The diagnosis of Alzheimer's disease can be improved by the use of biological measures. Biomarkers of functional impairment, neuronal loss, and protein deposition that can be assessed by neuroimaging ...(ie, MRI and PET) or CSF analysis are increasingly being used to diagnose Alzheimer's disease in research studies and specialist clinical settings. However, the validation of the clinical usefulness of these biomarkers is incomplete, and that is hampering reimbursement for these tests by health insurance providers, their widespread clinical implementation, and improvements in quality of health care. We have developed a strategic five-phase roadmap to foster the clinical validation of biomarkers in Alzheimer's disease, adapted from the approach for cancer biomarkers. Sufficient evidence of analytical validity (phase 1 of a structured framework adapted from oncology) is available for all biomarkers, but their clinical validity (phases 2 and 3) and clinical utility (phases 4 and 5) are incomplete. To complete these phases, research priorities include the standardisation of the readout of these assays and thresholds for normality, the evaluation of their performance in detecting early disease, the development of diagnostic algorithms comprising combinations of biomarkers, and the development of clinical guidelines for the use of biomarkers in qualified memory clinics.
Summary
The objective of this study was to analyse the co‐contraction behaviour of jaw and neck muscles during force‐controlled experimental grinding in the supine position. Twelve symptom‐free ...subjects were enrolled in the experimental study. Electromyographic (EMG) activity of semispinalis capitis, splenius capitis and levator scapulae muscles was recorded bilaterally with intramuscular fine‐wire electrodes, whereas that of sternocleidomastoideus, infrahyoidal, suprahyoidal, masseter and anterior temporalis muscles were registered with surface electrodes. EMG and force measurements were performed during tasks simulating tooth grinding on custom‐made intraoral metal splints. The mean EMG activity normalised by maximum voluntary contraction (% MVC) of each of the neck muscles studied during grinding was analysed and compared with previous data from jaw clenching at identical force (100 N) and (supine) position. The occurrence of low‐level, long‐lasting tonic activation (LLTA) of motor units was also documented. The mean three‐dimensional force vector of the grinding forces was 106 ± 74 N. In the frontal plane, the incline to the midsagittal plane ranged between 10° and 15°. In the midsagittal plane, the incline to the frontal plane was negligibly small. Posterior neck muscle activity during grinding ranged between 4.5% and 12% MVC and during clenching with 100 N between 1.8% and 9.9% MVC. Masticatory muscle activity during grinding ranged between 17% and 21% MVC for contralateral masseter and ipsilateral temporalis and between 4% and 6.5% for ipsilateral masseter and contralateral temporalis. LLTA had an average duration of 195 ± 10 seconds. The findings from this study do not support pathophysiological muscle chain theories postulating simple biomechanical coupling of neck and jaw muscles. Co‐contractions of neck and masticatory muscles may instead occur as a result of complex neurophysiological interactions.
Highlights • The adapted technique allows territories of multiple motor units to be obtained with one scan. • Larger and smaller motor units are recruited throughout the depth of the masseter. • ...Heterogeneous recruitment of motor units might functionally stabilize the muscle.
Abstract The paper describes the product development methodology, the architecture, the modules and features of the operating prototype, as well as future challenges of NAVMAT, a naval materials ...failure management system. The fundamental compound of the knowledge management platform is the recording and classification of a failure incident. NAVMAT supports different types of users, from the first Reporter to the Analyst and Forensic Engineer through appropriate workflows. In these workflows the incident-related information can be provided as text, files, images and videos, which can be easily associated to the incident and provide structured information. NAVMAT provides a number of Artificial Intelligence (AI)-enabled helpers. During the incident recording, NAVMAT brings into play reactive real-time search which suggests related incidents and literature to facilitate the editor. It also speeds up the classification of incidents by providing AI-suggested labels, chosen from the (multi-lingual) concepts contained in the system Ontology. On the other hand, the intelligent indexing and search infrastructure of the system supports easy identification and retrieval of past incidents, reports and publications, by applying Natural Language Processing. The prototype of the described system has been embedded as a web application validated by potential Users and is being prepared for Operation in a fleet environment.
Summary
This study was to compare the short‐term therapeutic efficacy of device‐supported sensorimotor training with that of standard splint therapy for patients with myofascial temporomandibular ...disorder (TMD) pain over a treatment period of 3 months. We tested the hypothesis that both types of intervention are equally effective for pain reduction. In addition, the electromyographic (EMG) activity of the temporal and masseter muscles was recorded under conditions of force‐controlled submaximum and maximum biting in intercuspation. Of consecutive patients seeking treatment for non‐odontogenic oro‐facial pain, 45 patients with myofascial TMD pain (graded chronic pain status, GCPS, I and II) were randomly assigned to 2 treatment groups (sensorimotor training and conventional splint treatment). Patients were evaluated 4 times (initial examination, 2, 6 and 12 weeks later) by use of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Electromyographic activity was recorded at the initial session and after 3 months. Ease‐of‐use of the treatment options was also evaluated. Significant (P < .0001) pain reduction (sensorimotor training 53%, splint therapy 40%) was achieved for both groups, with no significant differences (P > .05) between the groups. Force‐controlled sub‐maximum normalized electromyographic activity was significantly different between T0 and T3 for group A (sensorimotor training, P < .05) but was not significantly different for group B (splint, P > .05). For normalized maximum‐biting EMG activity in intercuspation, however, a significant increase in EMG activity was observed for group A for the masseter and temporal muscles (P < .001) and for group B for the masseter muscle only (P < .001). Moreover, sensorimotor training was significantly (P < .05) less easy to use than the splint. The results of this study confirm the pain‐reducing effect of sensorimotor training for patients with myofascial TMD pain (GCPS I and II). This innovative active treatment might be a promising option for TMD pain patients.
Penetrating injury (PI) is a relatively rare mechanism of trauma in the Netherlands. Nevertheless, injuries can be severe with high morbidity and mortality rates. The aim of this study is to assess ...fatalities due to PI and evaluate the demographic parameters, mechanism of injury and the resulting injury patterns of this group of patients in three Dutch regions.
Patients suffering fatal PI (stab- and gunshot injuries), in the period between July 1st 2013 and July 1st 2019, in the region of Amsterdam, Utrecht and The Hague were included. Data were collected from the electronic registration system (Formatus) of the regional departments of Forensic Medicine.
During the study period 283 patients died as the result of PI. The mean age was 44 years (SD 16.9), 83% was male and psychiatric history was reported in 22%. Over 60% of the injuries were due to assault and 35% was self-inflicted. Almost half of the incidents took place at home (47%). Injuries were most frequently to the head (24%) and chest (16%). Mortality was due to exsanguination (chest 27%, multiple body region's 17%, neck 9% and extremities 8%) and traumatic brain injury (21%). Up to 40% of the patients received medical treatment, surgical intervention was performed in 25%. The injuries to the extremities suggest a (potentially) preventable death rate of over 8%. Over 70% of the total population died at the scene.
Fatal PI most often involves the relatively young, male, and psychiatric patient. Self-inflicted fatal PI accounted for 35%, addressing the importance of suicide prevention programs. Identification of preventable deaths needs more awareness to reduce the number of fatal PI.
Multidelay arterial spin-labeling is a promising emerging method in clinical practice. The effect of imaging parameters in multidelay arterial spin-labeling on estimated cerebral blood flow ...measurements remains unknown. We directly compared 3-delay versus 7-delay sequences, assessing the difference in the estimated transit time and blood flow.
This study included 87 cognitively healthy controls (78.7 ± 3.8 years of age; 49 women). We assessed delay and transit time-uncorrected and transit time-corrected CBF maps. Data analysis included voxelwise permutation-based between-sequence comparisons of 3-delay versus 7-delay, within-sequence comparison of transit time-uncorrected versus transit time-corrected maps, and average CBF calculations in regions that have been shown to differ.
The 7-delay sequence estimated a higher CBF value than the 3-delay for the transit time-uncorrected and transit time-corrected maps in regions corresponding to the watershed areas (transit time-uncorrected = 27.62 ± 12.23 versus 24.58 ± 11.70 mL/min/100 g, Cohen's
= 0.25; transit time-corrected = 33.48 ± 14.92 versus 30.16 ± 14.32 mL/min/100 g, Cohen's
= 0.23). In the peripheral regions of the brain, the estimated delay was found to be longer for the 3-delay sequence (1.52408 ± 0.25236 seconds versus 1.47755 ± 0.24242 seconds, Cohen's
= 0.19), while the inverse was found in the center of the brain (1.39388 ± 0.22056 seconds versus 1.42565 ± 0.21872 seconds, Cohen's
= 0.14). Moreover, 7-delay had lower hemispheric asymmetry.
The results of this study support the necessity of standardizing acquisition parameters in multidelay arterial spin-labeling and identifying basic parameters as a confounding factor in CBF quantification studies. Our findings conclude that multidelay arterial spin-labeling sequences with a high number of delays estimate higher CBF values than those with a lower number of delays.
An asymptotic crack-tip solution under conditions of plane strain is developed for a material that obeys a special form of linear isotropic strain gradient elasticity. In particular, an elastic ...constitutive equation of the form
τ
=
τ
(
0
)
-
ℓ
2
∇
2
τ
(
0
)
is considered, where
(
τ
,
ε
)
are the stress and strain tensors,
τ
(
0
)
=
λ
ε
kk
δ
+
2
μ
ε
,
(
λ
,
μ
)
are the Lamé constants, and ℓ is a material length. Both symmetric (mode-I) and antisymmetric (mode-II) solutions are developed. The asymptotic solution predicts finite strains at the crack-tip. The mode-I crack-tip displacement field
u is of the form
u
1
=
Ax
1
+
ℓ
r
ℓ
3
/
2
A
1
u
˜
11
(
θ
,
ν
)
+
A
2
u
˜
12
(
θ
,
ν
)
+
O
(
r
2
)
,
u
2
=
Bx
2
+
ℓ
r
ℓ
3
/
2
A
1
u
˜
21
(
θ
,
ν
)
+
A
2
u
˜
22
(
θ
,
ν
)
+
O
(
r
2
)
,
where
(
x
1
,
x
2
)
and
(
r
,
θ
)
are crack-tip Cartesian and polar coordinates, respectively,
ν is Poisson’s ratio, and
(
A
,
B
,
A
1
,
A
2
)
are dimensionless constants determined by the complete solution of a boundary value problem. The
A- and
B-terms above correspond to uniform normal strains parallel
(
ε
11
)
and normal
(
ε
22
)
to the crack line, which do not contribute to the crack-tip “energy release rate” (
J-integral). Detailed finite element calculations are carried out for an edge-cracked-panel (ECP) loaded by point forces and the asymptotic solution is verified. The region of dominance of the asymptotic solution for the ECP geometry analyzed is found to be of order ℓ/10. The “energy release rate” is found to decrease with increasing ℓ.
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