Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitrile Derivatives for Air-Stable n-Type Organic Field-Effect Transistors: Critical Role of N-Alkyl Substituent on Device Performance.

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitriles (BDPMs) were synthesized as active materials for the use in air-stable n-type organic field-effect transistors (OFETs), whose optical and electrochemical properties were examined. BDPM-based small molecules exhibit deep lowest unoccupied molecular orbital levels, which are required in air-stable n-type OFETs. An OFET device that was based on BDPM-But and fabricated by vapor deposition provided a maximum electron mobility of 0.131 cm2 V-1 s-1 under ambient conditions.

Tunable functionalization of silica coated iron oxide nanoparticles achieved through a silanol-alcohol condensation reaction.

The surface properties of nanoparticles play an important role in their interactions with their surroundings. Silane reagents have been used for surface modifications to silica shells on iron oxide nanoparticles, but using these reagents presents some challenges. An alternative approach to modifying the surfaces of these silica shells was developed to impart different terminal functional groups, such as a thiol, alcohol, or carboxylic acid, through the use of alcohol-based reagents. This approach to surface functionalization of the core-shell particles was verified through chemical analyses and the attachment of gold nanoparticles. The use of the silanol-alcohol condensation reaction could be extended further to other surface functionalizations through the use of additional alcohol-based reagents.

Angular-Shaped Naphthalene Bis(1,5-diamide-2,6-diylidene)malononitrile for High-Performance, Air-Stable N-Type Organic Field-Effect Transistors.

The synthesis, characterization, and application of two angular-shaped naphthalene bis(1,5-diamide-2,6-diylidene)malononitriles (NBAMs) as high-performance air-stable n-type organic field effect transistor (OFET) materials are reported. NBAM derivatives exhibit deep lowest-unoccupied molecular orbital (LUMO) levels, suitable for air-stable n-type OFETs. The OFET device based on NBAM-EH fabricated by vapor deposition exhibits a maximum electron mobility of 0.63 cm2 V-1 s-1 in air with an on/off current ratio ( Ion/ Ioff) of 105.

Templates of the cartilage layers of the patellofemoral joint and their use in the assessment of osteoarthritic cartilage damage.

OBJECTIVE: To develop a methodology for generating templates that represent the normal human patellofemoral joint (PFJ) topography and cartilage thickness, based on a statistical average of healthy joints. Also, to determine the cartilage thickness in the PFJs of patients with osteoarthritis (OA) and develop a methodology for comparing an individual patient's thickness maps to the normal templates in order to identify regions that are most likely to represent loss of cartilage thickness. DESIGN: The patella and femur surfaces of 14 non-arthritic human knee joints were quantified using either stereophotogrammetry or magnetic resonance imaging. The surfaces were aligned, scaled, and averaged to create articular topography templates. Cartilage thicknesses were measured across the surfaces and averaged to create maps of normal cartilage thickness distribution. In vivo thickness maps of articular layers from 33 joints with OA were also generated, and difference maps were created depicting discrepancies between the patients' cartilage thickness maps and the normative template. RESULTS: In the normative template, the surface-wide mean+/-SD (maximum) of the cartilage thickness was 2.2+/-0.4mm (3.7mm) and 3.3+/-0.6mm (4.6mm) for the femur and patella, respectively. It was demonstrated that difference maps could be used to identify regions of thinner-than-normal cartilage in patients with OA. Patients were shown to have statistically greater regions of thin cartilage over their articular layers than the normal joints. On average, patients showed deficits in cartilage thickness in the lateral facet of the patella, in the anterior medial and lateral condyles, and in the lateral trochlea of the femur. CONCLUSIONS: This technique can be useful for in vivo clinical evaluation of cartilage thinning in the osteoarthritic patellofemoral joint.

Patellofemoral stresses during open and closed kinetic chain exercises. An analysis using computer simulation.

Rehabilitation of the symptomatic patellofemoral joint aims to strengthen the quadriceps muscles while limiting stresses on the articular cartilage. Some investigators have advocated closed kinetic chain exercises, such as squats, because open kinetic chain exercises, such as leg extensions, have been suspected of placing supraphysiologic stresses on patellofemoral cartilage. We performed computer simulations on geometric data from five cadaveric knees to compare three types of open kinetic chain leg extension exercises (no external load on the ankle, 25-N ankle load, and 100-N ankle load) with closed kinetic chain knee-bend exercises in the range of 20 degrees to 90 degrees of flexion. The exercises were compared in terms of the quadriceps muscle forces, patellofemoral joint contact forces and stresses, and "benefit indices" (the ratio of the quadriceps muscle force to the contact stress). The study revealed that, throughout the entire flexion range, the open kinetic chain stresses were not supraphysiologic nor significantly higher than the closed kinetic chain exercise stresses. These findings are important for patients who have undergone an operation and may feel too unstable on their feet to do closed chain kinetic chain exercises. Open kinetic chain exercises at low flexion angles are also recommended for patients whose proximal patellar lesions preclude loading the patellofemoral joint in deeper flexion.

Anterior cruciate ligament function after tibial eminence fracture in skeletally mature patients.

We compared anterior cruciate ligament function in skeletally mature patients after treatment of tibial eminence fractures with that of patients in two other groups: patients who had anterior cruciate ligament deficiency and patients who had undergone anterior cruciate ligament reconstruction using bone-patellar tendon-bone autografts. The Lysholm questionnaire was used to evaluate symptoms and KT-1000 arthrometry was used to determine objective knee laxity at an average follow-up of 5.2 years. Knee joint proprioception was assessed with a new method designed to test joint position sense. The Lysholm score for the tibial eminence group was 94 +/- 7. Only the patients in the anterior cruciate ligament-deficient group demonstrated statistically significantly increased laxity and inferior proprioception when the injured leg was compared with the uninjured leg. Both laxity and proprioception were statistically inferior for the anterior cruciate ligament-deficient group when compared with both the treated tibial eminence fracture group and the anterior cruciate ligament-reconstructed group. No statistically significant difference was observed between the anterior cruciate ligament-reconstructed and treated tibial eminence fracture groups. Correlation was observed between laxity and proprioception when all patients were analyzed. The results demonstrate that appropriate treatment of tibial eminence fractures restores stability and proprioception to the knee.

Immediate surgical repair of the medial patellar stabilizers for acute patellar dislocation. A review of eight cases.

An open surgical repair of the injured medial patellar stabilizers, including the vastus medialis obliquus muscle and the medial patellofemoral ligament, after acute patellar dislocation was studied in eight patients. At initial examination, all patients had tenderness over the adductor tubercle and a positive patellar apprehension sign. Four of eight patients had obvious ecchymosis over the adductor tubercle. Magnetic resonance imaging, diagnostic arthroscopy, and open surgical exploration documented injury to both the medial patellofemoral ligament and the origin of the vastus medialis obliquus muscle. In all patients, the torn muscle was retracted in an anterior and superior direction and an arthroscopic lateral release was performed followed by open primary repair of the medial patellofemoral ligament to the adductor tubercle and repair of the vastus medialis obliquus muscle to the adductor magnus tendon. Patients were evaluated postoperatively with the Kujala scoring questionnaire. The average follow-up was 3.0 years, with a minimum of 1.5 years. No patients experienced a recurrent dislocation. The average Kujala score was 91.9. Patients rated their return to athletic activity at an average 86% of their pre-injury level. The average subjective satisfaction was 96%. In appropriate cases of acute patellar dislocation, we recommend primary repair of the medial patellofemoral ligament and the vastus medialis obliquus muscle to avoid recurrent dislocation, chronic subluxation, pain, and disability.

Hamstrings and iliotibial band forces affect knee kinematics and contact pattern.

Many clinical studies have emphasized the role of the hamstrings and the iliotibial band on knee mechanics, although few biomechanical studies have investigated it. This study therefore examined two hypotheses: (a) with loading of the hamstrings, the tibia translates posteriorly and rotates externally and the tibial contact pattern shifts anteriorly; furthermore, the changes in tibial kinematics alter patellar kinematics and contact; and (b) loading the iliotibial band alters the kinematics and contact pattern of the tibiofemoral joint similarly to loading the hamstrings, and loading the iliotibial band laterally translates the patella and its contact location. Five cadaveric knee specimens were tested with a specially designed knee-joint testing machine in an open-chain configuration. At various flexion angles, the knees were tested always with a quadriceps force but with and without a hamstrings force and with and without an iliotibial band force. The results support the first hypothesis. Hence, the hamstrings may be important anterior and rotational stabilizers of the tibia, a role similar to that of the anterior cruciate ligament. The results also support the second hypothesis, although the iliotibial band force had a smaller effect on the tibia than did the hamstrings force. Both forces also changed patellar kinematics and contact, demonstrating that these structures should also be considered during the clinical management of patellar disorders.

Patellar stabilization: a quantitative evaluation of the vastus medialis obliquus muscle.

Twenty-one cadaveric knees were dissected to analyze the functional anatomy of the vastus medialis complex (VMC), which is composed of the vastus medialis obliquus (VMO) and the vastus medialis longus (VML) muscles. The physiologic cross-sectional area of the VMO for 20 of the knees was 29% of the total physiologic cross-sectional area for the VMC. These values differed in one knee with a dysplastic VMO. The quantitative description of the VMO provided by this study will facilitate future efforts to accurately model the physiologic function of the VMO in cadaveric investigations on patellofemoral mechanics. The effect of simulated pathologies and surgical reconstructions then may be determined with more certainty to improve patient management.

Anatomy of the human patellofemoral joint articular cartilage: surface curvature analysis.

Articular cartilage surfaces of 49 human patellae and 24 distal femora were characterized by identifying distinctive features with surface curvature analysis. Paired specimens from the same donor generally exhibited natural symmetry, so only results from nonpaired specimens were considered (39 patellae and 19 femora). In 23 of 39 patellae, proximal median and lateral transverse ridges extended to form an oblique ridge resembling a skewed lambda (lambda). Most of the unpaired patellae (37 of 39) exhibited only a single lateral transverse ridge, and most (32 of 39) had an odd facet. All but one patella exhibited a concave depression in the lateral and medial facets and a sellar area in the proximal region. All distal femoral surfaces exhibited a sellar trochlea. The concavity of the trochlea was greatest in the posterior aspect, near the intercondylar notch.

Sertraline in coexisting major depression and diabetes mellitus.

As many as 25 percent of patients with diabetes mellitus may also have depressive symptoms. Tricyclic antidepressants (TCAs) may produce increased appetite and weight gain with adverse consequences for diabetes. The selective serotonin reuptake inhibitors (SSRIs), however, may improve fasting blood sugar in laboratory studies. In an initial application, sertraline was administered at a dose of 50 mg/day in a 10-week open study to 28 non-insulin-dependent diabetes mellitus (NIDDM) patients with DSM-III-R major depression after a 2-week single-blind placebo washout period with a minimum 17-Item Hamilton Rating Scale for Depression (HAM-D) score of 18. The patient group included 16 males and 12 females with a mean age of 54.2 +/- 8.8 years. Results indicated (1) significant improvement in mean HAM-D (22.6 +/- 3.4 to 4.9 +/- 5.9, p < .001) and in mean Beck Depression Inventory (BDI) scores (21.9 +/- 10.5 to 12.7 +/- 8.3, p < .001); (2) fall in platelet serotonin (5-HT) content (79.7 +/- 22.5 to 13.6 +/- 12.7 ng/10(8) platelets, p < .001); (3) correlation of baseline platelet 5-HT content with response to sertraline by BDI scores (r = 0.51, p < .05); (4) improved dietary compliance for those with baseline value below 70 percent (59.7% to 69.1%, p < .005); and (5) 13 of 17 patients with baseline glycosylated hemoglobin A (HbA1c) levels greater than 8.0, showed a reduction (p = .018). Sertraline may be an effective antidepressant in patients with diabetes mellitus and response may be predictable by higher baseline platelet 5-HT content, with the potential to improve dietary compliance and reduce HbA1c measures. As with all open studies, replication is essential.

Treatment of depression in patients with diabetes mellitus.

BACKGROUND: Depression occurs frequently in patients with diabetes mellitus. Little has been published on the epidemiology, biochemistry, and treatment of depression in diabetic patients. METHOD: We searched MEDLINE for literature from January 1966 to July 1993 and cross-referenced the terms diabetes, glucose, hyperglycemia, or hypoglycemia, with each of the following: antidepressants, monoamine oxidase inhibitors, tricyclic antidepressants, fluoxetine, paroxetine, sertraline, and bupropion. The results reviewed were 20 papers on epidemiology, 15 papers on neurochemicals and glucose control, and 28 papers on antidepressants and factors of importance to diabetics. Additional papers were selected from the reference lists of the retrieved articles. RESULTS: The prevalence of depression in diabetics varies from 8.5% to 27.3%. Severity of depression correlates strongly with many symptoms of diabetes mellitus. The hydrazine monoamine oxidase inhibitors (MAOIs), e.g., phenelzine, potentiate animal models of hypoglycemia due to direct influence on gluconeogenesis secondary to the hydrazine structure, not to MAOI considerations. Dopamine and norepinephrine influences in these models appear to be hyperglycemic. Serotonergic influences, in the presence of MAOIs, which decrease serotonin metabolism, are in contrast hypoglycemic. Clinically, MAOI use is limited by the possible severity of the induced hypoglycemia, induced weight gain, and required diets. The tricyclic antidepressants may lead to hyperglycemia, to an increase in carbohydrate craving (from 86% to 200%), and impaired memory. Serotonin selective reuptake inhibitors (SSRIs) may be hypoglycemic (causing as much as a 30% decrease in fasting plasma glucose) and anorectic (causing an approximately 2-lb decrease), while possibly improving alertness. CONCLUSION: Depression is frequent among diabetic patients and impairs diabetic management. To maximize response of both depression and diabetic disorder, one should consider the SSRIs in preference over the TCAs.

The results of extensor mechanism realignment following failed lateral retinacular releases.

An evaluation of open extensor mechanism realignments performed in patients with previously failed lateral retinacular releases was performed. A 76 per cent and 66 per cent good to excellent objective and subjective result was found in this study. Radiography, muscle power determinations, failure determinations, and complications are discussed.

Conservative treatment of patellofemoral subluxation.

As pointed out in the preface of this book, patellofemoral subluxation is probably the most common knee problem seen in many orthopedists' offices today. Whereas the other authors have emphasized the anatomy and diagnosis, this article should serve as a dry but basic instruction on the exercise program that has been used in our clinic. We have had a success rate with this program of approximately 80 per cent. Certainly not all of the 20 per cent that fail require surgery. The classic exercises are quadricep sets, straight leg raises, hip abductors, hip adductors, hip flexors, and hamstring stretches, which have endured the test of time. The prevention of flexion extension activity, such as running the stadium stairs in order to strengthen the quadriceps of the patient with patellofemoral subluxation should be emphasized. Complications of conservative treatment, such as low back pain, iliopsoas tendinitis, and muscle soreness and the treatment of these is described. Finally, the importance of stretching the hamstring muscles is a cornerstone in the treatment of patellofemoral problems. Likewise, a tight IT band can put abnormal stress on the lateral aspect of the patella. In this article I have tried to point out our approach to conservative treatment of patellofemoral subluxation.

Stress injuries of the adolescent extensor mechanism.

Stress injury to the extensor mechanism is common, and we expect it to become more so as adolescent athletes train earlier and more vigorously. The clinical and radiographic findings of a number of these stress injuries are described. Our young athletes challenge us to continue studying these stress injuries with the goal of offering them more effective preventative programs. The success of our study will probably lie in the areas of stretching, cross training, and strength programs.

Unusual cause of knee pain in the older adult.

An unusual cause of knee pain in the older adult is presented. Two case reports illustrate diagnostic approach and treatment options.