Infrared study of H/D isotope exchange reaction of alkanes and Brønsted acidic hydroxyl groups on FER zeolite

H/D isotope exchange between n-alkanes and the acidic OD groups in ferrierite was observed by infrared spectroscopy. The real activation energies were estimated by adding the heats of adsorption to the apparent activation energies, resulting in almost the same value for all n-alkanes. The transition state for the reaction is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spatially-Adaptive Filter Units for Compact and Efficient Deep Neural Networks

International Journal of Computer Vision - Convolutional neural networks excel in a number of computer vision tasks. One of their most crucial architectural elements is the effective receptive...     

The New LMK Primary Standard for Dew-Point Sensor Calibration: Evaluation of the High-Range Saturator Efficiency

In the field of hygrometry, a primary dew-point standard can be realized according to several proven principles, such as single-pressure (1-P), two-pressure (2-P), or divided flow. Different realizations have been introduced by various national laboratories, each resulting in a stand-alone complex generation system. Recent trends in generator design favor the single-pressure principle without recirculation because it promises theoretically lower uncertainty and because it avoids problems regarding the leak tightness of the recirculation. Instead of recirculation, the efficiency of saturation, the key factor, is increased by preconditioning the inlet gas entering the saturator. For preconditioning, a presaturator or purifier is used to bring the dew point of the inlet stream close to the saturator temperature. The purpose of the paper is to identify the minimum requirements for the preconditioning system and the main saturator to assure efficient saturation for the LMK generator. Moreover, the aim is also to find out if the preconditioning system can be avoided despite the rather simple construction of the main saturator. If this proves to be the case, the generator design can be simplified while maintaining an accurate value of the generated dew point. Experiments were carried out within the scope of improving our existing primary generator in the above-ambient dew-point range up to +70°C. These results show the generated dew point is within the measurement uncertainty for any dew-point value of the inlet gas. Thus, the preconditioning subsystem can be avoided, which leads to a simplified generator design.     

Adverse reactions associated with autologous blood transfusion: evaluation and incidence at a large academic hospital

Malignant fibrous histiocytoma (MFH) in the stomach is very rare, and only four cases have been reported. As a result, there is still little understanding of its clinical and pathological features. We recently experienced two cases of gastric MFH. The first case was a 78-year-old man with epigastralgia and a loss of body weight. Endoscopy revealed an ulcerated submucosal tumor. A gastrectomy was performed and the diagnosis of MFH was made histopathologically. The second case was a 77-year-old man with pulmonary symptoms. An image diagnosis indicated a strong suspicion of lung cancer, and a right middle and lower lobectomy was thus performed. One month after the operation, a bleeding gastric tumor was found and therefore a gastrectomy was performed. Both tumors were diagnosed as MFH. From the analysis of six reported cases including ours, a preoperative correct diagnosis is found to be difficult although the lesion has grown to a considerable size at the time of operation. Since a metastatic lung lesion was first detected in two out of six cases, it is thus recommended that the stomach should be examined when lung MFH is found. Considering the high mortality and the short survival in the six cases, the prognosis for gastric MFH seems to be poorer than that in the extremities. However, lymph node metastasis is uncommon, and a curative resection is possible in some cases such as in our second case.     

Fog water as an alternative and sustainable water resource

As the world’s population and demand for fresh water increases, new water resources are needed. One commonly overlooked aspect of the water cycle is fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions. Fog water harvesting is being investigated as a sustainable alternative water resource for drinking water and reforestation. Fog water harvesting involves using mesh nets to collect water as fog passes through them. The materials of these nets, along with environmental factors such as wind speed, influence the volume of water collected. In this article, a review of current models for fog collection, designs, and applications of fog water harvesting is provided. Aspects of fog water harvesting requiring further research and development are identified. In regions with frequent fog events, fog water harvesting is a sustainable drinking water resource for rural communities with low per capita water usage. However, an analysis of fog water harvesting potential for the coastal areas of northern California (USA) showed that fog yields are too small for use as domestic water in areas with higher household water demands. Fog water shows particular promise for application in reforestation. Fog water irrigation can increase growth rates and survivability of saplings in reforestation efforts in regions with frequent fog events. Using fog collectors, denuded areas once dependent on natural fog drip can be restored, benefiting local hydrology and ecosystem recovery. Improvement in fog collector designs, materials, and models to increase collection efficiency, perhaps by inclusion of ideas from natural systems, will expand the regions where fog harvesting can be applied.     

Dynamical Studies of Zeolitic Protons and Adsorbates by Picosecond Infrared Spectroscopy

The application of (picosecond) nonlinear infrared spectroscopy to investigate zeolite catalysts and adsorbates is reviewed. In these time-resolved experiments, one specific vibration in the zeolite system (i.e., a zeolite or adsorbate vibration) is selectively excited with an ultrashort (tunable) mid-infrared pulse. The effect of this excitation and the subsequent energy relaxation can be monitored real time, providing information on the structure of the bare zeolite and adsorption complexes. More importantly, with this technique the picosecond energy flow at the catalytic site and the dynamics of the catalyst-adsorbate interaction can be investigated: Short-lived transient species (e.g., reaction intermediates) are observed and the picosecond relaxation rates and pathways at the catalytic site render insights into the dynamics of the interaction between the zeolite catalyst and its adsorbates at a molecular level. This illustrates the potential of time-resolved infrared spectroscopy in the investigations of catalytic systems.