.70–0.98), clinical model 0.58 (95% CI, 0.40–0.76), combined model 0.85 (95% CI, 0.71–0.99)). The calibration curves showed great consistency between the predicted value and actual event probability. The DCA showed that both the radiomics and combined models could add a net benefit on a large scale.

Conclusions
The radiomics model based on preoperative whole-liver PVP CE-CT could predict MLM within 24 months after RC surgery. Clinical features could not significantly improve the prediction efficiency of the radiomics model.
Management of multiple and unruptured cerebral aneurysms
Authors: Deniwar Mohamed Adel 
Published: September 2022

AbstractThe incidence of multiple aneurysms was 10.7–34% of CA. Multiple associated factors were found; hypertension was the most significant one and others like advancing age and female sex were also documented. The estimated prevalence of UA is 5–10%. They include those aneurysms that did not rupture and discovered incidentally and those presented with symptoms rather than SAH, e.g., cranial nerve palsy or mass effect. Unruptured intracranial aneurysms are diagnosed with higher frequency nowadays as a result of imaging techniques improvement. The reported annual rate of rupture of UA is approximately 0.7–1%. The natural history of unruptured cerebral aneurysms cannot be extrapolated from the evaluation of individuals with ruptured aneurysms. Multiple cerebral aneurysms pose an even greater risk than a single aneurysm; the risk of rebleeding from the original aneurysm is larger and occurs sooner. The natural course of the disease has led to a consensus that all multiple unruptured aneurysms should be treated when technically viable. However, the prophylactic treatment of multiple unruptured is still controversial. Weighing the risk of intervention to the risk of observation is a mandatory pathway. Factors like age of patients, size and location of the aneurysms influence the decision-making and the type of therapy to be elected.
The relationship between communication skills, sensory difficulties, and anxiety in children with autism spectrum disorder
Authors: Khaledi Hekmat , Aghaz Alireza , Mohammadi Alireza , Dadgar Hooshang , Meftahi Gholam Hossein 
Published: September 2022

AbstractBackgroundDespite the high prevalence of communicational differences, anxiety, and sensory processing difficulties in children with autism spectrum disorder (ASD), little is known about the nature of their experiences. Thus, the present study aimed to explore the correlation between communication skills, sensory difficulties, and anxiety in children with ASD. Fifty-three children with ASD (Mage = 8.51, SD = 2.51; males = 42) were recruited. The Persian version of the Short Sensory Profile (SSP), the Children’s Communication Checklist (CCC), and the Spence Children’s Anxiety Scale (SCAS) was used to assess the variables.ResultsThe overall sensory score of children with ASD was significantly and positively correlated with most of the communication skills (P < 0.05). The overall sensory score of children with ASD was significantly and negatively correlated with all anxiety subsets of these children (P < 0.05). The social relationships score of children with ASD had a significant and negative correlation with all subsets of anxiety and a significant and positive correlation with all sensory subsets (P < 0.05). The total score of communication was significantly and negatively related to all subsets of anxiety except separation anxiety (P < 0.05).ConclusionsSensory processing difficulties in ASD children appear to be significantly associated with communication skills and anxiety acts as a mediator between the two.
Continuous optical zoom microscope with extended depth of field and 3D reconstruction
Authors: Liu Chao , Jiang Zhao , Wang Xin , Zheng Yi , Zheng Yi-Wei , Wang Qiong-Hua 
Published: September 2022

AbstractMicroscope such as fluorescence microscope, confocal microscope and two-photon microscope plays an important role in life science, laser processing and other fields. However, most microscopes only have discrete zoom rates. In this paper, a continuous optical zoom microscope with extended depth of field and 3D reconstruction is demonstrated for the first time. It consists of a zoom objective lens, a microscope holder, an adjustable three-dimensional object stage, an Abbe condenser and an LED light source. The zoom objective lens is composed of several liquid lenses and solid lenses. By adjusting the applied voltage to the liquid lens, the proposed microscope can achieve a large continuous magnification from 10? to 60?. Moreover, an improved shape from focus (SFF) algorithm and image fusion algorithm are designed for 3D reproduction. Based on the liquid lenses, the axial focusing position can be adjusted to obtain images with different depths, and then the extended depth of field and 3D reconstruction can be realized. Our experimental results demonstrate the feasibility of the proposed microscope. The proposed microscope is expected to be applied in the fields of pathological diagnosis, biological detection, etc.
Delayed presentation of isolated female epispadias with urinary incontinence: a case report
Authors: Oyinloye Adewale Olaotan , Wabada Samuel , Abubakar Auwal Mohammed , Rikin Christopher Uruku 
Published: September 2022

Abstract
Background
Female epispadias is a rare congenital anomaly, with a quoted incidence of 1 in 480,000.These patients present with urinary incontinence and varying degrees of external genitalia abnormality. This report presents the delayed presentation and management of a 14-year-old female with urinary incontinence due to isolated epispadias.

Case presentation
This is the case report of a 14-year-old female with urinary incontinence noticed since infancy. Examination of the genitalia revealed a bifid clitoris, depressed mons pubis, underdeveloped labia, patulous urethral opening, and normal vagina. She had surgical repair of the anomaly and has subsequently achieved continence. She has been continent in the last 4 ½ years of follow-up and is now married with a 1-year-old child.

Conclusion
Female epispadias is a rare but often missed cause of incontinence. A high index of suspicion and careful genital examination will help in identifying this anomaly. Surgical correction achieves satisfactory outcome as regards continence and cleanliness. Long-term follow-up is essential.
Understanding microplastic pollution in the Nordic marine environment – knowledge gaps and suggested approaches
Authors: Jensen Sophie , Grøsvik Bjørn Einar , Halsband Claudia , Halldórsson Halldór Pálmar , Leslie Heather A. , Gunnlaugsdóttir Helga , Guls Hermann Dreki , Vorkamp Katrin , Granberg Maria E. , Sigurðsson Valtýr , Jörundsdóttir Hrönn Ólína 
Published: September 2022

AbstractThis paper examines a number of specific, practical recommendations to advance knowledge and move towards evidence-based solutions to microplastic (MP) pollution in the Nordic marine environment. The paper approaches the subject of MPs holistically, emphasises the knowledge gaps and challenges in answering pressing questions, discusses the limitations that so far have prevented these questions from being solved, and suggests approaches for answering them. The Nordic context is chosen due to the global importance of its ecosystem that is threatened by MP pollution, exacerbated by climate change. The research questions discussed pick up knowledge gaps identified in attempts to answer the most pressing questions of our time regarding marine MP pollution and are applicable to some or all seas of the Nordic region, from the Baltic and North Seas in the south to the Arctic in the north.The research questions relate to sources, sinks and transport of MPs, and how food webs are potentially impacted in Nordic marine environments. In addition, we point out the relevance for stakeholders expected to use the emerging knowledge. Through this exercise, using concrete examples, we aim to invite discussions on how a concerted effort by the Nordic countries can bring MP research to a higher level of understanding needed to address the MP pollution problem in Nordic marine habitats.