FIXATION PROCESS OF LAMINATED BAMBOO COMPRESSION FROM CURVED CROSS-SECTION SLATS

Removing the outer part of bamboo for manufacturing flat bamboo lamination has disadvantage on the density of the product. The purpose of this experiment was to investigate the fixation of compressed bamboo from curved cross-section slats. The compression of bamboo slats using densification technique was aimed for uniform density. Furthermore, steam treatments were conducted to fix the deformation. The compressed bamboo slats revealed that the density of the samples at the bottom parts increased from 0.40–0.56 g/cm3 to 0.89–1.05 g/cm3 after pressing with a compression level between 46.98–63.97%, while the samples in the middle parts increased from 0.70–0.83 g/cm3 to 1.02–1.18 g/cm3 with the compression level of 32.92–41.50%. These results were slightly higher than that of the upper parts, which was between 0.91–0.98 g/cm3. The recovery of set decreased and the weight loss increased with increasing temperature and steam treatment time. Fixation of compressive deformation could be achieved at 160°C within 60 minutes. The bottom parts of samples experienced a slightly greater weight loss compared to the middle parts, i.e. 8.38% and 7.49%, respectively. The anatomical structure of bamboo tended to deform during densification process. Furthermore, the steam treatments affected the colour of densified bamboo which became darker. From this experiment, it can be concluded that the manufacture of laminated bamboo from bamboo slats can be uniformed in strength by equalizing the density at the bottom and middle with the upper parts through the densification technique. However, further research should be conducted to know the delamination and shear strength of the bamboo lamination.

ENGINEERING DESIGN OF AUTOMATIC SELENOID STOVE TO REDUCE MUSCULOSKELETAL DISORDERS COMPLAINTS USING NBM AND RULA APPROACH

UKM Kenanga is a home industry producing various cassava chips based in Kubu Raya district, West Kalimantan. Complaints regarding musculoskeletal were identified in the process of frying chips. The complaints were carpal tunnel syndrome, low back pain, neck pain, as well as on the forearm and upper arm. Non-ergonomic working position contributes to these complaints. Therefore, it is necessary to perform this analysis and suggest a tool that would be helpful to reduce the worker’s complaints. Formerly, there haven’t been any early studies that cover the design of an automatic stove for the frying process based on biomechanical considerations, particularly on musculoskeletal disorder complaints.This study performs an analysis based on Nordic Body Map (NBM) and Rapid Upper Limb Assessment (RULA) concerning the process of frying the chips. Nordic Body Map analysis was used to identify body parts that were experiencing fatigue. Following the Nordic Body Map results, the automatic stove was designed to solve the employees’ complaints. RULA approach was used to analyze the condition after the employees carried out the work using the stove. The outcomes of this study are an automatic solenoid stove and a stool for the process of chips frying. RULA approach on the frying process with the manual stove and with the automatic solenoid stove resulted in L4-LV compression level reduced by 71.05%, whereas for Flex/Ext Compression was 87.97%

Intervertebral foramen injection of plerixafor attenuates CCD-induced low back pain in rats through down-regulation of Nav1.8 and Nav1.9

BackgroundLow back pain, an extremely common chronic pain, is now the number one cause of disability globally. On the chronic compression of the dorsal root ganglion (CCD) model, a typical low back pain model, previous study has discovered that C-X-C chemokine receptor type 4 (CXCR4) involved in mediating low back pain. However, the underlying molecular mechanisms and whether it has the potential to serve as an applicable target for clinical treatment of low back pain remains unclear. MethodsCCD-induced low back pain model was established by inserting stainless steel L-shape rod into the intervertebral foramen at L5 level. Multiple pain behaviors including mechanical hyperalgesia and allodynia, thermal hyperalgesia and cold allodynia were evaluated. The role of CXCR4 in CCD-induced pain was assessed by intraganglionar CXCR4 siRNA injection and intervertebral foramen injection of plerixafor, a selective CXCR4 antagonist. The expression change of CXCR4, Nav1.8 and Nav1.9 was examined by immunofluorescent staining.ResultsWe showed that the CXCR4 were dramatically up-regulated in the compressed dorsal root ganglion (DRG) neurons in CCD model, and intraganglionar CXCR4 siRNA injection significantly reduced CCD-induced multiple pain behaviors, including mechanical hyperalgesia and allodynia, thermal hyperalgesia and cold allodynia. The expression of Nav1.8 and Nav1.9 in the compressed DRG were also enhanced after CCD, and which were remarkably reversed by intervertebral foramen injection of plerixafor at the compression level. Moreover, intervertebral foramen injection at the compression level of plerixafor and ropivacaine as well as A-803467, a Nav1.8 selective blocker, were all able to reverse CCD-induced multiple pain behaviors. However, the analgesic duration of plerixafor maintained at least for 24 h which was much longer than that of A-803467 and ropivacaine. Finally, we found intervertebral foramen injection of plerixafor at the adjacent non-compression level has no effect on CCD-induced pain and intervertebral foramen injection of plerixafor in normal rats did not affect their basal pain sensitivity.ConclusionsOur study provides evidence that CXCR4-Nav1.8/Nav1.9 axis in compressed DRG contributed to CCD-induced low back pain and intervertebral foramen injection of plerixafor was a potential and applicable therapeutic strategy for the treatment of low back pain.

Anterior selective stabilization combined with laminoplasty for cervical myelopathy due to massive ossification of the posterior longitudinal ligament: report of early outcomes in 14 patients

OBJECTIVESurgical management of massive ossification of the posterior longitudinal ligament (OPLL) is challenging. To reduce surgical complications, the authors have performed anterior selective stabilization combined with laminoplasty (antSS+LP) for massive OPLL since 2012. This study aimed to elucidate the short-term outcome of the antSS+LP procedure.METHODSThe authors’ analysis was based on data from 14 patients who underwent antSS+LP for cervical myelopathy caused by massive OPLL and were followed up for at least 2 years after surgery (mean follow-up duration 3.3 years). Clinical outcome was evaluated preoperatively, at 6 months and 1 year postoperatively, and at the final follow-up using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy and the recovery rate of the JOA score. The following radiographic parameters were measured preoperatively, immediately after surgery, at 1 year after surgery, and at the final follow-up: the C2–7 angle, measured on lateral plain radiographs, and the segmental lordosis angle (SLA), measured on sagittal CT scans. The correlation between radiographic parameters and clinical outcomes was evaluated.RESULTSThe mean JOA score increased from 10.4 before surgery to 13.6 and 13.8 at 6 months and 1 year after surgery, respectively; at the final follow-up the mean score was 13.4. This postoperative recovery was significant (p = 0.004) and was maintained until the final follow-up. No patient required revision surgery due to postoperative neurological deterioration. However, the C2–7 angle gradually deteriorated postoperatively. Similarly, the SLA was significantly increased immediately after surgery, but the improvement was not maintained. The recovery rate at the final follow-up correlated positively with the change in C2–7 angle (r = 0.60, p = 0.03) and the change in SLA (r = 0.72, p < 0.01).CONCLUSIONSAntSS+LP is safe and effective and may be an alternative to anterior decompression and fusion for the treatment of patients with massive OPLL. No postoperative neurological complications or significant postoperative exacerbation of neck pain were observed in our case series. Not only reducing intervertebral motion and decompressing the canal at the maximal compression level but also acquiring segmental lordosis at the maximal compression level are crucial factors for achieving successful outcomes of antSS+LP.

Influence of Image TIFF Format and JPEG Compression Level in the Accuracy of the 3D Model and Quality of the Orthophoto in UAV Photogrammetry

The aim of this study is to evaluate the degradation of the accuracy and quality of the images in relation to the TIFF format and the different compression level of the JPEG format compared to the raw images acquired by UAV platform. Experiments were carried out using DJI Mavic 2 Pro and Hasselblad L1D-20c camera on three test sites. Post-processing of images was performed using software based on structure from motion and multi-view stereo approaches. The results show a slight influence of image format and compression levels in flat or slightly flat surfaces; in the case of a complex 3D model, instead, the choice of a format became important. Across all tests, processing times were found to also play a key role, especially in point cloud generation. The qualitative and quantitative analysis, carried out on the different orthophotos, allowed to highlight a modest impact in the use of the TIFF format and a strong influence as the JPEG compression level increases.

Enhancing Compression Level for More Efficient Compressed Sensing and Other Lessons from NMR Spectroscopy

Modern nuclear magnetic resonance spectroscopy (NMR) is based on two- and higher-dimensional experiments that allow the solving of molecular structures, i.e., determine the relative positions of single atoms very precisely. However, rich chemical information comes at the price of long data acquisition times (up to several days). This problem can be alleviated by compressed sensing (CS)—a method that revolutionized many fields of technology. It is known that CS performs the most efficiently when measured objects feature a high level of compressibility, which in the case of NMR signal means that its frequency domain representation (spectrum) has a low number of significant points. However, many NMR spectroscopists are not aware of the fact that various well-known signal acquisition procedures enhance compressibility and thus should be used prior to CS reconstruction. In this study, we discuss such procedures and show to what extent they are complementary to CS approaches. We believe that the survey will be useful not only for NMR spectroscopists but also to inspire the broader signal processing community.

The Convex Information Bottleneck Lagrangian

The information bottleneck (IB) problem tackles the issue of obtaining relevant compressed representations T of some random variable X for the task of predicting Y. It is defined as a constrained optimization problem that maximizes the information the representation has about the task, I ( T ; Y ) , while ensuring that a certain level of compression r is achieved (i.e., I ( X ; T ) ≤ r ). For practical reasons, the problem is usually solved by maximizing the IB Lagrangian (i.e., L IB ( T ; β ) = I ( T ; Y ) − β I ( X ; T ) ) for many values of β ∈ [ 0 , 1 ] . Then, the curve of maximal I ( T ; Y ) for a given I ( X ; T ) is drawn and a representation with the desired predictability and compression is selected. It is known when Y is a deterministic function of X, the IB curve cannot be explored and another Lagrangian has been proposed to tackle this problem: the squared IB Lagrangian: L sq − IB ( T ; β sq ) = I ( T ; Y ) − β sq I ( X ; T ) 2 . In this paper, we (i) present a general family of Lagrangians which allow for the exploration of the IB curve in all scenarios; (ii) provide the exact one-to-one mapping between the Lagrange multiplier and the desired compression rate r for known IB curve shapes; and (iii) show we can approximately obtain a specific compression level with the convex IB Lagrangian for both known and unknown IB curve shapes. This eliminates the burden of solving the optimization problem for many values of the Lagrange multiplier. That is, we prove that we can solve the original constrained problem with a single optimization.

Modulation masking release reduction as a function of time-compressed speech

ABSTRACT Purpose: to investigate the magnitude of the modulation masking release in sentence recognition as a function of compression level and modulation rate. Methods: sentences of the Brazilian Portuguese version of the Hearing in Noise Test sentences were used as stimulus. The sentence recognition thresholds were established as a function of speech compression level (0%, 33%, and 50%) in steady and modulated noise at different modulation rates (4, 10, 32 Hz). The analysis of variance was performed for repeated measures, using the 5% significance level. Results: sentence recognition thresholds were higher for higher compression levels in the different types of noise. However, thresholds were smaller for modulated noises. Also, the magnitude of modulation masking release decreased as speech compression level increased. Nevertheless, no difference was observed in compressed speech between different noise modulation rates, in relation to the speech compression level. Conclusion: the magnitude of the modulation masking release decreased as the speech time-compression increased. Also, the reductions in modulation masking release, in relation to the speech time-compression level, did not differ between the masking-noise modulation rates (4, 10, and 32 Hz).