Growth of vanadium dioxide thin films on hexagonal boron nitride flakes as transferrable substrates.

Vanadium dioxide (VO2) is an archetypal metal-insulator transition (MIT) material, which has been known for decades to show an orders-of-magnitude change in resistivity across the critical temperature of approximately 340 K. In recent years, VO2 has attracted increasing interest for electronic and photonic applications, along with advancement in thin film growth techniques. Previously, thin films of VO2 were commonly grown on rigid substrates such as crystalline oxides and bulk semiconductors, but the use of transferrable materials as the growth substrates can provide versatility in applications, including transparent and flexible devices. Here, we employ single-crystalline hexagonal boron nitride (hBN), which is an insulating layered material, as a substrate for VO2 thin film growth. VO2 thin films in the polycrystalline form are grown onto hBN thin flakes exfoliated onto silicon (Si) with a thermal oxide, with grains reaching up-to a micrometer in size. The VO2 grains on hBN are orientated preferentially with the (110) surface of the rutile structure, which is the most energetically favorable. The VO2 film on hBN shows a MIT at approximately 340 K, across which the resistivity changes by nearly three orders of magnitude, comparable to VO2 films grown on common substrates such as sapphire and titanium dioxide. The VO2/hBN stack can be picked up from the supporting Si and transferred onto arbitrary substrates, onto which VO2 thin films cannot be grown directly. Our results pave the way for new possibilities for practical and versatile applications of VO2 thin films in electronics and photonics.

Self-assembled structure of dendronized CdS nanoparticles.

Self-assembled dendronized CdS nanoparticles have been attracting considerable attention because of their photoluminescence properties depending on annealing treatments. In this study, their annealing-induced self-assembled structure was investigated via scanning transmission electron microscopy; thin foil specimens of self-assembled dendronized CdS nanoparticles were prepared by ultramicrotomy and the STEM images revealed their ordered structure and the effect of the annealing treatment. In addition, a structural order belonging to the P213 space group was identified via an autocorrelation analysis. The results indicated that this structural order could be achieved only over a few tens of nanometers.

Sequential transmission electron microscopy observation of the shape change of gold nanorods under pulsed laser light irradiation.

In situ sequential high-resolution observations were performed on gold nanorods under near-infra-red pulsed laser irradiation using a high-voltage electron microscope attached to a pulsed laser illumination system. The original nanorods were single crystals; the longer axes were oriented along [001]. Under laser light irradiation with λ = 1064 nm with an average intensity per pulse of 980 or 490 J/m2, the shape of the nanorods changed from rod to barrel surrounded by the {111} and {001} facets, while the original single-crystalline structure was maintained. The side surfaces with <110> direction were reconstructed into zig-zag fine structures consisting of narrow {111} facets. The temporal evolution of the volume and surface area during irradiation was evaluated based on the images, assuming that the particles have a rotational symmetry along their longer axes. The surface area was stepwise decreased during the shape change using pulse shots of 980 J/m2 while the volume was maintained. On the other hand, several repeated shots were required to induce the shape change when the averaged intensity was reduced to 490 J/m2 per pulse. In addition to the surface area, the volume was reduced under the latter condition during the shape change due to the evaporation of atoms. The quantitative analysis of the temporal changes indicates the heterogeneity of the atomic excitation or heating of gold nanorods induced by pulsed laser illumination.

Detection of picometer-order atomic displacements in drift-compensated HAADF-STEM images of gold nanorods.

Cs-corrected atomic resolution scanning transmission electron microscopy under a drift-compensated operation enabled us to acquire high-angle annular dark-field (HAADF) images of entire gold nanorods without distortion induced by specimen drift. The precision in locating the atomic columns was evaluated to be ±5 pm in the images thus obtained, which is comparable to the image pixel size. A high-precision HAADF image of a single-crystalline gold nanorod revealed that the tip portions at both ends tended to undergo outward displacements along the rod axis and inward contraction along the perpendicular direction. A single nanosecond pulse shot of laser light with a wavelength of 1064 nm and an average intensity of 7.3 kJ/m2 pulse deformed the nanorods into spherical shapes. Simultaneously, the particle interior was completely changed into a multiple twin structure. Substantial displacements of atomic columns on the order of several tens of picometers were confirmed to be localized in the corners of domains at multiple twin junctions. Both the magnitude and direction of displacements were linearly relaxed with increasing distance from a multiple junction.

Patient-based outcomes following surgical debridement and flap coverage of digital mucous cysts.

PURPOSE: The purpose of this prospective cohort study was to evaluate patient-based outcomes and complications following excision of mucous cysts, joint debridement, and closure with one of three types of local flaps. METHODS: From 2000-2011, 35 consecutive patients with 37 digital mucous cysts were treated surgically. The surgical procedure included excision of the cyst together with the attenuated skin, joint debridement on the affected side including capsulectomy, and removal of osteophytes. Depending on the size and location of the cyst, the skin defect was covered by a transposition flap (31 cysts), an advancement flap (two cysts), or a rotation flap (four cysts). RESULTS: At an average follow-up time of 4 years, 4 months, there was no wound infection, flap necrosis, or joint stiffness. Preoperative nail ridging resolved in seven of nine fingers, and no nail deformities developed after surgery. One cyst, treated with a transposition flap, recurred 10 months after surgery. The average satisfaction score for the affected finger significantly improved from 4.3 to 6.8, and the average pain score decreased from 4.7 to 2.3. CONCLUSION: This treatment protocol provides reliable results. Patients were satisfied with the reduction of associated pain and the postoperative appearance of the treated finger, and postoperative complications were minimal.

Arthroscopic Partial Capitate Resection for Type Ia Avascular Necrosis: A Short-Term Outcome Analysis.

PURPOSE: To examine short-term clinical results of arthroscopic partial resection for type Ia avascular necrosis of the capitate. METHODS: Patients who underwent arthroscopic treatment for type 1a avascular necrosis of the capitate with at least 1-year follow-up were identified through a retrospective chart review. The necrotic capitate head was arthroscopically resected with removal of the lunate facet and preservation of the scaphoid and hamate facets. Wrist range of motion, grip strength, and radiographic parameters--carpal height ratio, radioscaphoid angle, and radiolunate angle-were determined before surgery and at the latest follow-up. Patients completed a visual analog scale for pain; Disabilities of the Arm, Shoulder, and Hand measure; and the Patient-Rated Wrist Evaluation score before surgery and at the latest follow-up. RESULTS: Five patients (1 male, 4 females) with a mean age of 34 years (range, 16-49 years) and a mean follow-up duration of 20 months (range, 12-36 months) were identified during the chart review. All were type Ia (Milliez classification). Arthroscopy revealed fibrillation or softening with cartilage detachment at the lunate facet of the capitate head and an intact articular surface at the scaphoid and hamate facet. At the latest follow-up, the mean wrist flexion-extension was 123° (vs 81° before surgery) and grip strength was 74% (vs 37% before surgery). The visual analog scale score for pain; the Disabilities of the Arm, Shoulder, and Hand score; and the Patient-Rated Wrist Evaluation score before surgery showed a significant improvement following treatment. Radiographic parameters did not significantly change at the final follow-up, although the proximal carpal row trended toward flexion. CONCLUSIONS: Arthroscopic partial resection of the capitate head was an acceptable treatment for type Ia avascular necrosis of the capitate. It provided adequate pain relief and improved the range of wrist motion and grip strength during short-term follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Predictors of Postoperative Finger Stiffness in Unstable Proximal Phalangeal Fractures.

BACKGROUND: The purpose of this study was to determine the risk factors for postoperative finger stiffness after open reduction and internal fixation of unstable proximal phalangeal fractures using a low-profile plate and/or screw system. We hypothesized that dorsal plate placement is a risk factor for postoperative finger stiffness. METHODS: Seventy consecutive patients (50 men, 20 women; average age, 40 years) with 75 unstable proximal phalangeal fractures were treated with titanium plates and/or screws and evaluated at a minimum follow-up of 1 year. Thirty-six comminuted fractures and 24 intra-articular fractures were included, and 16 fractures had associated soft-tissue injuries. Plate fixation was performed in 59 fractures, and the remaining 16 were fixed with screws only. The implants were placed in a dorsal location in 33 fractures and in a lateral or volar location in 42 fractures. Finger stiffness was defined as a total active range of finger motion <80% for the treated finger. Univariate and multivariate analyses were performed on 8 variables: patient characteristics (age and sex), fracture characteristics (fracture comminution, joint involvement, and associated soft-tissue injury), and surgical characteristics (type and location of implants and removal of the implants). RESULTS: Postoperative finger stiffness occurred in 38 fractures. The multivariate analysis indicated that plate fixation (odds ratio, 5.9; 95% confidence interval, 1.5-24.0; P = 0.01) and dorsal placement (odds ratio, 3.0; 95% confidence interval, 1.1-8.3; P = 0.03) were independent risk factors for finger stiffness. CONCLUSION: We recommend the use of screw fixation as much as possible for unstable proximal phalangeal fractures using a midlateral approach.

Functional reconstruction of bilateral injuries to the dorsum of hand using radial forearm tendocutaneous flaps.

We treated a patient with skin and tendon defects of both hands as a result of injury by a heat press. There have been no reports of bilateral hand injuries being treated using simultaneous bilateral tendocutaneous flaps. In this case, we reconstructed the injured tissue using simultaneous bilateral radial forearm tendocutaneous flaps, with satisfactory results.

Comparison of the intramedullary nail and low-profile plate for unstable metacarpal neck fractures.

BACKGROUND: There is no robust evidence for the best treatment practice for metacarpal neck fractures. The purpose of this comparative study was to investigate whether the intramedullary nail or low-profile plate allows for good clinical and radiological results for displaced metacarpal neck fractures. METHODS: We prospectively reviewed 30 patients with a displaced metacarpal neck fracture who underwent surgery: 15 with intramedullary nails and 15 with low-profile plates. Radiographic and clinical outcomes of both groups were compared. Objective findings of range of finger motion and grip strength were assessed at 3, 6, and 12 months postoperatively. RESULTS: There was no non-union, and postoperative complications included extensor tendon rupture in one and transient ulnar nerve neuritis in two. Radiological parameters after the fracture healing were comparable between the two groups. Postoperative range of finger motion was better in patients with the intramedullary nail, and acquired grip strength in the low-profile plate group was superior to that in the intramedullary nail group. CONCLUSIONS: The current results indicate that both procedures are highly effective in maintaining fracture restorations. Plate fixation provides earlier recovery of powerful hand function, and intramedullary nailing allows a wide range of finger motion.

Assessment of pure single nerve root resection in the treatment of spinal schwannoma: focus on solitary spinal schwannomas located below the thoracolumbar junction.

BACKGROUND: The incidence of neurological deficits is reportedly low after sacrificing the affected nerve root during spinal schwannoma treatment. Although the incidence has been widely reported, the operative method for nerve root resection has been not clarified. To evaluate the safety of pure nerve root resection, we focused on solitary spinal schwannomas below the thoracolumbar level and investigated the effect of affected nerve resection. METHODS: Twenty-three spinal schwannoma patients were retrospectively examined. The mean age at surgery was 53 years. We investigated preoperative symptoms, duration of the disorder, postoperative neurological deficits, and clinical outcomes. In addition, we measured tumor size on computed tomography after myelography or on magnetic resonance images using image-analysis software. We retrospectively assessed correlations among duration of symptoms, tumor size, and postoperative neurological deficits. RESULTS: The tumors comprised 19 intradural schwannomas and 4 dumbbell-shaped schwannomas. No postoperative neurological deficits were observed in the intradural schwannoma patients. In contrast, three of the four dumbbell-shaped schwannoma patients experienced postoperative neurological deficits. Among these three patients, two recovered quickly whereas one never recovered. The mean duration of the disorder was 29 months. The postoperative modified JOA score (13.0) was significantly improved compared with the preoperative score (8.9). The mean maximum tumor sizes were 97.2 mm(2) for the intradural schwannomas and 884.0 mm(2) for the dumbbell-shaped schwannomas. There were no correlations among tumor size, duration of the disorder, and postoperative neurological deficits. CONCLUSIONS: On the basis of this study, we recommend pure single nerve resection for treatment of intradural spinal schwannomas before such tumors progress and involve other normal roots, because postoperative neurological deficits did not occur in our intradural schwannoma patients, irrespective of tumor size, when this procedure was used. However, dumbbell-shaped schwannoma patients should be carefully treated operatively, because high incidence of postoperative neurological deficits can be expected.

Wrist arthrodesis with vascularized fibular grafting.

Six patients underwent wrist arthrodesis using vascularized fibular grafting for treatment of a segmental bone defect across the wrist. Five patients had defects resulting from excision of a giant cell tumor at the distal radius, and one patient had a defect after debridement of a chronic infection. In all cases, bone union was achieved within 3 to 6 months after vascularized fibular grafting without additional procedures. Measurement of postoperative roentgenograms revealed that the average of fixed wrist angle was 13 degrees extension. Postoperatively, average grip strength on the affected side was 59% of that on the unaffected side, and the average range of forearm rotation was 123 degrees. The mean Enneking functional score was 84% at a mean follow-up period of 64 months. There was no recurrence of a tumor or infection. Wrist arthrodesis using vascularized fibular grafting is a useful procedure for the treatment of a segmental bone defect across the wrist.

A pilot feasibility study for ultrasound evaluation of living human wrist cartilage: site-specific differences in acoustic properties.

PURPOSE: The field of cartilage repair has changed dramatically in the past decade but has not answered the question of how to treat an articular cartilage lesion in the wrist. Indeed, the characteristics of wrist articular cartilage, such as cartilage thickness, hardness, and smoothness, have not been clarified. The purpose of this study was to evaluate and quantify the acoustic properties of wrist articular cartilage quantitatively using a new acoustic probe under arthroscopic observation. METHODS: We evaluated 10 consecutive patients (9 men, 1 woman) who were examined or treated arthroscopically. The mean age at evaluation was 27 years. In total, 468 points of wrist articular cartilage were investigated using the ultrasonic probe, and the data were transformed into a wavelet map by wavelet transformation. Two parameters, maximum magnitude and echo duration, which are indices of articular cartilage stiffness and macroscopic surface roughness, respectively, were used to evaluate the acoustic properties of wrist cartilage. RESULTS: The distribution pattern of the acoustic properties was similar to that of previous results for the ankle joint. The mean maximum magnitude and echo duration were 3.41 +/- 1.50 (range, 0.89-7.53) and 1.33 mus +/- 0.30 (range, 0.51-2.17 mus), respectively. For the scaphoid fossa, the maximum magnitude of the radial side was significantly lower than that of the ulnar side, and the echo duration of the radial side was significantly longer than that of the ulnar side. CONCLUSIONS: A new measurement system using an acoustic probe made it possible to perform a quantitative analysis of wrist articular cartilage, similar to the case for knee and ankle articular cartilage. In addition, site-specific differences in the acoustic properties of the distal radial cartilage were detected in living human wrist cartilage.

Vascularized proximal fibular autograft for treatment of post-traumatic segmental bony defects in the distal radius.

Vascularized proximal fibular autograft is reported as one of the reconstructive procedures for the wrists following tumor resection in the distal end of the radius. However, it is rarely performed for the treatment of segmental bony defects in the distal radius after trauma. A 19-year-old man who had traumatic bony defects in the distal radius involving the articular surface underwent vascularized proximal fibular grafting for reconstruction of the wrist. After surgery, he regained wrist functions, with 40 degrees of flexion, 45 degrees of extension, 90 degrees of pronation, and 45 degrees of supination. No evidence of instability or degenerative changes was noted in the reconstructed wrist at 3 years after surgery. Vascularized proximal fibular autograft appears a useful procedure both for reconstruction of the wrist in cases with segmental bony defects in the distal radius after trauma, as well as for after tumor resection.

Indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head.

BACKGROUND: The present study aimed to determine the indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. METHODS: Seventy-one hips (60 patients) were clinically followed for a minimum of 3 years. Average follow-up period was 7 years. Etiologies were alcohol abuse in 31 hips, steroid use in 27, idiopathic in 7 and trauma in 6. Preoperative staging of the necrotic lesion was done using the Steinberg's classification system. The outcomes of free vascularized fibular grafting were determined clinically using the Harris hip-scoring system, radiographically by determining progression, and survivorship by lack of conversion to total hip replacement. RESULTS: The average preoperative Harris hip score was 56 points and the average score at the latest follow-up examination was 78 points. Forty-seven hips (67%) were clinically rated good to excellent, 4 hips (6%) were rated fair, and 20 hips (28%) were rated poor. Thirty-six hips (51%) did not show radiographic progression while 35 hips (49%) did, and with an overall survivorship of 83% at 7 years. Steroid-induced osteonecrosis was significantly associated with poor scores and survival rate (68%). Preoperative collapse was significantly associated with poor scores, radiographic progression and poor survival rate (72%). A large extent of osteonecrosis greater than 300 degrees was significantly associated with poor scores, radiographic progression and poor survival rate (67%). There was no relationship between the distance from the tip of the grafted fibula to the subchondral bone of the femoral head and postoperative radiographic progression. CONCLUSION: In conclusion, small osteonecrosis (less than 300 degrees of the femoral head) without preoperative collapse (Steinberg's stages I and II) is the major indication for free vascularized fibular grafting. Steroid-induced osteonecrosis is a relative contraindication. Large osteonecrosis (greater than 300 degrees) with severe preoperative collapse (greater than 3 mm) is a major contraindication. Hips with 2 negative factors such as severe preoperative collapse and a large extent of osteonecrosis, require hip replacements.

Long-term outcomes of flap transfer for treatment of intractable venous stasis ulcers in the lower extremity.

There is little information about long-term outcomes of flap transfer for treatment of venous stasis ulcers in the lower extremity. Eleven patients who underwent free and pedicled flap transfer for treatment of intractable venous stasis ulcers were evaluated retrospectively. The operative procedures consisted of removal of the ulcer and surrounding lipodermatosclerotic tissue, venous stripping, and flap transfer. No ulcer recurrences in the territory of the transferred flap were identified for a mean of 11 years during the follow-up period. However, four patients developed new ulcers in the same leg after the flap transfer at 18, 24, 52, and 81 months. This was probably the result of incomplete excision of surrounding lipodermatosclerotic tissue. Three of four recurrent ulcers were healed with additional procedures. The results of this study indicated that flap transfer combined with venous stripping could lead to long-term healing of venous stasis ulcers. However, incomplete excision of surrounding lipodermatosclerotic tissue caused new ulceration around the transferred flap.

Restoration of elbow function with pedicled latissimus dorsi myocutaneous flap transfer.

Restoration of elbow function is a challenge for orthopaedic surgeons, and many procedures have been described. This study reviewed 17 patients who underwent latissimus dorsi myocutaneous flap transfer for functional reconstruction of elbow flexion or extension. Of the 10 patients who underwent reconstruction for elbow flexion, grade 4 strength of elbow flexion by manual muscle testing was obtained in 8 and grade 3 was obtained in 2. Mean postoperative active elbow flexion was 111 degrees . Of the 7 patients who underwent reconstruction for elbow extension, grade 4 strength of elbow extension was obtained in 3, grade 3 was obtained in 3, and grade 2 was obtained in 1. The 3 patients showing unsatisfactory restoration of flexion or extension strength had associated preoperative weakness of the latissimus dorsi muscle. Preoperative assessment of the latissimus dorsi muscle was most important for obtaining satisfactory results, because preoperative muscle strength influenced the postoperative functional outcome.

Tissue-engineered approach for the treatment of steroid-induced osteonecrosis of the femoral head: transplantation of autologous mesenchymal stem cells cultured with beta-tricalcium phosphate ceramics and free vascularized fibula.

Autologous mesenchymal stem cells (MSCs) cultured with beta-tricalcium phosphate (beta-TCP) ceramics and with a free vascularized fibula were transplanted into three patients with steroid-induced osteonecrosis of the femoral head. The average follow-up period was 34 months and the average patient age at the time of surgery was 28 years old. Fifteen milliliters of bone marrow was obtained from the patients 4 weeks before surgery, and was used for in vitro proliferation of MSCs. beta-TCP granules were immersed in the MSC suspension and the cells were further cultured for 2 weeks. Cultured MSCs/beta-TCP composite granules were implanted into the cavity that remained after curettage of necrotic bone; and finally, a free vascularized fibula was grafted. All hips showed preoperative collapse and radiographic progression was observed in two hips postoperatively. Osteonecrosis did not progress any further and early bone regeneration was observed. This tissue-engineered approach has potentials for the treatment of osteonecrosis. However, our results suggested that the present procedure could not be used for cases with severe preoperative collapse.

Oberlin partial ulnar nerve transfer for restoration in obstetric brachial plexus palsy of a newborn: case report.

An 8 month old male infant with Erb's birth palsy was treated with two peripheral nerve transfers. Except for rapid motor reinnervations, elbow flexion was obtained by an Oberlin's partial ulnar nerve transfer, while shoulder abduction was restored by an accessory-to-suprascapular nerve transfer. The initial contraction of the biceps muscle occurred two months after surgery. Forty months after surgery, elbow flexion reached M5 without functional loss of the ulnar nerve. This case demonstrates an excellent result of an Oberlin's nerve transfer for restoration of flexion of the elbow joint in Erb's birth palsy. However, at this time partial ulnar nerve transfer for Erb's birth palsy is an optional procedure; a larger number of cases will need to be studied for it to be widely accepted as a standard procedure for Erb's palsy at birth.

Giant-cell tumors of the carpus.

Giant cell tumor (GCT) of bone is a rare, benign tumor with some aggressive characteristics such as a high recurrence rate. The tumor usually occurs in the distal radius although it has been reported in the carpus. We reviewed 63 manuscripts published from 1935 to 2005 and report on the treatment of GCT of carpal bone in 29 cases. Intralesional procedures, such as curettage, were associated with a high incidence of recurrence (24%), whereas cases treated with an excisional procedure did not recur.

Post-traumatic big toe reconstruction using free flaps.

The big toe is of great importance for good stability and gait, but few reports have documented reconstruction of big toe defects. In this study, seven male patients, aged 17 to 59 years at surgery (average: 35 years), were treated for big toe defects. The metatarsophalangeal (MTP) joints of the big toe were intact in all patients. Five patients were treated with free peroneal flaps (including one perforator flap), and two with free scapular flaps; flap sizes ranged from 9 x 4 to 24 x 6 cm. Follow-up periods ranged from 10 to 29 months, (average: 16.6 months). The iliac was used as the grafted bone in four patients and the scapula in one. Six flaps survived completely, and bone unions were achieved within 3 months. One flap became partially necrotic due to arterial thrombosis. All patients returned to their original jobs, and the cosmetic appearances of all toes were acceptable.