95 research outputs found
New class of thermosetting plastics has improved strength, thermal and chemical stability
New class of thermosetting plastics has high hydrocarbon content, high stiffness, thermal stability, humidity resistance, and workability in the precured state. It is designated cyclized polydiene urethane, and is applicable as matrices to prepare chemically stable ablative materials for rocket nose cones of nozzles
Ablative resin Patent
Ablative resins used for retarding regression in ablative materia
Polyimide polymers provide improved ablative materials
Principle heat absorption of silica-reinforced plastic ablative materials occurs from the in-depth reaction of silica with carbon to form silicon monoxide and carbon monoxide. The higher the degree of completion of this reaction, the higher the capacity of the ablative material to absorb heat
Investigation of resin systems for improved ablative materials Final report, 19 Jun. 1964 - 31 Jul. 1965
Resin systems investigated for improving ablative materials for use with fluorine-containing liquid propellant system
Assessment of rotatory laxity in anterior cruciate ligament-deficient knees using magnetic resonance imaging with Porto-knee testing device
Purpose Objective evaluation of both antero-posterior
translation and rotatory laxity of the knee remains a target
to be accomplished. This is true for both preoperative
planning and postoperative assessment of different ACL
reconstruction emerging techniques. The ideal measurement tool should be simple, accurate and reproducible,
while enabling to assess both ‘‘anatomy’’ and ‘‘function’’
during the same examination. The purpose of this study is
to evaluate the clinical effectiveness of a new in-housedeveloped testing device, the so-called Porto-knee testing
device (PKTD). The PKTD is aimed to be used on the
evaluation of both antero-posterior and rotatory laxity of
the knee during MRI exams.
Methods Between 2008 and 2010, 33 patients with ACLdeficient knees were enrolled for the purpose of this study.
All patients were evaluated in the office and under
anesthesia with Lachman test, lateral pivot-shift test and
anterior drawer test. All cases were studied preoperatively
with KT-1000 and MRI with PKTD, and examinations
performed by independent observers blinded for clinical
evaluation. During MRI, we have used a PKTD that applies
antero-posterior translation and permits free tibial rotation
through a standardized pressure (46.7 kPa) in the proximal
posterior region of the leg. Measurements were taken for
both knees and comparing side-to-side. Five patients with
partial ruptures were excluded from the group of 33.
Results For the 28 remaining patients, 3 women and 25
men, with mean age of 33.4 ± 9.4 years, 13 left and 15 right
knees were tested. No significant correlation was noticed for
Lachman test and PKTD results (n.s.). Pivot-shift had a
strong positive correlation with the difference in anterior
translation registered in lateral and medial tibia plateaus of
injured knees (cor. coefficient = 0.80; p\0.05), and with
the difference in this parameter as compared to side-to-side
(cor. coefficient = 0.83; p\0.05).
Considering the KT-1000 difference between injured and
healthy knees, a very strong positive correlation was found
for side-to-side difference in medial (cor. coeffi-
cient = 0.73; p\0.05) and lateral (cor. coefficient = 0.5;
p\0.05) tibial plateau displacement using PKTD.
Conclusion The PKTD proved to be a reliable tool in
assessment of antero-posterior translation (comparing with
KT-1000) and rotatory laxity (compared with lateral pivotshift under anesthesia) of the ACL-deficient knee during
MRI examinatio
ACL injuries identifiable for pre-participation imagiological analysis: Risk factors
Identification of pre-participation risk factors for noncontact anterior cruciate ligament (ACL) injuries has been attracting a great deal of interest in the sports medicine and traumatology communities. Appropriate methods that enable predicting which patients could benefit from pre- ventive strategies are most welcome. This would enable athlete-specific training and conditioning or tailored equipment in order to develop appropriate strategies to reduce incidence of injury. In order to accomplish these goals, the ideal system should be able to assess both anatomic and functional features. Complementarily, the screening method must be cost-effective and suited for widespread application. Anatomic study protocol requiring only standard X rays could answer some of such demands. Dynamic MRI/CT evaluation and electronically assisted pivot-shift evaluation can be powerful tools providing complementary information. These upcoming insights, when validated and properly combined, envision changing pre-participation knee examination in the near future. Herein different methods (validated or under research) aiming to improve the capacity to identify persons/athletes with higher risk for ACL injury are overviewed.
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