Background: In March–April 2021, 23 patients at a 906-bed hospital in Delaware had surgical implantation of a bone graft product contaminated with Mycobacterium tuberculosis; 17 patients were rehospitalized for surgical site infections and 6 developed pulmonary tuberculosis. In May 2021, we investigated this tuberculosis outbreak and conducted a large, multidisciplinary, contact investigation among healthcare personnel (HCP) and patients potentially exposed over an extended period in multiple departments. Methods: Exposed HCP were those identified by their managers as present, without the use of airborne precautions, in operating rooms (ORs) during index spine surgeries or subsequent procedures, the postanesthesia care unit (PACU) when patients had draining wounds, inpatient rooms when wound care was performed, and the sterile processing department (SPD) on the days repeated surgeries were performed. We created and assigned an online education module and symptom screening questionnaire to exposed HCP. Employee health services (EHS) instituted a dedicated phlebotomy station to provide interferon-γ release assay (IGRA) testing for HCP at ≥8 weeks after last known exposure. EHS managed all exposed HCP, including nonemployees (eg, private surgeons) via automated e-mail reminders, which were escalated through supervisory chains as needed until follow-up completion. The infection prevention team notified exposed patients, defined as those who shared semiprivate rooms with case patients with transmissible tuberculosis. The Delaware Division of Public Health performed IGRA testing. Results: There were 506 exposed HCP in ORs (n = 100), the PACU (n = 87), inpatient units (n = 140), the SPD (n = 54), and other locations (n = 122); 83% were employed by the health system. Surgical masks and eye protection were routinely used during patient care. All exposed HCP completed screening by December 17, 2021. Furthermore, 2 HCP had positive IGRAs without symptoms or chest radiograph abnormalities, indicating latent tuberculosis infection, but after further review of records and interviews, we discovered that they had previously tested positive and had been treated for latent tuberculosis infection. In addition, 5 exposed patients tested negative and 2 remain pending. Conclusions: This large investigation demonstrated the need for a systematic process that encompassed all exposed HCP including nonemployees and incorporated administrative controls to ensure complete follow-up. We did not identify any conversions related to this outbreak despite high burden of disease in case patients and multiple exposures to contaminated bone-graft material and infectious bodily fluids without respirator use. Transmission risk was likely reduced by baseline surgical mask use and rapid institution of airborne precautions after outbreak recognition.

Funding: None

Disclosures: None

Electronic structures of single crystal pentacene are of great interest for the elucidation of charge carrier transport in organic semiconductor materials. Experimental observation of valence band dispersion was recently achieved on single crystal samples of pentacene; however, its intrinsic properties are still unresolved because past experiments were performed on specimens with surface oxides formed by exposure to the ambient atmosphere. In this work, X-ray photoelectron spectroscopy (XPS) and angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) were conducted on single-crystal pentacene samples prepared without ambient exposure. The XPS results confirmed the reduction of the abundance of oxide impurities on the present samples. The ARUPS measurements clearly resolved the valence band structures of the single-crystal pentacene in four symmetry directions of the surface Brillouin zone, indicating anisotropy of at least a factor of 2.4 for the intermolecular transfer integral and hole effective mass at the valence band maximum.

Field data from Stillberg (Switzerland), provided by SFISAR, have been analysed in order to understand the spatial distribution of snow transported by wind in avalanche-starting zones. The results have been used to develop a new empirical model for snowdrift distribution. This model constitutes the “snow-wind module” of the knowledge-based computer system called ELSA.

The model is based on an empirical parameter called the wind or “aeolien” coefficient. It represents the relation between two snow heights at a given place: the snow accumulated at the end of a wind period (or wind episode) and the snow available for transport at the beginning of the wind period. The wind coefficient has been established using field data from the Stillberg site.

In experimental snowdrifting mass-flux measurements many different instruments have been tested (Takeuchi, CEMAGREE Mases, etc.). Very often the results obtained are a function of the gauge used. However, in order to compare data from different instruments, orders of magnitude have to be similar.

Since 1992, snowdrifting has been studied at an experimental plot at La Molina ski resort (eastern Spanish Pyrenees). The alpine site, characterized by a plateau topography, is located at 2250 m.

In this paper, different gauges used to measure snowdrifting mass flux at this site are presented: one snow-collector column and two types of snow traps. Snow-collector columns (prismatic boxes) are permanent installations and are used to measure the mass-flux episode. Snow traps (Takeuchi, 1980: modified) are lighter and more mobile, and they are used for short experiments during a wind episode during which mass-flux data are obtained.

The three different gauges are compared and the rate of trapping efficiency is suggested from a comparison of the field data with estimated mass-flux data deduced from empirical formulae (Mellor and Fellers, 1986; Naaim-Bouvet and others, 1996). The mass-flux values obtained at the experimental site are lower than the estimated values.

Snowdrift formation has been monitored in the eastern Spanish Pyrenees since 1992 at an experimental study plot at the La Molina ski resort between 2000 and 2400 m. Several instruments were installed to characterize the wind, quantify snow-mass flux, detect snowdnfting episodes and measure the evolution of a natural snowdrift.

This plot is situated within a natural snowdrift and is equipped with measuring instruments such as snow poles, three columns of snow collectors (prismatic boxes) facing the dominant winds and an anemographic station.

During the 4 years of data acquisition, the thickness of the snowdrift has been measured and the snow collectors checked once each week. An active interest has been taken in the relationship between snowdrift development and drifting snow during a wind episode.

The relationship observed between wind, drifting snow and the development of the snowdrift is presented The results show: (1) the amount of snow collected in the snow collectors is related to wind intensity and to the availability and the quality of drifting snow, and (2) wind intensity principally affects the relative location of maximum snowdrift growth rather than controlling the thickness of the snowdrift.

By comparing the evolution of the snowdrift with Tabler’s (1975) model, we observed that it fits with the topographic features of our study area for the three seasons shown.

We investigated electronic structure of one-dimensional biradical molecular chain which is constructed by exploiting the covalency between organic molecules of a diphenyl derivative of s-indacenodiphenalene (Ph2-IDPL). To control the crystallinity, we used gas deposition method. Ultraviolet photoelectron spectroscopy (UPS) revealed developed band structure with wide dispersion of the one-dimensional biradical molecular chain.

The paper provides an account of an innovative collaborative work between composer/violinist Elo Masing, choreographer/dancer Jean Lee, and the Kreutzer String Quartet. The project challenges the conventions of music and dance collaboration by proposing a fundamentally new way of working across disciplines, establishing a profound interrelation between movement and sound production.

The work so far has mostly involved developing a new notation system for string instruments and dancer suitable for recording the sounds and movements the work in progress will primarily be based on. The paper will, at this stage, demonstrate only a fraction of the various possibilities of this new way of musician–dancer collaboration that is estimated to span over the next couple of years. The idea for the piece dates back to June 2010, when a structured improvisation was created in collaboration between Elo Masing and Jean Lee, commissioned for a conference at Roehampton University.

The innovative aspect of the project is manifested in the development of choreography and music together from the very beginning, using new sound and movement languages discovered in interdisciplinary improvisation sessions. In the center of the collaboration lies the definition of the roles of the musician and the dancer as equal, with equally complex compositional material and interchanging ideas. That means composing music and dance simultaneously and letting them influence each other.

The new notation system for string instruments focuses on the movements of string players, thus creating a possibility for relating music to dance in a more tangible and visual rather than conceptual and abstract way.

In 3D packaging, Through Silicon Vias (TSVs) with high aspect ratios and depths measuring tens of microns are filled by advanced Cu electroplating processes. Today's 300mm TSV plating platforms are intended to produce bottom-up via fill, no seam voids, and minimal, controlled overburden. To achieve this, the preceding Cu-seed coverage must be continuous at a constant resistance, and the plating chemistries optimized. However, other factors such as hardware configurations and simple depletion of the plating formulations during the extended TSV process can lead to high Cu overburden thickness requiring a high removal rate (HRR) chemical-mechanical polish (CMP) process to remove the thick Cu layer.

Presented here are CMP results of a thick Cu overburden (~6um) resulting from the fill of 5 x 25um TSVs on 300mm wafers. The goal is to uniformly polish the overburden and utilize the tool's endpoint system at Cu clear before the next step of conventional barrier CMP. Slurries were screened for removal rate, uniformity, planarization ability, and defectivity. This study focuses on achieving a removal rate of >2.5um/min through evaluation of several commercial slurries in a multi-step polish application. Cross-sections post-plating show the Cu overburden, barrier and liner layer. Cross-sections post-CMP quantify Cu recess, dielectric loss, and presence/absence of seam defects. The process selected is demonstrated to achieve good planarization results with low occurrence of polish defects, at a rate and selectivity suitable for emerging 3D TSV Cu CMP applications.

3D interconnect wafer-to-wafer or die-to-wafer integration requires a wafer thinning operation to expose copper (Cu)-filled through-silicon vias (TSVs) from the backside of the wafer. The wafer thinning flow uses edge trim, backgrind, backpolish, and chemical mechanical polishing (CMP). This paper presents an overview of the wafer grinding process. We have demonstrated the capability to edge-trim and backgrind 300 mm TSV and non-TSV wafers down to 30 microns (μm) while bonded to a handle wafer. TSV wafers were further processed on a CMP tool to remove the last few microns of Si, exposing the Cu-filled TSVs. Metrology techniques were used to inspect and measure the wafer edge trim and final thinned wafer thickness. The quality of the thinned wafer was characterized by atomic force microscopy (AFM) to observe surface roughness and by transmission electron microscopy (TEM) to quantify crystalline damage below the surface of the thinned wafer. Further characterization included measuring wafer thickness, total thickness variation (TTV), bow, and warp. Exposed TSVs were characterized by laser microscope to measure the height of Cu protrusions. These critical elements of a manufacturing-worthy 300 mm wafer thinning process for 3D are discussed.

Titanium and cobalt silicides have long been used as gate electrode materials for very large-scale integrations (VLSI) circuits. As scaling has pushed the industry to quarter micron technologies and below, cobalt has become the material of choice for forming silicides, since it can maintain its low resistivity on much narrower line widths. Oxidation of the cobalt film is a concern during silicide processing, as the cobalt oxide will not be removed during the cobalt etch step. To protect against the oxidation of the cobalt layer during the silicidation process, the reaction is conducted underneath a titanium nitride (TiN) capping layer. Variations in the TiN capping layer thickness were investigated to determine the affect on oxygen sensitivity of the cobalt silicide process. A strong correlation was found to the thickness of the TiN-capping layer, to the oxygen concentration required to oxidize cobalt during the silicidation process.