Distance Of Millimeters Research Articles

Biopolymer augmentation of the lag screw in the treatment of femoral neck fractures - a biomechanical in-vitro study

The cut-out of the sliding screw is one of the most common complications in the treatment of intertrochanteric fractures. The reasons for the cut-out are: a suboptimal position of the hip-screw in the femoral head, the type of fracture and poor bone quality. The aim of this study was to reproduce the cut-out event biomechanically and to evaluate the possible prevention of this event by the use of a biopolymer augmentation of the hip screw.Concerning the density and compression force of osteoporotic femoral bone polyurethane foam according to the terms of the Association for Standard Testing Material (ASTMF 1839-97) was used as test material. The polyurethane foam Lumoltan 200 with a compression force of 3.3 Mpa and a density of 0.192 g/cm3 was used to reproduce the osteoporotic bone of the femoral fragment (density 12 lbm/ft3). A cylinder of 50 mm of length and 50 mm of width was produced by a rotary splint raising procedure with planar contact.The axial load of the system was performed by a hydraulic force cylinder of a universal test machine type Zwick 1455, Ulm, Germany. The CCD-angle of the used TGN-System was preset at 130 degrees.The migration pattern of the hip screw in the polyurethane foam was measured and expressed as a curve of the distance in millimeter [mm] against the applied load in Newton [N] up to the cut-out point. During the tests the implants reached a critical changing point from stable to unstable with an increased load progression of steps of 50 Newton. This unstable point was characterized by an increased migration speed in millimeters and higher descending gradient in the migration curve. This peak of the migration curve served as an indicator for the change of the hip screw position in the simulated bone material. The applied load in the non-augmented implant showed that in this group for a density degree of 12 (0,192 g/cm3) the mean force at the failure point was 1431 Newton (± 52 Newton). In the augmented implant we found that the mean force at the failure point was 1987 Newton (± 84 Newton). This difference was statistically significant.In conclusion, the bone density is a significant factor for the stability of the hip screw implant. The osteosynthesis with screws in material with low density increases the chance for cut-out. A biopolymer augmented hip screw could significantly improve the stability of the fixation. The use of augmentation with a fast hardening bone replacement material containing polymer-ceramic changes the point of failure under axial load in the osteoporotic bone model and could significantly improve the failure point. Our study results indicate, that a decrease of failure in terms of cut-out can be achieved with polymer augmentation of hip screws in osteoporotic bones.

Enamel Matrix Derivative Versus Bioactive Ceramic Filler in the Treatment of Intrabony Defects: 12‐Month Results

This study examined the clinical efficacy of enamel matrix derivative (EMD) and bioactive ceramic filler (BCF) in the treatment of intrabony periodontal defects and evaluated factors influencing the treatment outcome. Thirteen chronic periodontitis patients, 41 to 74 years of age, who had two proximal intrabony defects in different jaw quadrants with > or =3 mm vertical radiographic bone loss were selected for this study. After initial therapy, the sites in each patient were randomly assigned to EMD or BCF treatment. Clinical attachment level (CAL), probing depth (PD), tooth mobility (TM), gingival recession (GR), bleeding on probing, and dental plaque were recorded at baseline and at 6 and 12 months. At surgery, the intrabony component was characterized by recording the number of bony walls, distance in millimeters from the buccal crest (BC) to the most apical point of the defect, distance from the cemento-enamel junction (CEJ) to the BC, and the mesio-distal width of the defect at the level of the bony crest. BCF treatment resulted in a significant gain in proximal CAL (P = 0.005) and a reduction in proximal PD at 6 months (P <0.001), but there was no further improvement from 6 to 12 months. Paired comparisons by time for the EMD group revealed a significant reduction in proximal PD at 12 months (P = 0.001), whereas the gain in proximal CAL approached significance (P = 0.056). Mean GR increased significantly from baseline to 6 months in both groups (P = 0.001). Regression analysis revealed that within the EMD group, smoking and TM negatively influenced the gain of attachment, whereas within the BCF group, gingival recession increased with age, increasing CEJ to BC distance, and increasing mesial-distal width of the defect. The gain in proximal attachment after treating intrabony defects by flap surgery with BCF was significant (P = 0.004) and twice that following treatment with EMD (P = 0.056). Patient and site variables affected the clinical outcome differently.

A comparison of a refrigerant and a topical anesthetic gel as preinjection anesthetics: A clinical evaluation

The authors used a split-mouth design to determine the effectiveness of a refrigerant compared with that of a topical anesthetic gel in reducing the pain experienced during a posterior palatal anesthetic injection. Sixteen participants received a five-second application of a refrigerant (1,1,1,3,3-pentafluoropropane/1,1,1,2-tetrafluoroethane) and a two-minute application of a topical anesthetic gel (20 percent benzocaine gel) in the posterior palatal area before an injection of a local anesthetic solution was administered with a 30-gauge needle. Participants rated the pain they experienced after each injection by using a 100-millimeter visual analog scale (VAS) with endpoints of "no pain" and "worst possible pain." The authors calculated VAS scores by measuring the distance in millimeters from the no pain end of the scale. They analyzed data with a paired t test (alpha = .05). The group receiving the refrigerant had a mean VAS score of 17.7 +/- 15.3 mm, and the group receiving the topical anesthetic gel had a VAS score of 26.2 +/- 18.0 mm. The use of the refrigerant compared with the use of topical anesthetic gel significantly reduced the pain experienced during administration of local anesthetic injections (P = .02). The use of a refrigerant as a preinjection anesthetic was more effective compared with the use of a topical anesthetic gel in reducing the pain experienced by participants who received a posterior palatal injection. The potential benefits of using a refrigerant rather than a topical anesthetic gel are pain reduction, decreased application time, ease of application and avoidance of displeasing taste.

Moving Live Dissociated Neurons With an Optical Tweezer

The use of an optical tweezer for moving dissociated neurons was studied. The main features of the tweezers are outlined as well as the general principles of its operation. Infrared beams at 980 and 1064 nm were used, focused so as to make a trap for holding neurons and moving them. Absorption by cells at those wavelengths is very small. Experiments were done to evaluate nonsticky substrate coatings, from which neurons could be easily lifted with the tweezers. The maximum speed of cell movement as a function of laser power was determined. Detailed studies of the damage to cells as a function of beam intensity and time of exposure were made. The 980 nm beam was much less destructive, for reasons that are not understood, and could be used to safely move cells through distances of millimeters in times of seconds. An illustrative application of the use of the tweezers to load neurons without damage into plastic cages on a glass substrate was presented. The conclusion is that optical tweezers are an accessible and practical tool for helping to establish neuron cultures of cells placed in specific locations.

Clinical Validation of Percutaneous Cochlear Implant Surgery: Initial Report

Percutaneous cochlear implant surgery consists of a single drill path from the lateral mastoid cortex to the cochlea via the facial recess. We sought to clinically validate this technique in patients undergoing traditional cochlear implant surgery. Prospective clinical trial. After institutional regulatory board-approved protocols, five ears were studied via the following steps. 1) In the clinic under local anesthesia, bone-implanted anchors were placed surrounding each mastoid. 2) Temporal-bone computed tomography (CT) scans were obtained. 3) On the CT scans, paths were planned from the lateral mastoid cortex, through the facial recess, to the basal turn of the cochlea both "manually" and "automatically" using computer software. 4) Customized microstereotactic frames were rapid-prototyped to serve as drill guides constraining the drill to follow the appropriate path. 5) During cochlear implant surgery, after drilling of the facial recess, drill guides were mounted on the bone-implanted anchors. 6) Accuracy of paths was assessed via intraoperative photodocumentation. All surgical paths successfully traversed the facial recess and hit the basal turn of the cochlea. Distance in millimeters (average +/- SD) from the midpoint of the drill to the facial nerve was 1.18 +/- 0.68 for the "manual" path and 1.24 +/- 0.44 mm for the "automatic" path and for the chorda tympani 0.986 +/- 0.48 for the "manual" path and 1.22 +/- 0.62 for the "automatic" path. Percutaneous cochlear implant access using customized drill guides based on preoperative CT scans and image-guided surgery technology can be safely accomplished.

Organic carbon sequestration in earthworm burrows

Earthworms strongly affect soil organic carbon cycling. The aim of this study was to determine whether deep burrowing anecic earthworms enhance carbon storage in soils and decrease C turnover. Earthworm burrow linings were separated into thin cylindrical sections with different distances from the burrow wall to determine gradients from the burrow wall to the surrounding soil. Organic C, total N, radiocarbon ( 14C) concentration, stable isotope values ( δ 13C, δ 15N) and extracellular enzyme activities were measured in these samples. Anecic earthworms increased C stocks by 270 and 310 g m −2 accumulated in the vertical burrows. C-enrichment of the burrow linings was spatially highly variable within a distance of millimetres around the burrow walls. It was shown that C accumulation in burrows can be fast with C sequestration rates of about 22 g C m −2 yr −1 in the burrow linings, but accumulated C in the burrows may be mineralised fast with turnover times of only 3–5 years. Carbon stocks in earthworm burrows strongly depended on the earthworm activity which maintains continuous C input into the burrows. The enhanced extracellular enzyme activity of fresh casts was not persistent, but was 47% lower in inhabited burrows and 62% lower in abandoned burrows. Enzyme activities followed the C concentrations in the burrows and were not further suppressed due to earthworms. Radiocarbon concentrations and stable isotopes in the burrow linings showed an exponential gradient with the youngest and less degraded organic matter in the innermost part of the burrow wall. Carbon accumulation by anecic earthworm is restricted to distinct burrows with less influence to the surrounding soil. Contrary to the initial hypothesis, that organic C is stabilised due to earthworms, relaxation time experiments with nuclear magnetic resonance spectroscopy (NMR) did not reveal any enhanced adsorption of C on iron oxides with C stabilising effect. Our results suggest that earthworm activity does not substantially increase subsoil C stocks but burrows serve as fast ways for fresh C transport into deep soil horizons.

Test of B/Ti multilayer reactive igniters for a micro solid rocket array thruster

In this study, reactive B/Ti multilayer igniters were investigated for the noncontact ignition of a micro solid rocket array thruster in vacuum. When current is supplied to the B/Ti multilayer igniter, the chemical reaction: 2B + Ti → TiB 2 + 1320 cal/g occurs, and sparkles are spread to a distance of several millimeters or more. The B/Ti multilayer igniters with three sizes were fabricated, and tested in six configurations of solid propellant. Although one rocket with ignition charge was ignited successfully, the noncontact ignition of the solid propellant was not achieved. However, the B/Ti multilayer igniters themselves generated small impulses of 10 −6 N s order, suggesting the possibility of self-propulsion.

Photosynthesis can be enhanced by lateral CO2 diffusion inside leaves over distances of several millimeters

This study examines the extent to which lateral gas diffusion can influence intercellular CO(2) concentrations (c(i)) and thus photosynthesis in leaf areas with closed stomata. Leaves were partly greased to close stomata artificially, and effects of laterally diffusing CO(2) into the greased areas were studied by gas-exchange measurement and chlorophyll fluorescence imaging. Effective quantum yields (Delta F/F(m)') across the greased areas were analysed with an image-processing tool and transposed into c(i) profiles, and lateral CO(2) diffusion coefficients (D(C'lat)), directly proportional to lateral conductivities (), were estimated using a one-dimensional (1D) diffusion model. Effective CO(2) diffusion distances in Vicia faba (homobaric), Commelina vulgaris (homobaric) and Phaseolus vulgaris (heterobaric) leaves clearly differed, and were dependent on D(C'lat), light intensity, [CO(2)], and [O(2)]: largest distances were approx. 7.0 mm for homobaric leaves (with high D(C'lat)) and approx. 1.9 mm for heterobaric leaves (low D(C'lat)). Modeled lateral CO(2) fluxes indicate large support of photosynthesis over submillimeter distances for leaves with low D(C'lat), whereas in leaves with large D(C'lat), photosynthesis can be stimulated over distances of several millimeters. For the plant species investigated, the surplus CO(2) assimilation rates of the greased leaf areas (A(gr)) differed clearly, depending on lateral conductivities of the respective leaves.

Reply to “Letter to the editor: ‘Ocular lens does not change volume during accommodation’”

reply: Thank you for providing a forum to answer the comments of Drs. Schachar and Liao ([5][1]). #### General comments. The number of experiments was not 7; it was a total of 20 divided in 3 sets: 7 relaxed-stretched, 6 relaxed-stretched-relaxed (see Table 1 in Ref. [2][2]), and 7 under oil (see

Effect of Two Different Bioabsorbable Collagen Membranes on Guided Bone Regeneration: A Comparative Histomorphometric Study in the Dog Mandible

This study compared bone regeneration following guided bone regeneration with two bioabsorbable collagen membranes in saddle-type bone defects in dog mandibles. Three standardized defects were created, filled with bone chips and deproteinized bovine bone mineral (DBBM), and covered by three different methods: control = no membrane; test 1 = collagen membrane; and test 2 = cross-linked collagen membrane (CCM). Each side of the mandible was allocated to one of two healing periods (8 or 16 weeks). The histomorphometric analysis assessed the percentage of bone, soft tissue, and DBBM in the regenerate; the absolute area in square millimeters of the bone regenerate; and the distance in millimeters from the bottom of the defect to the highest point of the regenerate. In the 8-week healing group, two dehiscences occurred with CCM. After 8 weeks, all treatment modalities showed no significant differences in the percentage of bone regenerate. After 16 weeks, the percentage of bone had increased for all treatment modalities without significant differences. For all groups, the defect fill height increased between weeks 8 and 16. The CCM group showed a statistically significant (P = 0.0202) increase over time and the highest value of all treatment modalities after 16 weeks of healing, The CCM showed a limited beneficial effect on bone regeneration in membrane-protected defects in dog mandibles when healing was uneventful. The observed premature membrane exposures resulted in severely compromised amounts of bone regenerate. This increased complication rate with CCM requires a more detailed preclinical and clinical examination before any clinical recommendations can be made.

Swimming against the Tide: Mobility of the Microtubule-Associated Protein Tau in Neurons

Long-haul transport along microtubules is crucial for neuronal polarity, and transport defects cause neurodegeneration. Tau protein stabilizes microtubule tracks, but in Alzheimer's disease it aggregates and becomes missorted into the somatodendritic compartment. Tau can inhibit axonal transport by obstructing motors on microtubules, yet tau itself can still move into axons. We therefore investigated tau movement by live-cell fluorescence microscopy, FRAP (fluorescence recovery after photobleaching), and FSM (fluorescence speckle microscopy). Tau is highly dynamic, with diffusion coefficients of approximately 3 microm2/s and microtubule dwell times of approximately 4 s. This facilitates the entry of tau into axons over distances of millimeters and periods of days. For longer distances and times, two mechanisms of tau transport are observed. At low near-physiological levels, tau is cotransported with microtubule fragments from cell bodies into axons, moving at instantaneous velocities approximately 1 microm/s. At high concentrations, tau forms local accumulations moving bidirectionally at approximately 0.3 microm/s. These clusters first appear at distal endings of axons and may indicate an early stage of neurite degeneration.

Occult Pneumothorax in Trauma Patients: Development of an Objective Scoring System

The incidence of occult pneumothorax (OPTX) has dramatically increased since the widespread use of computed tomography (CT) scanning. The OPTX is defined as a pneumothorax not identified on plain chest X-ray but detected by CT scan. The overall reported incidence is about 5% to 8% of all trauma patients. We conducted a 5-year review of our OPTX incidence and asked if an objective score could be developed to better quantify the OPTX. This in turn may guide the practitioner with the decision to observe these patients. This is a retrospective review of all trauma patients in a Level I university trauma center during a 5-year period. The patients were identified by a query of all pneumothoraces in our trauma registry. Those X-ray results were then reviewed to identify those who had OPTX. After developing an OPTX score on a small number, we retrospectively scored 50 of the OPTXs by taking the largest perpendicular distance in millimeters from the chest wall of the largest air pocket. We then added 10 or 20 to this if the OPTX was either anterior/posterior or lateral, respectively. A total of 21,193 trauma patients were evaluated and 1,295 patients with pneumothoraces (6.1%) were identified. Of the 1,295 patients with pneumothoraces, 379 (29.5%) OPTXs were identified. The overall incidence of OPTX was 1.8%: 95.7% occurred after blunt trauma, 222 (59%) of the OPTX patients had chest tubes and of the remaining 157 without chest tubes, 27 (17%) were on positive pressure ventilation. Of the 50 studies selected for scoring, the average score was 28.5. The average score for those with chest tubes was 34. The average score for those without chest tubes was 21. The positive predictive value for need of chest tube if the score was >30 was 78% and the negative predictive value if the score was <20 was 70%. Area under the receiver operator characteristic curve was 0.72, which was significant with p < 0.007. The OPTX score could quantify the size of the OPTX allowing the practitioner to better define a "small" pneumothorax. The management of OPTX is not standardized and further study using a more objective classification may assist the surgeon's decision-making. The application of a scoring system may also decrease unnecessary insertion of chest tubes for small OPTXs and is currently being prospectively validated.

Stochastic Simulations on the Reliability of Action Potential Propagation in Thin Axons

It is generally assumed that axons use action potentials (APs) to transmit information fast and reliably to synapses. Yet, the reliability of transmission along fibers below 0.5 μm diameter, such as cortical and cerebellar axons, is unknown. Using detailed models of rodent cortical and squid axons and stochastic simulations, we show how conduction along such thin axons is affected by the probabilistic nature of voltage-gated ion channels (channel noise). We identify four distinct effects that corrupt propagating spike trains in thin axons: spikes were added, deleted, jittered, or split into groups depending upon the temporal pattern of spikes. Additional APs may appear spontaneously; however, APs in general seldom fail (<1%). Spike timing is jittered on the order of milliseconds over distances of millimeters, as conduction velocity fluctuates in two ways. First, variability in the number of Na channels opening in the early rising phase of the AP cause propagation speed to fluctuate gradually. Second, a novel mode of AP propagation (stochastic microsaltatory conduction), where the AP leaps ahead toward spontaneously formed clusters of open Na channels, produces random discrete jumps in spike time reliability. The combined effect of these two mechanisms depends on the pattern of spikes. Our results show that axonal variability is a general problem and should be taken into account when considering both neural coding and the reliability of synaptic transmission in densely connected cortical networks, where small synapses are typically innervated by thin axons. In contrast we find that thicker axons above 0.5 μm diameter are reliable.

Postural development in school children: a cross-sectional study

BackgroundLittle information on quantitative sagittal plane postural alignment and evolution in children exists. The objectives of this study are to document the evolution of upright, static, sagittal posture in children and to identify possible critical phases of postural evolution (maturation).MethodsA total of 1084 children (aged 4–12 years) received a sagittal postural evaluation with the Biotonix postural analysis system. Data were retrieved from the Biotonix internet database. Children were stratified and analyzed by years of age with n = 36 in the youngest age group (4 years) and n = 184 in the oldest age group (12 years). Children were analyzed in the neutral upright posture. Variables measured were sagittal translation distances in millimeters of: the knee relative to the tarsal joint, pelvis relative to the tarsal joint, shoulder relative to the tarsal joint, and head relative to the tarsal joint. A two-way factorial ANOVA was used to test for age and gender effects on posture, while polynomial trend analyses were used to test for increased postural displacements with years of age.ResultsTwo-way ANOVA yielded a significant main effect of age for all 4 sagittal postural variables and gender for all variables except head translation. No age × gender interaction was found. Polynomial trend analyses showed a significant linear association between child age and all four postural variables: anterior head translation (p < 0.001), anterior shoulder translation (p < 0.001), anterior pelvic translation (p < 0.001), anterior knee translation (p < 0.001). Between the ages of 11 and 12 years, for anterior knee translation, T-test post hoc analysis revealed only one significant rough break in the continuity of the age related trend.ConclusionA significant linear trend for increasing sagittal plane postural translations of the head, thorax, pelvis, and knee was found as children age from 4 years to 12 years. These postural translations provide preliminary normative data for the alignment of a child's sagittal plane posture.

Microscale heterogeneity of Fe isotopes in &gt;3.71 Ga banded iron formation from the Isua Greenstone Belt, southwest Greenland

We present Fe isotope compositions for magnetite crystals from >3.7 Ga banded iron formation (BIF) from the Isua Greenstone Belt and younger, spatially related pyrite obtained in situ by secondary ion mass spectrometry (SIMS). Across a distance of several millimeters, individual magnetite crystals of BIF show δ 56 Fe values up to 2‰, and within single magnetite-rich layers, there is a >2‰ range in δ 56 Fe. The highest positive δ 56 Fe values are consistent with those predicted by the equilibrium fractionation factor for oxidation of ferrous to ferric Fe in aqueous solution at a likely Early Archean ocean temperature of ∼70 °C, and further suggest that subsequent precipitation of ferric oxides was sufficiently slow that kinetic fractionation effects were minimal. These high values also imply that the supply of oxidant was limited. Heterogeneity in δ 56 Fe values is attributed to diagenetic reactions occurring in limited-volume pore waters, isolated from the bulk ocean (δ 56 Fe = 0‰), with development of isotope reservoir effects. Secondary pyrite in BIF and a conglomerate also show a distinct enrichment in heavy Fe isotopes, interpreted as redistribution and/or fractionation during postformational events.

Long-Range Propagation of Plasmon Polaritons in a Thin Metal Film on a One-Dimensional Photonic Crystal Surface

We present experimental results on ultralong-range surface plasmon polaritons, propagating in a thin metal film on a one-dimensional (1D) photonic crystal surface over a distance of several millimeters. This propagation length is about 2 orders of magnitude higher than the one in the ordinary Kretschmann configuration at the same optical frequency. We show that a long-range surface plasmon polaritons propagation may take place not only in a (quasi)symmetrical scheme, where a thin metal film is located between two media with (approximately) the same refraction index, but also in a scheme where the thin metal film is located between an appropriate 1D photonic crystal and an arbitrary (air, water, etc.) medium. The ultralong-range surface plasmon polaritons are potentially important for biosensors, plasmonics, and other applications.

EXTRALARYNGEAL BIFURCATION OF THE RECURRENT LARYNGEAL NERVE: A COMMON VARIATION

Extralaryngeal bifurcation and trifurcation of the recurrent laryngeal nerve (RLN) is not well described in anatomical texts. This significant anatomical variation is important because prevention of vocal cord paralysis requires preservation of all branches of the RLN. The aim of this study was to examine the prevalence of extralaryngeal bifurcation of the RLN seen during thyroid/parathyroid surgeries. All patients undergoing total thyroidectomy, hemithyroidectomy and parathyroidectomy (excluding all minimally invasive procedures) carried out by a single endocrine surgeon from November 2003 to December 2004 were included. Operative data obtained prospectively included the location of the nerve, number of branches and the distance in millimetres from the inferior border of the cricothyroid to the point of bifurcation. A total of 213 (right = 114, left = 99) RLN in 137 patients were studied. Seventy-seven (36%) nerves bifurcated or trifurcated before entry into the larynx. Bifurcations were more common on the right (43%) than on the left (28%) (P = 0.05). Trifurcations were seen in eight nerves, seven on the right and one on the left (P = 0.05). Bilaterally branched RLN were observed in 14 (18%) of 77 patients undergoing a bilateral procedure. One non-RLN was identified on the right. The median distance from the cricothyroid to the point of division was 18 mm on the right and 13 mm on the left. Extralaryngeal division of the RLN is a common anatomical variant occurring more frequently on the right. Unseen branches of the RLN are at risk of injury during surgery. Therefore, great care is required following presumed identification of the RLN to ensure that there are no other unidentified branches.

Spatial Solitons in Twisted Nematic Layer

In this work we investigate light beam propagation in twisted nematic liquid crystalline film. Due to the optical reorientational nonlinearity light beam is self-focusing and finally the spatial solitary wave is created. With increasing the nonlinear effect the direction of light beam propagation is also changing. The samples were filled with 6CHBT nematic liquid crystal and the propagation of light beam at the distance of few millimeters was measured. Nonlinear self-focusing was obtained for a light power of few tenths of milliwats.

Heat‐treated BMP‐2 depots release BMP‐2 in its bioactive form

AbstractSmall depots of locally fixed bone morphogenetic protein‐2 (BMP‐2), which were dried onto biocompatible carriers and afterwards heat‐treated, induce a local differentiation of contacting osteoblastic cells. Here we investigate whether such depots may act via a release of bioactive BMP‐2. For in vivo experiments we employed a modified gap‐healing approach using dump bell‐shaped implants made from titanium plasma‐sprayed Ti‐6Al‐4V, which were coated with BMP‐2 at only one side. Four weeks after implantation into the cancellous bone of the lateral femur condylus of adult sheep we observed a polar formation of new trabecular bone close to the side where BMP‐2 had been immobilized. We also tested whether BMP‐2 depots stimulate remote cells under cell culture conditions and found that alkaline phosphatase (ALP) of MC3T3‐E1 cells was induced over a distance of several millimetres. Experiments show that BMP‐2 at least in part desorbs from air‐dried and heat‐treated BMP‐2 depots in its bioactive form. Local depots of BMP‐2 may therefore allow to improve bone formation next to metal implants at predefined sites.

Crystal-edge scanning tunnelling spectroscopy on aluminium-doped magnesiumdiboride

We report on the first scanning tunnelling spectroscopymeasurements on the edge of aluminium-doped magnesium diboride(Mg1−xAlxB2,x = 0.085) single crystals. Totarget their edge (∼30 µm thick) we have developed a low temperature STM facility featuring a home built compact STMhead coupled to an inertially driven carriage. This allows linear submicronic positioningover millimetric distances. We demonstrate the capabilities of our system by showingreproducible tunnelling spectra obtained both parallel and perpendicular to the crystallinec axis. Tunnelling on the edge reveals the gap originating in the highly 2Dσ band but in contrastwith pure MgB2 does not showthe signature of the π gap.